Copyright is owned by the Author of the thesis.  Permission is given for 
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PROSPECTS FOR SUSTAINABLE CROP 
PRODUCTION TECHNOLOGIES IN EAST TIMOR 
A thesis presented in partial fulfilment of the requirements for the 
degree of Doctor of Philosophy (PhD) in 
Natural Resource Management 
Institute of Natural Resources 
Massey University 
Palmerston North, New Zealand 
EDMUNDO DA SILVA SOARES VIEGAS 
2007 
ii 
TABLE OF CONTENTS 
Content Pages 
T able of Contents. . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ii 
L ist of Boxes.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. vi 
List of Tables... ....... ..... ....... ........ ........................ ............... ... ....... vii 
List of Figures . ... .............. ... .. ............. .... .. ... ......... .. ....... ............... xi 
Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  xiii 
L ist of Abbreviations ................................................................... '" xiv 
Abstract. . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ... xvii 
Acknowledgements............... ........................................................ xix 
CHAPTER 1 GENERAL INTRODUCTION... . . .... . . . .. . . .. .  ... ........... 1 
1.1 INTRODUCTION..................................................... 1 
1.2 BACKGROUND....................................................... 3 
1 .3 RATIONALE..... ........................................ .............. 7 
1 .4 HyPOTHESiS ......................................................... 7 
1.5 OBJECTiVES ......................................................... 8 
1.6 ORGANIZATION OF THE THESiS.............................. 8 
REFERENCES........................................................ 12 
CHAPTER 2 
2.1 
2.1.1 
2.1.2 
2.2 
2.2.1 
2.2.2 
2.2.3 
2.2.4 
2.3 
2.3.1 
2.3.2 
2.3.3 
2.3.4 
CHAPTER 3 
3.1 
3 .2 
DEVELOPING EAST TIMOR AGRICULTURE: 
SUSTAINABILlTY IMPLICATIONS ........................... .. 14 
INTRODUCTION ................................................ .. '" 14 
The Ministry of Agriculture, Forestry and Fisheries 
( MAFP) ......... ...................... ................... ................ 15 
The role of MAFP. .. ...... ..... . .. ................ . ........... ...... .. 16 
AN OVERVIEW OF THE AGRICULTURAL SySTE M....... 17 
Land, people and agriculture ..................................... . 
Agricultural production systems ................................. . 
Perceived issues and problems ................................. . 
Land use policies and productivity .............................. . 
SHIFTING CULTIVATION WITH SLASH AND BURN .. . .. . 
Understanding shifting cultivation ............................... . 
Crop and soil indicators ...................................... ...... . 
Reconciling contrasting views .................................... . 
F inding solutions .................................................... . 
REFERENCES ....................................................... . 
AGRICULTURAL MECHANIZATION: MANAGING 
17 
21 
29 
34 
36 
37 
40 
46 
48 
59 
TECHNO-CUl TURAl CHANGE............ ... . .. . .... . ... ... 62 
I NTRODUCTION... ........ .... ...... ... . ........ ..... ..... ........... 62 
HISTORICAL BACKGROUND ............ .... .................... 63 
3.3 THE SCOPE OF AGRICULTURAL MECHANiZATION.... 65 
3.4 MECHANIZATION TECHNOLOGIES............ ...... ......... 68 
3.4.1 Hand-powered tools............ ..................................... 69 
3.4.2 Animal traction ... ............ . ................................... ..... 70 
3.4.3 The introduction of tractors........................................ 71 
3.5 THE TRACTOR MOBILE BRIGADES  (MBs).. ................ 72 
3.5.1 Public Management... .. ............................................ 76 
3.5.2 NGO's Management................................................. 77 
3.5.3 Private Companies...... ......... .. .... ... .. ................ ......... 79 
3.5.4 Analysis.. . .... .. .............. . .. . ... ......... .... ..... .. .......... .. ... . 80 
3.6 RATIONAL TECHNOLOGY DEVELOPMENT......... ....... 83 
3.7 MANAGING TECHNICAL CHANGE.. ... . ......... .... ....... .. 86 
3.8 MECHANIZATION POLiCy.... ........... .................... .... 92 
3.9 CONCLUDING RE MARKS.................................. ....... 93 
REFERENCES................ ....................... ................. 94 
CHAPTER 4 FOOD POLICY , AGRICULTURE AND ECONOMIC GROWTH ........... . .. . . .. . ...................... ....... .......... . ... 97 
4.1 INTRODUCTION...... .. ....... ................................ ...... 97 
4.2 AGRICULTURE AS THE ENGINE OF GROWTH........... 98 
4.3 FOOD SECURITy........................... ........ ...... ......... .  100 
4.3.1 The importance of root crops .......... ........... ................ 101 
4.3.2 Food supply.... ..... .. . .. ......... .... ...... ............. ..... ... ...... 102 
4.3.3 A ccess to food sources ... ....... ......... ..... .. . .......... ........ 103 
4.3.4 Food and nutrition ........................... .................... ..... 104 
4.4 A FOOD POLICY APPROACH................................... 106 
4.4.1 Research and extension............................................ 107 
4.4.2 I nfrastructure... ....................................................... 107 
4.4.3 Price interventions. ................................................... 108 
4.4.4 Land tenure ............... ................ . ... ....... .................. 108 
4.5 CHALLENGES FOR THE FUTURE............................. 109 
4.5.1 U rbanization and production demand ........ ................... 109 
4.5.2 Labour and mechanization ............... .......................... 109 
4.5.3 Productivity growth............ ........................ .... ........... 110 
4.5.4 Agricultural sustainability ...... . ... ..... ......................... ... 111 
4.6 CONCLUSIONS ...................................................... 112 
REFERENCES...................................................... .. 113 
CHAPTER 5 TILLAGE AND EDAPHIC CHANGES: IMPACTS ON CROP AND BIOMASS PRODUCTION ........................ 117 
5.1 INTRODUCTION..................... ................................ 117 
5.1.1 SCOPE AND LI MITATIONS....................................... 119 
5.1.2 OBJECTIVES ............................ .......................... ... 119 
5.2 LITERATURE REVIE W... . . ..... ........... ..... ..... ...... ........ 121 
5.2.1 I ntroduction. ............................................... .. .......... 121 
5.2.2 Principles of tillage ............ ...................... .. ... ............ 122 
iii 
5.2.3 T illage systems and the environment ... ... ...... ..... .... ...... 126 
5.2.4 T illage and cropping systems............. ................. ....... 130 
5.2.5 T illage effects on selected soil properties........... .... ....... 139 
5.2.6 Concluding remarks ...... ........................................... 155 
5.3 RESEARCH METHODOLOGIES................................. 157 
5.3.1 Experiment 1.......................................................... 157 
5.3.2 Experiment 2......... ............... ..................... .... .......... 160 
5.3.3 Statistical analysis.................................................... 171 
5.4 RESULTS......... . ... .............. ..... .................... ... ....... 172 
5.4.1 Experiment 1 (Dili, East T imor)................................... 172 
5.4.2 Experiment 2 (Palmerston North, New Zealand)............. 174 
5.5 DiSCUSSiON .......................................... ............ ... 191 
5.5.1 I ntroduction ............................................................ 191 
5.5.2 Soil compaction: penetration resistance and bulk density. 191 
5.5.3 Soil water properties...... .... ..................... .. ......... ....... 194 
5.5.4 Soil aggregate stability & MWD .. ..................... ............ 196 
5.5.5 Soil porosity ................... ........................................ 197 
5.5.6 Hydraulic conductivity. ..... ....................... .............. .... 199 
5.5.7 Chemical properties... ................ ....................... ....... 200 
5.5.8 Crop yield and biomass production ............................. 203 
5.6 CONCLUDING REMARKS...................... .............. .... 204 
REFERENCES............... .................................... ..... 206 
CHAPTER 6 TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, 
AND SOIL SEDIMENT AND NUTRIENT LOSSES . . . . . . . . .  222 
6.1 INTRODUCTION.............................. ............ ............ 222 
6.1.1 G eneral background ........................... ...................... 222 
6.1.2 Scope and limitations ........................ .... ....... .......... ... 223 
6.1.3 Objectives . . ... .. ........... .. . ... .. .... ........ . . ... .............. ..... 223 
6.1.4 Rainfall simulator........... ....... ........... ...................... ... 223 
6.2 SOIL DEGRADATION AND TILLAGE-INDUCED 
EROSiON ............................................................... 225 
6.2.1 Introduction ......... .............................. ..................... 225 
6.2.2 Soil erosion ......... ............... ........................... ......... 226 
6.2.3 Nonpoint source pollution: soil and water quality ... ...... ... 228 
6.2.4 Surface water runoff and leachate .............................. 230 
6.2.5 Concluding remarks ...... .................. ................ ......... 231 
6.3 RESEARCH METHODOLOGIES.................. .............. 232 
6.3.1 Experimental site ..................................................... 232 
6.3.2 Soil sampling for runoff and leachate measurement ........ 232 
6.3.3 Rainfall simulator ................ ..................................... 233 
6.3.4 Runoff, sediment and leachate measurement ................ 234 
6.3.5 pH of runoff and leachate .......................................... 235 
6.3.6 Nutrient concentration of runoff and leachate ....... .......... 235 
6.3.7 Statistical analysis ............. ................ . ........ ... ........... 235 
6.4 RESULTS.. .... ... ..................... ..................... ............ 236 
6.4.1 Water runoff ... ........................................................ 236 
iv 
6.4.2 Water leac hate .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . .  237 
6.4.3 Soi l  sediment . . . . . . . . . ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  238 
6.4.4 Soi l nutrients . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  240 
6.5 D ISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .  241 
6.5.1 Water runo ff, soi l sediment and nutrient losses . . . . . . . . . . . . . .  241 
6.5.2 Water leachate and nutrient losses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  243 
6.5.3 Non-point source pol l ution . . . . . . . . . . . . . . . . . . . .. . . . . . . . . .  . . . . . . . . . . .  243 
6.6 CONCLUDING REMARKS . . . . . . . . . . . . . . . . . . . .  .................... 245 
REFERENCES . . . . . . . . . . . . . .  ...................... ......... ........... 246 
G E N ERAL DISC USSION: I M P LICATIO N S  OF 
CHAPTER 7 RESEARC H F I N D I N G S  TO EAST TIMOR 
AGRICU LTU RAL DEVELO P M ENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 252 
7.1 I NTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  ........ ........... 252 
7.2 THE TRADITIONAL SETT ING OF AGRICULTURAL 
DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  252 
7.3 AGRICULTURAL PRODUCTIVITY: MANAGING 
TECHNOLOG ICAL CHANGE . . . . . . . . . . . . . . . .  ................ ..... 254 
7.4 AGRICULTURAL PRODUCTIVITY: FOOD POLICY 
IMPLICATIONS . . .  ...... ... .................. ...... .... ..... .... ... ... 256 
7.5 PARADIGM SH IFT TOWARDS SUSTAINABI LlTY? . . . . . . . . 257 
7.6 SOIL AND WATER CONSERVATION . . . . . .  . . . . . . . . . . . . . .. . . . .  258 
7.7 POLICY IMPLICATIONS FOR EAST TIMOR 
AGRICULTURAL DEVELOPMENT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  259 
7.8 AGENDA FOR FUTURE RESEARCH . . . . . .  .................... 260 
REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .  . . . . .  262 
v 
Box 1 
Box 2 
Box 3 
Box 4 
LIST OF BOXES 
Four Main Findings of the Mi l lenn ium Ecosystem Assessment 
2005 
East Timor's vision for 2020 
MAFP' s Poli cy Objectives 
Nutritional comparison of rice, rooUtuber, legumes and edible 
greens (Bradbury & Holloway, 1 988) 
vi 
4 
1 5  
1 6  
1 05 
Table 1 . 1 
Table 2 . 1  
Table 2 .2 
Table 3 . 1  
Table 3 .2 
Table 3 .3 
Table 3 .4 
Table 3 .5 
Table 3.6 
Table 3 .7 
Table 3 .8 
Table 3 .9 
Table 4 . 1  
Table 4 .2 
Table 4 .3 
LIST OF TABLES 
Summarized research setting 
Selected characteristics of East Timor's population 
1 0  
1 8  
Agro-climatic zones i n  East T imor 1 9  
Selected agricultural development indicators of East Timor 66 1 96 1  - 1 999 
Estimated inputs of human,  animal and mechanical power, 
tractor use i ntensity and labour i ntensity for crop production 69 
in selected countries of Asia 
Number of tractors, paddy and maize production (ton) ,  East 73 Timor 1 997-2000 
Selected agricultural tools and equipment by d istrict, 1 997 74 
Selected NGOs working i n  agriculture , target area and 78 beneficiaries, 2006 
Fixed and Variable cost for Kubota MX5000 and Kubota 82 
M9000 tractors (US$/year) 
Working area (ha) and est imated cost of tractor charge fee 83 
Total land area, percentage of agricultural area, total 
population (TP) ,  percentage of agricultural population (AP) ,  85 and GNP per capita of selected countries in the Asia Pacifi c  
Region 1 998 
Mean productivity and annual g rowth rates of cereals ,  tubers 
and root crops, ferti l izer consumption and number of tractors 86 
i n  selected countries i n  Asia Pacific reg ion 
East Timor major staple food crops: cropping area, 
production and yield 1 992-1 997 1 03 
East Timor major legumes: cropping area, production and 1 03 yield 1 992-1 997 
Composition of the work force in East Timor (thousands) 1 1 0 
Selected soi l  chemical ind icators as affected by ti l lage and 
Table 5.1  cropping management (CT=conventional t i l lage,  MT=manual 1 72 
t i l lage, NT=No-ti l lage) before (BC) and after (AC) cropping 
Soil bulk density and water content under different ti l lage 
Table 5.2 and cropping regimes (CT=conventional ti l lage ,  MT=manual 1 73 
t i l lage, NT=No-ti l lage) 
Selected crops and weed ind icators during development 
Table 5 .3 stage (CT=conventional t i l lage, MT=manual t i l lage, NT=No- 1 73 
t i l lage) 
vi i 
Table 5.4 
Table 5.5 
Table 5.6 
Table 5.7 
Table 5.8 
Table 5.9 
Table 5.10 
Table 5.11 
Table 5.12 
Table 5.13 
Table 5.14 
Crop yield and by-products on 12 /10102 (CT=conventional 174 tillage, MT=manual tillage, NT=No-tillage) 
Effects of tillage practices and cropping regime on soil 
penetration resistance (Mpa) (measured on 6th January 
2004 ) (CT=conventional tillage, MT=manual tillage, NT=No­
tillage, PP=Permanent pasture) 
Effects of tillage practices and cropping regime on soil 
penetration resistance (Mpa) (measured on 2ih March 
2004 ) (CT=conventional tillage, MT=manual tillage, NT=No­
tillage, PP=Permanent pasture) 
Effects of tillage practices and cropping regime on soil bulk 
density (gcm-3) measured on 1 ih March 2004 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture) 
Effects of tillage practices and cropping regime on soil bulk 
density (gcm3) measured on April 2004 (CT=conventional 
tillage, MT=manual tillage, NT=No- tillage, PP=Permanent 
pasture) 
Tillage effects on soil water properties at 0 - 10 cm topsoil 
(measured using Low Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture) 
Tillage effects on soil water properties at 10 - 20 cm subsoil 
(measured using Low Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture) 
Tillage effects on soil water properties at 0 - 10 cm topsoil 
(measured using High Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, RAW=readily available water) 
Tillage effects on soil water properties at 10 - 20 cm subsoil 
(measured by High Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, RAW=readily available water) 
Temporal volumetric soil water content by TOR 
measurement (CT= conventional tillage, MT=manual tillage, 
NT=No-tillage) 
Effects of tillage practices on soil water-stable aggregates of 
the 0 -10 cm soil layer using 30  minutes wet-sieving ( % ) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, MWO=mean weight diameter) 
175 
176 
178 
178 
179 
179 
180 
181 
181 
182 
Table 5.15 Effects of tillage practices on soil water-stable aggregates of 183 
the 10 -20 cm soil layer using 30 minutes wet-sieving (%) 
viii 
Table 5.16 
Table 5.17 
Table 5.18 
Table 5.19 
Table 5.20 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, MWD=mean weight diameter) 
Soil porosity and related parameters in the 0 -10 cm topsoil 
as affected by tillage and pasture management (measured 
using Low Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, PSD=Pore size distribution, 
AFP=Air-filled porosity, WFP=Water-filled porosity) 
Soil porosity and related parameters in the 10 -20 cm subsoil 
as affected by tillage and pasture management (measured 
using Low Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, PSD=Pore size distribution, 
AFP=Air-filled porosity, WFP=Water-filled porosity) 
Soil porosity and related parameters at the 0 -10 cm topsoil 
as affected by tillage and pasture management (measured 
using High Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, PSD=Pore size distribution, 
AFP=Air-filled porosity, WFP=Water-filled porosity) 
Soil porosity and related parameters at the 10 -20 cm subsoil 
as affected by tillage and pasture management (measured 
using High Tension Moisture Release Analysis) 
(CT=conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture, PSD=Pore size distribution, 
AFP=Air-filled porosity, WFP=Water-filled porosity) 
Saturated and unsaturated hydraulic conductivity of soil 
layers under different tillage and pasture management (CT= 
conventional tillage, MT=manual tillage, NT=No-tillage, 
PP=Permanent pasture) 
184 
185 
186 
186 
187 
Tillage effects on soil chemical properties (CT= conventional 
Table 5.21 tillage, MT=manual tillage, NT=No-tillage, PP=Permanent 187 
pasture) 
Table 5.22 
Table 5.23 
Total C, total N (tlha), and CN ratio at the top 0 -10 cm soil 
affected by tillage treatments and pasture management 
(CT=conventional tillage, MT=manual tillage, NT=no-tillage, 
PP=permanent pasture) 
Potato tuber and biomass yield (t/ha) under different tillage 
treatments (CT= conventional tillage, MT=manual tillage, 
NT=No-tillage) 
188 
188 
Barley grain and biomass yield (tlha) under different tillage 
Table 5.24 treatments (CT= conventional tillage, MT=manual tillage, 189 
NT=No-tillage) 
ix 
Weed biomass on potato and barley plots (t/ha) (CT= Table 5.25 conventional tillage, MT=manual tillage, NT=No-tillage) 189 
Distribution of 10 most evident weeds* in the unweeded 
Table 5.26 potato plots (%) (CT=conventional tillage, MT=manual 190 
tillage, NT=no-tillage) 
Table 6.1 
Table 6.2 
Table 6 .3 
Water runoff (ml) as affected by tillage and pasture 
management (measured under simulated rainfall on 25th 
March 2004 ) (CT= conventional tillage, MT=manual tillage, 
NT=No-tillage, PP=Permanent pasture) 
Water leachate (ml) every ten minutes as affected by tillage 
and pasture management (measured under simulated 
rainfall on 25th March 2004 ) (CT= conventional tillage, 
MT=manual tillage, NT=No-tillage, PP=Permanent pasture 
E stimated soil sediment losses (kg/ha) as affected by til age 
and pasture management (measured under simulated 
rainfall on 25th March 2004 ) (CT= conventional tillage, 
MT=manual tillage, NT=No-tillage, PP=Permanent pasture; 
ANOVA was performed on log transformed data) 
Tillage effects on soil water pH and Nitrogen losses (CT= 
236 
237 
239 
Table 6.4 conventional tillage, MT=manual tillage, NT=No-tillage, 240 
PP=Permanent pasture) 
x 
xi 
LIST OF FIGURES 
Figure 1 . 1 Map of East Timor 1 1  
Figure 2 . 1  The East Timorese perception of land (Soares, 2001 ) 20 
Figure 2.2 Ecological profi le and production level of tropical home 24 gardens ( Ninez,  1 987) 
Figure 2 .3  East Timor Crop Calendar 26 
Figure 2.4 A theoretical presentation of the relationshi p  between fal low 44 period and productivity (Mertz, 2002) 
Figure 3 . 1  Mechanization Possibi l ity Curve (MPC) (Adapted from Rijk ,  67 1 989) 
Figure 3.2 Capital-saving versus labour-saving technical change 87 (Adapted from Rijk ,  1989) 
Figure 5 . 1  Schematic  lay-out of the experimental plots at the Di l i  S ite 1 58 
Figure 5 .2 Schematic lay-out of the experimental plots at the 1 63 Palmerston North S ite 
Figure 5 .3  Core samples being taken i n  the field for hydraul ic 1 65 conductivity measurement 
Figure 5 .4 Potato and barley growth at the mid-cropping season 1 66 (6/1 /04 ) 
F igure 5 .5 Soi l  penetration resistance measurement 1 67 
Figure 5 .6 Wet-sieving tank  1 69 
Figure 5 .7  S ieving for the extraction of 2 - 4 mm soil aggregates 1 69 
Figure 5 .8 Measurement of (a) saturated and (b) unsaturated hydraul ic 1 71 conductivity 
Regression analysis between soi l depth (cm) and soi l 
penetration resistance (Mpa) under the CT (conventional 
Figure 5 .9  ti l lage), MT (manual t i l lage), NT (no-ti l lage) and PP  1 76 
(Permanent pasture) treatments measured duri ng early 
summer potato and barley growing season 2003 
Regression analysis between soil depth (cm) and soil 
penetration resistance (Mpa) under the CT (conventional 
F igure 5 . 1 0  t i l lage), MT (manual ti l lage), NT (no-ti l lage) and PP 177 
(Permanent pasture) treatments measured after potato and 
barley harvest 2004 
Figu re 6 . 1  A soil core soon after extraction from the field 232 
Figure 6 .2 Schematic diagram of the apparatus special ly designed for 233 runoff and leach ate measurements (Guo et al . ,  1 999) 
Figure 6 .3  
Figure 6 .4 
Figure 6 .5  
Figure 6 .6  
A rainfall s imulator developed by Massey University's 
I nstitute of Natural Resources 
Til lage effects on total surface water runoff under one-hour 
simulated rainfal l  
Ti l lage effects on total water leachate under one-hour 
s imulated rainfal l  
Ti l lage effects on total soil loss under one-hour s imulated 
rainfal l (ANOVA was performed on log transformed data) 
xii 
234 
237 
238 
240 
xi i i  
Appendices 
Appendix 2 . 1  Map o f  the agro-cl imatic zones o f  East Timor 57 
Appendix 2 .2  Map of  sucos (vil lages) where root and tuber crops 58 are among the three most significant crops (2001 )  
Appendix 2 .3  Map of  sucos (vi l lages) where maize was reported as 59 one of the three most sign ificant crops (2001 ) 
Appendix 2.4 Map of sucos (vi l lages) where rice was reported as 60 being one of the three most significant crops (2001 ) 
Appendix 2 .5  Map showing the presence and seasonality of 6 1  irrigation (2001 ) 
ACF 
ACIAR 
ADB 
AFP 
AGSE 
AMCAP 
ANU 
AP 
AS 
AusAID 
BD 
B IMAS 
BPS 
Buw 
Bw 
C 
CC 
CH4 
CO2 
CNRT 
CPR 
CT 
DA 
DAP 
DD 
DIT 
ET 
ETADEP 
ETTA 
FAO 
FAO/RAP 
ABBREVIATIONS 
Action Contre la  Faim 
Austral ian Centre for I nternational Agricultural Research 
Asian Development Bank 
Air-fi l led porosity 
Agricultural Engineering Service 
Ainaro and Manatuto Community Activation Project 
Austral ian National University 
Agricultural popu lation 
Aggregate stabil ity 
Austral ian Agency for I nternational Development 
Bulk density 
B imbingan I ntensifikasi Massa 
Biro Pusat Statistik 
Barley unweeded 
Barley weeded 
Carbon 
Continuous cropping 
Methane 
Carbon d ioxide 
Concelho Nacional da Resistencia Timorense 
Crop-pasture rotation 
Conventional t i l lage 
District administration 
Draft animal power 
Double d isking 
Di l i  Institute of Technology 
East Timor 
Ema maTA Dalan ba Progresu 
East Timor Transitional Administration 
Food and Agriculture Organ ization 
FAO Regional Asia  & Pacific 
xiv 
FAOSTAT 
Fe 
GDP 
GIS 
GlM 
GMD / Dgm 
GNP 
GoTl 
HDI 
HT 
ISO 
KPa 
Kunsat 
IT 
MAFP 
MS 
MPC 
MR 
MT 
MWD / Dmw 
N 
NGO 
N02 
NT 
NZ 
NZAID 
P 
PP 
PASC 
PR 
PSD 
PUSlAWITA 
FAO Statistics 
Field capacity 
Gross domestic product 
Geographical i nformation system 
General l inear model 
Geometric mean d iameter 
Gross net product 
Government of Timor-leste 
Human Development Index 
High tension 
International Students Office 
Ki lopascal 
Saturated hydrauli c  conductivity 
Unsaturated hydraul ic conductivity 
low tension 
M inisterio de Agricultura , Florestas ,  e Pescas 
Mobi le brigade 
Mechanization Possib i l ity Curve 
Moisture release 
Manual t i l lage 
Mean weight d iameter 
N itrogen 
Non-governmental organization 
N itrous oxide 
No-ti l lage 
New Zealand 
New Zealand Assistance for I nternational Development 
Phosphorus 
Permanent pasture 
P i lot agricultural service centre 
Penetration resistance 
Pore-size distribution 
Pusat latihan Wirausaha Tani 
xv 
Puw 
Pw 
RAW 
RDTL 
SAS 
SOC 
SOM 
SON 
SWCC 
TOR 
TIDS 
TP 
UNDP 
UNEP 
UNICEF 
UNTL 
WB-JAM 
WC 
WFP 
WFP 
WSA 
WSSP 
ZT 
Potato unweeded 
Potato weeded 
Readily avai lable water 
Republ ica Democratica de Timor-Leste (Democratic Republic 
of Timor-Leste) 
Statistical Analysis System 
Soil organic carbon 
Soil organic matter 
Soil organic nitrogen 
Soil water characteristic curve 
Time domain reflectometry 
Timor Institute of Development Studies 
Total population 
United Nations Development Programme 
U nited Nations Environment Programme 
United Nations Chi ldren's Fund 
Un iversidade Nacional de Timor-Leste 
World Bank Joint Assessment Mission 
Water content 
World Food Program 
Water-fi l led porosity 
Water stable aggregates 
Water Supply and San itation Project 
Zero til lage 
xvi 
xvii 
Abstract 
The prospects of sustainable crop production technologies in East Timor were 
d iscerned with relevant case studies and experimental data. An overview of the 
agricultural development in East Timor with particular emphasis on the traditional 
farming and cropping systems was presented complemented by the d iscussion on 
the aspects of agricultural mechanization and technolog ical change and their socio­
economic ram ifications on food security . Empirical data from ti l lage tria ls ,  
establ ished both i n  East Timor and New Zealand, were gathered and discussed in 
the quest for a better understanding of ti l lage effects on soil structure and crop 
production environment. 
The agro-cl imatic zones of East Timor provide a wel l -defined set of ecological 
boundaries upon which further col laborative research work can be developed .  
Given land resources as one  of the major capital investments i n  agriculture 
development, the drive towards improvement and technical change in agriculture 
should be d i rected i n  a balanced combination ,  whenever appropriate , between 
technolog ies of land-saving (hybrid seeds, i rrigation , and dra inage) or labour-saving 
(mechanization , herbicides , varieties and cropping techniques) characteristics. 
Moreover, the justification for acqui ri ng an improved technology for traditional 
farmers , to some extent, needs to conform to the features of their  subsistence mode 
of farming .  The emphasis in technology d issemination ,  therefore , wi l l  have to shift 
from communication to education . 
Experimental results of th is study on the effects of t i l lage ,  and no-ti l lage i n  particu lar 
as a form of conservation t i l lage, on the edaphic changes affecting croppi ng 
environment general ly concur with the find ings known in the l iterature. Organic 
carbon levels are general ly restored with cropping i n  East Timor. In add ition ,  soil 
bu lk density and crop gra in and biomass yield were not affected by t i l lage 
treatments. Soil compaction was significantly affected by t i l lage as shown by d ata 
from the Palmerston North experiment. Soil aggregate stabi l ity i n  the 0-1 0  cm 
topsoi l  was simi lar under al l  the ti l lage treatments . Manual ti l lage (MT) had the 
greatest number of soi l  aggregates on sieve after a 30-minute wet-sieving (68.3%)  
xvi i i  
fol lowed by no-ti l lage (NT) (65 . 1 ) , permanent pasture (PP) (62.6) and conventional 
t i l lage (CT) (56 .5) .  S imi larly, the top 0-1 0 cm soi l  u nder MT had significantly larger 
macroporosity ( 1 6 .4%) than CT (9.23), NT ( 1 1 .5 ) ,  and PP  ( 1 0.6) .  MT and CT 
significantly reduced the total C whereas N levels were significantly decreased by 
ti l lage (CT, MT and NT) compared to permanent pasture at the top 0-1 0  cm soi l 
l ayer. Barley gra in and biomass were unaffected by ti l lage whereas potato tuber 
yield and biomass were significantly less under no-ti l lage. Conventional t i l lage 
significantly increased water runoff but produced less leachate compared to no-ti l l  
and permanent pasture. Total soi l  sediment loss was significantly lower under PP 
(95. 8  kg/ha) and NT ( 1 32 .9) compared to CT (3556 .7)  and MT (4652.2) .  pH of water 
runoff was significantly reduced under ti l lage treatments compared to that from 
permanent pasture whereas n itrogen losses were unaffected . 
There are at least four major publ ic pol icy components that wi l l  play vital roles i n  the 
development of sustainable crop production technologies in East Timor: ( i )  
Agricultural research and development ( i i )  Agricultural extension (i i i )  I nternational 
and reg ional networking (iv) Shift of pol icy focus. The pol icy approach needs to be 
decentral ized and broad-based and conservation agriculture should be promoted as 
opposed to conventional production agriculture .  Three major areas for the future 
research agenda include : ( i )  I ntegrated Farming Systems ( i i )  Soi l  ti l lage and erosion 
( i i i )  Appl ied science and technology. The last component may cover d iscipl ines such 
as: food pol icy analysis ,  farm machinery selection and testing, soi l  testing and 
mapping , land evaluation and G IS ,  bio-energy technologies, improved local seed 
varieties, adaptive fodder crops for improved grazing and pasture management, 
appropriate agro-forestry and soil and water conservation technologies and cash 
crop in itiatives. 
xix 
ACKNOWLEDGEMENTS 
After a being long overdue, this thesis came to an end , and I must first and foremost 
praise Lord the Almighty for granting me the strength and perseverance to get 
through these long years of study. His blessings were also sent through many 
generous people without whom this study could not reach this far. My deepest 
gratitude goes to Prof. Peter Kemp  for his invaluable contribution to this study as my 
Chief-Supervisor. H is patience and guidance through the experimental and writing 
phases is very much appreciated . Despite being 'extra' student for h im ,  it did not 
make me less extraordinary , on the contrary, I was, in times, g iven special t ime and 
priority . I thank Assoc .  Prof. Alex Chu ,  my Co-supervisor, for being with me from the 
beg inn ing unti l the end , and for his critical th inki ng which helped setting up the 
d i rection of this study,  and for his trust and friendsh ip .  My thanks are also due to Or. 
Ashraf Choudhary and fami ly for their support and friendsh ip ,  which counts back to 
my early years at Massey University. Or. Choudhary helped with the talks with 
MFAT-NZ for the scholarship and later gave invaluable support during the first two 
years of my doctoral study. 
There are a number of staff at Massey whom I l ike to thank for thei r  help, support, 
encouragement, and assistance: Or. Oave Scotter and Or. lan Yule for the fruitful 
d iscussions; Mark Osborne,  Tom Todd ,  and Craig McGi l l  for their help during my 
field experiments; Bob Toes, lan Furkert, Ross Wallace , James Hanly, Glenys 
Wal lace and Ann West for assisting me during the laboratory work. Mr. John Oando 
of Landcare Research helped me a lot with the analysis of soil physical properties, 
which I s incerely appreciate . The NZAID and the ISO of Massey University are 
tremendously supportive with the financial assistance and on other log istic matters 
during my stay in New Zealand .  To them I owe a very deep debt of gratitude. I'm 
also thankful for the Helen E. Aikers scholarsh ip received during the extended 
period of my study. 
The cheerfulness and a joyful environment to study on campus count a lot, and I 
thank my international friends, too many to count individual ly, for provid ing me with 
xx 
plenty of these. I must pay special tribute to my friends at ETZA-NZ, Bhoj Bahadur 
Kshatri and Maya Kshatri , Zeferino Ti lman and Dulj i ra Sukboonyasatit, Tearoa and 
Josephath , and Helder and Magy da Costa for thei r  countless help, particularly 
d uring the last months of my stay in New Zealand ,  prior to the com pletion of this 
thesis. Soccer has been an 'addiction' which I developed by accident, and to my 
soccer team-mates ,  kiwis ,  Pakistani ,  and i nternational ,  I extend my sincere 
appreciation for their warm friendship.  
I owe immense gratitude to many people i n  East T imor, my homeland , especial ly to 
HE  Eng .  Estanis lau da Si lva, Min ister of MAFP; HE  Mr. Francisco Benevides, Vice­
M inister for Coffee and Forestry; Mr. Cesar da Cruz, State Secretary for Region IV 
(formerly Permanent Secretary of MAFP ) ; and Eng .  Mario Nunes, National Di rector, 
Forestry Division and many other MAFP officers for their support and assistance 
during the East T imor fieldwork. I s incerely thank Mr. Joao Tilman for al lowing me to 
set up experimental plots on his farmland and my cousin Mario Romualdo Soares 
who helped monitoring the experiments. The friendship and moral support from my 
colleagues i n  East Timor especial ly Joao Saldanha, Anacleto Ribeiro, Marcel ino 
Magno, Francisco Guterres ,  and staff members of TIDS, and Estanislau Saldanha 
and Joao Cancio of DIT are grateful ly appreciated . I am also deeply grateful for the 
love and constant prayers from my parents, my parents-in-law, and a multitude of 
relatives . Lastly, I devote my final words of appreciation to my wife Natal ia Viegas 
and our beautifu l  chi ldren Sheena,  Shannon, Semantha, Egfdio and Victor Dias 
Viegas for thei r caring love and sacrifice over many long years in New Zealand . 
To the proud farmer of East Timor I dedicate this humble work. 
[ZJ GENERAL INTRODUCTION 
1.1 I NTRO D U CTION 
East Timor has emerged as the newest i ndependent country in the world after 
centuries of political and socio-economic hardship under successive foreign colon ial 
occupations .  Moreover, East Timor has to bear a costly and inhumane period of 
severe destruction fol lowing the aftermath of the August 1 999 pro-independence 
referendum.  After a brief transitional period under the United Nations administration, 
and formally regaining its sovereignty as a nation state on 20 May 2002 , it is now 
firmly driven towards achieving its reconstruction and development goals. The 
daunting tasks of having to start the development from scratch include improving 
food security, al leviating poverty and promoting the sound use of natural resources, 
for which the agricu lture sector plays key fundamental roles (GoTl, 2006) .  
I t  is  argued that many of the environmental problems of today's world are not the 
result of a 'bad' science but, rather, inadequate policies, institutions, and 
management systems. Therefore, a process of pol icy and institutional reforms is 
underway within  the agriculture sector of East Timor with the aim of creating a small 
but effective bureaucracy in the publ ic sector al lowing a wider and fu l l  participation 
from the private sector and the agricultural community in view of attaining long-term 
sustainable agricultural development. This process has been complex and slow 
partly because of the big adjustments undertaken from a previously huge 
bureaucracy during Indonesian times and largely due to the inadequate information 
and supporting resources for pol icy planning and formulation (MAFP,  2004). 
Developing institutions at various levels that will foster a pol icy d ialogue on issues 
related to food , agriculture and the environment is fundamental to identifying 
medium to long-term development strategies . It is also pivotal to setting up priorities 
for research and analysis on food , agriculture, and natural resource development 
policies that wi l l  help generate and share information regarding policy chal lenges 
Chapter 1. GENERAL INTRODUCTION 2 
and useful strategies for East Timor i n  its endeavours to secure food and nutrition for 
the whole population ,  improve people 's l iving standards and preserve the natural 
resource base (MAFP, 2005) .  
This doctoral research project was designed to d iscuss the big three issues, namely 
food security, poverty reduction , and natural resource base protection through smal l  
and tangible ways with emphasis on the agricu ltural production sustainabi l ity. This is 
l ine with the l inkages between Mi l lennium Development Goals and poverty reduction 
such as (i) economic growth and rural development (ii) increasing basic socia l  
services and productive resources ( i i i )  improving environmental regeneration ( iv) 
human security, food security, i ncreasing participation and empowerment (UNDP ,  
2006) .  
I n  a setting l ike the present East Timor, as in many othe r  developing countries, these 
issues are closely i nterrelated in a fashion such that they may evolve into a cycle 
(poverty-hunger-environment degradation) almost impossible to break unless proper 
strategic pol icy measures are taken since the onset. To help inform such pol icies in 
East Timor, it is  argued that the use of the major agricu ltural resource base which is 
the soi l , by a specific farmer or household in a designated agro-ecosystem , has 
influential economic impacts to the household members and their  l iving environment. 
Judicious and effective management of soil may have a major impact on soil 
productivity and erosion control , particularly in  semi-arid regions l ike East Timor 
(Sandlund et al . ,  2001 ) .  
The experimental focus of th is research was therefore l imited to the manipulation of 
soil by d ifferent ti l lage systems and how that affects the structural properties of the 
soil under study and its ramifications on crop production. To put this into East 
Timorese perspective, manual t i l lage was compared to no-ti l lage and mechanical 
ti l lage using mouldboard plough ,  and with barley (Hordeum vulgare L.) and potato 
(Solanum tuberosum L . )  (New Zealand site) and corn (Zea mays L.)  and mung bean 
(Vigna radiata L.) (East Timer s ite) as the test crops. I n  addition , no ferti l izers er 
chemical inputs were applied and efforts to eradicate weeds were kept m inimal . In 
Chapter 1. GENERAL INTRODUCTION 3 
essence, as it is portrayed both i n  the experimental chapters as well as in the 
l iterature study chapters, the nature of the analysis is to contrast the human powered 
(traditional) farming system versus machine powered (modern) farming system ; and 
the community tuber crop-based production system aga inst the cereal production 
system. A summarized research setting is  presented in Table 1 . 1 below. 
1.2 BAC KG RO U N D  
Many countries worldwide today are facing the key issue of meeting the food and 
nutrition needs of their growing populations thus putting a tremendous pressure on 
the agricultural sector as the prime source of food production.  On a global scale ,  
agricu lture has been very successful in meeting a growing demand for food 
production during the later half of the 20th century. This has been due mainly to 
scientific advances and technological innovations ,  including the development of new 
plant varieties, the use of ferti l izers and pesticides , and supported by extensive 
irrigation infrastructures (Gliessman , 1 998, Zi lberman et aI . ,  1 997) .  
This success however, was achieved at the expense of the overdrawing and the 
degradation of the natural agricultural resources - soi l ,  water, and natural genetic 
d iversity. So far, the global agricultural system is not environmental ly benign and 
poses a long-term sustainabi l ity concern . Scientific agricu lture and conventional 
farming embedded in modern agriculture today tend 'to drive ecology out of the 
input-output equation' (Pesek, 1 994), and cannot continue to produce enough food 
for the global population over the long-term because it deteriorates the conditions 
that make agriculture possible (Gl iessman,  1 998) .  A report has just been recently 
released on a four-year global assessment on ecosystem change, coordinated by 
the United Nations Environment Programme (UNEP) .  The aim was at assessing the 
consequences of ecosystem change for human wel l-being and to establ ish the 
scientific basis for actions needed to enhance the conservation and sustainable use 
of ecosystems and their contributions to human wel l-being (Watson and Zakri , 
2005) .  The main findings of this assessment were quite alarming as presented in  
Box 1 .  
Chapter 1. GENERAL INTRODUCTION 4 
Four Main Findings of the Millennium Ecosystem Assessment 2005 
• Over the past 50 years, humans have changed ecosystems more rapidly and extensively than in any 
comparable period of time in human history, largely to meet rapidly growing demands for food, fresh 
water, timber, fibre and fuel. This has resulted in a substantial and largely irreversible loss in the 
diversity of life on Earth. 
• The changes that have been made to ecosystems have contributed to substantial net gains in human well­
being and economic development, but these gains have been achieved at growing costs in the form of 
the degradation of many ecosystem services, increased risks of nonlinear changes, and the exacerbation 
of poverty for some groups of people. These problems, unless addressed, will substantially diminish the 
benefits that future generations obtain from ecosystems. 
• The degradation of ecosystem services could grow significantly worse during the frrst half of this 
century and is a barrier to achieving the Millennium Development Goals. 
• The challenge of reversing the degradation of ecosystems while meeting increasing demands for their 
services can be partially met under some scenarios that the MA has considered but these involve 
significant changes in policies, institutions and practices that are not currently under way. Many options 
exist to conserve or enhance specific ecosystem services in ways that reduce negative tradeoffs or that 
provide positive synergies with other ecosystem services. 
Source: Watson and lakri (2005) 
The issues are particu larly del icate for developing countries of the tropics where a lot 
of pressure has been put on agricultural production to keep in pace with the 
population growth and th is ,  in  turn, has led to severe environmental degradation and 
ecosystem change (Lal ,  2000). For these countries, a rapid agricultural development 
growth is constrained by various factors most notable among these include c l imatic 
conditions (Sanchez, 2000), lack or l ittle  use of inputs, poor technology transfer and 
pressure of population growth on land (Clarke and Bishop, 2002) ,  and the use of 
marginal lands thus causing severe land degradation (Lal ,  2000) .  Many countries in 
Asia ,  in their efforts to intensify and increase their food production ,  have introduced 
machinery and equ ipment which were neither tested locally, nor matched with the 
particular soi ls to be ti l led . I n  add ition, shortage of trained technicians and farmers in 
the use of equipment introduced has had its negative impact. The experiences of 
various countries testify to the problems with such inadequately planned transfer of 
technology. I n  many cases the targeted yields have not been maintained and 
serious land degradation has been caused (Salokhe and Ramal ingam, 1 998) .  
The task ahead is not only to increase food production but at the same time to 
ensure that the natural resource base, namely the soi l ,  is properly managed so as to 
Chapter 1. GENERAL INTRODUCTION 5 
be able to sustain future generations. This major challenge cannot be successfully 
met without modernization of production technology supported by the development 
of appropriate socio-economic and research institutions and intensive education. 
However, there is the need for testing technology developed elsewhere under local 
conditions that will improve farming practices under the prevailing socio-economic 
situations. On the other hand, traditional farming systems have not changed much 
since the early 20th century (Lal, 1995). 
Shifting cultivation and bush fallow rotation is widely used in the tropics. Shifting 
cultivation involves clearing and burning natural vegetation, cultivation of the cleared 
area for a season or two, then moving to a new plot while the old one regains its 
fertility under natural vegetation regrowth (Richards, 1985) Attempts to intensify the 
agricultural production in the tropics either by pursuing the traditional or modern 
methods of cultivation have caused wide concerns with regards to resource base 
deterioration. Lal (1995) identified general issues of agricultural sustainability in 
humid and arid/semi-arid tropics as follow: 
1. High subsistence agricultural usage of the land, 
2. Reduction in fallow period, 
3.  Soils of low fertility and low yields due to resource-based and no-input 
agriculture, 
4. Soil degradation due to fertility depletion, accelerated erosion, structural 
deterioration and reduction in soil organic matter, 
5. High risks of crop failure, 
6. Water shortage and 
7 .  Difficulties of mechanizing farm operations. 
While these issues are generally relevant to East Timor, little attention has been 
drawn to identify and measure them adequately. Instead, successive political 
regimes have tried to modernize the agricultural sector without first establishing a 
firm ground of understanding based on the local knowledge of farming. Efforts were 
sought to replace or at least de-emphasize the traditional modes of farming instead 
Chapter 1. GENERAL INTRODUCTION 6 
of improving them. Despite great efforts at agricultural modernization during the last 
two decades of the Indonesian regime particularly, East Timor's agriculture of today 
remains predominantly subsistent, geared by farmers with small-sized holdings 
towards using traditional modes of farming within local kinship clans. 
East Timor's sUbsistence agricu lture is mainly characterized by a rice mono cropping 
in  the lowland areas and a mixed cropping system in the uplands .  Agricultural publ ic 
pol icies during the last two regimes, namely Indonesia and the United Nations ,  were 
d riven towards achieving food self-sufficiency with great emphasis on rice. The 
current government of the newly independent East Timor seems to be moving 
towards the same d irection .  However, as much has been said, East Timor is not an 
efficient rice producer (WB-JAM, 1999). Evidence has shown that whi le  local rice 
produce is very much appreciated because of its organic brand, imported rice is 
avai lable at the market with a far cheaper price. Thus, from a food security point of 
view, efforts should be diverted from maximizing the rice production to diversifying 
the food sector with other comparatively advantageous local food resources of 
cereal , legumes, and especial ly root crops (MAFP, 2005). 
Due to the complexity involved and resources l im itations, the experimental 
component of this  PhD research project is based primarily on soi l  ti l lage for crop 
production and its results d iscussed within the broad context of agricultural 
mechanization development in East Timor. There are two contrasting  situations 
where t i l lage could play a major role in susta in ing a long-term crop and food 
production while preserving the natural resource base. The first situation is the 
upland mixed farming using traditiona l  sh ift ing cultivation , which impl ies clearing and 
burn ing of vegetation but the ti l lage and d isturbance of so i l  are kept min imal .  The 
other  is the rice cropping system in the lowlands where the use of machinery is  
extensive and the mechanical treatment of so i l  is general ly excessive following the 
conventional methods of cropping .  An experimental design of appropriate 
mechanical  means to achieve a sustainable yet energy efficient crop production 
forms the basis of this study. 
Chapter 1. GENERAL INTRODUCTION 7 
The l iterature research component covers an in-depth l iterature study drawing 
research evidences and experiences from other countries particularly those with 
similar developmental and geographical characteristics. It covers three major topics 
namely traditional agriculture, agricultural/rural technology, and the importance of 
root crops in  the food pol icy. The results wil l help support the policy design on 
agricu ltural mechanization and food pol icy for East Timor. 
3 . 3  RATIO NALE 
1 .  The traditional farming system is an integrated part of East Timorese culture and 
in many ways reflects the local values, tradition ,  and knowledge. The system is 
stable and sustainable however it is inefficient and has low productivity. 
2 .  Matching of the agricultural technologies integral to the respective ecosystem 
zones wi l l  enhance and provide sustained development of cropping systems and 
l ivelihood of farmers . 
3 .  Root and tuber crops constitute a major d iet component for a vast majority of 
East Timorese people particularly for the farming communities in  the uplands. 
Their role therefore should not be less important than other staple foods in  the 
formulation of the nation's food pol icy. 
1.4 H YPOTH ESIS 
1 .  A sustainable long-term productivity cannot be achieved unless a proper policy 
framework for East Timor agricultural development is pursued . 
2 .  The existing agriculture development pol icies may exert enormous pressure on 
marg inal lands of the hi l l  countries, especial ly if inappropriate set of crop 
production technolog ies are used. 
3 .  The application of conservation principles wil l reverse the degradative trends of 
the current agricultural production systems. 
Chapter 1. GENERAL INTRODUCTION 8 
1 . 5  O BJ ECTIVES 
The main objective of this research is  to assess the existing crop production systems 
in East Timor and offer prospective technological outcomes for long-term agricultu ral 
sustainabi l ity. 
The specific objectives are: 
1.  To evaluate the existing cropping systems in East Timor, those using traditional 
modes of farming and mechanized systems in selected ecosystems .  
2 .  To provide strategies for food security and sustainable crop production with in  a 
food policy approach in East Timor. 
3. To investigate selected soil physico-chemical properties , crop yield ,  and biomass 
production performances under different soi l ti l lage management. 
1 .6 O RGAN IZATION OF T H E  T H E S I S  
The rest of the thesis i s  structured as fol lows : 
Chapter 2 - This chapter contains a general overview of the existing cropping 
systems in East Timor and updated figures of agricultural development indices. 
Special emphasis is  given to the d iscussion of the prevai l ing traditional modes of 
farming in  the uplands (shifting cultivation) as they a re,  under increased population 
pressure, largely viewed as environmentally destructive. Research evidence and 
experiences from other countries with traditional farming systems are presented with 
a l iterature synthesis on soi l degradation and agricultural production sustainabil ity. 
Chapter 3 - This chapter presents views on agricu ltural mechanization/ technology 
development in  a broad context with particular emphasis given to agricu ltural 
technology status in East Timor. Recent assessment results on agricultural 
machinery recovery program during the UN-Administration period and h istoric data 
during Portuguese and Indonesian regimes will be the base of analysis. A 
comparison study based on international and regional experiences complements this 
Chapter 1. GENERAL INTRODUCTION 9 
study. Conservation agriculture technologies wi l l  also be d iscussed and a 
prel iminary agricu ltural mechanization scheme is proposed to the new government 
of the independent East Timor. 
Chapter 4 - This chapter synthesizes the i nformation gathered earl ier in the previous 
two chapters and presents views on food pol icy scenarios relevant to East Timer's 
conditions. Two present situations worthy of attention are the lowland rice based 
cropping system and the upland maize/root crop based cropping system . In  either 
case, the technology development needs to be devised through a proper strategy 
and pol icy p lan ,  taking into consideration the socio-economic status of the majority 
of the population l iving in  rural areas. A food pol icy approach is employed i n  order to 
achieve a better understanding of various dimensions of food security appropriate to 
East Timor. 
Chapter 5 - Experimental results , d iscussion and analysis, are presented in  th is 
chapter .  As mentioned earl ier, the focus is to assess the impacts of d ifferent t i l lage 
systems ,  namely manual ti l lage , no-ti l l ,  and conventional t i l lage on selected soi l 
physical and chemical characteristics and thei r impl ications on crop yield and 
biomass production . The crops chosen for testing were corn , mung beans, barley 
and potato. A major experiment was set up in Palmerston North New Zealand to 
compensate for the poor results from a small experiment attempted earl ier in Di l i ,  
East Timor (Figure 1. 1 ). 
Chapter 6 - Simulated rainfal l  experimental results comparing the effects of different 
ti l lage practices on water runoff and leachate, sed iment, and nutrient losses are 
presented in  this chapter. The experiments were carried out i n  a laboratory at 
Massey University Campus, Palmerston North , New Zealand .  
Chapter 7 - The final chapter presents a general d iscussion synthesizing the 
find ings , from l iterature and experimental data, and draws out pol icy implications and 
areas for future research related to East Timor agricultural development. 
Table 1. 1 Summarized research setting 
National Existi ng Systems I agricu ltu ral related Research Scope I Scope for Proposed outcomes I 
issues Featu res Improvement recommendations 
• Identifying key policy issues and 
research study areas (Chapter 1 )  
• Shifti ng cultivation 
predominantly using • Defining the issues and Rural technology development based 
Poverty Al leviation slash-burn method consolidating the measures in agriculture the existing traditional agro-
ecosystem setting (Chapter 2) 
• Rainfed upland mixed • Specifying the first key 
cropping (root & tuber, discussion area: mechanization 
beans, maize, and rice) and rural technology 
advancement (Chapter 3) 
Food Security • Rice and maize 
• Specifying the second key Root & Tuber Crop Based Cropping 
cu ltivation in the lowland d iscussion area: root crop-based System and Food Policy Approach 
areas (rainfed and 
cropping systems (Chapter 4)  
i rrigated) • Implementing through 
experimenting: soil tillage and 
crop adaptation (Chapter 5) 
• Low technology inputs 
and low crop and land • Implementing through 
Environmental 
productivity experimenting: t i l lage-induced Selective conservative mechanization erosion and non-point source 
Degradation pollution (Chapter 6) program with emphasis on conservation 
• Subsistent production 
/ min imum ti l lage 
• Determining pol icy implications 
and future research needs 
(Chapter 7) 
T 1 25 
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1 260 
Figure 1 . 1 Map of East Timor 
OoitXWlnwnt a P\iocw+li;oiping � .... iooi Carlo;TophiC Soi;ctiOn 
R E F E R E N C E S  
Clarke, L .  J .  & Bishop, C .  (2002) Farm Power - Present and Future Avai labi l ity i n  
Developing Countries. ASAE Annual International MeetinglCIGR World 
Congress, 30 July 2002. Chicago. 
Gl iessman , S. R. ( 1 998) Agroecology: ecological process in sustainable 
agriculture. Ann Arbor Press , Chelsea M I ,  USA. 
GoTL (2006) Combating Poverty as a National Cause: P romoting Balanced 
Development and Poverty Reduction . Democratic Republic of Timor-Leste, 
D i l i  East Timor. 
Lal , R. ( 1 995) Ti l lage systems in the tropics : management options and 
sustainabi l ity impl ications.  FAO Soils Bulletin No. 71 .  FAO. 
Lal ,  R. (2000) Soil Management in  the Developing Countries . Soil Science, 1 65, 
57-72. 
MAFP (2004) Pol icy and Strategic Framework. Republ ica Democratica de Timor 
Leste, M inistry of Agriculture, Forestry and Fisheries , Dil i ,  East Timor. 
MAFP (2005) Prel iminary Report on Donor's Agricultu ral and Rural Development 
Conference, 3-5 March 2005.  M in isterio da Agricu ltura, Florestas e Pescas, 
RDTL, D i l i ,  East Timor. 
Pesek, J .  ( 1 994) H istorical perspective . Sustainable Agriculture Systems (eds J .  L .  
Hatfield & D .  L .  Karlen) ,  pp. 1 - 1 9 .  Lewis Publ ishers CRC Press, I nc . ,  U SA. 
Richards ,  P. ( 1 985) Indigenous Agricultural Revolution. Hutchinson Education, 
London . 
Salokhe ,  V .  M .  & Ramal ingam , N .  ( 1 998) Agricultural Mechanization in  South and 
South East Asia .  International Conference of the Philippines Society of 
Agricultural Engineers, 21-24 April, 1998. Los Banos , Phi l ippines. 
Sanchez, P. A. (2000) Linking cl imate change research with food security and 
poverty reduction in the tropiCS. Agriculture, Ecosystems & Environment, 82, 
371 -383 . 
Chapter 1. GENERAL INTRODUCTION 1 3  
Sandlund , O .  T . ,  Bryceson,  I . ,  Carvalho, D .  d . ,  Rio, N . ,  Si lva, J .  d .  & Si lva , M .  I .  
(2001 ) Assessing Environmental Needs and Priorities in East Timer: I ssues 
and Priorities . UNOPS and N INA-N IKU ,  Di l i ,  East Timor. 
UNDP (2006) Human Development Report 2006 Timor-Leste The Path out of 
Poverty: I ntegrated Rural Development. United Nations Development 
Programme, Di l i  East Timor. 
Watson , R. T.  & Zakri , A.  H .  (2005) Mil lennium Ecosystem Assessment Synthesis 
Report. The United Nations Environment Programme. 
WB-JAM ( 1 999) East Timer, Bui lding a Nation, a Framework for Reconstruction 
and Development; Agriculture Background Paper. The World Bank Joint 
Assessment Mission . 
Zi lberman , D . ,  Khanna, M .  & Upper, L. ( 1 997) Economics of new technologies for 
sustainable agriculture. The Australian Journal of Agricultural and Resource 
Economics, 41 , 63-80 .  
'2l DEVELOPING EAST TIMOR AGRICULTURE 
� 
Sustainabi l ity Impl ications 
2.1 I NTRO D U CTI O N  
Agriculture i s  the backbone o f  East Timor's economy by provid ing the l ivel ihood 
source for almost the entire rura l  and part of the urban popu lations, accounting for 
more than a fourth of GDP and generating a l imited foreign exchange especially 
through coffee export. The agriculture sector therefore wil l inevitably be a major 
driving force to support a sound and sustainable development growth for the country 
in  the future . However, g iven its SUbsistence nature , the chal lenges are enormous .  
The farmers produce for self-consumption , with basic inputs including unpaid fami ly 
labour, smal l  landhold ings, basic tools, and rely mostly on rainwater (GoTL,  2003). 
Nevertheless, the government has embarked on a programme to design pOl icies and 
strategies 1 at the macro-economic level to respond to these chal lenges with 
substantial support from the civi l society and the international community (GoTL, 
2006) .  
The National Development Plan with the visions for the year 2020 (Box 2) m ight look 
promising only in theory as the country is faced with mu lti-faceted constraints in a l l  
aspects of development, from poor physical infrastructure,  l im ited human and 
financial resource capabi lities , to inadequate law apparatus, not to mention 
unfavourable natural conditions for agricu ltural production in many parts of the 
country. The Ministry of Agriculture,  Forestry, and Fisheries (MAFP in Portuguese 
acronym) is  moving ahead with translating these visions i nto strategic action plans, 
especial ly as they are in  a large part related to, or dependant on, this sector. As it is 
explicitly stated as wel l  as i nherently embedded in  some of these visionary 
statements ,  the founding of an agricultura l  production system which is productive, 
1 See Planning Commission (2002) ,  State of the Nation Report; GoTL (2003) Timor-Leste, Poverty in 
a New Nation :  Analysis for Action; and GoTL (2004) Timor Leste: M il lennium Development Goals 
Report. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 15 
sustainable and cu lturally appropriate will be of major importance . This chapter aims 
to provide insights on how this could be best achieved . 
East Timor's vision for 2020 
• East Timor wil l be a democratic country with a vibrant trad itional culture and sustainable 
envi ron ment; 
• It wil l be a prosperous society with adequate food, shelter and cloth ing for all the people; 
• People will be l iterate , knowledgeable and skil led. They wil l  be healthy, and live a long , 
productive l ife. They will actively participate in economic, social and political development, 
promoting social equal ity and national unity; 
• People wil l no longer be isolated , because there will be good roads, transport, electricity, 
and commun ications in the towns and villages, in all regions of the country; 
• Production and employment wil l increase in al l sectors - agriculture, fisheries and forestry; 
• Living standards and services will improve for al l East Timorese, and income wil l be fa i rly 
d istributed ; 
• Prices wil l be stable, and food supplies secure, based on sound management and 
susta inable util ization of natural resources; 
• The economy and finances of the state will be managed efficiently, transparently, and wil l 
be free from corruption; and 
• The state will be based on the rule of law. Government, private sector, civi l  society and 
commun ity leaders wi l l  be fully responsible to those by whom they were chosen or elected . 
Source : Planning Commission (2002), National Development Plan 
2 . 1 . 1 The M i n i stry of Ag ricu ltu re, Forestry and Fisheries (MAFP) 
As was mentioned earl ier, the pol icy and institutional reforms are now underway 
especially in the public sector in various administrative levels .  With a dramatical ly 
lower number of agents compared to the large staff membership under the 
I ndonesian regime2 , MAFP is now carrying a heavy task to consol idate its plans and 
efforts to meet the increasing needs of the farming popu lation . Box 3 presents the 
key policy objectives of MAFP. 
Up to the present t ime, the government and MAFP in particu lar have benefited qu ite 
substantial ly from working in partnership with donor countries , international agencies 
and NGOs, and national development partners especial ly farmer groups. However, 
MAFP found it difficult deal ing with the piecemeal nature of most donor and NGO 
2 MAFP currently employs about 235 staff, 41 % of which are based at the national level , 1 7% in the 
capital, Di l i ,  and 4 to 1 0  staff in each of the rest of the districts. During Indonesian times there were 
700 agricultural extension workers at the vi llage level alone (see MAFP, 2004). 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Implications 1 6 
projects and therefore decided to create a Coordination Secretariat partly to prevent 
overlapping and dupl ication of project activities. Official assessment indicates that 
there are a significant number of areas and communities uncovered or l ightly served 
by the donor-funded projects. I n  add ition, a large proportion of these projects wil l  
scale down their funding in the very immediate future (MAFP, 2004). This poses , 
apart from the already unevenly distributed donors' projects across the country and 
their consequent impact ,  a worrying situation where MFAP has to sustain its 
programs with a very l imited budget and to cope with a wider area and commun ity 
coverage. 
MAFP' s Poli cy Objectives 
• Improve the level of food secu rity of the ru ral population and to ra ise self-reliance 
• I ncrease value-addition of agriculture , forestry and fisheries products by fostering output 
processing and marketing 
• Active sustainable production and management of natural resources 
• Contribute to the balance of trade by gaining revenue from commodity export and by 
substituting imports 
• I ncrease income and employment in rural areas 
2 . 1 .2 The Role of MAFP 
Source: MAFP (2004), Policy and Strategic Framework 
From communications with MAFP officers and personal observation during several 
vis its to East Timor along the course of this study, it is argued that the role of MAFP 
has been very l imited to pol icy and strategy design, staff and institutional capacity 
bui ld ing,  information dissem ination and the creation of basic infrastructures3. The 
latter include ,  but are not l im ited to,  the ongoing reconstruction and maintenance 
efforts on numerous irrigation schemes ,  meteorological stations, and rural markets . 
Supported by the international development partners selected programs were a lso 
introduced targeting various sub-sectors in agriculture .  These range from the 
3 Much of the information were collected whi le acting as a Facil itator for the MAFP Donor's Agriculture 
and Rural Development Meeting in Fuiloro ,  Lospalos, East Timor 3 - 5 March 2005. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 1 7  
provision of agricultural mach inery and equ ipment, improved crop seeds, biological 
weed eradication ,  pi lot projects on agro-forestry and protected areas, l ivestock 
breeding and vaccination to marine resource protection programs.  
Selected agricu ltural schools in  the country wi l l  also soon be under MAFP's 
supervision with the view to strengthen the knowledge capacity of the youth in 
practical agricu ltu re carried out in parallel with other capacity bui ld ing in itiatives at 
the farming community levels .  A research and extension division has also been set 
up to support the policy formulation and i nformation dissemination components of 
the min istry's duty with the search and provision of empi rically valid database4. The 
research component is, in the view of this study, the most critical aspect of any 
agricu ltural development scheme, especial ly in finding innovative ways to use the 
country's l imited resources to support a dynamic yet sustainable agricultural 
development transformation.  
2.2 AN OVE RVIEW O F  T H E  AGRI C U LTU RAL SYST EM 
2.2 . 1  Land, people a n d  agricultu re 
East Timor is a small (approx. 1 4 , 6 10  km2) country with a population of 787,338 
people based on the Suco (vi l lage) Survey in 200 1 5. Selected characteristics of the 
popu lation are presented in  Table 2 . 1  below. 
Geographically, it has d ifficult characteristics to support a highly productive 
agricu ltu re system with rugged , erosion-prone terrain and poor soils in large parts of 
the territory. Of the 1 ,460,938 hectares of land area,  35% are located at more than 
500 m latitude , 44% are in the 1 00 - 500 m a ltitude range, and only 2 1  % are 
lowlands under 1 00 m altitude (Keefer, 2000). 
4 MAFP has produced a website contain ing substantial information about the sector's main activities, 
providing especially a significant number of l i terature sources (see www .qov.east-timor.orq/MAFF/) 
5 Provisional count of 2004 population ind icates an increase to 924,642 people. For detai ls see 
www .dne.mopf.qov.tp. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 1 8  
Table 2 . 1  Selected characteristics of East Timor's population 
East East East Asia Low Population Timor Timor Indonesia & Pacific Income 2001 1 999 Countries 
Po�ulation (millions) 0.79 0.91 2 10  1 ,855 2,460 
Population density (people per 
square km) 55 60 1 1 6 1 1 6 76 
U rban population (% of total 
population) 24 1 1  41 35 32 
Population ages 0 - 14 (% of 
total population) 49 41 31 27 37 
Population ages 1 5  - 64 (% 
total population) 49 57 64 67 59 
Population ages 65 and older 
. (% of total population) 2 2 5 6 4 
Dependency ratio (% of 
dependents to working age) 93 77 54 50 70 
Life expectancy at birth (years) 57 56 66 69 59 
Female 59 58 68 7 1  60 
Male 56 54 64 67 58 
Source: GoTL (2003) ,  Timor Leste , Poverty in a New Nation : Analysis for Action 
A mountainous spine transverses the territory from west to east (refer to the map in 
Appendix 2 . 1) resu lting in two rainfa l l  patterns in the northern and southern coasts of 
the divide as described in Table 2 .2 .  Diverse microcl imates occur with a ltitude such 
that rai nfal l  i ntensity, wind velocity, and cloud generally increase with the increase in 
altitude whi le d irect solar rad iation and ambient temperature decrease . A general 
pattern of adaptive agricultural production can be observed as result of these 
microclimatic d ifferences where rice is  commonly cropped in warmer lowland areas, 
maize in  the med ium a ltitudes , and root crops are found at higher a ltitudes (World 
Bank, 2002 , Keefer, 2000). 
Permanently cropped land, such as house gardens and rice fields ,  is recogn ized by 
custom as individual property. Ownership of the vast majority of land,  however, is 
determined by clan-inherited usufruct rights under traditional customary law. 
Traditional land rights are secured by the recogn ition of neighbouring community 
group members and the borders marked by natural objects such as river, mounta in ,  
and rocks or  man-made erected wood or tree fences (Saldanha and Guterres, 
2002) .  The in it ial right of i nd igenous people/clans can be passed on to their  heirs. 
Those who are not members of the group that own the land only have rights over 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 1 9  
produce from the land and such a land ownership system fosters shifting cu ltivation 
which causes land fertil ity to decrease (Xavier, 2001 ) . 
Table 2 .2 Agro-cl imatic zones in East Timor 
Altitude Annual Months of Zones Features Rainfal l  (m) (mm) Rain 
(i) Mono-modal rainfall pattern (NW monsoon) 
A Northern Lowlands (coastal lands) - < 1 00 < 1 000 4 - 5  1 47 ,045 ha = 10% (Nov - March) 
B Northern Slopes (land in northern 1 00 - 500 1 000 - 5 - 6  h i l ls) - 336,627 ha = 23% 1 500 (Oct - March) 
Northern Highlands (hi l ls and 6 - 7  C mountains in the north) - 290,553 ha > 500 > 1 500 (Oct - April) = 20% 
(ii) Bi-modal rainfall pattern (NW monsoon & SE trades) 
Southern Highlands (hi l ls and 9 
D mountains in the south) - 21 5,021 ha > 500 > 2000 (Nov - Apri l ;  
= 1 5% May - July) 
Southern Slopes (hi l l  lands in the 1 500 - 8 E 1 00 - 500 ( Nov - March; south) - 304,981 ha = 21 % 2000 May - July) 
Southern Lowlands (costal land in the Around 7 - 8  F < 1 00 (Nov - March; south) - 1 66,700 ha = 1 1  % 1 000 May - July) 
Source: (Keefer, 2000, Fox, 200 1 ) 
Saldanha and Guterres (2002) ,  studying the relationship between customary land 
ownership and agricultural  production in  two sub-d istricts of East Timor, reported 
that the customary land ownership is insign ificantly affected by the administrative 
regimes of Portugal ,  I ndonesia ,  and the United Nations. I n  other words,  the 
customary ownership has provided some sort of land tenure security over a period of 
centuries. However, they found no relationship between the security of land 
ownership under customary law and agricultural production,  presumably due to the 
subsistence nature of the agricultural production and the unava ilabi l ity of 
transactions with in the customary land ownership system . A case study with a 
simi lar finding was reported by Saeed ( 1 982) in Pakistan ,  i nvestigating the reasons 
for the fai l ing publ ic policies designed to al leviate poverty. The study suggests that 
the absence of an economic force that should encourage land ownership by its 
cultivators is a key factor responsible for the poor economic condition of the working 
rural household that form the majority of the rural popu lation . 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 20 
I n  East Timorese context, land and environment are deeply rooted in the whole 
cu ltural  setting where environment is regarded not only as the l iving area for a 
certain clan but more than that it is the place where the history of the existing l ineage 
can be found,  the site of ancestors' graveyards,  the place of a clan 's sacred a ltar 
and other cosmological ly related affa irs (Soares, 2001 ) (Figure 2. 1 ) . Cu lture,  i n  
Timorese perception accord ing to Soares ,  is a lso the means to take care of the 
"environment" , and the latter may not exist should cultu re not be respected . Both are 
interrelated and are the very means for human survival .  I t  is probably s imi lar to 
Jhum, a trad itional farming practice considered as a way of l ife and cu lture for the 
tribal communities in parts of I ndia and Bang ladesh (Choudhury and Sundriya l ,  
2003). 
Altar, ritual centre, cosmos 
Houses of l i neage 
Cultivation area, gardens 
Bush , herd ing camps 
� 
Male world 
Graveyards, border areas 
Figure 2 . 1  The East Timorese perception of land (Soares, 2001 ) 
How the slash and burn practice general ly employed for land clearing and 
subsistence farming prevai ls as a result of the shortage of labour and efforts , or the 
need , to "save time and energy" (Soares, 2001 ) is viewed with in this cu ltu ral mindset 
is a matter of great debate. The view of traditional farming systems as generally 
sustainable but modern shifting cu ltivation practices being increasingly regarded as 
degradative to the environment has long and widely been studied (Altieri , 2002, 
Chidumayo, 1 987, Alegre and Cassel ,  1 996, Brady, 1 996, Arnason et a l . ,  1 982, 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Implications 21 
Albers and Goldbach, 2000) .  This case study wi l l  be further explored later in this 
chapter. 
2.2.2 Agricultural production systems 
The main production systems are as fol lows: 
a. Upland mixed-crop cultivation 
This can be found predominantly everywhere in the uplands ,  general ly h i l ly and 
sloped contours,  with rainfal l  as the sole source of water. The main crops grown 
are cassava (Manihot esculenta) , sweet potato (Ipomoea batatas) , maize (Zea 
mays L.) and upland rice (Oryza sativa) , i ntercropped with vegetables and 
legumes such as squash (Cucurbita) , pumpkin (Cucurbita spp.) , mung beans 
(Vigna radiata) , red beans (Vigna angularis) , green peas (P.sativum) , etc . .  The 
vi l lage survey carried out in 2001 reveals the coverage of root / tuber crops and 
maize crop production areas as shown in Append ices 2 .2 and 2 . 3 ,  respectively 
(GoTL,  2001 ) . Fruit trees such as banana, citrus ,  papaya , mango, coconut and 
jackfru it are also commonly found in the gardens . Al l  these types of vegetation 
are cropped surrounding the housing section which is commonly situated in an 
elevated area. I n  this case Figure 2 . 1  cou ld best viewed as a downward looking 
contour of a mounta in .  Exception may be made to coffee growing areas such as 
Liqu iya ,  Ermera ,  Aileu and Ainaro where coffee trees were planted and 
uncontrol lably grown i nto aged and neglected plantations, resu lting in 
vulnerabi l ity to d isease (currently shade trees but also potentia l ly coffee bushes) 
and low yields (Curnow, 2003 , Old and Cristovao, 2003) and leaving very l ittle 
room for intercropping with other commod ity crops. 
b. Rice cultivation 
The bulk of the rice production comes from wetland rice mono-cropping in the 
valley terraces and in the al luvial soils and river basins in the lowlands.  There a re 
however, small scale rice production systems in the uplands as mentioned 
above . The rice production coverage a rea accord ing to the vil lage survey in 2001 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Implications 22 
(GoTL, 2001 ) is described in Appendix 2 .4 .  Based on the reliabi l ity of water 
supply the fol lowing rice cropping systems can be observed : 
( i )  Upland rice cultivation. Unl ike in  wet cultivation where rice is broadcast or 
transplanted into pudd led soi l ,  upland rice is grown in dry soil cond itions  thus 
it is commonly known as dry-land paddy rice (arroz sequeiro in Portuguese 
and padi gogo i n  I ndonesian language) .  It is  part of a diversified cropp ing 
system for subsistence produced on a small scale in areas with abundant 
rainfa l l .  Depend ing on the topography and contour rel ief down the areas 
surrounding the housing base the fol lowing types of variation can be found: 
Paddy rice in terraces. For water conservation and irrigation pu rposes 
these terraces are typical ly located on fortified slopes or gently undu lating 
plains in areas with abundant rainfa l l  where possibi l ity exists for micro­
catchments of ra infa l l  water runoff. The embankments surrounding the 
plots help conserve the soil moisture over the cropping season which is 
l imited to one crop per year and soil fertil ity is restored through fal lowing 
for the rest of the year. In certa in areas, grass and fodder plants are grown 
post-rice for animal grazing . 
Rice cultivation along the stream / spring catchment areas. Simi lar to the 
terraces mentioned above but with an extended period of water supply 
from the streams and mountain springs.  It is common in areas with 
abundant and evenly distributed rainfall throughout the rainy season . The 
streams and springs, supported by a sufficiently recharged ground water­
table, wi l l  continue to supply water flow for one or two months after the wet 
season. This provides scope for a better crop sequence or diversification 
as well as a prolonged used of land for productive cropping.  
( i i )  Irrigated rice cultivation. This is the main source of rice production in  the 
country typical ly found on the flood plains of river basins in lowland areas. 
Traditional or techn ical irrigation schemes, channel l ing water from the 
seasonal or perennial river flows, provide water supply for this cropping 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 23 
system . Appendix 2.5 provides a visual presentation of areas covered by 
irrigation in East Timor based on the vi l lage survey in 2001 (GoTL, 200 1 ) .  
There are areas where the water supply is rel iable to support more than one 
cropping season provided timely harvest, post-harvest and the subsequent 
land preparation activities are secured . A major constraint towards this aim is 
the lack of power input (man ,  animal ,  and machinery) to support i ntensive 
crop production . This is a major component, in terms of pol icy and resource 
al location, in the current food crop division of MAFP as well as during the 
previous regimes . Basic infrastructure such as irrigation schemes, large scale 
mechanization, and the introduction of chemical inputs and a series of rice 
and cereal sufficiency driven pol icies were devoted to this d ivision .  
c .  Home gardens. Th is type of agricu ltural production i s  perhaps the system most 
commonly practiced by every (farming )  household , both in the uplands (upland 
mixed cropping described above) and the lowlands . A huge variety of rain-fed 
crops are grown simultaneously in the garden from staple food such as maize ,  
cassava , and sweet potato, vegetables, and fru it crops as  mentioned earl ier for 
the upland mixed-cropping system .  This system contributes largely to the root 
and tuber crops and maize production described earlier in  Appendices 2 .2  and 
2 .3 .  Some people with expert knowledge may also grow med icinal plants as well 
as spice crops in their  backyard gardens whi le they a lso use specific spots in the 
area to raise domestic animals from poultry to pigs, goats , and cattle6. 
6 It was widely campaigned during Indonesian times, dupl icating efforts implemented elsewhere in 
I ndonesia, to use the gardens as source for traditional medicine (' l iving pharmacies) and food 
production (' l iving kitchen ' )  so as to ease the burden of having to purchase these products from the 
market. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 
PASSION FRUIT Passiflora spp. CoIocuia $pp. 
PAPAYA CA1HUA PACAY SQUASH 
Cyclanthera Inga feuillei 
pedata. 
2 
3 
MAIZE SWEET POTATO 
Figure 2 .2  Ecological profile and production level of tropica l  home gardens 
(Ninez, 1 987) 
24 
The home gardens are typically characterized by vegetation 'stories' or layers , 
imitating the tropical forest structure as described by Niiiez ( 1 987). The top 
'storey' consists of tall trees forming a protective canopy against tropical sun and 
torrentia l  rains .  It supplies nourishment (mainly fru it), and adds to spontaneous 
soil regeneration (fal len leaves) whi le maintaining relatively constant moisture 
and temperature levels . A lower layer features staple and fruit production (e .g .  
Musa spp . ,  mango, papaya and Inga spp .  the most common in the tropics) ,  
followed by bush-level growth (e.g .  cassava , maize ,  peppers, tomatoes, beans) 
in a third layer. In-ground and ground-covering species (roots and tubers and 
Cucurbitacea) form the last layer, whi le cl imbing species transverse the lower 
stories (Figure 2.2). 
Home gardens possess a number of sustainabi l ity attributes, with regard not o nly 
to their abi l ity to meet a number of farmers' needs without negatively affecting the 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 25 
resource base, and in many cases even improving it, but also to their potential to 
meet several economic, socia l ,  ecological  and institutional cond itions which 
contribute to their sustainabi l ity (Torquebiau , 1 992) .  
The main attributes that have been identified as contributing to the sustainabi lity 
of these systems are biophysical advantages such as efficient nutrient cycl ing 
offered by mu lti-species composition , conservation of bio-cu ltu ral d iversity, 
product d iversification as wel l  as non-market values of products and services, 
and social and cultural values including the opportunity for gender equal ity in 
managing the systems (Kumar and Na ir, 2004) .  A 3-year home garden study in 
Vietnam covering four  d ifferent ecosystems concludes that richness and stabi l ity 
of home gardens make them important sites for in situ conservation with in  eco­
zones,  and great scope exists for the util ization of th is i nformation to improve 
nutritional and income-generating development projects (Trinh et a l . ,  2003) .  
The crop production calendar for major staple foods in  East Timor generally follows 
the pattern described in Figure 2 .3 .  
d .  Tree crops cultivation. Coffee plantations are typical for this kind of  crop 
cu ltivation dominating the central and western upland areas of Ainaro,  Aileu , 
Liqu ica, and Ermera7 . Attempts have been made to expand this cultivation to 
commercially competitive crops such as cocoa , vani l la ,  and cloves .  Coconut is 
another major tree commodity trad itional ly grown in plantation 'scale' in a reas of 
eastern d istricts of Baucau and Viqueque.  Copra , although not in a big scale ,  has 
long been an export commod ity since Portuguese times .  The coconut oil is 
currently at the in itial phase of exportation as wel l .  Large scale cultivation projects 
of tree and fru it crops were attempted du ring I ndonesian administration covering a 
wide area of the territory with m ixed results .  These were specifical ly targeted at 
introducing new varieties of citrus ,  mango, banana ,  papaya , and other tropical and 
sub-tropical fru its. Cashew nut plantations were also introduced in the southern 
7 Coffee is the most important export commodity providing $4.8 mi l l ion of the $6 mil l ion export 
earn ings in 2002 (with the exception of oil and gas) and a significant source of seasonal 
employment (see MAFP, 2004). See also Piedade (2003) for an overview of the coffee industry. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 26 
areas with very little success ,  mainly due to minimal government control and 
security reasons. 
Harvest: 
F igure 2 .3  East Timor Crop Calendar 
e .  Collection of forest products. Forests provide not only timber for housing and 
firewood for cooking but they are also place for potential market products such as 
tamarind (Tamarindus indica) and candlenut (A/eurites mo/ucana) as  wel l as 
staple food crops such as sago, yams, wild beans,  etc. In add ition , sandalwood 
(Santa/um a/bum) has been for centuries provid ing a s ignificant share in export 
revenues. There also non-timber forest products with potential for domestic and 
export markets such as honey, bamboo, and rattan .  I t  also gives space for 
occasional grazing for domestic animals such as buffaloes and horses ,  but it is 
primari ly the natural ecosystem for wild flora and fauna as essential components 
of the biod iversityB. I t  is argued that this very precious resource has undergone a 
significant degree of depletion over the years . 
8 East Timor is located in the "Wall ace Zone" where the Indo-Malaysian and Australasian flora and 
fauna overlap, thus provid ing it with an area of great biological d iversity (see MAFP, 2004). It is 
therefore vitally important that the forests should be properly managed to protect th is valuable 
biod iversity. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 27 
f. Livestock production9. This is a sub-sector of the agriculture industry provid ing 
significant power source for farming , nutrient source for plants through l ivestock 
manure as well as protein source for the popu lation . Water buffaloes a re 
commonly used for rencah (a system of herding an imals in flooded rice fie lds to 
puddle the soil in preparation for rice planting) apart from being used for g ift 
exchanges during cu ltural encounters. Cattle a lso, l ike goats in provid ing meat 
and mi lk ,  are being trained in some parts of the country to plough the soil for plant 
cu ltivation . Until recently, horses are occasional ly being used , apart for 
transportation purposes ,  to thresh the paddy rice post-harvest. Pou ltry (not i n  a 
commercial sense), the cheapest affordable protein source , can be found in 
a lmost every household i n  rural and peri-urban commun ities . 
g .  Off-shore and inland fish production 10. Communities in coastal zones can afford 
the lUXUry of supplementing their d iet with sea food products. However, despite 
l iving right close to the beach , East Timorese fishermen are not tra ined or wel l­
equipped to explore the much more resourceful deep sea potentia ls .  On the 
contrary, the production is main ly derived from a short catchment zone us ing 
traditional fishing gear a imed at meeting the immed iate needs of the popu lation .  
There are however on-going efforts through bi lateral co-operations to take fu l l 
advantage of the sea resources and to increase national domestic revenue.  
Despite promising, concerns are that this cou ld resu lt in an unbalanced share 
both i n  the production and in the revenue d istribution given the currently low level 
of human scientific resources and ski l l  abi l ity in this area. Sti l l  in view of 
d iversifying rather than maximizing production , efforts are also being placed at 
reviving the in land fish  ponds  once introduced during the I ndonesian 
administration.  Fresh water fish, natural ly avai lable in  the lakes and rivers and 
through these fish ponds wil l inevitably enrich the a l ready diversified food and 
nutrition sources of the farming communities. 
9 See MAFP (2004) for a summarized presentation of MAFP's pol icies and strategies for l ivestock 
development. 
10 More on fisheries development see MAFP (2004). 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 28 
The agricu ltu ra l  production systems described above overlap one another or 
mutual ly co-exist as such that a single household may be i nvolved in more than two 
production systems. The a im is to divers ify production , balance seasonal 
requ irements, and spread the risk of crop fai lure (MAFP, 2004) .  The operation of 
these systems however, has been severely d isrupted due to the d islocation ,  
resettlement, and migration of communities especially during I ndonesian times and 
during the tragic transition towards independence (WB-JAM , 1 999). 
Overal l ,  crop cultivation dominates the agricu lture sector, with l ivestock, fisheries ,  
and forestry contributing a much smaller role (GoTL, 2003). Although there is scope 
to increase food production by increasing the cu ltivation a rea , the low level of 
technology and inputs used currently, strongly favour an intensive approach based 
on enhanced and balanced use of ferti l izers , h igher yield i ng seed varieties and 
i rrigation (MAFP ,  2004) .  MAFP real izes that due to the growing  economic needs of 
the population it is necessary that the focus of production strategies should move 
beyond commod ity crops to cash crops with h igher margins such as cashew nuts, 
mangos, spices, vani l la ,  pineapples, passion fru it, guavas ,  sandalwood and cut 
flowers . In add ition, this should be fol lowed by establ ishing small processing 
industries such as for producing roasted nuts, mango pulp, guava jam, and passion 
fru it concentrate (MAFP, 2004). 
The discussion of the agricu ltu ral production systems wil l  be deducted to more 
specific topics later in the next chapters . How these production systems evolve i n  a 
rural community setting where trad itional knowledge is often ignored and a l ienated 
rather than transformed by modern scientific know-how through agricultural  
mechanization is d iscussed in Chapter 3 .  Another important aspect is how these 
production systems contribute to the food security of the country's population which 
wi l l  be the focus of d iscussion of Chapter 4 .  The whole analysis wi l l  be enl ightened 
by the descriptive analysis in the next sections. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustai nabi l ity Impl ications 
2.2.3 Perce ived issues and problems 
29 
The people in East Timor l ive in d ifferent ecosystem types, facing varying natural 
and man-made conditions. Around the time of independence in 2002 and prior to the 
elections the local-level concerns were much more focused on the economy and 
basic human needs than on the pol itical situation . A survey revealed that about 41 
percent of East Timorese view infrastructure issues as u rgent local needs, and 1 9  
percent rate items such a s  water supply, roads, markets, communication and 
electricity as the top priority. One third of the e lectorate (33 percent) cites food 
security as one of the top two local problems, and almost al l  of those say it is the 
primary problem (The Asia Foundation,  2002) 
Another su rvey carried out by Sandlund et a l .  (200 1 )  in  ru ral and urban areas of East 
Timor around that t ime also identified particular issues and problems some of wh ich 
are d iscussed below: 
(i) Water quality and availability 
The avai labi l ity of clean water for domestic and non-domestic use is a general 
problem found in the rural and urban areas. In most cases, people depend on 
surface water and water qual ity is normal ly particu larly poor in the rainy season. 
Access to water is obviously more d ifficu lt in the dry season (Sandlund et al . ,  200 1 ) . 
This issue has been the focus of programs by many international agencies such as 
UNDP, CARE , and AusAID to mention just a few. Major water supply projects have 
been carried out by UNDP for d istrict town water supply systems of Di l i  (2000-2004) 
and Liqu iya ,  Manatuto, and Lospalos (2002-2003); for irrigation such as the 
rehabi l itation of Lacl6 I rrigation Scheme (2002-2003); and rural water and san itation 
services in Aileu and Baucau (2001 -2003) (GoTL and UNDP,  2005). CARE Canada 
has also been involved in i rrigation rehabi l itation and soi l conservation as wel l as 
rural community water and environmental health projects in East Timor. The latter 
project in particu lar was implemented in 2001 -2004 focusing primarily on poor ru ral 
areas covering 23,808 people in 74 hamlets (www .care.ca) .  AusAID through Water 
Supply and Sanitation Project (WSSP) have helped re-establ ish the community 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 30 
based water supply and sanitation systems in ru ral  d istricts and the provision of 
technical experts in Viqueque,  Bobonaro, and Coval ima from 2002-2005. The total 
beneficiaries on completion of th is  project are estimated at 66,000 people in 77 
communities (www .ausaid .gov.au) .  
It is yet to be assessed how these projects have helped the communities to f i  nd 
solutions for their water supply and sanitation needs in the med ium to long run .  Of 
major concern is the operation and maintenance by the commun ities of the faci l ities 
a l ready in place ,  the expansion of the projects to cover popu lation needs in much 
remote areas , and the long term commitment from the funding agencies. Estimates 
in 2003 suggest that overal l  about 55 percent of the population has access to safe 
water. I t  is over 70 percent in u rban areas , but only around 50 percent in  highland 
and rural areas of  the country (UN ICEF ,  2003). 
A study by Cruz et al. (2005) in two sub-districts of Viqueque, a project area of 
AusAIDIWSSP,  reveals that water supply cond itions at household level are relatively 
poor both in Uatucarbau and Viqueque .  Only 34% and 44% of the population in 
Uatucarbau use enough water (�30 l iter/capita/day) du ring rainy season and dry 
season respectively. Simi larly in Viqueque, only 25% of the respondents have 
enough water during ra iny season while during dry season the number decreases to 
24%. Comparatively, the level of external assistance i n  water supply to Viqueque 
(43%) is better than to Uatucarbau (33%).  Due to its closer d istance to Di l i ,  
Viqueque has a better position and received more water supply aid as compared to 
the remote sub-district of Uatucarbau .  
(ii) Agricultural production and market imperfections 
Many reported issues related to agricu ltural  production are in  fact legacy effects of 
the 1 999 troubles. Many arable lands are left underuti l ised due to the lack of draught 
animals,  crop seeds ,  and ferti l izers , which are hardly affordable by local popu lations.  
I n  some a reas, farmers prefer to be paid in cash rather than food implemented 
through WFP's "Food for Work" program so they could be able to invest in  seeds, 
ferti l isers and tools to increase their agricu ltural output and become economica l ly 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 31  
self-sustained . I n  other parts, despite being primarily subsistent farmers,  they are 
wi l l ing to produce more, but there is no market outlet for surplus production . 
Moreover, free provision and/or avai lability of cheap imported food especially rice 
consequently undermines local markets (Sandlund et a I . ,  2001 ) .  
Meanwhile a government document reports a series of promising outcomes to boost 
the domestic production through mu lt ipl ication of qual ity seeds .  Through the AMCAP 
project of the UNDP it was able to pi lot multipl ication of seeds (rice ,  maize, soybean, 
mung bean) on 71  hectares in  Manatuto yielding 1 86 .5  tonnes of high qual ity seeds 
and in Natarbora (a resourcefu l agricultu re area in the southern lowlands of 
Manatuto d istrict) seed production i ncreased by 400%.  I n  addition, a large part of the 
hand ti l lers orig inal ly d istributed to CNRT (the Timorese National Resistance 
Council) have been repai red and relocated to MAFP and three mechan ical 
workshops with spare parts procurement founded by 2004 (GoTL and UNDP,  2005). 
The sloping nature of the landscape also influences the economy of the upland 
communities. Market access is often l imited because it costs too much to develop 
and maintain infrastructure where slopes are steep and topography undu lates 
(Jackson and Scherr, 1 995). Decreasing number of agricu ltu re labourers due  to 
urbanization ,  particu larly to Di l i  and other d istrict towns, is another major issue 
affecting agricultural production in  rural areas. The impact of th is migration is that the 
vi l lages are drained of labour, thus reducing the capacity to plant and harvest 
leading to much of the land resources being underuti l ized (Sandlund et a I . ,  200 1 ) . 
The search for job opportunities, leisure ,  and quick money is generally the cau se for 
the rural youth to move into cities, and to quite often be left with despair when 
confronted with a very competitive labour market in the cities d ue to the 'openness' 
of the country brought about by g lobal ization .  
(iii) Deforestation and land degradation 
Sandlung et a l .  (2001 ) reported the damage by torrential rains and flash floods 
identified in almost al l  the d istricts causing severe soi l erosion and landslides in the 
uplands and d isaster floods in the lowland areas. The study found some people in 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Implications 32 
the community related this problem to the deforestation on the steep h i l lsides as the 
cause. Others, however, do not regard the removal of forest as a problem and seem 
reluctant to take preventive action to arrest soil erosion and other forms of soi l 
degradation.  The lack of market access in upland areas may also influence whether 
land users are i nclined to practice land conservation and may constra in  their abi l ity 
to use the land sustainably (Jackson and Scherr, 1 995) .  
The causes of erosion as a major source of soi l  degradation and ways to remedy the 
impacts on the social environment of East Timor have always been a long time 
concern . The issue was identified as a major problem since the t ime the Portuguese 
colonial regime began a seriously planned economic development of its then 
overseas province (Gonyalves, 1 963) .  The problem persisted with l ittle or no 
remediation towards the end of the regime. The agriculture development during the 
last two decades of the Portuguese rule ( 1 953- 1 975) is well summarized by Reis 
(2000) . 
Government reports indicate some efforts being undertaken with regards to 
reforestation . The government has embarked on pi loting upland farming techniques 
(based on the principles of soi l and water conservation and agro-forestry) i n  23 
locations covering 16 .9 hectares of farm land (GoTL and UNDP,  2005) .  The 
University of Hawai i  (c . q .  Col lege of Tropical Agriculture and Human Resources) has 
also for some time been offering advice in this field (Friday, 2003 ,  Friday, 2004).  A 
literature synthesis on strategies and policies to address the issue of soil 
conservation compatible with East Timor's conditions can be found in Gusmao's 
(2003) study.  Some of the soil and water conservation techniques are not new and 
have been introduced in  the past by national NGO's such as PUSLAWITA and 
ETADEP in the hi l ls of Di l i  and by other NGOs in other parts of the country 1 1 .  A 
proposal on land reform in East Timor has been advanced in order to prevent further 
1 1  This information is drawn mainly from personal experience and active involvement in  promoting 
social reforestation (among other activities) in the sub-d istrict of Maubara - Liquiya wh i le serving as 
an NGO worker under the Satya Wacana Christian Un iversity commun ity development program 
( 1 991 - 1 995). 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 33 
land degradation including the redistribution of land and land titl ing for tenure 
security (UNDP,  2006). 
Based on case materials Fujisaka ( 1 994) found that farmer adoption of innovative 
conservation practices has been minimal at the community level . He argued that 
farmers do not adopt because they do not face the problem targeted by the 
innovation , farmer practice is equal to or better than the innovation,  the innovation 
does not work, extension fai ls ,  the innovation costs too much , and 'social '  factors . 
These reasons may be of great relevance to the case of East Timor. Despite 
acknowledging the existence of some of the root causes of soil degradation, the 
extent to which the soil and the environment has been degraded is sti l l  largely 
unknown. It was generally argued in  the past that research of this kind takes time 
and a large sum of financial resources the government cannot afford . Therefore, it 
was not uncommon to find statistical reports on certain socio-economic indicators 
largely avai lable as opposed to the lack of environmental health stud ies or soi l 
quality assessment reports (Viegas, 2002) .  I t  is  therefore imperative that MAFP is 
allocated with sufficient funding to gradual ly improve its resources capabil ity for 
research and development in this very important area . 
Evidence from other countries and MAFP's own l imited human resources, provide 
compel l ing reasons to suggest a requirement for more farmer participatory research 
(Poudel et a l . ,  2000 , Astatke et al . ,  2003, Sanginga et a l . ,  2004, Fuj isaka , 1 989). It is 
a lso best to l ink science research with pol icy research where researchers are 
requ ired to be: ( i )  concerned at many scales , from local to global ;  ( i i )  able to predict 
and a l low for the influences of technical change; ( i i i )  able to model b iophysical 
processes and behavioural norms and responses in an integrated way (Hazell and 
Wood , 2000). The empirical  facts drawn from these research programmes wi l l  better 
inform and provide the base upon which proper policies cou ld be designed and 
appropriate measures taken towards achieving a sustainable land use and forest 
management. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Implications 
2.2.4 Land use pol icies and p roductivity 
34 
Given the prevai l ing conditions on one hand and the developmental visions laid 
ahead as described earl ier on the other, the tasks to fi l l  the gap between these two 
ends pose enormous risks and challenges. Attempts to modernize East Timorese 
agriculture have been overwhelmingly great in  the recent past but they failed to bring 
a decent transformation to the agricultural production practices in the country. I t  is 
argued that the efforts to stimulate more intensive farming systems in a particu lar 
region , and more broad ly to al leviate rural poverty and improve food security, must 
be based on a solid understand ing of rural land use and livelihood strategies, and 
the factors that drive them (Shriar, 2002). 
Experiences in many parts of the world provide a large body of evidence on the 
arduous tasks of designing policies and strategies to reconcile the often confl ict ing 
aspects of a productive and sustainable agricu ltural production system (Shriar, 200 1 , 
Shriar, 2002 , Saeed , 2000, Sanchez and Leakey, 1 997 , Pichon , 1 996, P ichon et a I . ,  
2002) .  Many Asian countries while adopting land use policies to increase agricu ltu ral 
output have indeed created what is known as a green revolution resulting in 
increased food production. However, they have not created any lasting 
improvements in food security (Saeed , 2000) .  On the contrary, these pol icies have 
precipitated trends that point towards an impending decl ine in food production . As 
much as they represented a wel l-intentioned effort to improve food supply for 
ind igenous use and agricultural  output for export, these policies were implemented 
without intimately understanding the societal and ecolog ical dynamics that 
precipitated a condition of shortage in the first place (Saeed , 2000). 
I n  sub-Saharan Africa , the per capita food production continues to decrease even 
though this region compares favourably with other tropical regions in terms of 
climate and soil resources. Sanchez and Leaky ( 1 997) attribute this to (i) the need 
for an enabl ing pol icy environment that favours smallholder rural development; ( i i )  
the need to tackle soil fert i l ity depletion as the fundamental biophysical constraint to 
food security and ( i i i )  the need for more intensive and diverse land use ,  based on the 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 35 
domestication of indigenous trees to produce high va lue products while increasing 
agro-ecosystem resi l ience . It is assumed that this decrease is a lso due the lack of 
population control . 
Frontier regions feature some d istinct characteristics that have a profound i nfluence 
on the strategies of farmers therein .  These characteristics include an abundance of 
land but relatively l imited labour, land tenure insecurity, poor market cond itions and 
infrastructure , l im ited presence of research , extension and other agricultural 
services ,  and a low level of community and farmer organization (Shriar, 2002). In the 
Amazon frontier, P ichon's ( 1 996) study seeks to increase understanding of the micro 
and macro-level forces that propel land-use decisions in  the Amazon and offer 
insights about how farmers' land-use decisions may be altered to bring about forms 
of resource use that are consistent with the constra ints and opportunities of the 
frontier environment. The analysis suggests that to be effective, any policy or 
technology-based effort on the part of governments or researchers to alter colonist 
land-use systems must begin to look systematically at the production systems of 
agricultural colonist popu lations a lready present in  frontier environments . This 
knowledge is  essential to understand the social and economic factors affecting 
present land use and choice of technology. It is also important for understanding 
factors influencing farmers' demand for more optimal systems of land use that are 
consistent with varying agro-ecological potentials, demographic situations ,  and the 
management capacity of the farmer. 
A critical chal lenge for both forest conservation and human welfare is to i nduce a 
more rapid process of agricultural intens ification, and thereby l imit the degree to 
which it occurs out of desperation,  caused by a scarcity of forest land on which to 
practice swidden or shifting cu ltivation for example. I n  add ition to creating off-farm 
employment opportunities, a key objective should be to foster the cond itions and 
develop the systems that wi l l  make it economical ly feasible and possible for farmers 
to i ntensify i n  ways that are agronomically and environmenta lly sustainable . This can 
help them l im it pressure on remaining forest, both on and off their properties (Shriar, 
2002) .  
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 36 
Saeed (2000) ,  translating the interaction between agricultural management policies 
and the agro-ecologica l system mechanisms into a system dynamics model ,  
foresees a possible sharp decl ine in  agricu ltural production across the board in the 
absence of sustainable agricultural technolog ies. Unfortunately, sustainable 
agricultural technologies, even when available ,  wil l  not be put into practice as long 
as the technological and economic considerations governing agricu ltural pol icy 
remain d ivorced from environmental information concerning land resources and soil 
ecology. Short-term private gains in production will be sought at the cost of the 
decay of the common resource system that sustains agriculture.  Thus, an 
institutional framework needs to be created , so that appropriate ecological 
information becomes a regular basis for the economic decisions leading to 
appropriate technological choices.  
2 . 3  S H I FTI N G  CU LTIVAT I O N  WITH S LASH AND B U RN 
Shifting cultivation continues as the economic mainstay of upland communities in 
many developing countries worldwide (Rasu l and Thapa , 2004 , Dendi et a l . ,  2005,  
Porro, 2005, Sommer et al . ,  2004) .  However, the conditions that historically 
underpinned the sustainabi l ity of rotations with long fal lows have largely vanished 
(Sunderl in ,  1 997). The imperative to evolve more permanent forms of land use has 
been exacerbated by rapid population growth, gazettement of remnant wild lands into 
protected areas, and state pol icies to sedentarize agricu lture and discourage the use 
of fal lows and fire (Cairns and Garrity, 1 999) .  
There are many compel l ing examples where shifting cu ltivators have successfu lly 
managed local resources to solve local problems.  Technical approaches to 
stabi l izing and improving productivity of shifting cu ltivation systems have not been 
notably successful (Cairns and Garrity ,  1 999, Greenland , 1 975) .  Farmer rejection of 
researcher-driven solutions has led to greater recognition of farmer constraints 
(Fujisaka ,  1 994). This experience underl ined the need for participatory, on-farm 
research approaches to identify solutions (Hazell and Wood , 2000 , Astatke et a l . ,  
2003, Poudel et a l . ,  2000, Sanginga et a l . ,  2004) .  The challenge i s  to document and 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 37 
evaluate ind igenous strategies for intensification of sh ifting cu ltivation through a 
process of research and development. This process involves identification of 
promising indigenous practices , characterization of the practices, val idation of the 
uti l ity of the practice for other commun ities , extrapolation to other locations ,  
verification with key farmers ,  and wide-sca le extension (Cairns and Garrity, 1 999). 
2.3.1 U nderstanding shifting cultivation 
Shifting cu ltivation ,  a lso known as swidden cultivation or/and s lash and burn by its 
method of land clearing , describes an act of removing a l l  the vegetation in a certain 
area by slash ing ,  drying and burning them in-situ for cropping pu rposes in rotation 
with a reasonably long fallow period . It involves three basic components (Kleinman 
et a I . ,  1 995): ( i ) conversion;  ( i i )  cropping ; ( i i i )  fal low . During the conversion stage , 
slashing and burning serve to remove shad ing canopies, reduce pest competition ,  
and help releasing nutrients from the stored biomass and make them avai lable for 
the crops (Kleinman et aI . ,  1 995) .  Cropping practices vary depending on the needs ,  
whether for subsistence o r  cash/budget cropping or both (Ninez, 1 987) .  Fallow is  a 
lengthy period after cropping designed to halt degradation and restore soil ferti l ity 
(Kleinman et aI . ,  1 995) by replenishing soi l organic matter, thereby improving soil 
structure and protecting the soil from erosion and excessive water run-off (Brady, 
1 996) .  
After hundreds of years as a sustainable form of land use ,  shifting cultivation has 
been mal igned as i nefficient and as a major cause of irreversible damage to tropica l  
ecosystems (Albers and Goldbach , 2000) .  I t  i s  widely recogn ised however, that 
under certain demographic conditions, shifting cultivation is a susta inable system 
proven by its long history of adherence in many places around the world by local 
farming communities (Brady, 1 996 , Kle inman et aI . ,  1 995). Only when land use 
pressure increases due to increases in population densities and fal low periods are 
shortened (Cramb , 1 993) or shifting cultivation is intensified (Arnason et aI . ,  1 982) 
does it run the risk of degrading the soil qual ity and productivity. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 38 
The intensification of land use by shift ing Maya agriculturists in Bel ize, Central  
America, has led to a decl ine in soil fertil ity and crop yields. Examination of eleven 
nutrients in crop plants and soil ,  and changes in  nutrient levels with the length of the 
cropping period indicated that phosphorus  was the l imiting factor for plant growth . 
Physica l  analyses of the soil and visual evidence suggested that erosion is  a 
contributing factor to decl in ing soil qual ity (Arnason et a l . ,  1 982). This is  one of the 
most compel l ing reasons for a change from slash-and-burn to continuously cropped 
agricu ltural systems in heavily populated areas in the humid tropics (Alegre and 
Cassel , 1 996) .  Publ ic pol icies in  Laos for example are set to el iminate slash and 
burn practiced by about 25% of the four m i l l ion people (mainly of rice) on a third of 
the country's cropped area. Weeds, low and possibly decl in ing soil fert i l i ty, 
intensification of the cropping cycle, rats (plus birds ,  wild pigs), and i nsects lowered 
rice yields or reduced system sustainabi l ity (Fuj isaka , 1 991 ). 
As summarized by Sunderl in ( 1 997) shifting cu ltivation practices become less 
sustainable as: ( i )  rotation of fa l low plots is shortened or el iminated ; (i i) tradition 
gives way to modernity; ( i i i )  subsistence crops are replaced by cash crops; (iv) fami ly 
capital is replaced by external funding ; and (v) farms are close to urban areas. The 
increased population pressure is also another major factor that contributes to the 
decreased sustainabil ity of shifting cultivation practices (Jarosz, 1 993, Krautkraemer, 
1 994) .  Shifting cu ltivation effects if any do not however appear in  isolation.  As it is 
the case in Laos , the forest ecosystem has been degraded by a series of activities 
such as logging,  burning,  and rice mono-cropping. The potentia Is for environmental 
rehabi l itation through natural succession appear to be minima l .  Farmers cannot 
adopt high labour and cash cost innovations. It is  recommended that an improved 
fallow is needed as an i ntermediate step prior to crop diversification ,  adoption of 
agroforestry technologies, and sedentary agricu lture (Fuj isaka , 1 991 ) .  Well managed 
alternative systems to s lash-and-burn can reduce soil structure deterioration , 
maintain soil ferti l ity, and promote long-term productivity (Alegre and Cassel ,  1 996) .  
I n  East Malaysia, some vi l lages are sti l l  h ighly dependent on shifting cu ltivation ,  
while for others it is very much a spare-time activity. I n  the long term , the 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 39 
sustainabi l ity of al l  these farming systems wil l  depend not only on interna l 
adjustments by the farmers themselves, but on a whole range of developments i n  
the economic envi ronment, such as  increased avai labi l ity of non-farm employment 
and improvements in rural infrastructure (Cramb,  1 993) .  The study reveals that 
shifting cultivation is only one component of a larger farming system and that 
farmers are well aware of the productivity and sustainabi l ity aspects of the whole 
system thus manage shifting cultivation as a means towards that end and not as an  
end itself. 
I n  other cases, shifting cu ltivation is not just concerned with growing staple food for 
sUbsistence l iving but also with cash crops and tree commodities .  In some parts of 
Indonesia, shifting cultivation is used to grow coffee and rubber (Chomitz and 
Griffiths , 1 996). Their study concluded that tree crops rather than the subsistence -
oriented shifting cU ltivation play a major role in deforestation .  Another study in  
I ndonesia , assessing the role of shifting cu ltivation in the loss of rainforests by 
Lawrence et al. ( 1 998) found that the rate of primary forest conversion increased 
dramatical ly from 1 990 to 1 995. This however was due not to soil degradation or 
popu lation growth but rather to changes in the socio-economic and pol itica l 
envi ronment faced by shifting cu ltivators . Although the loss of primary forest i s  
appreciable under shifting cu ltivation,  the impact is less than that of  the major 
alternative land-uses in the region : t imber extraction and oil palm plantations. De 
Jong ( 1 997) early suggested that swidden agricultural systems maintain an 
important degree of biod iversity, and that production of rubber, fru its , or timber in  
forests which are manipulated in various degrees is a viable option to the 
development of swidden agriculture .  Such alternatives can increase local income ,  
sustain compatible population densities, and sustain the Indonesian timber industry 
while preserving the country's biod iversity. 
On a global scale,  a study by Fearnside (2000) reveals that biomass burning and 
decomposition and soil carbon release from tropical forest conversion, shifting 
cultivation and secondary vegetation currently emit substantial amounts of 
greenhouse gases; these forests have the potential for large additional emissions.  
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 40 
An estimated 3 . 1  x1 09 t of biomass carbon is exposed to these forms of burning each 
year in  tropica l  countries, of which 1 . 1  x 1  09 t C is emitted through combustion and 
49x1 06 t C is converted to charcoal .  Of the carbon converted to charcoal ,  26-31 x 1  06 
t C would represent black carbon as defined by resistance to oxidation at 3400 C .  
Carbon emitted annually through decomposition processes totals 2 . 1  x1  09 t C. The 
total gross emission ( including burning and decomposition emissions both from 
aboveground and from belowground biomass and from the top meter of soil is 
3.4x1 09 t of carbon ,  of which 3 .3x1  09 t is i n  the form of C02 . 
2 .3.2 Crop and soil indicators 
Resu lts of basel ine studies are useful tools to mon itor and evaluate environmental 
cond itions especia l ly with regards to agricu ltural production systems. Th is is 
especia lly important when related to find ing alternatives to slash and burn shifting 
cultivation covering a variety of agro-ecosystem conditions (Andriesse and 
Koopmans, 1 984 , Andriesse and Schelhaas , 1 987b, Andriesse and Schelhaas, 
1 987a) .  By obtaining reliable data from a series of standard ized monitoring studies 
conducted under d ifferent soi l and cl imatic cond itions, it may be possible to 
formulate statements applicable to bush-fal low systems general ly (Andriesse and 
Schelhaas, 1 987a). 
(i) The resulting effects of the burning and the ash 
A study on Jhum i n  Bangladesh shows that the ash from the burnt vegetation was 
found to add more avai lable Ca ,  Mg ,  K, S, Fe, Mn ,  and Zn to the soil than was 
removed in runoff sediments , whereas soil C ,  N ,  P, and Cu contents decreased . X­
ray d iffraction ,  Mossbauer and infrared spectroscopy, and total chemica l  analysis of 
the clay fractions from selected soil samples in  profi les from upper, middle,  and 
lower parts of a s lope in  the Jhum catchment showed composition and properties of 
the fractions that were almost identica l ,  i rrespective of soil depth and s ite position 
(Abdul et al . ,  2004) .  
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 41  
The study confirms the resu lts of an  earl ier study in  Sri Lanka and  Tha iland where 
successful burns resulted i n  a 20-25% decrease in organic carbon (approximately 
55-58% organic matter), 5-1 0% decrease in  CEC and < 1 0% decrease in organic P. 
The top 25 cm was mainly affected . There were no significant changes in soil N ,  
although N of the biomass was completely lost, probably from volatil ization . I n  
contrast, an incomplete burn i n  Sarawak resulted i n  a 20% increase in  C and N ,  a 
1 0% increase in  CEC and a 4% increase in organic P .  Incomplete burns, and 
consequently lower temperatures at the su rface, may have the advantage of add ing 
partly decomposed organic matter to the soi l ,  thereby saving N .  The d isadvantage is  
the fewer bases wi l l  be added (Andriesse and Schelhaas, 1 987b). 
Simi lar findings were also reported from case studies examin ing nutrient dynamics 
for a h i l l  rice-fal low system located on the eastern escarpment of Madagascar 
presented by Brand and Pfund (1 998), in the Eastern Amazon by Holscher et al. 
( 1 997), and in  the northern Zambia (Chidumayo, 1 987) .  At representative slash-and­
burn sites , the soil-pool of P and K increased from 1 00% beneath 5-year-old fa l low 
vegetation to 1 66% and 1 26% at harvest , but Ca and Mg decreased . Comparisons 
between fal low and burnt fields showed that 95-98% of phytomass-fixed and 22-
24% of soi l-fixed C and N were lost by burn ing .  Paddy at harvest only contained 1 -
7%  of the nutrients in the burnt phytomass of the previous stand (Brand and Pfund ,  
1 998). Repeated sampl ing on  two 'slash and burn' plots , showed significant 
increases in pH ,  CEC, extractable K, Ca and Mg,  but decreases in extractable Na 
and AI , C and N content i n  the plots from 7 -year old fa l low to the fi rst-year cropping  
field (Holscher et a I . , 1 997) .  I n  the chitemene sh ifting cu ltivation system (Northern 
Zambia) crops are grown in  a small ash garden made by burning a pi le of wood 
cleared from a larger area . The burning increased soil NHrN content by 40-50% ,  
with a further i ncrease of 1 5% after 262 mm  of ra infa l l .  I n  contrast, the soil i n  unburnt 
plots lost up to 30% NH3-N . The content of other major nutrients, such as, P ,K ,  Ca ,  
Mg ,  and Na a lso increased in  the top soi l immediately after burning . The increase in  
soil NH3-N after burning was attributed to the reduction in m icrobacterial activi ty .  
These soi l nutrient changes appear essential i n  the production of finger mi l let i n  
northern Zambia (Chidumayo, 1 987). 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 42 
Nutrient depletion is also a l imiting factor in the sustainabi l ity of sh ifting cultivation 
systems in Eastern Madagascar. A study by Brand and Pfund ( 1 998) showed that 
nutrients regenerated rapidly in the fal low vegetation , which after 1 year contained 
already 36-57% of the previous phytomass pool ,  whereas topsoil nutrient 
concentrations started to i ncrease only after 3-5 years of fallow. The topsoi l  cation 
content increased during the early stages of shifting cultivation, but under long-term 
shifting cultivation,  the soil nutrients fel l  to approximately 2/3 of the in itial stock. The 
nutrient stock of the most degraded vegetat ion unit (grassland) was merely 1 . 1-
6 .5% of the nutrient stocks i n  the rainforest. The establ ished nutrient balances 
showed , that the dynamics and the depletion depend greatly on the spatial and 
temporal scale of observation, on the topography of the sites and on the type of 
nutrients (Brand and Pfund ,  1 998). 
A study in Cote d ' l voire (Reuler and Janssen , 1 993b,  Reuler and Janssen ,  1 993a) 
i nvestigating  the i nfluence of burning slashed vegetation on crop performance duri ng 
three seasons at two sites, one with a 4-year-old (4-Y) secondary vegetation and the 
other with a 20-year-old (20-Y) vegetation suggested that at both sites, burning 
significantly decreased the number of weed seedl ings. The lowest number of 
seed l ings was found on the burnt plots of the 20-Y site . Ash production amounted to 
approximately 2 .5  ton ha-1 at both s ites . Nutrient contents of ashes were also about 
equal at both sites . An exception was K content, being higher in  ash from 4-year-old 
vegetation .  They concluded that in the local shifting cu ltivation system, the 
combination of ash depletion and i nfestation of weeds are the main reasons for 
abandoning the fields. 
Ferti l ity improvement from the ash as a result of burning was most evident in  the top 
25 cm soil with considerable increases in available S (2-60%), avai lable P (50-
300%), Ca ( 1 0-1 00%), Mg ( 1 5-45%) and K (6-80%).  Changes were most 
pronounced i n  the surface 5 cm but were sti l l  noticeable at 25 cm , and in cases even 
down to 75 cm. Increases in base content, with the exception of K, were qu ite 
substantial where much ash had concentrated due to pi l ing up of fel led vegetation .  
The burning of the pi led vegetation had not only influenced local temperatures in  the 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 43 
upper few centimetres , with a strong decreasing effect on organic matter and 
n i trogen content, but had also increased alka l inity, preventing crop g rowth at such 
s ites .  The practice of pi l ing is  therefore considered counterproductive. Leach ing of K 
and S ,  in  particular , and some Mg d id occur in  the Sri Lanka soil within 4 months of 
burn ing (Andriesse and Schelhaas , 1 987b) .  
A laboratory study on soil burning in  Sarawak (Malaysia) through a temperature 
range of 20-350DC suggests a decrease in cation exchange capacity and val ues for 
most exchangeable cations was observed whereas values for pH,  electric 
conductivity, base saturation and avai lable P increased . The burning resu lted in a 
s ignificant d isappearance of organic matter and the subsequent release of nutrients 
stored therein .  It is suggested that the microbiologica l  changes from heating are 
probably of greater importance than the chemical ones, taking into account the 
normal rooting depth of annual crops of about 25 cm (Andriesse and Koopmans, 
1 984 ) .  
Key disadvantages to burning are losses due to volatil ization of n itrogen and sulphur 
as wel l  as smal ler quantities of phosphorus and potassium.  Those losses can be 
el iminated by preparing fields without the use of fire, offering the hope of more 
efficient nutrient cycl ing and improved sustainabil ity . The effect of a shorter fallow in  
traditional s lash-and-burn systems is widely known to  reduce the system's 
productivity (Figure 2.4) ,  a point confirmed by Kato et al. ( 1 999). I n  the absence of 
burning , the reduced biomass had the opposite effect and increased rice yield and 
the subsequent cowpea and cassava yie lds, most l ikely due to a reduction in P 
immobi l ization . 
(ii) The effects on soil structure 
The dynamics of soil physical properties under slash-and-burn and some alternative 
systems were the subject of a study by Alegre and Cassel ( 1 996) in Peru evaluating 
the effects of d ifferent land-clearing methods and post land-clearing management 
systems on soil physical properties such as: bulk density, soil water characteristic, 
infi ltration rate, aggregate stabi l ity, and penetrometer cone resistance . Mechanica l  
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Implications 44 
clearing reduced the infiltration rate from 420 mm h -1 before clearing to 35 mm h-1 
for the straight blade and 95 mm h-1 for the shear-blade bulldozing. Straight-blade 
clearing damaged soi l  structure the most as ind icated by a decrease in the 
percentage of larger soil aggregates . The practice of p lanting on raised beds 
prevented foot compaction of soil near the plants ; bulk density was 1 . 1 4  and 1 .29 
gcm-1 for bedded and flat planted soi l ,  respectively. They conclude that the greatest 
change in soil physical properties occu rs during mechanical land clearing .  Agro­
forestry systems improved soil physical p roperties when cover crops and trees were 
i ncluded in the system. 
(a) _ _ _ _ _ _  �_..,... ____ ...... 
Unn�c�ssary 
>-t----'-->-IR .. ·�MfQtion years 
Fallow yeors 
Cu!ti ltcU ion Fal low Y@Qrs 
1 I I 
I . ; 
Fall in soil 
p4"oductivity 
Cultl\'at i on Fallow ye;;,; - - - - - - - - - - - -- -
I I I I I J 
o 5 10  lS 20 2S )0 35 40 45 years 
Figure 2 .4 A theoretical presentation of the relationship between fallow 
period and productivity (Mertz, 2002) 
I n  a different study with regards to grain production it was revealed that the greatest 
average relative grain-yields in descend ing order were produced by the following 
management systems: slash I burn I flat-plant I fertilizer I lime (94% average relative 
gra in-yield ) > slash I burn I bedded I fertilizer I lime (90%) > shear-blade I burn I disk 
I bedded I fertilizer I lime (88%) > shear-blade I burn I disk I flat-plant I fertilizer I 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Implications 45 
lime (86%) (Alegre et aI . ,  1 990) .  Of the various agro-forestry systems evaluated 
(mu lti-strata , peach palm production,  shifting agricultu re low i nput and high input 
continuous cropping) bu lk density was lower after 4 years for the systems with trees 
or cover crops. Mean annual  soil loss for al ley cropping on s loping soi ls was 0 .2 Mg 
ha-1 year-1 compared with 53 Mg ha-1 year-1 for two annual  crops per  year .  The 
infi ltration rate after 5 years of intensive grazing on five associations of legumes with 
grasses was reduced from 1 27 to 4 1  mm h -1 . Overgrazing caused severe soi l  
compaction and reduced earthworm b iomass (Alegre and Cassel ,  1 996). 
A study in Brazi l  was a imed at evaluating the fol lowing systems: native forest 
(control) ,  recently deforested (slash and burn) ;  a two-year old crop of palm tree 
(Bactris gasipaes) ; and a fou r-year old Brachiaria (Brachiaria brizantha) pasture 
(Araujo et a I . ,  2004) .  Selected phys ical and chemical  characteristics (granulometry ,  
water-d ispersed clay, soi l bu lk density, soil res istance to penetration ,  sed iment 
parameters ; chemical, exchangeable cations,  avai lable phosphorus,  pH in  water and 
in  KCI , exchangeable a lumin ium ,  organic carbon, su lfu ric acid d igestion ,  equi l ibri um  
phosphorus ,  and humic SUbstances) were compared .  I t  was found that the soil under 
Brachiaria pasture presented the highest so i l  bulk density values in  the A horizon , 
which suggests a tendency to compaction . The eva luated nutrients and organic 
carbon contents were low and concentrated in  the top surface layer .  Potassi um  
showed a drastic decrease in  the soil u nder Brachiaria pasture,  probably due  to 
losses by erosion , burn ing ,  and grazing.  Among organic compounds,  the humin 
fraction prevailed i n  all evaluated systems.  
A 2-year study of soil composition and erosion comparing a Jhum cultivated 
catchment and a neighbouring non-burnt catchment showed additional loss by runoff 
of about 30 Mg ha-1 (41 . 1  from the burnt site minus 1 1 .5 from the non-bu rnt s ite) of 
upland soi l ,  contain ing substantia l  amounts of plant nutrients, as a result of burning . 
The main loss occurred with in  2 to 3 months after burn ing ,  but after 1 year ,  losses i n  
the Jhum cu ltivated catchment were the same as i n  the non-burnt catchment. 
Furthermore ,  as almost half of the sediment was deposited in lower parts of the 
catchment, the net loss (export) was 1 5 .5 Mg ha-1 , which corresponds to only 3 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 46 
times the upper critical l imit (about 5 t ha-1 y(1 ) of sustainabi lity, indicating that Jhum 
fa l lowed for more than 3 years may be sustainable (Abdul et al . , 2004). 
S imi lar to the Jhum system in Bangladesh , the growing rural population in the 
chitemene shifting cultivation reg ion of northern Zambia has caused deforestation 
which has resulted in the reduction of (a) the length of the fallow period from 25 
years to 1 2  years, (b) the per person woodland requ irement of m 1 . 1 ha to 0 . 53 ha 
and (c) the frequency of clearing new chitemene gardens from yearly to once in two 
years. These responses to d iminishing wood resources have artificially increased 
the population carrying capacity from 2 .4 to 1 8 .7  persons per km2 . This has enabled 
the survival of the chitemene shifting cultivation land use system in northern Zambia 
(Chidumayo, 1 987). 
2 .3.3 Reconcil ing contrasting views 
There has recently been a genuine shift to susta inable agricu ltural policies in the 
developing world particularly in the tropical countries, and East Timor is no exception 
(Anderson and Deutsch , 200 1 ) . It is particu larly important considering the close 
association of traditional  upland farming, the economic  mainstay for upland 
communities in many countries in  Southeast Asia ,  with resource-poor farmers , land 
degradation , soil and water losses, and increasing pest problems (Fuj isaka , 1 994, 
Cairns and Garrity, 1 999) .  
A major focus of debate regarding the up land agriculture is on how to control sh ifting 
cu ltivation from depriving the people concerned from fulfi l l ing min imum subsistence 
requirements as well as taking a tol l of forest and land resources (Rasul and Thapa, 
2003) .  The role of shifting cultivation in  East Timor and elsewhere as a means to 
uti l ise spare resources to provide a considerable proportion of household food 
requirements and to act as a buffer, reducing the impact of perturbations in  the 
economic environment (Cramb, 1 993) may no longer be appl icable. I t  is argued that 
nutrient depletion is an important l imiti ng factor for agricu ltural  sustainabi l ity in 
shifting cultivation systems (Brand and Pfund ,  1 998) and finding its a lternatives 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Implications 47 
however is  not an easy task particularly considering the on-going confl icting 
evidence from empirical studies. 
Official sources in  East Timor appear to l ink soi l degradation and forest cover 
depletion with the practice of shifting cu ltivation accompanied by slash and burn sti l l  
commonly employed by peasant farmers particularly in  the upl ands (MAFP , 2004 , 
Anderson and Deutsch , 2001 ) .  From the publ ic pol icy point of view this matter has to 
be dealt with care to prevent poorly planned official schemes such as reforestation / 
agro-forestry projects during I ndonesian administration being repeated . The issue of 
traditional farming and the shifting cultivation farmers has never been addressed 
sufficiently in the past. Research evidence from I ndonesia ,  where it is sti l l  commonly 
believed that swidden agricultu rists are responsible for about half of country's annual 
deforestation , shows that swidden agriculture has been stigmatized , rather than 
recognized for its potential for resource conservation. De Jong's (1 997) study in 
West Kal imantan of Indonesia suggests that new forest management practices are 
part of and not superior to swidden agricu ltural practices. 
On the other end of the spectrum ,  there is a large body of evidence suggesting that 
modern agriculture brought about by revolutionary technology waves has indeed 
increased the agricultural production qu ite substantial ly (Gliessman, 1 998) .  
However, empirical stUdies suggest that future increase beyond th is  level of 
production may not be possible without further jeopardizing the ecosystem resource 
base (Pesek, 1 994) .  I t  cannot continue to produce enough food for the global 
popu lation over the long term because it deter iorates the conditions that make 
agriculture possible (G l iessman ,  1 998) .  
It is therefore important that a new approach to natural resource management must 
be developed so that new management systems can be tailored and adapted in  a 
site-specific way to highly variable and d iverse farm conditions typical of resource­
poor farmers (Altieri , 2002) .  This is especial ly relevant for publ ic pol icies trying to 
address the problems faced by rural communities in the tropical uplands Who have 
been practis ing shifting cultivation accompanied by s lash and burn for centuries. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainability Implications 48 
2.3.4 F i n d i n g  solutions 
Research and extension have offered farmers on-farm innovations - such as 
applying green-revolution technologies to shifting cultivation  (Greenland,  1 975) ,  
forms of agroforestry (Fujisaka, 1 994 , Kajembe et  a l . ,  2005) ,  fi re-free alternatives 
(Kato et a I . ,  1 999) or slash and mulch (Norgrove and Hauser, 2002) - intended to 
improve sustainabi l ity of upland agro-ecosystems. However based on experience, it 
is argued that the population growth and expansion of state control over common 
resources cannot help to control shifting cultivation as long as its structural causes 
are not addressed (Rasul and Thapa, 2003) .  
Their study suggests that an  effective shifting cultivation control strategy would 
require :  ( 1 ) granting land ownership rights to shifting cu ltivators , (2)  l inking shifting 
cultivation areas with local and regional market centres through infrastructure 
development, and (3) provision of necessary support services such as extension , 
credit and marketing (Rasul  and Thapa , 2003) .  This is ,  in the view of the present 
study, highly relevant to the East Timorese cond itions (UNDP,  2006). I t  wi l l  mark a 
mi lestone that wi l l  lead not only to improving trad itional sh ifting cu ltivation practices 
but to a more gradual and sustainable agricu ltural change led by the farmers 
themselves, something that governments i n  the past fai led to address. 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 49 
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Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabi l ity Impl ications 56 
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Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 
Appendix 2 . 1 .  Map of the agro-climatic zones of East Timor 
c:::::::J Nort�lern coast lowland 
c:::::::J Northern Slopes 
[:::::J Northern upland 
[:::::J Southern upland 
[:::::J Southern slopes 
[:::::J Soull'8rn coast lowland 
Source : Fox (2001 ) 
57 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 
Appendix 2 .2 .  Map of sucos (vi l lages) where tuber and root crops are among the three most significant crops (200 1 ) 
-
Sucos where cassava or 
sweet potato are sign ificant crops 
Source: GoTL (200 1 ) 
58 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Implications 
Appendix 2 .3 .  Map of sucos (vil lages) where maize was reported as one of the three most significant crops (2001 ) 
Source : GoTL (2001 ) 
Harvest at least twice 
annually 
Harvest at least once 
annually 
59 
o 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 
Appendix 2.4 .  Map of sucos (vi llages) where rice was reported as being one of the three most significant crops (200 1 )  
Three times each year 
Two t imes each year 
Oct. ,  Nov. Dec. or January 
L Feb . ,  March,  or April  
June, July,  August, or September 
Source: GoTL (2001 ) 
() 
60 
o 
Chapter 2. DEVELOPING EAST TIMOR AGRICULTURE: Sustainabil ity Impl ications 
Appendix 2 .5 .  Map showing the presence and seasonal ity of i rrigation (200 1 ) 
I rrigation Presence 
Sucos having i rrigation (286) 
I rrigation Period 
Seasonal only 
Source : GoTL (200 1 )  
61 
AGRICULTURAL MECHANIZATION 
Managing Techno-Cultural  Change1 
The farmer who has access to and knows how to use what science knows about soils, plants, 
animals, and machines can produce an abundance of food though the land be poor (Schultz, 1 964) 
3 . 1  I NTRODU CTION 
Agriculture is the mainstay of East Timor's economy, yet pursuing it , as an engine of 
growth and source of adequate food production wi l l  be, for a considerable period of 
time, hampered by a complexity of socio-economic, political , and techno-cu ltural 
constraints. Facing such conditions, and given that the vast majority of vil lages and 
population l ive from agriculture as the main source of food and income, the core 
objectives of development should be rural oriented . Survey data suggests that food 
and cash shortages are of major concern nationwide. 2 Cash shortage in particular 
wil l be a major constraint to introducing improvements in rural areas where the 
majority of the poor l ive. 
At the national level ,  there is increasing wil l ingness to adopt strategic agricultural 
development plans to address issues such as poverty al leviation ,  hunger and 
malnutrition . I nclusive in such plans is the necessity to pursue improved 
technologies, which enhance food security, wh ile preserving the resource base. 
Farmers , extension workers and pol icy makers wi l l  be frequently required to make 
decisions on the level of technology that is suitable for individual farmers . This 
involves determining appropriate combinations of manual , animal and mechanical 
powered technologies that are technically su itable and meet economic and social 
development objectives. 
1 Earlier version of this chapter was published in :  Agriculture: New Directions for a New Nation East 
Timor (Timor-Leste) (eds . )  Da Costa, H . ,  Pigg in ,  C., Da Cruz, C.J . ,  Fox, J .J . ,  Proceed ings of a 
Workshop 1 -3 October 2002, Di l i ,  East Timor, Organized by UNTL, RDTL, ANU ,  and ACIAR, pp. 
32-44 
2 See details of vil lage and household descriptive data in the Poverty Assessment Report, a work in 
partnership by the East Timor Transitional Admin istration (ETTA), the Asian Development Bank 
(ADB), Word Bank and UNDP (2001 ). Much of the data were also reported in  East Timor: State of 
the Nation (Planning Comission, 2002) 
Chapter 3 AGRICULTURAL MECHAN IZATION:  Managing Techno-Cultural Change 63 
3 .2 H I STO RI CAL BACKG RO U N D  
Many records have been documented about the colonial past, however very l ittle is 
known about agricultural technology development, especially during the pre-1 975 
Portuguese administration.3 The country's agricultural subsistence setting ,  as has 
been described earl ier in Chapter 2, persists in spite of developmental efforts over 
many decades of successive regimes. After the plantation-based agricu lture was 
establ ished in the 1 950s, the government embarked on creating the foundation 
infrastructures of a modern economy. The opening of new land for rice cultivation 
and improvement of i rrigation systems in the major agricultural centers of Viqueque 
and Baucau in the 1 960s marked the start of a new agricultural era .  The introduction 
of tractors in substantial numbers and the establ ishment of several rural extension 
centers such as those in Natarbora, Betano and Loes occurred during this period . 
Apart from governmental efforts , missionary col leges such as Fatumaca, Fui loro, 
and Maliana may have contributed to the introduction and promotion of agricultural 
machinery use.4 New varieties of rice namely IR-5 and IR-8 were brought from the 
I nternational Rice Research I nstitute in Los Banos Phi l ippines and introduced and 
d isseminated successful ly. I nterestingly, rice farmers in some parts of East Timor 
are sti l l  using variants of these early seeds. Another innovation introduced alongside 
with the seeds was the transplanting method of rice cultivation . 
A simi lar path was fol lowed during more than two decades of the Indonesian regime. 
The agricultural development thinki ng was mainly preoccupied with the problem of 
how to achieve food self-sufficiency through the adoption of 'green revolution '  
technologies such as large-scale machinery, hybrid seeds, chemical ferti l izers and 
irrigation networks. Agricultural development priorities, as opposed to the 
3 Data on selected agricultural development indicators can be found at FAOSTAT (www .fao.org) , 
covering a period from 1 961 to 2000. See also Saldanha and Da Costa ( 1 999) for an overview of 
development pol icies from Portuguese reg ime to the end of Indonesian ru le . Of Portuguese era, an 
official data source of development ind icators was the Speech Report of Governor Aldeia in 1973 
cited by the authors. 
4 In terms of sustainabil ity and reliabil ity, the management of agricultural machinery in these 
missionary colleges provides a model of success. The Fui loro School of Agriculture in Lautem and 
Fatumaca Technical School in Baucau for instance, apart from being educational institutions, have 
long been aSSisting local farmers with the provision of mechanical tools and equ ipment. 
Chapter 3 AGRICULTURAL MECHAN IZATION:  Managing Techno-Cultural Change 64 
Portuguese era , were given to regions offering less security threats in the western 
part of the territory, namely Maliana and Suai .5 Despite being referred to as a period 
of uncertain development (Saldanha and Da Costa , 1 999) ,  the last decade of the 
I ndonesian era provided some measurable achievements. Data during this period 
are essentially useful for future potential assessments and policy design ,  especially 
in the area of agriculture and rural development. 
Al l the developmental assets were severely damaged during the September 1 999 
tragedy. The transitional phase under the United Nations administration was in part 
aimed at recovering those assets and setting up necessary foundations for the new 
country's short-term and long-term development plans. There is a great deal of 
interest among the country's pol icy makers to adopt mechanization as a means to 
enhance agricultural productivity. Despite being potential ly promising in theory, the 
success of such a plan depends on a large number of factors - largely site-specific 
and others being macro in  nature. Consequently, the real cost of mechanization and 
its impacts have to be assessed over time. An approach that could make this task 
possible is to put in place realistic mechanization development policies and 
strategies right from the outset. 
Table 3 . 1  presents a general picture of East Timor agriculture developed over the 
years, recorded from the last decade of Portuguese regime unti l the period of 
Indonesian administration .  Figures are mainly estimates and should , therefore, be 
approached with caution . However, they may provide a rough ind ication ,  especial ly 
of the pre-1 975 status of mechanical power and labour input. Since the introduction 
of the PIano de Fomento (Five-Year Development Plan)6 , the use of tractors has 
gradually increased . Not surprisingly, however, labour intensity was also on the rise , 
5 See Fox, J .  (2001 ) Diversity and Differential Development in East Timor: Potential Problems and 
Future Possibilities. East Timor: Development Challenges for the World's Newest Nation (eds H .  H i l l  
& J .  Saldanha), pp. 1 55-1 74 .  Institute of Southeast Asian Stud ies, Singapore. for an anthropological 
viewpoint on East Timor's agricultural development with especial emphasis on its stages of 
transformation .  
6 Piano de Fomento started i n  1 960 with development priorities given to vital sectors such as 
infrastructure (transportation and communication), agriculture, education and health. I ntroduction of 
new plants (cinnamon, cacao and other fruits) occurred during this period . 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 65 
suggesting that the agricultural production has been predominantly labour-intensive 
(Gl iessman , 1 998) . 
Table 3 . 1 :  Selected agricultural development indicators of East Timor 1 961 - 1 9991 
Indicators 1 96 1  1 965 1 970 1 974 1 980 1 985 1 990 1 995 
Tractor in use 7 8 98 1 1 0 1 14 1 1 5  1 1 5  1 1 5  
Tractor use 
intensity 1 1 429 1 0000 81 6 727 702 696 696 696 
(ha/tractor) 
Agricultural 
labour force 244 259 280 31 3 273 298 322 360 
lthousands) 
Agricultural 
workers as a 
percentage of 86.8 86.3 85.9 85.5 84.8 84.4 83.6 82 .8 
labour force 
(percent) 
Agricultural 
labour intensity 3.05 3.23 3 .5 3 .9 3 .5 3 .6 3 .95 4.5 
(worker/ha) 
Cereal yield 1404 1 1 97 1 277 1 500 1 305 1 492 1 608 1 954 (kg/ha) 
Cereal import 
(thousand metric 0.8 1 .9 2.4 2 .5 na na na 392 
ton) 
1 .  Based on FAOSTAT database (www.fao.org). na: data not available. 
2. Figures for rice only, from East Timor provincial statistics. 
3 . 3  TH E S C O P E  OF AG RI C U LT U RAL M EC HAN IZAT I O N  
1 999 
1 1 5  
696 
3 16  
82 .3  
4 . 1  
1 962 
502 
Agricultural mechanization embraces the use of tools, implements and machines for 
farming and land development, production, harvesting, and on-farm processing .  
Within the historical and economic context, there are seven stages of evolution in  
agricultural mechanization (Rijk, 1 989, Speedman, 1 992): 
1 .  Stationary power substitution ,  where mechanical power is substituted for human 
power used in stationary process, 
2. Motive power substitution, stage where operation systems previously based on 
human power are replaced by mechanical power, 
Chapter 3 AGRICULTURAL MECHAN IZATION:  Managing Techno-Cultural Change 66 
3. Human control substitution , where mechanization is emphasized on substituting 
operations previously control led by human decision making , 
4 .  Adjusting the cropping systems to the requirements of mechanization (cropping 
system adaptation) ,  
5 .  Adjusting farming systems to the requirements of mechanization (farming system 
adaptation) , 
6 .  Adjusting plant physics to the requi rements of mechan ization (plant adaptation) ,  
and 
7.  Automation , where operations i n  agricultural production are fully automated . 
The sequence of these stages is generally identifiable at the farm level .  7 I n  many 
developing countries including East Timor, stages I and 1 1  are clearly pronounced , 
and often adopted simultaneously. I n  other countries, stage I I I  may be implemented 
on a few large state plantations whi le the majority of farmers have not yet adopted . 
F igure 3 1 shows the early mechanization development stages and all the possible 
mechanization technologies the farmer may select represented by the 
Mechanization Possibil ity Curve (MPC) (Rijk, 1 989). The reasons for mechanization 
are mainly expressed in economic terms such as i ncrease in labour productivity, 
increase in land productivity, and decrease in production costs . Therefore, the 
mechanization stages may be presented as the result of change in factor prices. The 
relative factor price for capital/labour in slope I i ndicates a cost minimizing . process 
representing stage I (labour-intensive) whi le stages I I  and I I I  require a greater 
capital-using process with a relative price change to L'K' and L"K" respectively 
(capital-intensive) .  
A jump from stage I to I I  and higher stages for many developing countries is not 
simple as it is governed by a number of factors and issues. Land and labour 
endowments, demand for off-farm labour, and demand for agricultural products are 
the major factors determining the rate and pattern of mechanization .  Issues involved 
7 Another grouping of agricultural operations is based on the relative intensity of the use of power as 
compared to the use of human judgment namely power intensive ( land preparation, threshing, 
mi l l ing, etc. )  and control intensive (weeding, sifting, fruit harvesting , etc . ) .  See Pingali et al ( 1 987). 
Chapter 3 AGRICULTURAL MECHAN IZATION : Managing Techno-Cultural Change 67 
may range from choice of techniques, technology transfer and adoption , and type of 
techn ical changes to farming system evolution (Clarke, 2000, Clarke and Bishop , 
2002) .  A comprehensive analysis wi l l help identify the impacts of mechanization on 
land and labour productivity, employment, income distribution, and change in social 
and cultural values across d ifferent regions and agro-ecosystems within a country 
(Schultz, 1 964) . Public sector role wil l  be pivotal i n  setting up the right direction 
based on a long-term vision for East Timor's mechanization program.  I nternational 
and regional experiences and studies conducted elsewhere may serve as useful 
references (Kaimowitz, 1 993 , Salokhe and Ramalingam, 1 998). 
MPC 
o L" L' L Labour 
Figure 3 . 1  Mechanization Possibi l ity Curve (MPC) 
(Adapted from Rijk, , 1 989) 
Table 3.2 demonstrates a clear differentiation in mechanization stages among 
selected countries in Asia during the period of green revolution up to the most recent 
times. Figures for Japan , Taiwan ,  and South Korea suggest a higher degree of 
mechanization and larger degree of urbanization as indicated by the decl in ing use of 
human power. I nterestingly for Japan , the machine hours were also decreasing , 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 68 
which may suggest the preferential use of larger machi nes allowing rapid completion 
of work. A very low labour i ntensity also indicates a very advanced mechanization 
stage ,  where field operations are ful ly mechanized involving some degree of 
automation . Rice cropping in Taiwan is nearly 1 00% mechanized from planting to 
harvesting . For other countries, the increasing labour use was mainly induced by the 
adoption of labour-intensive modern rice varieties while the increasing machine 
hours were largely devoted to land preparation and threshing, particularly in the 
Phi l ippines and Thailand (Duff and Kaiser, 1 984) .  
A tremendous increase in  the irrigated area in many Asian countries promoted by 
extensive irrigation schemes to increase cropping intensity has been one of the 
major reasons to acquire more power inputs. The number of tractors , as one of the 
major power sources and other farm machinery has been in an increased trend in all 
Asian countries (Salokhe and Ramal ingam, 1 998). Mechanization in most of these 
countries is associated with rice production as the main crop. A different scope and 
degree of mechanization may be promoted by countries having crops other than rice 
as the main crop l ike Pakistan (wheat) , Sri Lanka (tea, spices), and Malaysia 
(rubber, oil palm) .  Apart from that varied geography characteristics also requires 
different types of machinery and equipment. These are part of soil and crop 
technical aspects related to mechanization that needs to be considered for a 
successful and sustainable mechanization program in East Timor. 
3 .4 M EC HANIZATI O N  T E C H NOLOGI E S  
Both at academic and pol icy-making levels much of the controversy over agricultural 
mechanization has emerged from the fact that it is often considered only as the 
appl ication of mechanical power technology, particularly tractors . There are, 
however, three main levels of mechanization technology needing consideration : 
hand-tool, draft animal , and mechanical power technologies8 with varying degrees of 
8 See Clarke and Bishop (2002) for a detailed analysis of farm power present status and future 
projections for developing countries. Countries were categorized into six farm power typologies: 
predominantly manual ; sign ificant use of draft animal power (DAP); OAP predominant; significant 
use of tractors; tractors dominant; and fu lly tractorized . 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 69 
sophistication with i n  each level (Rijk, 1 989), on the basis of capacity to do work, 
costs, and in some cases precision and effectiveness (Morris, 1 985). 
Table 3.2 Estimated inputs of human , animal and mechan ical power, tractor use 
intensity and labour intensity for crop production in selected countries of 
Asia 
Tractor use Labour intensity intensity 
Country Input (hours/ha) a (ha/tractor) C (worker/ha) C 
Category b 1 956 1 970 1 975 1 978 1 990 2000 1 990 2000 
H 1 4 1 0  1 1 78 8 1 5  694 
Japan A 1 5  2 - - 2.4 2 .4 0 .89 0.57 
M 1 44 1 85 1 79 148 
H 1 088 985 778 601 
Taiwan d A 1 22 1 03 5 1  36 na na na na 
M 40 56 84 98 
H 1 356 1 284 1 1 76 937 
Korea A 92 1 0 1 80 56 51 .2 1 0  1 .68 1 .24 
M 4 8 1 8  48 
H 504 552 640 640 
Phi l ippines A 200 1 36 1 36 1 36 923.4 873.9 1 . 1 1  1 .23 
M 42 45 45 45 
H 490 480 470 462 
Tha i land A 1 70 1 65 1 60 146 356 .8  8 1 .8 0.97 1 . 1 7  
M 1 0  1 5  20 30 
H 1 2 1 8  958 992 1 285 
India A 230 247 221 1 25 1 71 .5 1 1 1 . 3 1 . 35 1 .55 
M 1 20 na na 1 1 3  
H 61 9 637 637 637 
Pakistan A 3 1 2  308 284 1 28 78. 8  68. 5  0.98 1 . 1 1 
M na na 2 6 
H 1 200 na na 1 448 
Nepal A 31 2 na na 304 522 .9 645.2 3.75 3 .76 
M na na na 2 
a. Figures estimated for rice production only. Source: Duff and Kaiser ( 1 984) 
b. Category: H=human; A=animal; M=mechanical 
c. From FAOSTAT data (www.fao.org) 
d .  Tractor use intensity and labour intensity data not avai lable (na) from FAOSTAT. Taiwan official 
source indicates that agricultural machines have gradually replaced labour input in farm production 
since the 1 970s. For rice production , the labour input was only 255 hours per hectare in 1 996, a 69 
percent decrease in labour input compared to 1 970 (www . coa.gov.tw/engl ish/agricultural/) 
3.4.1 Hand-powered too ls 
The predominant form of rural technology is based on manual labour, with the hand 
hoe as a basic ingredient. The main attributes of this system are that it represents a 
low-cost, low-energy, labour-using, family-oriented technology, wh ich is closely 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 70 
attuned to traditional and subsistent farming methods such as shifting cultivation and 
intercropping, and is largely self-sufficient, drawn on locally made implements 
(Morris ,  1 985) . Much of the agricultural production i n  the rural communities is  
emphasized on risk minimization intended for home consumption with only a smal l  
part passing through market channels. 
Hand-powered tools are the most used technologies by East Timorese farmers. 
These tools cover a wide range of varieties from axe and machete for land clearing , 
hoe and steel digging sticks for seedbed preparation and tuber and root crop 
harvest, to sickle and knife for weeding and harvest. Other hand-powered tools 
include those for winnowing ,  rice polish ing , maize grinding, candlenut, coconut and 
coffee processing,  most of which can be easily found in any traditional household 
both in upland and lowland communities. Given the simpl icity in the nature of many 
traditional implements , much scope exists for increasing productivity by improved 
hand tools and man-powered equipment. 
A study by Clarke and Bishop (2002) revealed that humans are the most significant 
power source in Sub-Saharan Africa countries where 65% of the land is cultivated by 
human power. In Central and Western Africa , they account for an estimated 85% 
and 70% of harvested area respectively, while the land cultivated by humans is 
estimated at 40% in East Asia and 30% in South Asia. 
3.4.2 An imal traction 
Animal traction is often seen as an outdated and backward technology. Therefore, 
rapid agricultural development is often taken to imply the bypassing of the animal­
traction stage and going directly from hand tools to the use of tractors and other 
purchased inputs such as ferti l izers and pesticides. This is also the case in  East 
Timor. Except for the rencah system using a group of water buffaloes to puddle the 
soi l ,  horses for transport and rice threshing, there is little, if not negl igible, evidence 
of the use of animal traction in combination with implements for land preparation and 
crop husbandry. Efforts were attempted during I ndonesian times to introduce the 
luku system, a mouldboard-plough pul led by a single or a pair of oxen, for primary 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 7 1  
and secondary ti l lage. I t  involved the use of Bali cattle and was demonstrated 
primarily by I ndonesian farmers who were relocated to several transmigration 
centers in East Timor. It lacked the dissemination effect probably due to technica l  
reasons such as lack of animals and ski l ls i n  animal husbandry, and lack of fodder. 
Also it may be due to the cultural aversion of local farmers to the use of animals for 
work. However, g iven the minimal adoption of modern technologies seen elsewhere , 
possible ways should be explored for the reintroduction of appropriate animal 
powered technologies. 
Animal power is sti l l  widely used in China. I ndian agriculture has been traditional ly  
dependent on draft animal and human power as major sources of energy. During the 
1 960s several newly independent African countries, among them Tanzania, Zambia,  
Guinea, Ghana, and Cote d' lvoire, adopted pol icies that were designed to leapfrog 
the animal traction stage by provid ing tractors and tractor-hire services at subsid ized 
rates. Most of these attempts at rapid tractorization fai led , and several countries 
subsequently reverted to encouragement of animal-draft power (Pingal i et aI . ,  1 987) .  
As mentioned earl ier, in countries with advanced mechanization levels, the use of 
animal power has been gradually decreasing (Korea and Taiwan)  and even total ly 
displaced as is the case in  Japan (refer to Table 3 .2) .  
3.4.3 The i ntroduction of tracto rs 
Tractors were imperative to modernization i n  the view of many, including the policy 
makers in the past . During the last decade of Indonesian administration, through the 
agricu ltural intensification program (B IMAS), a huge number of tractors and 
implements were introduced annual ly. 
Table 3.3 indicates the machinery status in 1 997, an approximate figure to that of 
the pre- 1 999 crisis, and the situation in 2000, at a time when the machinery demand 
for land cultivation was at its peak. The inclusion of crop production does not 
necessarily imply a resu lting effect from the use of tractors. In fact, the use of 
mechanization is not the sole factor contributing to increased yield . The concept of 
net contribution effect (increased crop production) and substitution effect (machinery 
Chapter 3 AGRICULTURAL MECHAN IZATION: Manag ing Techno-Cultural Change 72 
substituting for labour) helps explain the relationship between the two (Ruthenberg , 
1 985), since it is difficult to view the specific economic benefits of mechanization 
technology in isolation . So the crop production in those years comes as a result of 
mechanization being appl ied in conjunction with other crop production technologies 
such as irrigation , improved seeds, the use of ferti l izers and pesticides, labour and 
higher levels of management. Available data for 1 997 on selected tools and 
equipment is g iven in Table 3.4. 
According to Rijk (1 989) a statistical correlation between the level of mechanization 
and yield does not necessarily indicate a causal relationship and may lead to the 
incorrect conclusion that mechanization increases production . I n  many cases the 
increased production induced by factors such as ferti l izer appl ication and good 
irrigation may result in higher net income, which in turn cou ld stimulate 
mechanization investment. Research results also indicate that when adjustments are 
made for the level of ferti l izer used , yield differences between mechanically and 
traditionally ti l led fields become inSignificant (Bernsten et aI . ,  1 984 , Duff and Kaiser, 
1 984 ) .  
3 . 5  TH E T RACTOR M O B I L E  B RI GA D E S  (M Bs) 
The goodwi l l  of policy makers in the recent past to adopt tractorization as a means 
to speed up the agricultural crop production was understandable, especial ly in a time 
when the need for food was paramount. The smal l-scale mechanization scheme 
suggested through the World Bank-led joint assessment mission in November 1 999 
came to be a big-scale one in realization ,9 which may not be easy to sustain over 
time. 
Earl ier assessments on the tractor brigades (MBs) suggested that farmers had l ittle 
or no understanding of what was necessary for maintenance and that spare parts 
were difficult to obtain .  At the policy-making level ,  requests emerged for the need of 
9 The distribution of hand-powered tools was part of the smal l-scale mechanization scheme. Paral lel 
with this were the immediate projects of water buffaloes population recovery, reconstruction of 
meteorology stations, and the rehabil itation of major irrigation networks. 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 73 
i nternational expertise to assist with the plann ing and implementation of 
mechanization promotion programs (Wi lson , 2000, Watahiki , 2000) .  Only one spare 
parts dealer exists in Dil i and parts have to be imported , especial ly from Surabaya . 
Local manufacturers are non-existent even since the I ndonesian period. Private 
sector repair and fabrication workshops are currently running in smal l-scale un its . 
The Chinese Government has aSSigned a team of engineers and techn icians from 
May - December 2002, to assess the latest condition of al l  the agricultural 
machinery and to train Timorese operators and mechanics in the repair and 
maintenance (Benevides, pers. comm.  2002). 
Table 3.3 Number of tractors, paddy and maize production (ton) ,  East Timor 1 997-
2000 
Number of tractors 1 996/1 997c 1 999/2000c 
Districts 
1 997/98a Aug 2000b Paddy Maize Paddy Maize 
Aileu 9 6 1 ,700 1 0,500 1 ,41 1 9,240 
Ainaro 9 1 1  1 ,600 4 ,500 1 ,072 3 , 1 95 
Oecussi 72 6 5,300 8,800 1 , 325 3,080 
Baucau 42 37 12 ,000 14 ,000 9,720 1 3 ,300 
Bobonaro 1 27 22 1 5 ,000 28,600 8, 1 00 1 5,444 
Covalima 14  1 7  5,000 1 6,000 3,600 12 , 1 60 
Di l i  6 7 200 2,000 1 72 1 ,900 
Ermera 14  6 3,300 6,200 2 ,838 4 ,774 
Lautem 24 7 3,200 7 ,700 2 ,880 7 ,392 
Liqu ica 6 6 500 5,000 2 10  1 ,400 
Manatuto 1 3  29 4,800 4,000 3 ,984 3,680 
Manufahi 47 20 2,200 5 ,000 1 ,848 5,000 
Viqueque 34 1 4  1 7,200 14 ,000 1 3,760 1 4 ,000 
TOTAL 4 1 7  1 88 72,000 1 26,300 50,920 94 ,565 
(43,200) (30,552) 
a. From Dinas Pertanian Tk. I records. Figures include the non-operational tractors. F igures for 
Oecussi ,  Baucau , Bobonaro, Manufahi and Viqueque consist mainly by hand-tillers. 
b . Source: Wilson (2000). 
c. Source: FAOIWFP Special Report (April 2000). 1 996/97 figures were taken from BPS records. 
Figures in  bracket are polished rice taken as 60% from unhusked paddy. 
Since all the tractors are operating in the d istricts where there is l ittle institutional 
support, the operation of these mach ines faces enormous difficulties .  When 
mach inery is stationed in remote parts of the country, it is very difficult to keep it 
properly fuel led ,  lubricated , and serviced . Not surprisingly, many machinery 
breakdowns do occur, and often these occurrences coincide with the time when the 
Chapter 3 AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 74 
mach ines are under greatest stress especial ly during the peak cultivation season . 
Since the avai labi l ity of spare parts and competent mechanics is extremely scarce, 
delays in getting the machines operational can be lengthy (Bernsten et al . ,  1 984). 
Table 3.4 Selected agricultural tools and equipment by district, 1 997 
Districts Pedal/power S ickle Water Hand/power M ist blower Swing fog thresher pumps sprayer 
Aileu 4 95 2 1 02 1 5  0 
Ainaro 4 0 0 61 2 5 
Ambeno 49 0 2 37 2 20 
Baucau 66 36 0 33 2 30 
Bobonaro 1 2  0 4 2 1 6  5 25 
Koval ima 54 0 6 48 0 20 
Di l i  0 0 7 1 6  1 1 1 0 
Ermera 5 1 75 6 57 1 0 
Lautem 4 0 0 79 7 0 
Liqu ica 3 0 0 33 3 0 
Manatuto 2 0 0 36 1 20 
Manufahi 32 34 0 1 78 2 20 
Viqueque 4 1  0 0 1 20 7 20 
Total 276 340 27 1 01 6  48 270 
Source : East Timor Provincial Agriculture Department records 
The MBs have been dissolved and the tractors and implements are now being held 
under the responsibi l ity of the agricu ltural d ivision of the District Administration (DA). 
Given the very l imited publ ic sector resources to manage the machinery fleet as 
mentioned above , Wi lson (2000) identified 5 possible ways for long-term machinery 
management (and ownership) . l O  
1 .  I ncorporate the MBs with in  the Pilot Agricultu ral Service Centers (PASCs), 
2. Transform the MBs to farmer-owned co-operatives, 
3. Contract arrangement with local ly-owned business companies with MBs' staff 
becoming shareholders, 
4. Farmer group ownership through credit scheme, 
5 .  I ndividual farmer ownership through credit scheme. 
10  Sim ilar types of ownership were suggested earlier by Watahiki (J ICA, 2000). 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 75 
Currently MAFP has identified several problems needing immediate policy 
interventions such as 1 1 :  
1 .  Large areas of potential arable lands left underuti l ized , 
2 .  Lack or poor soil t i l lage resulting in  late crop establ ishment which leads to low 
crop intensity and yield and frequent crop fai lures , 
3 .  Limited access to ti l lage operation systems which can provide timely and 
affordable t i l lage services, 
4. Farmers unable to afford the cost of medium to large size tractors. 
A sound agricultural machinery management may help address these issues. Based 
on earl ier assessments (Watah ik i ,  2000, Wilson ,  2000) and short communications i n  
D i l i ,  there are three practical options 1
2 
under which the current agricultural 
machinery can be properly managed : 
1 .  Publ ic management scheme 
a .  ASC (Agricultural Service Centres), formerly PASC 
b. Agricultural Schools 
2. Agricultural NGO's management scheme, 
a .  Farmer group ownership through credit system 
b. I ndividual ownership through credit system 
3 .  Private Companies' management scheme 
These options are regarded as short-term possible and feasible immediate response 
with the existing managerial resources should the tractors are made available .  
However, they should be approached with caution . There are major efforts needed 
at setting up prior necessary conditions for each option to be material ized in  a 
specific region , particularly for public ownership schemes which were proven less 
1 1  Source: various MAFP's recent documents. 
12 This is more to address the current needs to properly allocate the tractors and implement sets 
recently purchased by MAFP. Short communications were conducted with NGO's and ASC 
representatives to briefly gather their opin ions and assess their commitments to own or manage 
agricultural mach inery for educational and/or profit purposes for the rural community The author 
argues that the whole scheme should be regarded as an on-going machinery management trial ,  
which will be assessed over time. 
Chapter 3 AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 76 
successful in the past. Exceptional cases may exist outside these options where 
there are already individual farmers or g roups of farmers capable of managing small 
tractors. 
3 . 5 . 1  Public management 
During a short introductory period , a subsidized tractor-hi re service run by 
government agencies can be beneficial through a demonstration scheme.  The 
demonstration effect, l inked with extension efforts wi l l  help promote technology 
adoption leading to machinery ownership by farmers. In the long-run ,  ASC 
(agriculture service centre) or similar government-owned centres in the future are 
required to focus primarily on promoting and facil itating research (Viegas, 2002, 
Tripp, 2001 ) .  I n  th is regard ,  research for the improvement of manual and animal 
powered technologies as described above deserve priority. Conservation t i l lage 
practices and technologies such as minimum and no-ti l lage using manual or animal 
draft to engine powered seed dri l l s  may as wel l be trial led in the long-run .  
On a short-run however, publ ic di rect intervention is  inevitable as  was proven in the 
past, despite with very l ittle success. Many shortcuts have contributed to largely a 
fai lure in technology adoption and dissemination at the community l evel . Evidence 
suggests that there were insufficient public resources as well as inadequate 
domestic and international network to promote a rapid agricu ltural recovery as well 
as to sustain its growth . Therefore, given the inexperience of ASC and publ ic 
agricultural schools 1 3 in running and managing tractors for educational and business 
purposes, additional ski l l  tra in ing and education packages are required . These could 
range from training on bookkeeping, finance, and operation and maintenance to 
setting up machinery workshops. 1 4  How these centres and schools wil l evolve in the 
1 3  ASC currently covers three centres namely Maliana, Viqueque, and Aileu while agricultural schools 
refer to the two schools in Natarbora and Bobonaro (short communication with Mr. Carlos 
Granadeiro of MAFP). 
14 ASC has experience in operating Rice Mil l  Units, trad ing of mil led rice, animal feed and fertilizer. It 
also supports the rural economy by providing farmers with small credit with interest rate of 1 0% / 
annum (Based on a short communication with Mr. Adel ino Rego of ASC on 1 8/1 /06). 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 77 
near future may have been foreseen and its measures establ ished within MAFP's 
strategy and policy plans. 
3. 5.2 NGO's management 
Farmers are used to working in  (kinship) groups therefore, with proper assistance in  
developing manageria l  and entrepreneurial ski l ls these groups could be transformed 
into potential and profitable co-operatives . On machinery management however, 
past experience has suggested that handing the tractors d irectly to individual 
farmers without proper assistance in operation and maintenance, is not a viable 
option . Besides, the capital cost of owning and managing agricultural machines and 
equipment is proven to be too high for small farmers. This is further exacerbated by 
the current uncertain cl imate in profitable agricultural business where the return of 
investment is very low. 
However, there is opportunity for improvement, especial ly if it takes up in itiatives 
which are based on sound applied research and experimentation results. The 
former, as mentioned earl ier, will be much of government role to promote through 
centres such as ASC or the Research Division of MAFP. Of the latter, a lot can be 
learnt from the non-governmental organizations (NGOs), especial ly those engaging 
in rural community and agricu ltural development. Many of these NGOs have 
experienced a long and healthy relationship with local farming communities. 
Therefore, with mutually beneficial arrangements , these NGOs are in a better 
position to provide the ti l lage services. 1 5  I n  a very foreseeable future, providing there 
is timely service and assistance, either from the publ ic sector or other private sector 
components , one individual or a group of farmers could certainly manage their own 
machinery in a sustainable fashion. 
15  HALARAE and ET ADEP were the two prominent national NGOs working in agriculture and 
community development approached to discuss the management options offered by the MAFP. 
During an interview with Mr. Paulo Amaral, the Director of HALARAE on 1 8/1 /06 he expressed 
great enthusiasm to accept the offer. Likewise, Mr. Gilman Santos, Director of ETADEP, in a short 
communication with the author on 1 9/1/06 , offered his comments and a simi lar positive attitude to 
take up  the role of managing the tractors for the benefit of the farmers. There are few other NGOs 
engaged in promoting sound agricultural and environmental practices such as HABURAS and 
HASATIL which could also be considered as government partners in this venture. 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 78 
The nature of partnership between MAFP and the NGOs wil l  be based on a 
contractual agreement where both parties wi l l  discuss and agree upon certain 
cond itions and abide by certa in ru les. HALARAE and ETADEP are two nationa l  
NGOs with rel iable profi les and reputation that can offer potential ly fruitful 
cooperation with MAFP in various aspects of community and rural development. 
Natarbora (Manatuto) and Welaluhu (Same) are potential agricultural areas of East 
Timor, where both HALARAE and ETADEP have already establ ished sol i d  
partnership with local communities . Sare I Raimate have long been regarded as  fie ld 
office of ETADEP for many years . Table 3 .5 presents some detai ls of area and 
number of beneficiaries currently benefited from working in partnership with these 
two particu lar NGOs. 
Table 3 .5 Selected NGOs working in agricultu re,  target area and beneficiaries, 2006 
Farm land (Ha) Farmers' 
NGO Location I rrigated Dry Total groups Farmers 
land 
HALARAE1 Natarboral 1 69 204 373 7 80 Manatuto 
Natarbora 
(Manatuto) and 1 72 1 72 1 1  1 30 
ETADEP2 Welaluhu 
(Same) 
Sare/Ermera 1 2 1 81 222 32 544 
1 .  Compi led by the author based on data from Mr. Paulo Amaral, the Director of Halarae. Halarae has 
experienced working on seed multipl ication, a project funded by UNDP/UNOPS in Natarbora and plans to 
expand its scope to machinery management. The figures represent area, farmers, and farmers' groups 
identified as in need of tillage service. 
2 .  Compiled from recent Etadep progress reports. These figures are the actual working area and number of 
farmers and farmers' groups serviced by 3 (three) units of Massey Ferguson tractors in each location, 
NatarboralWelaluhu and Sare/Raimate. Farmland in Natarbora and Welaluhu are cropped with a variety of 
cropping systems with rice, maize, beans , vegetables, and other horticulture crops. 
These factual conditions may provide valuable information for MAFP to start with the 
management of the current agricultural machinery fleet considering particularly the 
lessons underlying the experiences of the NGOs over many years of engagement at 
the grass-roots level . Expansion to wider land area and community coverage is 
permitted upon success , or s imi lar schemes can be replicated in other potentia l  
agricultural areas such as Viqueque and Mal iana. I n  the mean t ime,  ASC and 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 79 
Bobonaro agricultural school can set up pi lot projects in these two d istricts, whi le  
Baucau, Lospalos, and Suai  can be covered in a later stage. Areas where the 
tractors wi l l  be a l located to in each district can only be determined based on a 
specific survey. However, there is great scope for agricultural mechanization in the 
lowland ecological  zones along the southern and northern coasts ,  provid ing road 
and farm infrastructure allow the entry and mobil ity of farm machinery. 
3.5.3 Private companies 
The entry of private contractors into the h ire market wil l also be encouraged beyond 
the introductory period mentioned above. I n  the medium to long run ,  however, the 
involvement of the publ ic sector wil l be l imited , ideal ly, to pol icy making and creation 
of an environment conducive to private sector investments. This was proven to be 
difficult during the recent past , where local rice price for example,  mainly from 
irrigated lowland rice production systems which involve a great deal of mechanical 
power for t i l lage, harrowing and puddl ing ,  has no competitive market advantage. 
Different from the NGOs, these companies request some degree of profit in  return to 
thei r professional service. Local experience suggests that the overal l  production cost 
is too high causing business in agricu ltural food crop production not attractive for 
investment. 1 6  Subsid ies in fuel price and tax cut on imported machinery spare parts 
can provide incentives for greater involvement of business companies in agricultural 
production. Therefore, dependant on area size and crop commodities, these firms 
together with farmers and farmers' groups and with special subsidies from the 
government, can make attractive and lucrative deals out of rural agriculture. Past 
experiences of Dragon Service Co. suggest a great deal of work related to tractor 
operation and ti l lage services in areas of Manatuto, Baucau , Viqueque, and Liquica .  
Based on an i nterview with its management, the company is  wi l l ing to negotiate the 
conditions of a management scheme for the agricultural machineries.  
16  An opinion shared by a representative from the Dragon Service Ltd. Delta Comoro. Formerly Rio 
de Oiro Ltd . ,  it owns a qu ite reliable agricultural machinery pool and a mechanical workshop. It has 
previous experience in land clearing and seedbed preparation for low land rice production in Uatu­
lari and Natarbora. Largely of F IAT type, its tractors and spare parts are mainly imported from 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 80 
3.5.4 Analysis 
Main problems confronted with the introduction of tractors revolve around issues 
such as: poor avai labi l ity of spare parts; low realization of tractors util ization per 
season; poor ski" of tractor operators and owners ;  low mobil ity associated with poor 
infrastructure; and technical ly inefficient machinery design with respect to the socio 
economic conditions of the farmers. Table 3 .6 presents a calculated operational and 
maintenance cost of two type of tractors, recently purchased by MAFP ,  operating i n  
favourable normal field conditions .  
This is a basel ine running cost for these two particular tractors and the real cost may 
increase depending on the actual field conditions and the type of work required . To 
what extent of area a tractor can cover is largely a function of factors such as field 
conditions, weather, soil types and operator's ski" , and this may substantial ly affect 
the abil ity of the farmers to h ire the ti l lage service. Again ,  based on the calculated 
baseline cost and related ci rcumstances mentioned above, the rationale for charging 
a certain fee in a certain location may differ from place to place (Table 3 .7) .  A charge 
of $50/ha is appl ied if a medium and large size tractor can provide service to an area 
of 200 and 300 hectares, respectively, to be able to recover its minimum running 
costs . 
Additional fees may accrue due to transport and mobi l ization costs of the machinery 
if the farmlands are dispersedly located . Moreover, in relation to the recovery of the 
purchasing capital of the machineries , MAFP and its partners may need to careful ly 
weigh the urban - rural d imensions of the localities. A set of strategic pol icy 
decisions must be made on whether to invest in  poor communities l iving in ferti le but 
isolated lands such as Natabora and Welaluhu or rather to further promote the 
already established growth-centered communities in parts of Baucau and Mal iana 
for example. 
northern Australia. The agricultural branch of the firm is currently engaged in horticulture and 
vegetable production in Loes (based on interview with Mr. Tonito Madeira on 1 9/1 /06). 
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 81 
A rough estimation of the investment return , should the government undertake the 
management options described above through a revolving fund or credit scheme, is 
not entirely promising . From a farmer's perspective, the heavy burden is on the 
capital (ownership) and maintenance costs, even if it is shared collectively by a 
group of farmers, or even if the credit period is expanded to 1 0  years. However, the 
overal l  scheme can sti l l  go ahead with the assumption that the issues mentioned 
earlier in  this section are tackled properly over the next 5 to 1 0  years. As with 
regards to the establ ishment of mechanical workshops, it is probably feasible to set 
up one attached to each 'Secretariado do Estado para a Corrdena<;ao da Regiao' 
(State Secretariat for Region Coord ination) I ,  1 1 ,  I l l ,  and IV in Baucau , Manufahi ,  
Ermera , and Mal iana, respectively, with the central workshop located in  Di l i .  
Chapter 3 AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 
Table 3 .6  Fixed and Variable cost for Kubota MX5000 and Kubota M9000 tractors (US$/year) 
Tractor / horsepower Fixed Cost (i) 
Depreciation I nterest Maintenance Housing 
Kubota MX 5000 
51 HP 3798 1 1 60 .5 1 055 1 05 .5  
Kubota M 9000 
92 HP 53 1 0  1 622 .5 1 475 1 47 .5  
Variable cost (i i) 
Fuel Oi l  Grease Operato,-L 
Kubota MX 5000 
51 HP 2856 57 34 402 
Kubota M 9000 
92 HP 51 52 1 03 62 402 
Total Operational and maintenance Cost 
Kubota MX 5000 (5 1 HP) 
Kubota M 9000 (92 HP) 
Note: 1 .  Assumed no tax on personal property as well as no insurance scheme available. 
Tax & 
I nsurance1 
-
-
TireJ 
600 
600 
2.  Estimated at $ 1  O/hour for both operator + helper on an 8 hour/day work basis over 400 hours tractor work/year. 
82 
Total cost (i) 
6 1 1 9  
8555 
Total cost (ii) 
4049 
641 9  
1 01 68 
1 4974 
3. Maintenance cost for one tire (tear and wear) is estimated at $1 50/year. Prices for new front and rear tires for medium and large tractors 
are around $300 and $1 200, respectively. 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 83 
Table 3 .7  Working area (ha) and estimated cost of tractor charge fee 
Operational Tractor fee 
Tractor and maintenance $30/ha $40/ha $50/ha $60/ha $70/ha $80/ha 
cost ($/year) 
Kubota MX 5000 
(51 HP) 101 68 339 254 203 1 70 1 45 1 27 
Kubota M 9000 
(92 HP) 14974 499 374 299 250 2 14  1 87 
3.6 RATIO NAL TEC H NO LOGY D EV E LO P M E NT 
Experience in many countries indicates that land l imitations are not necessarily a 
critical constraint to the growth of agricultural output. Austral ia ,  Japan, and New 
Zealand for example, have achieved relatively high crop productivity despite 
agricultural land and labour resource l imitations (Table 3.8 and 3 .9) .  Following the 
typology of Clarke and Bishop (2002) these countries fal l  into the category of fully 
tractor powered where agriculture is  no longer the dominant sector. In countries 
such as Bangladesh ,  I nd ia ,  Nepal ,  Vietnam , and East Timor where GNP is low 
(Table 3 .8) and there is an ample surplus of labour, land productivity through higher 
yields and cropping intensity is required , thus providing additional employment . 
Simi larly, expansion, control and efficiency in i rrigation are also ways to improve the 
productivity of agricultural land in  the high man/land ratio economies of Asia. 
Cereal and root crops/tubers data during the last five years of Indonesian 
administration in East Timor provide an interesting insight on the country's 
agricultural development. Rice, maize, cassava, and sweet potato are the four major 
staple crops for East Timor (see Chapter 2 for general overview of the traditional 
agriculture setting and Chapter 4 for selected food crop production data) .  By being 
staple crops, may a l ready provide an incentive for farmers to produce more, mirrored 
by a significantly higher yield growth comparatively to some countries in Asia Pacific 
(Table 3 .9) .  Other factors may have contributed to th is growth , especial ly those 
derived from public pol icies during that time to stimulate production to meet self­
sufficiency needs ,  including policies on mechanization .  More on the importance of 
staple crops in  food pol icy wil l be the subject of d iscussion in Chapter 4 .  
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 84 
As was d iscussed earl ier, high level of mechanization ,  however, does not necessari ly 
imply higher crop productivity. Data from selected Asia Pacific countries indicates 
only a moderate relationship between the number of tractors/1 000 ha and cereal 
productivity (r = 0 .53) .  On the contrary, ferti l izer consumption has a very strong 
relationship with cereal yield (r = 0 .84) .  Simi larly GNP per capita has a highly positive 
correlation (r = 0 .86) with the investment in tractors (FAO/RAP,  1 999). 
Depending on their land and labour endowment, countries could rely on d ifferent 
technological strategies in agricultural growth . Japan, for example, emphasized yield­
rai sing technology up to 1 950's, while mechanization played only a minor role.  
Fol lowing th is pattern ,  Korea and China also initial ly emphasized yield-increasing 
technology and later pursued mechanization .  On the contrary, rather than yield 
increasing technology, the Un ited States of America emphasized mechanica l 
technology even before 1 880. Unl ike other Asian countries , Thai land has also rapidly 
expanded its agricu ltural area enhanced by mechanization , rather than pursuing 
yield-raising technology (Rijk, 1 989). 
Both strategies were employed in East Timor during the Indonesian era, part of a 
national pol icy to address the issue of food self-sufficiency as mentioned earl ier .  
Yield raising technologies such as hybrid seeds were i ntroduced but such 
technologies usual ly require i nputs to achieve thei r potential .  These additional inputs 
are often hardly affordable which consequently leaves the farmers with very l ittle 
option but to revert to their local seeds. 
A chosen strategy and its net effects of technological change on farm productivity , 
farmer's income, and societal welfare are highly dependent upon agricultural 
production systems.  This is particu larly chal lenging confronting subsistence-based 
communities in East Timor, which are by nature conservative and use methods and 
techniques that have withstood the trial of t ime. 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 85 
Table 3.8 Total land area , percentage of agricultural area, total population (TP) ,  
percentage of agricultural population (AP) ,  and GNP per capita of selected 
countries in the Asia Pacific Region 1 9981 
Agricultural Total Agricultural Total land land as 
area percentage of population population GNP per (TP) (AP) as Country ( 1 000 ha) total land ( 1000) percentage of capita area3 (TP) (US$) (%) (%) 
Australia 768230 6 .9 1 8329 4 .80 20090 
Bangladesh 1 30 1 7  63.3 1 22650 58.70 260 
East Tima? 1 461 43 882 70 348 
Fij i 1 827 1 5 .6 786 4 1 .50 2470 
I ndia 29731 9  57. 1 9661 92 56.30 380 
Indonesia 1 81 1 57 1 7. 1  203380 46. 1 0  1 080 
Iran 1 62200 1 2  64628 28.70 2200 
Japan 37652 1 1 .4 1 26038 4 .80 40960 
Korea 9873 1 6.6  4573 1 10. 50 106 10  
Malaysia 32855 23. 1 20983 1 9 .90 4370 
Nepal 1 4300 20 .8  223 16  93.30 21 0 
New Zealand 26799 1 2 .2 3761 9.20 1 5720 
Pakistan 77088 28 1 44047 52.20 480 
P. New Guinea 45286 1 . 5 4499 78.50 1 1 50 
Phil ippines 2981 7 3 1 . 9  71 430 41 .20 1 1 60 
Sr i  Lanka 6463 29.2 1 8274 47.20 740 
Thailand 5 1 089 40 59736 51 .20 2960 
Vietnam 32549 22 . 1  76387 68.60 290 
1 .  Source: FAO/RAP ( 1 999). 
2. Source East Timor in Figures 1 997 (total land, agricu ltural land, TP, AP) ; GNP estimated as non-oil 
GDP. 
3 .  Arable land and permanent crops land excluding permanent pasture, forests and woodland , and 
other land (RAP Publ ication 1 999/34). 
Chapter 3 - AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 86 
Table 3 .9 Mean productivity and annual growth rates of cereals ,  tubers and root 
crops, fertilizer consumption and number of tractors in selected countries 
in Asia Pacific region 1 
Countries Cereal Growth Tubers & Growth Ferti l izer Tractors 
Yield 1 988-98 root-crops 1 988-98 Consumption /1 000 ha 
1 998 (%) yield (%) 1 997 (kg plant 1 997 1 998 (kg/ha) (kQ/ha) nutrients/ha) 
Austra lia 1 952 1 .8 30838 1 .4 42.6 6.67 
Bangladesh 2669 1 . 3 1 0960 1 . 1 1 30. 1 0.66 
East Timo.-2 2650 4.7 4245 8 na 0.66 
Fiji 2089 -0 .8 1 0792 1 3.0 67.4 26.92 
India 2207 2 .2  1 701 1 0.9 95.3 8 .54 
Indonesia 3789 0 .6 1 1 726 0.2 79.5  2 .32 
I ran 1 92 1  4 .8 1 94 1 1 3.4 59.4 1 2 .40 
Japan 5849 1 268 1 9  0.6 366 499.77 
Korea 6631 1 20842 0.0 471 . 1  64 .61  
Malaysia 2957 0 .9 951 3 -0 . 1  1 57 .8 5.69 
Nepal 1 968 0 . 7  8092 1 .6 36.7 1 .66 
New Zealand 5379 2 .3  42679 4.7 2 1 0 .7 24 .75 
Pakistan 2 1 59 2 .2  1 4 1 64 2 .5  1 23. 1 14 .90 
P. N .  Guinea 4 1 70 7 . 7  5338 -2 .6 1 9.4 1 .8 1  
Phi l ippines 224 1 2 . 3  6669 -0.3 85 . 1  1 .23  
Sri Lanka 31 56 0.8 81 74 -0.8 1 1 1 .7 3 .54 
Thailand 2466 1 .8 1 4200 -0 .3 72 .3 7 .31  
Vietnam 3838 3 701 3 -0 .8 2 1 8 .3 1 7.08 
1 .  Source: FAO/RAP ( 1 999). 
2 .  Source: East Timor in Figures 1 997; ( i) cereal yield is the average of rice and maize yields only, 
annual growth from 1 992-1 997 ( i i )  tuber and root crops yield is the average of cassava and sweet 
potato yields only, with annual growth from 1 992-1 997 ( i i i ) data on fertil izer consumption is not 
available, use is negl ig ib le if any. 
3 . 7  MANAG I N G  TE C H N I CAL C HA N G E  
One of the major capital investments i n  agriculture development i s  in  the form of land . 
I n  the context of technical change, any form or patterns of agricultural technology can 
be g rouped as land-saving (hybrid seeds ,  i rrigation,  ferti l izers , and drainage) and 
labour-saving (mechanization, herbicides , varieties and cropping techniques) as  
shown in Figure 3 .2 .  A techn ical change is land-saving if the labour/land ratio 
increases ( 1 1 ) while technical change is labour-saving if the labour/land ratio 
decreases (b). 10 is  the original situation and I n  represents a neutral technical change. 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 87 
This technical  change, where the move from 1 1 to h occurs along an isoquant reflects 
the view mentioned earl ier that mechanization substitutes for mechanical and animal 
power. The net contributor view on the other hand sees mechanization as engine of 
growth due to better ti l lage, more timely operations, and a l lowing more cropping 
intensities (more output from less inputs) and can be represented by a move from 1 1 
or h towards I n .  Both views can happen at once. 
o L" L' L Labour 
Figure 3 .2 Capital-saving versus labour-saving technical change 
(Adapted from Rijk ,  1 989) 
When given the choices, farmers wi l l  weigh up the relative attributes of a lternative 
approaches to technical change. Traditional farmers are efficient a l locators of 
avai lable resources according to their knowledge of technology (Schultz, 1 964) and 
therefore tend to make rational decisions about new technology (French and 
Schmidt, 1 985). According to Schultz ( 1 964) every new technology represents a 
d isequi l ibrium impulse which causes inefficient resource allocation. African 
experience suggests that the dominant theoretical perspective on technical change 
and innovation in  small-sca le  agriculture (change under constrained maximization) is 
argued to be highly effective in identifying problems with smal l-scale agricultu re 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 88 
(Omamo and Lynam,  2003) .  Only through learning and experimentation will a new 
equi l ibrium be achieved . I n  fact , empirical evidence suggests that i nvestment i n  
human capital through education enhances early technology adoption and promotes 
greater productivity (De Souza F i lho et a l . ,  1 999, Omamo and Lynam, 2003). 
Based on contemporary research findings, French and Schmidt ( 1 985) summarize 
four major components influencing technology acceptabil ity and transfer as follows: 
1 .  Technology compatibi l ity with the biophysical and cultural envi ronments, 
2. The avai labi l ity of resources that faci l itate the adoption of technology, 
3 .  The adequacy of technology to address the needs of the target population , and 
4.  The appropriateness of the transfer mechanism . 
I n  order for a technology to be appropriate the first three components have to be met 
and channelled through a proper transfer process. The level ,  appropriate choice and 
subsequent proper use of mechanized agricu ltural i nputs has a d irect and significant 
effect on achievable levels of land productivity, labour productivity, the profitabi l ity of 
farming ,  and ult imately the qual ity of life of the farmers (Clarke , 2000) .  
Much of the technology-induced innovation proceeds along with the evolution i n  
farming systems .  I n  this context, i t is relevant to mention four common sequentia l  
phases of farming system research (Clarke and Bishop, 2002, Clarke, 2000): 
1 .  The examination of existing production systems with respects to constraints 
(appraisal) ;  
2 .  The identification of potential improvements (experimentation); 
3 .  The evaluation of promising product possibi l ities under local farmers' conditions  
(design) ;  and 
4.  Extension to more farmers' fields ( implementation) .  
For traditional  farmers , therefore, the justification for acquIring an improved 
technology, to some extent, needs to conform to the features of the i r  subsistence 
mode of farming .  Fol lowing Morris ( 1 985) some of its features relevant to technology 
change warrant important mention. 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cu ltural Change 89 
1 .  Farm size and structure. 
Land characteristics such as topography, drainage, natural vegetation , and 
accessib i l ity can l imit mechanization feasib i l ity. Land holdings are smal l  for the 
majority of the population , with about 24% of households owning less than 0 .5  ha,  
and a further 60% between 0 .5 and 1 .5 ha each (Planning Commiss ion ,  2002) .  Farm 
sizes, therefore ,  are general ly smal l ,  and mechanization wil l  make l ittle headway, 
unless machi nes appropriate for smallholdings are avai lable or substantia l  farm 
amalgamation takes place or through collective management of cooperatives. 
Land tenure is quite a del icate matter in East Timor with a complexity of legal issues 
involved . L im ited access to  land ownership ,  or  where land properties based on 
customary law is common , often means that farmers do not possess the col lateral 
needed to qual ify for medium-term mach inery credit. I nheritance customs, combined 
with population pressure can lead to excessive fragmentation and dispersal of 
hold ings. Land reform including the redistribution of land and issuing of land titles to 
secure land tenure is one of the solutions being proposed to the government (UNDP,  
2006) .  
2 .  Population, labour and gender. 
Family is usual ly the most rel iable labour source . Excessive tractorization is usua l ly 
associated with labour displacement in  areas where labour is abundant. However the 
relative deterioration in access to basic social services in rural areas has forced a 
s ignificant i ncrease in  rural-urban migration . Labour shortages during critical periods, 
such as weeding ,  can act as a constraint on overal l  productivity (MAFP ,  2004) .  
GoTL (2003) argued that employment and creation of jobs are the core of improving 
l iving standards in East Timor. The publ ic sector during Indonesian administration for 
example, employed 28,000 people ,  whereas the current payrol l  is only half that 
n umber. Therefore, creating an adequate number of formal and informal job 
opportun ities to meet the needs of the country's youth is one of the key chal lenges 
for East Timor (GoTL,  2003) .  
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 90 
Women play an important role in virtual ly all the agricultural production cycle. A 
survey in  East Timor in 2003 indicated that of the women working in  agriculture , only 
1 % receives cash income, as opposed to 25% working in  non-agriculture. Even in  the 
non-agriculture sector, only half the women (52%) worked throughout the year while 
the rest work part of the year ( 1 8%), or on an occasional basis ( 1 9%) (Min istry of 
Health , 2003) .  Observing the impact of technology on women, some researchers 
argue that, far from being beneficiaries,  the role of women can deteriorate as a result 
of farm mechanization. Men are quicker to associate with machinery, leaving the 
unmechanized and most tedious jobs for women (Clarke and Bishop, 2002) .  
3. Subsistence farming. 
Growth wil l  have to start with agriculture,  predominantly subsistent, which employs 
around three-quarters of the labour force. Most farmers are engaged in subsistence 
cultivation , employing fami ly members on small plots of land with average holdings of 
around 1 .2 hectares. Current productivity is low, output per worker is less than one­
tenth of that in industry and services and , as a result, agriculture generates only one­
fifth of GDP (UNDP,  2006). 
There are two main groups of farming in East Timor namely the lowland rice and 
maize cultivation and upland mixed farming.  The former is being gradually influenced 
by the use of tractorization in many production centers. The latter is sti l l  very much 
associated with bush-fal low and shifting cultivation. I n  both cases, the production is 
typified by low and unreliable yields ,  un improved species, low use of ferti l izer or 
animal fodder, and l imited pest and d isease measures 1 7 .  
4.  Low income and poverty 
One of the immed iate concerns of development in East Timor is  the rise of poverty 
across the country. About 4 1  % of the people l ive below the poverty l ine of $0 . 55 per 
day and the percentage of those l iving in rural areas is even higher at 46% (World 
Bank, 2002) .  East Timor's low human development index (HO I )  corresponds to a 
high level of poverty (UNDP,  2006). 
1 7  See Chapter 2 for a detailed overview of the traditional agriculture setting of East Timor. 
Chapter 3 - AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 91  
A necessary condition for East Timor to alleviate this poverty level i s  to achieve 
sustained economic growth . About one-seventh of the population l ives within  1 0% of 
the poverty l ine,  suggesting that poverty is responsive to growth . However, the 
economy has experienced a rol ler coaster ride over the past five years (UNDP ,  
2006). The number of poor people i s  about 341 ,000 (43% of the total population) .  Of 
this, 1 5% l ive in urban areas and 85% of poverty occurs in rural areas . Consequently, 
poverty is mainly a rural phenomenon. Of the rural area poverty, lowland areas are 
home for about 47% poor whi le 38% l ive in the highlands (Planning Commission ,  
2002) .  Within th is picture, i t  leaves little room for the introduction of any form of new 
technology, much of which remains expensive and inherently risky . Recent reports 
emphasized the urgent needs for an integral rural development aimed at empowering 
rural communities of East Timor to come out from the poverty-environment 
degradation cycle (GoTl, 2006 , UNDP ,  2006) .  
5. Institutional support. 
Efforts to guide modern science and technology to solve poor people's food and 
nutrition problems are l ikely to be successful only if supported by appropriate pol icies 
and institutions (Pinstrup-Andersen, 200 1 , MAFP ,  2004) .  Mechan ization requires 
institutional support in the form of input supply, marketing ,  credit, extension and 
train ing ,  and adaptive research . General ly, the more capital-intensive and the less 
indigenous the technology, the greater are the demands for institutional support. I n  
the long run ,  productivity growth is l ikely to come from three main sources :  
agricultural research , technology transfer systems (extension and education) ,  and 
agricultural support facil ities (Saeed , 1 982, Kaimowitz, 1 993, Mayer and Blaas, 
2002) .  I nternational research data suggests that investment in  research and 
development raises agricultura l  value added sufficiently to give very satisfactory rates 
of return within the agricultural sector in both Africa (22%) and Asia (31 %) ,  but much 
less so in Latin America ( 1 0%) (Thirtle et a l . ,  2003) .  For the Asia and Pacific (A-P) 
region , the investment in agriculture and agricultural research and technology 
development is low and decl in ing - despite a very high rate of return on investment in 
A-P agricultural research (48 percent during 1 958-98) (FAO/RAP, 2002). 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 92 
3 . 8  M E C H A N IZATION PO L I CY 
Given the role of mechanization i n  the process of getting agriculture moving ,  and its 
important socia l  ramifications ,  mechanization pol icy becomes an important aspect of 
agricultural  planning . International  experience shows that agricultural  mechanization 
strategy formulation has been initiated for a number of countries in partnership with 
the Agricultural Engineering Service (AGSE) of FAO (Clarke, 2000, Rijk ,  1 989). 
According to C larke (2000) national governments are required to provide the basic 
conditions for a largely self-sustain ing development of agricultural mechanization 
with in  a policy of min imum intervention . 
I t  is particularly chal lenging for East Timor where its communities are by nature 
conservative and use only modest methods and techniques of farming.  A selective 
mechan ization is deemed necessary, as an attempt to remove smal lholder power 
constraints , whi le avoiding the wasteful and u ndesirable effects of over­
mechanization , particularly labour displacement (Morris ,  1 985, Schultz, 1 964). This 
involves, by means of detai led farm management and agricultural engineering study, 
the identification of power peaks and the most appropriate , cost-effective way of 
deal ing with them (Schultz, 1 964) .  
At the present levels of productivity, i t  i s  debatable whether the average smallholder 
should g ive priority either to yield-increasing inputs such as improved seeds and 
fertil izers, or  to mechanization .  I n  practice the two are often inseparable. Publ ic 
policies should be put in p lace, especial ly those most d irectly related to agriculture 
and rural technology development. Such policies should be careful ly designed and 
tai lored towards identifying and matching the existing ecological zones with 
appropriate technological innovations . An alternative view on learn ing , adaptation, 
and problem solving of science and technology proposed by Omano and Lynam 
(2003) is highly relevant. 
The structure, management and funding of the MAFP's systems, as described earl ier  
in  Chapter 2 ,  has become under internal  scrutiny to meet the challenges of boosting 
agricultural productivity and national i ncome. Given its l im ited size and emerging 
Chapter 3 - AGRICULTURAL MECHANIZATION: Managing Techno-Cultural Change 93 
capacities , one efficient way to achieving these goals, is the need for the public 
sector to be decentral ized and refocused on its strategic and regulatory functions. 
Thus ,  al lowing the private sector to take over most of the program execution activities 
on a competitive and contractual  demand-driven basis. 
3 . 9  C O NC L U D I N G  REMA R KS 
Change is inevitable. The chal lenge is how to manage a gradual and evolutionary 
transformation with minimum social and cultural costs . Technical change for instance,  
cannot be viewed as the replacement of an entire set of traditional activities by a new 
set of modern activities. Certain  tasks need to be modernized first, then others, unti l  
eventually the complete transition to modern farming is made. What is needed is a 
task-by-task analysis of the components of technology acceptabil ity and transfer 
mentioned above . 
From a pol icy point of view a 'selective approach' of mechanization is highly relevant 
to East Timor. It requires a careful assessment of mechanization needs, an appraisal 
of avai lable technology, and the formulation of policy measures, which wou ld 
encourage the development, and selection of an appropriate mechanization that 
supports the overall agricultural development objectives. 
Chapter 3 - AGRICULTURAL MECHAN IZATION: Managing Techno-Cultural Change 94 
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Speedman,  B .  ( 1 992) Changes i n  agriculture: challenges for education in agricultural 
engineering .  Proc. Agricultural Engineering and Rural Development 
Conference 2. A Pergamon-CNPIEC Joint Publication ,  Beij ing ,  China.  
Thi rt le, C . ,  Lin , L .  & Piesse , J .  (2003) The Impact of Research-Led Agricultural 
Productivity Growth on Poverty Reduction in Africa , Asia and Lat in America. 
World Development, 31 , 1 959-1 975.  
Tripp,  R. (200 1 ) Agricultural Technology Policies for Rural Development. 
Development Policy Review, 1 9, 479-489 . 
UNDP (2006) Human Development Report 2006 Timor-Leste The Path out of 
Poverty: I ntegrated Rural Development. Un ited Nations Development 
Programme, Di l i  East Timor. 
Viegas, E. (2002) Penelitian :  Peranannya dalam Pembangunan Pertanian 
Berkelanjutan . Suara Timor Lorosae (STL) . Di l i . 
Watahiki , T .  (2000) Present Situation and Mechanized Rice Cultivation in East Timor. 
J ICA, Di l i . 
Wilson ,  P .  (2000) Report of Technical Monitoring M ission , Immediate Recovery and 
Improvement of Agricultural Production .  UNDP,  Di l i . 
World Bank (2002) East Timor: Policy Chal lenges for a New Nation ,  Country 
Economic Memorandum.  The World Bank, Washington D .C .  USA. 
WWW. coa. tw/engl ishl assessed in 2002 
www. fao.org assessed in 2002 
'4l FOOD POLICY, AGRICULTURE AND ECONOMIC 
� 
GROWTH1 
4.1 INTRODUCTION 
The economic system i n  East Timor that emerged from many years of I ndonesian 
adm inistration fai led to develop an i nd igenous managerial capacity; promoted a 
culture of dependence on the government as the key provider of employment, d i rect 
transfers and subsidies; and bui lt up an i nfrastructure which was very costly to 
maintain (MAFP, 2004 , MAFP,  2005). 
A smal l  country l i ke East T imor needs to develop economic pol icy guided by 
rational ity and efficiency considerations. A rapid ,  broad-based and sustainable 
economic development is one sure means of employment creation,  poverty 
al leviation,  and improved l iving standards for al l  East Timorese . For the agricultu ral 
sector, this is in l ine with "the development of an ecologically sustainable and 
profitable agricultural system leading towards economic self-sufficiency and 
competitiveness", as the mission statement that emerged from two major 
conferences on East Timor strategic development plan (CNRT, 1 999, CNRT,  
2000f For farming commun ities, this mission impl ies the provision of adequate, 
appropriate , and timely technology, services, and market access to i ncrease their 
productivity and income .  
Fo r  convenience ,  a broader discussion of macroeconomics is avoided3. The 
macroeconomic pol icies related to agricu lture can be d ivided i nto two groups: those 
about wh ich there is general agreement on the need of government intervention ,  
and those about which d isagreements sti l l  remain (Timmer, 1 991 ) .  The former 
i nclude agricultural research , large-scale i nfrastructure investment ( incl ud ing 
i rrigation) and marketing infrastructure .  And the latter, involve exchange rates, price 
1 An earl ier version of this chapter was presented as a paper at the 'Action P lan of the Ministry of 
Agriculture, Fisheries, and Forestry (MAFF) 2002-2003 Workshop', 8-9 J uly 2002, Di l i ,  East Timor. 
2 The National Council of Timorese Resistance (CNRT in Portuguese acronym) was the organizer 
of two major conferences i n  d rafting a Sustainable Development Plan for East Timor prior to its 
independence. The first one was held in Melbourne Austral ia in 1 999 and the second was in Tibar, 
Liqu ica, East Timor in 2000. 
3 This topic has been dealt with qu ite extensively elsewhere (among others Hi l l  and Saldanha, 2001 ; 
Tarrant, 1 980; Timmer et a l . ,  1 983; and T immer, 1 998a). 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 98 
i nterventions, land tenure, and agri cultural extension . I n  other  words ,  the former are 
mainly dealt with by budget pol icy, which has a d irect impact on food , and 
agricultural pol icy through fund ing of p rojects, programs, and rural  investments 
(Timmer, 1 99 1 ). 
This chapter aims at synthesizing rel evant topics d iscussed earl ier in previous 
chapters in a contextual food pol icy approach . A l i terature synthesis on food 
security and agricultural development is presented and some key agricultural 
development chal lenges in the future are pointed out. As argued by Timmer 
( 1 998a), there i s  no country i n  the world that has ever sustained the process of 
rapid economic g rowth without first solving the problem of food security. Putting i n  
the context of  East Timor, a special emphasiS is  p laced on the importance of  root 
and tuber crops i n  the popular d iet and n ational economy. 
4.2 AGRICULTURE AS THE ENGINE OF GROWTH4 
Discussion i n  previous chapters has emphasized,  quite extensively, the role of 
agricultu re as the mainstay of East Timor's economy. However, to pursue 
agri culture as the engine of growth several condit ions have to be met as outl ined by 
Johnston and Mel ior ( 1 96 1 ) . They offer five ways in whi ch the agricu ltural sector 
can contribute to overal l  economic g rowth:  
1 .  Meeting  the food demands of a wealthier and g rowing u rban population, 
2 .  I ncreased exports as a means of earn ing foreign exchange, 
3.  Provid ing labour for the expanding sectors of the economy, 
4 .  Providing capital for i nvestment in the growing i ndustrial sectors of the economy, 
5. I ncreased cash i ncomes in the rural sector serve to i ncrease demand for the 
p roducts of the industrial sector. 
The contribution of the agriculture sector i nto East Timor' s  real GDP for the years 
1 998,  1 999 and 2000 was 24 .5, 25.5 and 2 1 .3%,  respectively .  Rural  population 
working as labour in agricu lture in the year 2000 was 75% of the total rural labour 
( I rawan,  2002) .  The agricu lture sector ,  therefore , should be a priority in economic 
development of East Timor, as this wil l also he lp the non-agriculture sector. Apart 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 99 
from the Johnston and Mel ior ( 1 96 1 ) l i nkage mentioned above , there a re two other 
sets of l i nkages between the agricultural sector and the non-agricultural sector that 
helps the g rowth of the agriculture sector (Saldanha and Da Costa , 1 999) .  
( i )  Lewis l inkage: the agricultural sector provides the non-agricultural sector with 
labour and capital . 
( i i ) T immer l inkages: where the contribution of agricultural growth to productivity in  
the non-agriculture economy stems from several sources: greater effic iency i n  
decision making as rural enterprises claim a larger share of  output; h igher 
productivity of industrial as urban b ias is reduced ; h igher productivity as nutritional 
standards  are improved; and l ink between agricultural p rofitabi l ity and household 
investments in rural human capital , which raise l abour productivity whi le faci l itating 
rural-urban migration .  
Timmer (2000) also emphasizes the importance of recogn izing that agriculture and 
the rural economy are g reatly i nfluenced by pol icies and outcomes in the rest of the 
economy. Of equal ly g reat importance are the non-market based inter-sectoral 
l inkages through which agriculture contributes ind i rectly to economic g rowth.  
According to Block and Timmer ( 1 994) these l i nkages arise from governmental 
learning by doing , increased economic stabi l ity , food security , and the relative 
effi ciency of rural  household decision-making .  A study in Kenya i nd icates that 
agricultural productivity contributes significantly to non-agricu ltural productivity 
(Block and Timmer, 1 994) .  
I t  is  therefore very important that adequate resources in East T imor  a re channel led 
into the agriculture sector to serve as the engine of economic g rowth . Da Costa 
( 1 995) points out that specific objectives for East Timor's agriculture should be set 
primari ly at increasing the level of nutrition of the people ;  improving the qual ity of 
agricultural commodities,  l ivestock and fisheries for inter-district market; providing 
val uable agricultural products for inter-regional market, and improving the qual ity of 
commodity - coffee - for both national and overseas market5. Much has been said 
4 For detai led discussion on economic growth in East Timor see Saldanha, J .  M. (200 1 ) Economic 
Growth in East Timor. Working Paper No. 09. East Timor Study Group, Di l i ,  East Timor. 
, See Da Costa, H. (200 1 )  Linkages between global ization ,  trade, investment and the envi ronment. 
Working Paper No. 07. East Timor Study Group, Di l i ,  East Timor. for the analYSis of comparative 
Chapter 4 - FOOD POLICY ,  AGRICULTURE AND ECONOMIC GROWTH 1 00 
about poverty i ncidence i n  East Timor i n  previous chapters. Empowering the 
farmers to produce surplus  food for sale is the first step on the ladder out of poverty 
(Hodges, 2005) .  And vice-versa,  a study by Adelman and Berck ( 1 990) suggests 
that poverty-reducing development strategies are the most food-securing  
strategies.  Likewise,  comprehensive food security and  poverty al leviation must be 
the foremost priority of the science and technology agenda (FAO/RAP, 2002). 
4.3 FOOD SECURITY 
Based on past achievements, one could easi ly expect that a continued i ncrease in  
food production  would not real ly be a major problem for East Timor (World Bank ,  
2002, FAOIWFP, 2000) .  However, experiences i n  many countries i nd icate that 
despite their i ncreased food production ,  there was sti l l  widespread malnutrit ion 
(FAO/RAP , 1 999,  FAO/RAP, 2002 , Tarrant, 1 980). Even l ittle correlat ion is found  
between national food ava i labi l it ies and  food i nsecurity (Smith et al . ,  2000). 
Literature also suggests that solution to food security is the pre-condition for a 
sustained and rapid economic growth (Timmer, 1 998a).  There are at least three 
major d imensions of food security :  avai labi l ity, accessibi l i ty ,  and uti l ization 
(Tweeten ,  1 997 ,  Timmer, 2000). 
1 .  AVAILABIL ITY of sufficient quantities of food of appropriate qual ity, suppl ied 
through domest ic production or imports ;  
2 .  ACCESS by households and i ndiv iduals to adequate resources to acqu i re 
appropriate foods for a nutrit ious d iet; and , 
3 .  UTIL IZATION of food through adequate d iet, water, sanitation ,  and healthcare . 
Food pol icy,  which encompasses a set of government efforts on food-related 
issues, should be put in place to be able to address such complex d imensions i n  a 
comprehensive manner (Timmer, 2000, P instrup-Andersen ,  2000). With respect to 
food uti l ization i n  East Timor i n  part icu lar, this  study proposes i ncorporating as 
advantages of East Timor's agriculture sector and its l inkages with globalization, trade, investment 
and the environment. 
Chapter 4 - FOOD POLICY,  AGRICULTURE AND ECONOMIC GROWTH 1 0 1 
much as poss ib le i nto the domestic food pol icy the use of tradit ional food crops 
such as cassava , sweet potato and other  root crops. 
4.3.1  The i m po rta nce o f  root cro ps 
Given its importance in the national and popular diet, root and tuber crops could 
play an important role in feeding the g rowing population of East Timor. Apart from 
cultural cons iderations on the communit ies' fami l iarity with tuber and root crops,  
cereal production as shown by h istorical data suggests a continued cereal deficit 
over the years (Central Board of Statistics , 1 997,  FAO/WFP, 2000, FAOIWFP, 
2003) .  Whi le the u rban populations consume rice as their  main staple food , the ru ral 
communit ies sti l l  rely on maize, and root and tuber crops as their major food and 
nutrient sources .  Despite the annua l  production increase of  cerea ls ,  legumes, a nd 
root crops as p resented in  Table 4 . 1  and 4.2 ,  the country is  sti l l  heavily dependant 
on food importation and food aid to cover its national food deficit. The fig ures in  
these tables and earl ier descriptions i n  Chapter 3 may demonstrate the significance 
of the root and tuber crops in  re lation to other major food crops. 
A n umber of studies suggests that many of the developing world 's  poorest farmers 
and food i nsecure people are h ighly dependent on root and tuber crops as a 
contri buting ,  if not the princ ipal ,  source of food , nutrition , and cash income (Scott et 
al . ,  2000, FAOIWFP,  2000, FAOIWFP,  2003).  Hence ,  an  improved understanding of 
the production , uti l ization,  trade ,  and estimated future economic importance of these 
crops has potentially far-reaching impl ications for i nvestments in agricultural 
research at both the international and , more importantly, national  l evels (Scott et al . ,  
2000). 
Empirical energetic significance of root Ituber crops and their contribution in  rural 
industries may be, among other factors, of great re levancy to East Timor. Evenson 
and De Boer ( 1 978) ,  analysing aggregate data on worldwide energy production and 
resource al location in semi-subsistence food product ion system ,  emphasized the 
potentia l  contribution of i ncreased root and tuber crop productivity in  food 
energetics. They conclude that, with in  their envi ronmental range,  the major tropical 
root and tuber crops a re capable of superior energy yields over most other food 
crops both i n  monoculture and mixed cropping and therefore can be the dominant 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC  GROWTH 1 02 
factor i n  rais ing energy output per unit area i n  either pure or mixed stands . (Evenson 
and De Boer, 1 978) .  I n  Asia ,  root and tuber crops (cassava , sweet potato and 
potato) supply most of the starch used by industries ,  largely rural-based , where 
smal l  fi rms coexist with large starch mi l l s  to provide i ntermediate p rocessing despite 
d iseconomies of scale (Fugl ie ,  2004). 
Research on cassava and pulse in  East Timor is  increasing under  the Seeds of Life 
Project with some promis ing resu lts. Severely l imiting soi l  i ron and zinc 
concentrat ions to newly i ntroduced cassava breeding l ines were found in  Baucau 
and Betano .  Such micronutrient deficiencies are usual ly  very easy and inexpensive 
to rectify. I n  spite of that, these l i nes signi ficantly out-yie lded the local cassava 
varieties (Howeler et al . ,  2003) .  Sweet potato and cassava developmental status 
and future prospects have been presented by Setyono et al. ( 1 992) .  
Especial ly with regards to t i l lage6 , root and  tuber crops are sensitive to soil 
compaction ,  i nadequate aeration or poor drainage and therefore respond favorably 
to i ntensive t i l lage, fol lowed by ridging or mounding (FAO/WFP,  1 994 , Howeler et 
al . ,  1 993) .  However, l arge differences exist between crops, with potato, sweet 
potato and yam requ i ring more i ntensive cultivation than cassava and taro (Howeler 
et al . ,  1 993) .  In order to reduce erosion as well as production costs, cassava should 
be grown with as l ittle ti l lage as possible as long as high yield can be mainta ined .  
Contour ridg ing and mulching are other practices that not on ly tend to increase 
yields but a lso reduce erosion losses. 
4.3.2 Food supply 
Food avai lab i l ity h ighl ights supply of food (from production ,  stocks and imports) at 
the national level and production and inventory at the farm level . There are no major 
problems facing the population in terms of food supply accord ing to F AO/WFP 
assessment reports (FAO/WFP, 2000, FAO/WFP, 2003). The national requirements 
for major staple food have been estimated at 1 82 ,000 tons for 2003/4 ,  whi le the 
domestic production only reached two thirds of the requi rements ( 1 22 ,000 tons) .  
The deficit was covered by importation  and food aid (FAOIWFP,  2003). 
6 Til lage practices and thei r i mpacts on soi l  losses and crop and biomass yield wi l l  be the main focus 
of d iscussion in Chapter 5 and 6 .  
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 03 
Table 4 . 1  East Timor major staple food crops: cropping area ,  production and yie ld 
1 992-1 997 
C rop Variable Year 1992 1993 1994 1995 1996 1997 
Hectares 1 8 , 897 1 9 ,860 2 1 ,740 1 8 , 084 21 ,202 2 1 ,7 1 1 
Rice Tonnes 56, 359 64,060 66,985 46,696 69,465 7 1 ,958 
Tonnes/Ha 2 .98 3 .23 3 .08 2 .58 3 .28 3 .3 1  
Hectares 60,423 6 1 ,056 62,020 56, 1 38 64,434 63 ,388 
Maize Tonnes 94 , 354 1 04 ,424 1 1 5 ,680 1 03,039 1 22 ,493 1 26 , 321 
Tonnes/Ha 1 .56 1 .71  1 .87 1 .84 1 .90 1 .99 
Hectares 1 3 , 3 1 2  1 2 ,940 1 9, 1 0 1 1 8, 994 1 9 ,490 20,51 5 
Cassava Tonnes 51 , 568 69,9 1 0  74, 3 1 8 75,642 78, 1 25 85,287 
Tonnes/Ha 3,87 5,40 3 ,89 3 ,98 4 ,01 4 , 1 6  
Sweet Hectares 2 ,749 4,052 5, 1 67 4,634 4,304 4 ,271 Tonnes 1 0 ,433 1 9 , 1 1 4  1 8 , 026 1 8 ,246 1 7 , 1 1 1  1 7 ,648 potato 
Tonnes/Ha 3 .80 4 .72 3 .49 3 .94 3 .98 4 .33 
Source: Central Board of Statistics ( 1 997) 
Table 4 .2 East Timor major legumes: cropping area, production and yie ld 1 992-
1 997 
C ro p  Vari a b le 
1992 
Mung Hectares 4,754 Tonnes 3 ,926 beans 
Tonnes/Ha 0.83 
Hectares 3 ,367 
Peanut Tonnes 2 ,929 
Tonnes/Ha 0.87 
Hectares 1 ,524 
Soybean Tonnes 1 ,230 
Tonnes/Ha 0 .8 1  
Source: Central Board o f  Stat istics ( 1 997) 
4.3.3 Access to food so u rces 
1993 
4,986 
4,238 
0 .85 
3,597 
3,20 1  
0 .89 
1 , 867 
1 , 587 
0 .85 
Yea r  
1994 1995 1996 1997 
1 ,424 2 ,963 3 ,823 3 ,977 
1 , 1 99 2 ,496 3 ,688 4 ,079 
0 .84 0 .84 0 .96 1 .03 
4 ,701  3 ,845 4 ,846 5 ,095 
4,5 1 3  3 ,8 1 1 5, 1 24 5,500 
0 .96 0 .99 1 .06 1 .08 
851 1 , 1 48 1 , 1 84 1 , 399 
809 91 5 1 , 38 1 1 ,686 
0 .95 0 .80 1 . 1 7  1 .2 1  
Food accessibi l ity concerns the effective demand and purchasing power of 
consumers . It is obvious from the present s ituation that food security is pr imari ly a 
function of buying power from earnings or transfers . Ma in  development ind ices 
show that the majority of the population fal ls  below the poverty l ine (GoTL, 2006, 
UNDP ,  2006).  Food self-suffic iency, as was the core objective of development of 
the food sector in East Timor during the past decade,  s hould be de-emphasized 
al lowing more focus  on food security (MAFP,  2004) .  
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 04 
The l i terature suggests that no matter how much food is  produced it wil l  have l ittle 
effect on those who a re u nable to buy it (FAO/RAP, 1 999, FAO/RAP, 2002 , 
Tarrant, 1 980). I nd ia  for example, i n  the 1 976,  1 977,  and 1 978 had considerable  
stocks of  g ra in  after three successive good production yea rs (Tarrant, 1 980) .  
Imports were reduced to zero and i n  certa in special circumstances I nd ia began 
export ing g rains .  Despite this there was sti l l  widespread malnutrition and yet further 
improvements in  production would have done l i ttle to remove this  (Tarrant,  1 980). 
To combat hunger and poverty, it is worthwhi le learning l essons from other  
countries and a quite useful l esson would be that of I ndonesia. I ndonesia used the 
agri cu ltural sector and the rural economy to provide  the foundation that permits the 
development strategy to pursue growth , stabi l ity, and equity Simultaneously and to 
pursue them in a complementary rather  than a competitive fashion (Timmer, 
1 998b) .  I t  impl ies structuring the development growth process from the very 
beginning to help solve the problem of poverty. From a b roader view of 
development it inevitably means find ing a strategy for raising the productivity of 
rural labour, and emphasizes the agricultural development of smal l  farmers .  
Projecting  from the current s ituation ,  it i s  not unexpected that i n  the short-run food 
insecurity may prevail i n  many areas, affect ing a l arge number of people . Currently, 
this lack of access to food is due to d isruption of i nterna l  markets, poor roads, and 
l imited means of  transportation ,  as well as the loss of  productive assets and income 
generating activities.  At the microeconomic level , i nadequate and i rregular access 
to  food l imits labour productivity and reduces investment in  human capita l .  At the 
macroeconomic level , periodic  food crises undermine pol itical and economic 
stabi l ity, reducing both the level and the efficacy of investment (Timmer, 1 998a). An 
appropriate domestic food pol icy is  expected to remove th is food insecurity . 
4.3.4 Food a n d  n utrit ion 
Ideal ly, food security means that a l l  persons at a l l  times utilize the food necessary 
for an active and healthy l ife (Tweeten,  1 997) .  People may sti l l  experience food 
insecurity if food is  avai lable and accessib le ,  but they fai l  to consume adequate 
nutrients . It is therefore, a matter of g reat concern that consideration  be g iven to 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC  GROWTH 1 05 
other vital food security components such as education , i nformation systems,  
health, and nutrition .  
From a nutritional paint of  view, however, the crucial variable may be food 
production,  rather than agricultural production as a whole. I n  this regard ,  it is worthy 
of attention to i nclude traditional food crops such as maize, cassava, sweet potato, 
and other root crops in the domestic food pol icy. H istorical ly, pol icy makers and 
researchers have paid very l ittle attention to root crops, as most of the ir  efforts have 
been concentrated on cash crops or the more fami l iar grains .  Root crops were 
regarded as food mainly for the poor, and have played a very minor role in the 
i nternational trade (FAOIWFP, 1 994) .  According to this source, very few people 
from tropical countries suffer from a simple protein deficiency.  The most prevalent 
deficiency is protein-energy, i n  which an overal l  energy deficiency forces the 
metabolism to util ize the l imited i ntake of protei n  as source of energy. This is an 
area in which root crops cou ld play a more significant role as additional source of 
d ietary energy and protein .  
A short summary of nutritional val ues comparing selected foodstuffs i s  g iven below: 
Box 4. Nutritional comparison of rice, root/tuber, legumes and edible greens 
(Bradbury and Hol loway, 1 988) 
Energy rice (boi led ) - root crops - legumes > edible greens 
Protein  legumes > edible g reens > rice (bOi led) > root crops 
Minerals (Ca, Fe) legumes > edible greens - root crops > rice 
Vitamins edib le  greens > root crops - legumes > rice 
The contribution of root crops in the domestic d iet may be insignificant for the time 
being, due to the low yields. However their genetic potential for producing 
i ncreased yields is high and has not yet been ful ly exploited . In addition , some root 
crops are highly adaptable,  producing reasonable yields from marg inal lands with 
h ighly erratic rainfal ls .  This very fact has heightened the attention  being paid to 
tuber crops i n  many cou ntries i n  Africa e .g .  Kenya and Zambia (FAOIWFP,  1 994), 
I ndonesia (Setyono et al . ,  1 992) and the South Pacific  (Bradbury and Hol loway, 
1 988) .  I n  the case of East Timor, the misconception that root crops are a poor food 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 06 
source has long prevai led, partly because of the lack of appreciation of the number 
of people who depend on these root crops,  and the number of l ives that have been 
saved du ring the strugg le for independence by root crops . Therefore, more 
attention should be g iven to the potentia l  of root crops by researchers and pol i cy 
makers in  the future . 
4.4 A FOOD POLICY APPROACH 
Literatu re and evidence in many countries  suggest that food security is i nseparab le 
with overcoming poverty . Because poverty is a function of the level and d i stribution 
of national i ncome, food security cannot be separated from economic development. 
In essence , according to Tweeten ( 1 997 ), food security embodies d isciplin es 
ranging from nutrition at the i nd ividual l evel , to family economics at the household 
level , to al l -weather road construction and mai ntenance at the reg ional level, to the 
economic development pol icy at the national level, and to trade and aid at the 
i nternational  leve l .  At the national level food security has two principal components: 
( i )  b road-based , sustainable economic p rogress relying on the private sector under 
supportive publ ic  policies to raise most people out of poverty and food insecurity; 
and ( i i )  targeted food g rants to those who lack resources and income or other 
means of food security. 
Food pol icy encompasses the government col lective efforts to infl uence the 
decision-making environment of food producers, food consumers,  and food 
marketing agents (Timmer et a l . ,  1 983) in  order to address the issues of food 
security mentioned above . The objectives of a n ational food pol icy in  most 
societies,  which are of g reat re levancy to East Timor, a re:  
1 .  Effi cient g rowth i n  the food and agricu ltural sectors, 
2. I mproved income distribution ,  primari ly through efficient employment creation ,  
3 .  Satisfactory nutritional status for the enti re population through provis ion of a 
subsistence floor, 
4. Adequate food security to ensure against bad harvests , natural d isasters , or 
uncertai n  world food suppl ies and prices . 
It i s  not with in  the scope of th is paper to provide a food pol icy analysis ,  a s  it 
involves research and analysis on food pol icy components and objectives ,  and the 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 07 
identification of government in it iatives to achieve these objectives .  Rather, a 
general overview on food pol icy as part of economic development i s  provided .  As 
has been mentioned earl ier, food security, which embodies the above objectives, i s  
an inherent part of economic development. And accordi ng to  T immer (1 998a) the 
food and agricultural sector cannot grow rapidly and efficiently for prolonged 
periods of time un less a set of macroeconomic pol icies is in p lace whose ma in  
purpose i s  to  stimulate the rest of the economy to grow rapidly and efficiently .  
4.4. 1 Researc h  a n d  exten s i on 
Agricultural research and extension in  the future can have a very high economic 
payoff. I t  i s  worth trying to do i n-country basic research ,  but the payoff is usual ly 
h igher from appl ied research emphasizing the local adaptation of technolog ies from 
elsewhere (Thi rt le et al . ,  2003, FAO/RAP,  2002) .  It i s  widely recognized that the 
major impetus behind technolog ical change is research and development, whi le 
education and experience are critical to improving managerial capabi l ities to make 
efficient use of a given technology (Bravo-Ureta , 2002) .  
Extension has traditional ly been considered a role of government. However, i t  is 
worthwhile to consider that the government may not be able to provide free 
extension services to al l  farmers du ring the post-transitory period . The government 
schemes may not be the most effective in provid ing services ,  and a more workable 
approach may be to pass the extension role to the p rivate sector i nclud ing NGO's  
(Nitta and Yoda ,  1 995, Fujisaka, 1 994) ,  i n  other  words ,  through the privatisation of 
extension service (Bravo-U reta , 2002). 
4.4.2 I n frastruct u re 
Road , bridge,  seaport, airport, electricity, communication , and major i rrigation 
faci l it ies are among the basic infrastructure faci l it ies the WB-JAM put forward as 
priorities  in the reconstruction phase (WB-JAM , 1 999) .  These faci l ities in the short 
and long run can be worthy publ ic investments serving the p rivate sector and food 
security. I n  addition,  appropriate infrastructure makes p rivate markets work wel l  and 
raises national income. Sen ( 1 989) suggests for a publ ic d istribution system geared 
to the needs of the vulnerable sections of the commun ity can bring the essentials of 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 08 
l ivel ihood with in  easy reach of people whose l ives may remain otherwise relatively 
untouched by the progress of real national  i ncome.  
4.4.3 Price i nterventions 
Price i nterventions generally cover three main areas: agricultura l  i nput price policy, 
agri cultural product pol icy, and agricultural finance pol i cy. A common operational 
approach in the macroeconomic context i s  food price stabi l ization , which confers 
several benefits (Timmer, 1 989). For food producers, it reduces the risk they face 
making productive investments. The reduced risk may help by promoting farmers' 
i nvestments in new innovations and technologies leading to i ncreased farm 
productivity. Consumers benefit from stable food prices because they do not  have 
to i ncur the transaction costs from real locating their budgets frequently, nor face the 
risk of a sudden and sharp deterioration in their real i ncome. 
4.4.4 L a n d  te n u re 
The key issue i n  land tenure policy is how it can be used to improve both equity and 
efficiency. One way of increasing rural employment and agricultural production is 
through real location of the resources of production ,  espeCial ly land . Land reform 
including the redistribution of land and issu ing of land titles to secure land tenure is 
one of the solutions being proposed to the government (UNDP,  2006). The land 
reform in  Tawain ( 1 949-53) i s  an example of successful land tenure promoting 
widespread technical  change in Tawainese agriculture of today (Griffin ,  1 979). 
African experience suggests two viable ways to improve the food security status of 
the landless and the land-poor farmers .  F irst, i s  to g ive them access to land ,  and 
secure their use rights by implementing a land redistribution  pol icy. Second is  to 
enable the land less to engage i n  viable non-farm employment opportunit ies 
(Tolossa , 2003) .  
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 
4.5 CHALLENGES FOR THE FUTURE 
4 . 5 . 1  U rban ization and p ro d u ctio n  demand 
1 09 
I n  the future , a massive u rbanization wil l  be of major concern , need ing especial 
attention . An increased need is  foreseen for basic infrastructure, as well as urban­
oriented food security pol ic ies (McCal la ,  1 998). With these changes wil l  come the 
need for i ncreased investment in 'the beyond the farm gate marketing system '  to 
accommodate a very large  increase in the demand for marketing services .  
Accord i ng to McCal la (1 998), at  l east five factors wi l l contribute to the i ncrease i n  
th is demand : ( a )  expanded use  of purchased i nputs in  i ntensified farming systems;  
(b) a more than doubl ing of  the volume of food moving from farms to towns and 
cities ;  (c) the i ncome induced demand for peri shable products (fruits, vegetables,  
and animal products); (d)  i ncreased demand, with ris ing incomes,  for additional 
services (e .g . ,  packaging , portion contro l ,  and location) to be incorporated i nto food ;  
and (e) the possibi l ity of expanded non-traditional  exports to industria l  countries. 
4.5.2 Labo u r  a n d  mec h a n izati o n  
There are some problems  and  prospects of  agricu ltural mechanization i n  the 
developing countries,  some of which have been d iscussed earl ier in Chapter 3 
(Morris ,  1 985, EI-Hossary, 2002). They are farm s ize and tenure, characteristics of 
tractor stock (ownership ,  condition  and annual use) ,  management and technical 
problems ,  i nstitutional aspects of farm mechanization (extension service , research 
and tra in ing i nstitutions, repair  and  maintenance network and local production of 
farm equ ipment). In addition ,  trends of agricu ltural mechanization in most 
technolog ical advancing countries are energy saving in agricultura l  mechanization 
and research and development i n  the world of industry (EI-Hossary, 2002) .  
Table 4 .3  describes the composition of  work force i n  East Timor. Both the rural and  
u rban labour forces are estimated to be on the  rise i n  the next 10  years. Many of 
the factors stimulating labour demand become, in  the right circumstances,  a 
stimu lation for farm mechanization  and hence lead to a reduction  in  labour demand 
(Tarrant, 1 980) .  Where multiple cropping is possib le ,  s peed is  of the essen ce i n  the 
preparat ion of the ground and the p lanting of each crop.  S im i larly, the harvest must 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 1 0  
be quickly accompl ished to clear the g round for the next crop .  Government fiscal 
pol icies may actively encourage mechanization .  I nternational aid from some donor 
countries to East Timor is channel led in the form of farm machinery ,  and th is may 
encourage mechanization as wel l .  Government-sponsored schemes for the 
provision of rural  credit, especial ly as these generally favour  larger  farmers  whose 
lands make suitab le col lateral for loans,  may encourage the purchase of machinery 
at low real prices (MAFP, 2004).  
Table 4.3 Composition of the work force i n  East Timor (thousands) 
I n d i cator 2004 2007 201 0 201 5 
Rural labour force 206.9  229.8 255.4 300.7 
- Subsistence farming 1 39 .7 1 52 .9 1 65.0 1 77 .2 
- Commercial activit ies 67 .2 76.8 90 .4 1 23.5 
Urban labour  force 6 1 .0 72 .2 85 .6 1 1 3. 5  
- Public sector 1 7 . 5  1 9.5  23.0 30.0 
- Private sector 43 .5 52 .7 62 .6 83 .5 
Unemployed 21 .4 23.4 25 .7  28.8 
Total work force 289 .3 325.4 366.7 443 .0 
Memo items:  
- Subsistence farming (%) 48.3 47.0 45 .0 40.0 
- Unemployed (%) 7.4 7 .2 7 .0 6 .5 
- Rural labou r  force 77 .2 76 . 1  74 .9  72.6 
Source: GoTL (2006) 
The effect of farm mechanization is to create the need for a sma l l ,  ski l led labour 
force to use and maintain the equ ipment .  However, farm sizes are general ly sma l l ,  
and mechan ization wi l l  make l ittle headway unless either  technology provides 
machines appropriate for smal lhold ings or substantia l  farm amalgamation takes 
place. But where conditions are l ess suitable (for example irrigated land is  a smal ler 
proportion of cultivated land) and provided government incentives are avai lable to 
the farmer through cheap credit, and to manufacturing industry through tariff 
pol icies and subsid ies , mechanization wi l l  d isplace substantial q uantit ies of rural 
l abour. 
4.5.3 P rod uctivity growt h 
Future productivity growth is  l i kely to come from three main sources: agricultura l  
research , technology transfer systems  (extension and education) ,  and agricultura l  
support pol icies.  Over the long-term, the chal lenge for researchers w i l l  be to 
Chapter 4 - FOOD POLICY ,  AGRICULTURE AND ECONOMIC GROWTH 1 1 1  
continue to sh ift the production frontier u pward (outward) through development of 
new technolog ies . The major source of upward movement wil l  continue to be 
varietal improvement (Morris and Byerlee,  1 998) .  In East Timor however,  it is 
worthwhi le to de-emphasize the i ntroduction of the h igh yie ld ing varieties (HYV's)  
seeds,  al lowing more focus on the improvement of  local seeds .  The 
encouragement of  the use of  these modern varieties in  many countries to  reduce 
their imports of food has been made possible so far only by subsid izing both i nputs 
and outputs. One of the major i nputs is ferti l izer. And for a newborn country, 
subsidies for farming inputs and outputs could be very costly and therefore a 
careful analys is  on selective subsidy pol i cies is  requ i red (MAFP,  2004) .  
Decentralization in  agricultural research wil l  be requ i red , leadi ng to it being  more 
strongly farmer-oriented , and more closely l inked to the technology dissemination 
process . G reater farmer participation wi l l  be needed to adapt technologies to local 
circumstances ,  to improve the effic iency of technology transfer activities . Farmer 
organizations wi l l  i ncrease in  importance relative to ind ividual farmers, because 
many new i nformational technolog ies wil l  have to be managed at the district and 
vi l lage levels (Fuj isaka, 1 994, MAFP ,  2005). The emphasis in  technology 
d issemination wi l l  have to shift from communication to education . I nstead of merely 
seeking to del iver specific messages to farmers ,  extension agents will have to 
concentrate on providing farmers with the knowledge and ski l ls needed to better 
manage information-intensive technolog ies. Agricultura l  support policies a lso wil l 
have to change to accommodate the emerging information-based technolog ies 
from input subs id ies to increased i nvestment in  publ ic good aspects of technology 
development and dissemination (Kaimowitz, 1 993,  Saeed,  1 982) .  
4.5.4 Ag ri c u ltu ral sustai n a b i lity 
The agricultural system must be both sustainable and h ighly productive in the futu re 
if it is to feed the growing human popu lation. For th is twin  chal lenge to be met, 
Poincelot ( 1 986) recommended a new approach to agriculture and agricultural 
development that bui lds on resource-conserving aspects of trad it ional ,  l ocal ,  and 
small-sca le agriculture whi le  at the same time drawing on modern ecolog ical 
knowledge and methods .  Traditional  agriculture, despite its market l imitations,  can 
provide models and practices valuable in developing susta inable agriculture.  The 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 1 2  
mainstream approach to modernizing agricu lture o n  the other hand,  apart from i ts 
successes promoted by scientific advances and technological innovations, has led 
to dependency on external i nputs, e .g .  seed , ferti l izer, pesticides, mach inery and 
fossi l fuels (Gl iessman, 1 998) .  
In essence, agricultural practices tend to degrade the resource base and the 
challenge for modern agriculture is to min imize this degradation . East Timor, as a 
semi-arid region,  has a different d imension as here one is deal ing with low-in put 
technology, and resource-poor farmers working i n  a highly unpredictable 
agrocl imate and with a highly variable and low qual ity natural resource base . In this 
context, sustainable agriculture is largely a function of the socioeconomic 
cond itions and is frequently control led by these conditions. A great chal lenge for 
East Timor agriculture scientists in the future is to find alternative ways to increase 
agricultural productivity whi le preserving or even improving the agricultural resource 
base. 
4.6 CONCLUSIONS 
This chapter concludes by stressing the importance of solving the problem of food 
security if the process of a rapid economic growth is to be sustained . Three 
d imensions of food security, namely food avai labi l ity, accessibi l ity, and uti l ization 
have been briefly highl ighted . Because food security concerns primari ly the buying 
power of ord inary citizens, it is i nseparable with poverty. Furthermore, poverty in 
turn , is a problem that can be solved only by profitable and equitable economic 
development. In  th is context, an appropriate domestic food pol icy may he lp reduce 
hunger and poverty. The incorporation of the traditional food crops into the 
domestic food pol icy is especial ly put forward into d iscussion . 
Chal lenges i n  the future ,  both for the government and private sectors are 
undoubtedly enormous. Production demand in view of potential massive 
u rbanization ,  productivity growth demand, debate of rural labour versus 
mechanization ,  and more importantly the u rgent need for a sustainable agricultural 
strategy are among the main topics chal lenging East T imor agricu lture in the future. 
Chapter 4 - FOOD POLICY, AGRICULTURE AND ECONOMIC GROWTH 1 1 3 
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TILLAGE AND EDAPH IC CHANGES 
Impacts on crop and biomass production 
5 . 1  INTRODUCTION 
I n  recent decades, the possible adverse effects of conventional ti l lage on the 
agricultural  resource base have become increasingly apparent. Greater attention is  
turned to techniques that requ i re less d isruption of the land itself, i ntroducing new 
soi l  and water management techniques (Barkin ,  2001 ) and other  alternative 
management methods .  Many of these alternatives have been based upon the 
principle of reducing the n umber and i ntensity of t i l lage operations ,  which a re 
commonly known as conservation ti l lage p ractices (Gajri et a l . ,  2002) .  The most 
obvious advantage of conservation ti l lage from an environmental v iewpoint is its 
role in m inim izing the risk of erosion . Surface residues protect soil structural 
conditions at the surface from the energies of raindrop impact and surface flow and 
the soil losses due to wind erosion .  Aggregate breakdown , surface seal ing and 
crusting , and clogging of worm holes or voids between structural uni ts is  reduced 
(Bradford and Huang,  1 994) .  
Ri ley e t  a l .  ( 1 994) suggested that many of the changes caused by  conservation 
ti l lage practices are interrelated , and their consequences may be of g reater or 
lesser importance ,  depending on the soil type and on the external constraints of the 
cl imate . These changes can be summarized as fol lows: 
• Accumulation of avai lable nutrients (phosphorus and potassium )  and organic 
matter near the soi l  surface; 
• I ncreased bulk density and penetration resistance in upper and central topsoi l  
layers; 
• Lower a i r-fi l led porosity and gaseous exchange and, sometimes,  h igher water­
hold ing capacity ;  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES; Impacts on crop and biomass production 1 1 8 
• Lower surface i nfi ltration rates, but i n  some cases, increased hydraul ic 
conductivity between topsoil and subsoi l ;  and 
• Greater aggregate stabi l ity, greater earthworm activity, and more favourable 
conditions for promoting pore continu ity .  
Holland (2004) summarizes that conservation til lage can improve soil structure and 
stabi l ity thereby faci l itating  better drainage and water hold ing capacity that reduces 
the extremes of water logging and drought. These improvements to soil structure 
also reduce the risk of runoff and poll ution of surface waters with sediment, 
pesticides and nutrients. In addition, by reducing the intensity of soil cultivation it 
lowers energy consumption and the emission of carbon dioxide, whi le  carbon 
sequestration is rai sed though the increase in soil organic matter (SOM).  
This chapter aims to present some empirical evidence based on field experiments 
on how different ti l lage systems  exert different impacts on soil properties and crop 
performances. Of prime importance is to find out specific relationships between 
selected parameters under study and to contribute to a better understanding of soil 
- mach ine - crop interactions. Supported by research data from other sources, the 
discussion wi l l  help complement the topics d iscussed in the early chapters . With 
chapter 2, particularly  on the issue of traditional sh ifting cultivation ,  th is study helps 
to support pol icy design to avoid replacing the slash and burn , especial ly on the 
slopes, with i ntensive t i l lage-based cropping systems.  Moreover, the use of manual 
t i l lage in this study may provide i nsights and confirm some research findings 
discussed in chapter 3 on mechanization . I n  addition , potato as a tuber crop is 
tested under various ti l lage management systems, wh ich can also make relevant 
contributions to the d iscussion on food policy in chapter 4 .  
Due to a wide range of resource l im itations ,  i t  was not possible to set up specific 
experiments or fie ld surveys in East Timor to address the issues discussed i n  the 
respective chapters . This research therefore was l imited only to study the impacts of 
soil t i l lage on selected soil physical and chemical properties to provide an 
assessment of so i l  structure su itabi l ity for crop production management. As part of 
the broader objectives stated earl ier, the assessment was contextual ly employed 
into two contrasting environmental settings. The semi-arid environment of East 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and b iomass production 1 1 9 
Timor with its generally trad itional mode of farming was the first focal poin t  
( Experiment 1 - ET) .  However, due to  the l ack of  supporting systems, and part ly 
because of financial and t ime constraints, the establ ishment of a proper 
experimental station could not be rea lized in  East Timor. Instead, only a small 
experiment was carried out in  a local farmer's paddy rice fie ld on the outskirts of 
Di l i ,  the capital of East Timor. Due to the l imitations cited above , this experiment 
was merely designed as a qu ick test of the research methodology to a specific 
environmental condition of East Timor. I n  anticipation of the min imal  results from 
this fieldwork, and to complement these results with others from a d ifferent 
envi ronmental background, another set  of experiments was carried out at  Massey 
Un iversity Campus in  Palmerston North , N ew Zealand (Experiment 2 - NZ). 
5.1 . 1  Scope and l i m itatio n s  
This study covers changes in  selected soi l  physical  and chemica l  properties that 
occur as a result  of implementing d ifferent ti l lage systems .  Their impacts on crop 
yield and biomass are also investigated . 
It is acknowledged however, that the results obtained under New Zealand 
cond itions are not transferable to East Timor's as such g iven the s ite-specific  and 
crop-specific nature of an experiment of th is kind .  Contrasting  soi l  and cl imatic 
cond itions in these two countries strongly d ictate each own specific characteristic 
for t i l lage and crop production research . Nevertheless the principles and lessons 
can be learnt and the results may contribute both ways, to East Timor and to  New 
Zealand , i n  find ing a better understand ing of  a traditional  farming system and in  
seeking better ways to preserve so i l  and water resources for a susta inable 
agri culture. 
5.1 .2 Objectives 
The specific objectives of this research were :  
( i )  To measure selected soil physical and chemical properties under  d ifferent t i l lage 
systems i . e .  no-ti l lage, manua l  t i l lage ,  mouldboard plough (ET) and permanent 
pasture (NZ) (as control treatment) .  The important soi l  properties  considered in 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 20 
this research are soil penetration resistance , soi l  bu lk density, soil water 
content, soil hydraul ic conductivity ,  soi l porosity, soil aggregate stabi l ity, and 
selected soil chemical properties such as soil pH ,  total C and N and Olsen P .  
( i i )  To measure and compare selected crop yield and total biomass of corn , 
mungbeans, potato, barley, and weeds under a semi-arid and temperate 
cl imate as affected by d ifferent t i l lage treatments . 
( i i i )  To examine the relationsh ip between soi l  physical and chemical characteristics 
and crop and biomass production mentioned above . The d iscussion is further 
focused on the extension of improvement of such soi l properties and their 
impacts on crop and biomass resulted from the until led plots relative to the 
conventional ly cultivated plots. 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 21 
5.2 LITERATURE REVIEW 
5.2. 1 I ntroduction 
Til lage is a major input in agricu ltural production aiming at optimising crop 
production and conserving or improving production resources. It is traditional ly 
carried out by the use of plough , an ancient tool for soi l and seedbed preparation . 
Ploughing ,  despite its long h istory, is  sti l l  among the least scientifical ly understood 
practices in  terms of its impact on soi l and environment qual ity and on the 
sustainable use of natural resources (Lal , 2004a) .  It is performed to bury the crop 
residues, incorporate ferti l izers and amendments into the soi l ,  k i l l  weeds ,  obtain a 
good seedbed , modify the hydrothermal regime and aeration status ,  and improve 
root penetration (Gajri et al . ,  2002) .  
When used judiciously t i l lage can al leviate soi l-related constraints to crop 
production such as compaction, crusting, low infiltration , poor d rainage, 
unfavourable soi l moisture and temperature regimes, disposal of undesirable 
biomass and wastes, and pest management (Lal , 1 99 1 ). I ntensive ti l lage on the 
other  hand can lead to deterioration of soil structure , reduced infi ltration,  
accelerated runoff and erosion , water pollution , leading to d iminished friabi l ity and 
lower workabi l ity and degradation of soi l  and environment (Kay and Munkholm ,  
2004, Carter, 1 994) .  The use of large-scale mach inery favouri ng i ncreased field 
size, accompanied by e l imination of hedgerows and the sods to support draft 
an imals, led to considerable erosion by wind and water in parts of the United States 
of America (Wolf and Snyder, 2003) .  
There i s  however no universal agreement on what constitutes efficient ti l lage as it is  
largely soi l and crop-specific and governed by both b iophysical and socio-economic 
factors (Hi l lel , 1 980, Lal , 1 995,  Carter, 1 994) .  Conventional t i l lage with annual 
mouldboard plough ing is sti l l  the most common practice in humid areas whereas 
reduced ti l lage has been extensively adopted in subhumid and semiarid areas with 
h igh erosion risks (Kay and Munkholm ,  2004) .  Sprague ( 1 986) noted that under 
certain soil and cl imatic conditions, intensive use of ti l lage has caused excessive 
soil degradation , inadequate control of weeds ,  undesirable soil moisture 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 22 
management coupled with time and energy inefficiency. These wil l  lead to 
deterioration of soil physica l ,  chemica l ,  and biological qual ity over the long-run 
(Erkossa et al . ,  2006). 
I t  is therefore imperative to find alternative means to improve production with the 
creation of a sound environment for crop growth which conserves and recharges 
soil and water resources. Conservation ti l lage is one of the means which may offer 
opportun ities to attai n  these objectives. One of the main reasons for developing 
conservation ti l lage systems according to Steed et al .  ( 1 994) was the need to arrest 
various forms of soil degradation caused by the traditional ti l lage systems. The 
purpose of th is review is to briefly describe and examine the differing principles and 
practices of conventional and conservation t i l lage,  its environment impacts, and i ts 
effects on crop performance and soi l  properties . 
5.2 .2 P ri n c i ples of t i l l age 
Ti l lage can be described as a method of mechan ical ly modifying structural un its of 
soi l  for the purpose of improving plant and soil productivity (Smucker and Erickson , 
1 988) by creating conditions for gas, water, chemical , and heat movement in 
agricultural soi ls  that provide an optimal habitat for crop growth (Leij et al . ,  2002). It 
is  performed in a certain  sequence/combination requ i red to prepare soil ,  p lant 
seeds, and control weeds (Gajri et a l . ,  2002) .  Til lage using contemporary power and 
implement systems can excessively t i l l  and compact many soil types with few 
passes. I n  th is case , ti l lage can drastical ly change and at the same time destabi l ize 
soi l structure (Hadas, 1 997) .  
Th ree primary aims are general ly attributed to t i l lage: ( i )  control of weeds, ( i i )  
i ncorporation of organic matter into the soi l ,  and ( i i i )  improvement of soi l structure 
(H i l le l ,  1 980, Cassel and Nelson , 1 985) .  An auxi l iary function of ti l lage, sti l l  
i nsufficiently wel l  understood which thus incurs a great deal of  research worldwide,  
i s  the conservation of soi l moisture involving rain  infi ltration , runoff, and evaporation 
(Castro Fi lho et a l . ,  1 991 , Singh et al . ,  1 993 ,  Biamah et al . ,  1 993, Aina  et a l . ,  1 99 1 , 
Freebairn et a l . ,  1 993, Unger and Cassel ,  1 99 1 , Gicheru et al . ,  2004) .  Also, by 
burying the plant residues and loosening the soil surface, it enhances the surface 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and b iomass production 1 23 
energy and water exchange, permitt ing relatively rapid drying and warming in  the 
spring (Robinson et aI . ,  1 994) .  
Since the soi l  is normally at field capacity after winter, the conventional system 
impl ies a major risk of soi l  compaction ,  and the new types of seed dri l ls al low early 
sowing of spring cereals without harrowing (Arvidsson et a l . ,  2000) ,  which cou ld  be 
an important factor influencing crop yields (Robinson et a l . ,  1 994) .  The study by 
Arvidsson et a l .  (2000) revealed that early sowing made more than 30 days before 
conventional sowing increased yield by an average of 1 1  % .  It is also advantageous 
for traditional management systems where early planting is  prohibited since crops 
are severely affected by water logging and fungal diseases (Erkossa et a l . ,  2006). 
1 .  Conventional til lage 
Conventional agriculture has long been based on the practice of cultivating the soil 
completely, deeply, and regularly (Gl iessman , 1 998) .  A clean finely ti l led paddock, 
clean fence rows and straight rows of crop were the stamp of a farmer who was 
both skilful and good (Coughenour and Chamala, 2000) .  
This cUltivation practice , referred to here as conventional t i l lage, involves a 
combination of primary and secondary ti l lage operations normally performed in 
preparing seedbed for a given crop grown in a given geographical area (Mannering 
et al . ,  1 987) .  Fawcett ( 1 987) mentioned that the systems under conventional ti l lage 
are those wh ich total ly d isturb the soi l  surface and bury residue from the previous 
crop . I t  is sti l l  used as the preferred t i l lage option for soils with internal d ra inage 
problems e .g .  clay soils with poor structure or for pure sandy soi ls  (Erkossa et a l . ,  
2006, KOIler, 2003, Robinson et  a l . , 1 994). According to K61 1er (2003) the 
justification for this common practice varies from yield security, residue-free 
improved seed bed preparation ,  and (precision) dri l l ing to weed control and burying 
weed seeds. 
Traditionally, the mouldboard plough has been used worldwide as the primary tillage 
too l .  Another  common p rimary ti l lage tool is the d isk plough ,  comprising a hardened 
steel round concave disk of 50 to 95 cm i n  d iameter (McKyes, 1 985) .  Chisel plough ,  
subsoilers, and rotary ploughs also find use in  many areas; they break and loosen 
the soil without i nverting it (Hi l le l ,  1 980) .  Secondary tillage, performed after primary 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 24 
treatment, aims to improve seedbed levelness and structure ,  increase soi l 
pu lverization , conservation of moisture ,  destruction of weeds, chopping of crop 
residues and the l ike .  Disk harrows , spike harrows, spring-tooth harrows , sweeps , 
drags, and cultipackers are among the common implements used to refine coarse 
soil conditions du ring secondary ti l lage (McKyes ,  1 985, Hi l le l ,  1 980). 
Two contradicting effects general ly occur in  the soil during t i l lage, soi l  loosen ing as 
the effect from the t i l lage implements and soil compression by the tractor whi le it is 
pu l l ing the implement. Following ti l lage, the soil structure tends to readjust back 
towards its orig inal state as rainfa l l ,  the burrowing of worms, pressures exerted by 
roots, the cause of frost and wetting-and-drying combine to cause changes in the 
arrangement of the particles (Briggs and Courtney, 1 985). When these 
readjustments are incomplete, repeated t i l lage may result in a progressive change 
in  soi l structure .  I n  some cases this leads to long-term damage to the soi l or to a 
state of unstable equi l ibrium (La l ,  2004a) .  I n  add ition , farmers can be locked into a 
cycle of continuous plough t i l lage (K6l 1er , 2003) or soi ls are more rel iant on ti l lage 
practices to mainta in  physical cond itions favourable to crop production and become 
"addicted" to t i l lage (Robinson et al . ,  1 994) .  K611er further argued that based on 
contemporary research evidence, mouldboard plough can no longer be considered 
as the only basic implement for soi l  cu ltivation .  And after typifying and symbolizing 
agricu lture around the world for centuries, conventional ti l lage has been supplanted 
in many advanced agricu ltural economies by what has become known as 
conservation ti l lage and cropping agricultu re (Coughenour and Chamala, 2000). 
2 .  Conservation t i l lage 
Recent trends i n  t i l lage research have been aimed at min imizing t i l lage operations 
and travel (both to reduce costs and to avoid soi l compaction ) whi le tai loring each 
operation to its specific zone and objective (Hi l le l ,  1 980). This approach , in it ial ly 
known as min imum ti l lage, underlies various t i l lage methods under the term of 
conservation t i l lage , a term named by the Un ited States Soi l Conservation Service 
in 1 977 (Gajri et a I . ,  2002). The emphasis i s  on leaving the soi l surface covered with 
residue after planting rather than merely reducing the number of trips across the 
fields. Thus conservation ti l lage , according to the Resource Conservation Glossary, 
is "any ti l lage system that reduces loss of soil or water relative to conventional 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 1 25 
t i l lage; often a form of non inversion ti l lage that retains protective amounts of residue  
mulch on the  surface" (Mannering and Fenster, 1 983). More specifica l ly, i t  i s  
commonly defined as  any ti l lage system that maintains a t  least 30% residue cover  
on  the soil surface after planting to reduce water erosion or  small g rain residue 
equivalent on the surface dur ing the critical erosion period to reduce wind erosion  
(Baker et al . ,  1 996,  Mannering et a l . ,  1 987,  K6l1er, 2003). 
Due to its broad defi n ition , conservation t i l lage was further defi ned as an umbrel la 
term used for ti l lage i nten sity ranging from zero-ti l lage (no-ti l lage) to other forms of 
non-inversion soi l t i l lage practices that have the potentia l  to increase (or at least 
mainta in )  crop yie ld ,  and reduce soi l  water runoff relative to conventional t i l lage 
(Baker et a l . ,  1 996,  K6l1er, 2003) .  With i n  th is range of definit ions emerge several 
types of conservation ti llage systems described by Mannering et al. ( 1 987) such as: 
no-ti l l  or slot p lanting ;  ridge-ti l l ;  strip-ti l l ;  mu lch-ti l l ;  and reduced-ti l l .  Space wil l  not 
permit a detai led elucidation of each of these conservation ti l lage practices . Rathe r, 
for convenience of discussion , conservation ti l lage is broadly divided in to two 
categories (Wi l locks , 1 984) as cited below: 
1 .  No-ti l lage - where vegetation is control led using an herbicide and the seed is 
d i rect d ri l led i nto the undisturbed seedbed using  specia l ised dri l l ing equipment. 
No-ti l lage is the most recogn ised category of conservation ti l lage. 
2 .  M in imum-ti l lage - where vegetation is control led using an  herbicide, fol lowed by a 
l ight cultivation or reduced cultivation prior to establ ishing the seed us ing 
conventional d ri l l ing equipment. 
No-ti l lage farming is a relatively new concept made possible through the 
development of herb icides that can provide good weed control without using t i l lage 
(Baker et a l . ,  1 996) .  Where conditions suit ,  no-ti l lage is the ideal method of crop 
establ ishment in terms of m in imal i nputs and maxim izing opportun i ties (Wil locks , 
1 984). This has led to the rapid ly g rowing interest i n  and adoption of no-ti l lage 
systems of crop production throughout the world .  Research resu lts from the tropics 
ind icated the potential of no-ti l l  and conservation t i l lage methods for soil and water 
conservation (Lal , 2004a). In temperate agroecosystems,  conservation ti l lage has 
enabled farmers ,  whi le conserving soi l  and water resou rces, to change cropping 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 26 
systems substantial ly, for example from crop-pastu re rotation to continuous 
cropping (Coughenour and Chamala, 2000). 
Despite its i ncreasing coverage, it is  not inappropriate to suggest that for 
considerations of any form of conservation ti l lage adoption , the interaction between 
soil type and  climate is of prime importance. Conservation ti l lage practices 
developed in one location may not be suitable for another location ,  where conditions  
can d iffer greatly (Carter, 1 994).  Therefore ,  due to burgeon ing constraints along the 
d imensions of soi l ,  climatic, crop condit ions, and institutional and policy d ivides, the 
functional knowledge of conservation ti l lage and cropping systems, although 
suffused by modern science ,  i s  specific to  place (Coughenour and Chamala ,  2000 ) .  
5.2 .3 T i l l a g e  systems a n d  t h e  envi ro n m ent 
1 .  Greenhouse gas emissions 
Ti l lage causes certain physical and biological changes in the soil which influence 
the release of greenhouse gases, namely CO2 , N20,  and CH4, into the atmosphere 
(Bal l  et a l . ,  1 999, Gajri et a l . ,  2002) .  Carbon d ioxide (C02) is produced in the soi l 
through the metabol ism of plant roots, m icroflora, and fauna ,  and decomposition of 
organic material by micro-organisms (AI-Kaisi and Yin , 2005,  Bal l  et al . ,  1 999). I ts 
emission is caused by oxidation/mineral ization of soil organic matter through 
plough ing ,  low or unbalanced use of ferti l izers, removal/bu rn ing of crop residues, 
and low or no rate of appl ications of biosolids includ ing compost, green manu re, 
and sludge (Lal , 2004b) .  The magnitude of C02 loss from the soi l due to t i l lage 
practices is h igh ly related to the frequency and intensity of soi l  d isturbance caused 
by ti l lage (AI-Kaisi and Yin ,  2005). AI-Kaisi and Yin concluded that soi l  C02 emission 
is general ly lower with less intensive ti l lage alternatives relative to mouldboard 
plough , with the greatest d ifferences occurring at the time immediately fol lowing 
t i l lage operations .  An earl ier study by Bal l  et a l .  (1 999) confi rms these CO2 findings. 
There are , however, contradictory resu lts documented by Baggs et a l .  (2003) who 
found larger CO2 emissions in the zero ti l l than in the conventional ti l l treatments. 
General ly , no-ti l l  systems are proved to promote C sequestration and could be an 
important land-use component for greenhouse gas mitigation (Diekow et al . ,  2005) .  
A global data analysis study on carbon sequestration was presented by West and 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 27 
Post (2002) .  They suggested that when assessing the potential for C sequestration 
in agricu ltural so i ls ,  it is  particu larly important to consider the crop rotation being 
used , in  addition to ti l lage operations and inputs to production.  A recent study i n  
south-central Texas suggests that the use of no-ti l lage (NT) significantly improved 
soil aggregation and soil organic carbon (SOC) and soi l organic n itrogen (SON) 
sequestration in  surface but  not subsurface soi ls (Wright and Hons, 2005b). Another 
study in North Dakota revea led that under no-ti l lage (NT), an estimated 233 kg C 
ha-1 was sequestered each year in annual cropping system [spring wheat (SW) 
( Triticum aestivum L. )-winter wheat (WW)-sunflower (SF) (Helianthus annuus L . )] ,  
compared with 2 5  kg C ha-1 with min imum t i l lage (MT) and a loss of 1 4 1  kg C ha-1 
with conventional t i l lage (CT) (Halvorson et al . ,  2002). This study confirmed the 
resu lts of an earl ier study in the Parana State of Brazi l  (Sa et a l . ,  2001 ), wh ich 
suggested that no-ti l lage C sequestration potential for South Brazi l was estimated 
as 9 .37 Tg C y(1 . 
I n  a broad context, however, the contri bution of agricultural operations to these 
emissions is fairly smal l .  The clearing of native ecosystems for agricultural use i n  
the tropics is argued to be the largest non-fossi l fuel source of CO2 input to the 
atmosphere (Vlek et a l . ,  2004 , Smi l , 1 994). A study in Norway confi rmed that out of 
a total emission of CO2 in 1 998 of 41 .4 mi l l ion metric ton (MMT) ,  agriculture 
contributed only 0 . 1 57 MMT, or <0 .4% of the total emissions (Singh and Lal , 2005) .  
Methane (CH4) is generated biological ly from the decomposition of organic matter 
including biosol ids and manure under anaerobic  cond itions, biomass burning ,  
animal metabolism ,  and flooded rice fie lds (Chareonsi lp et a l . ,  2000, Lal , 2004b ,  
Smi l ,  1 994) .  Ferti l izers and manures are the principal causes of N02 emissions (La l ,  
2004b) .  The study by S ingh and Lal (2005) revealed that, contrary to the C02 
emission mentioned above, the methane and nitrous oxide (N20)  gases emitted 
from agricu ltural  activities contributed to 32.5% and 51 .3% of their respective total 
emissions in Norway. Early resu lts from the study of Ball et al . ( 1 999) show that CH4 
oxidation rates may best be preserved by no-ti l lage. By contrast, a study in S .E .  
England (UK) found that emissions o f  N20 were two to seven t imes higher from 
fertil ized zero t i l lage (ZT) treatments than from ferti l ized conventional ti l lage (CT) 
treatments (8aggs et al . ,  2003). These authors i ndicated that this could possib ly 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 28 
resu lt from the anaerobic conditions under the mulch with local ized concentrations 
of m ineral ized C and inorganic fert i l izer N03 - which were conducive to 
den itrification .  
2 .  Agrichemicals 
The type of t i l lage used dictates the movement of soi l  and water through erosion, 
runoff and leach ing and the transport of agrochemicals either bound to soi l  particles 
or in  solub le form (Gajri et  a l . ,  2002,  Hol land , 2004) .  The increased use of ferti l izer 
is recogn ized as a potentia l  source of environmental pol lution , specifical ly with 
respect to water quality (Lal , 1 99 1 ) .  Whi le conservation ti l lage practices may 
conserve energy as wel l  as the soi l ,  l ittle is known of how these practices effect 
solu te transport through the soil and reach the underlying ground water (Gish and 
Coffman, 1 987) .  I n  contrast, plough-based t i l lage methods may enhance risks of 
soil erosion , increase rates of mineral ization of soi l organic matter, and accentuate 
emission of radioactive gases from soil related processes (Watts and Hal l ,  1 996) as 
d iscussed earlier. 
A study by Zhao et al. (200 1 ) , i nvestigating the effects of ti l lage and nutrient source 
on water qual ity, revealed that sediment,  total P, soluble P, and NH\-N losses 
main ly occurred in surface runoff and the NO-3-N losses primari ly occurred in 
subsurface ti le d rainage . Analyzing the combined surface and subsurface flow, the 
study further  indicated that the mouldboard plough (MP) treatment resulted in nearly 
two times greater sediment loss than ridge til lage (RT) (P < 0 .0 1 ) .  Ridge til lage with 
u rea lost at least 1 1  times more NH+ 4-N than any other treatment (P < 0.0 1 ) . Ridge 
t i l lage with manure also had the most total and soluble P losses of al l  treatments (P 
< 0 .0 1 ) .  Zhao et al . (2001 )  concluded that til lage systems that do not incorporate 
surface residue and amendments appear to be more vulnerable to soluble nutri ent 
losses main ly in surface runoff but also in subsurface d rainage (due to macropore 
flow).  On the other hand,  t i l lage systems that thorough ly m ix residue and 
amendments in  surface soi l appear to be more prone to sediment and sediment­
associated nutrient (particulate P) losses via surface runoff. These resu lts were later 
confirmed by Nissen and Wander (2003) ,  studying the management and soil-qual ity 
effects on ferti l izer-use efficiency and leaching.  They reported that although total 
leached N was similar in all cropping systems under study , increased macropore 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES : Impacts on crop and biomass production 1 29 
flow i n  NT cores led to greater leaching of ferti l izer N and less leaching of soil­
derived N ,  as well as greater moisture stress and decreased plant N uptake . 
Contrasting resu lts , however, were found in a sim ilar study by J iao et a l .  (2004) 
where d issolved N and d issolved P loads were not affected by t i l lage and were 
s imi lar fol lowing corn (Zea mays L . )  in a continuous corn rotation and soybean 
[Glycine max (L . )  Merr . )] in a soybean/corn rotation production .  The study revealed 
that soi l s  receiving inorgan ic fert i l izer had a 70% greater n itrate (N03-N) load and 
48% less d issolved reactive P than soi ls  receiving organic ferti l izer. This evidence 
suggests that ferti l iz ing soils  with a combination of inorganic and organic ferti l izers 
might be a good way to reduce both N03-N and d issolved reactive P transport to 
water systems . The overal l results suggest that the leach ing of dissolved N and 
d issolved P compounds is influenced more by the type of ferti l izer appl ied than 
ti l lage or cropping practices. Simi larly, Zhu et al. (2003) reported that ti l lage had no 
effect on total leachate col lected during the 6-yr experiment by either pan (228 mm 
y(1 ) o r  wick (558 mm y(1 ) Iysimeters. The resu lts of their study found that the flow­
weighted NO-rN concentrations and NO-3-N masses i n  leachate were not 
s ignificantly different between ti l led and NT, but increased with increasing N-rate (at 
0 ,  1 00 ,  and 200 kg N ha- 1 , flow-weighted NO-3-N concentrations were 3.5 , 8 .2 ,  and 
23.9 mg L-1 and NO-3-N masses were 1 7 , 39 ,  and 1 1 2 kg ha-1 y(1 , respectively). 
They concluded that under the ir  experimental conditions ,  NT wil l  not result in  more 
NO-3 leaching than chisel-ti l lage over a multiyear period . 
One thrust i n  research deal ing with ti l lage systems is to define the best 
management practice for pesticide appl ication which maintains a high level of 
chemical efficacy without accentuating non-point source pollution on non-target 
areas (Mi l ler and Donahue, 1 990) . The success of no-ti l lage systems for example, 
depends on the successfu l use of herbicides (Stewart, 2004) .  Moreover, there is a 
tendency to use the more pers istent types for better long-term weed control ;  these 
are more l ikely to be persistent long enough to move into waters (M i l ler and 
Donahue,  1 990) .  A simulation work by Malone et a l .  (2003) ,  looking at alachlor and 
atrazine transport through the undisturbed soi l blocks using the Root Zone Water 
Qual ity Model (RZWQM), suggests that differences in soi l properties other than 
macroporosity such as a lower soi l  matrix saturated hydraul ic conductivity and 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 30 
porosity i n  subsurface soi l  (8-30 cm) can cause percolate to occur sooner through 
macropores on NT than on MP and cause h igher herbicide concentrations in 
percolate on NT, even when the macropores at 30 cm (nmacro) do not differ 
between t i l l  and no-ti l l .  
Research evidence suggests that no-ti l lage o r  any other greatly reduced ti l lage 
systems require a h igher level of management (Stewart, 2004). One of the main 
d isadvantages of no-ti l l  i s  that ,  as with fert i l izers, pesticides are more difficult to 
i ncorporate, thus they requ ire different pest-control strategies and formulations 
(Baker et al . ,  1 996) .  Crop rotation is one strategy that would reduce the amount of 
pesticides requ i red and would be a logical consideration to help reduce 
environmental pollution from croplands (Mi l ler and Donahue,  1 990). 
5.2 .4 Ti l lage a n d  cropp i n g  systems 
1 .  Continuous, rotational cropping and pasture management 
Whi le conventional ti l lage is mostly associated with monoculture ,  planting crops in a 
designated sequence and rotation has found new parameters with no-ti l lage . With a 
no-ti l lage system ,  harvesting can be fol lowed immed iately by planting of the 
succeeding crop, thus reducing the t ime lag between crops (Coughenour and 
Chamala ,  2000) .  Summer fal low (fal low) is sti l l  widely used on the North American 
Great Plains to replenish soil moisture between crops. A study was done by 
Campbel l  et al. (2005) to examine how fal lowing affects soil organic carbon (SaC) 
in various agronomic and cl imate settings by reviewing long-term studies in the 
m idwestern USA (five sites) and the Canadian pra iries ( 1 7 s ites) .  Another study, 
however, ind icated that cropping systems in  the Great Plains have gradual ly 
evolved over the past two decades from rel iance on summer fal lowing to continuous 
cropping under reduced or no-ti l lage (Schlegel et a l . ,  2005) .  Machado and F reitas 
(2004), in a study on no-ti l lage in Brazi l ,  concl uded that no-ti l lage farming 
represents a rad ical change i n  agronomic practices in the country, by e l iminating 
soil turnover, promoting agrobiodiversity through crop rotations ,  and keeping the soi l  
surface covered with residue mUlch , regarded as especial ly important under tropical 
and subtropical cl imates. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 3 1  
Recent experimental crop rotations aided by conservation ti l lage were attempted i n  
the h ighlands of Ethiopia to tackle the issue of soil quality deterioration and 
consequent reduced productivity characterizing the Vertisols in the area (Erkossa et 
al . ,  2006) .  A simi lar study was carried out in the northwest region of I ran on 
conservation ti l lage and straw mulch management aimed at improving soil water 
storage efficiency and increasing the potential in dry cl imates to promote i ntensive 
winter wheat ( Triticum aestivum l . )  cropping (Hemmat and Eskandari , 2006). A 
recently publ ished long-term experiment was conducted in the dryland semi-arid 
tropical Alfisols (Typic Haplustalf) in  southern I nd ia under a sorghum (Sorghum 
vulgare (L» -castor bean (Ricinus communis (L» rotation with the objective of 
selecting the appropriate land management treatments and to identify the key 
ind icators of soil qual ity (Sharma et al . ,  2005) .  
A study conducted in the central Great Plains suggests that growing a legume cover 
crop in place of fal low in  a winter wheat - fal low system can provide protection 
against erosion whi le adding N to the soi l .  However, water use by legumes may 
reduce subsequent wheat yield (Nie lsen and Vigi l , 2005) . Legumes, with their 
adaptabi l ity to different rice-based cropping systems,  offer opportunities to i ncrease 
and sustain productivity and income of rice farmers .  In the i rrigated lowland areas ,  
legumes (soybean , peanut and mungbean) are general ly grown i n  rotation with rice 
(rice-rice-Iegume rotation) or (rice-legume-legume rotation) with two or more 
i rrigations during the season (Adisarwanto et al . ,  1 996). Rotation of rice-cowpea i s  
also bel ieved to be  suitable for the h umid tropic soils (Benites and Ofori , 1 993) .  
Recent study suggests that legumes, incorporated at 1 -2 tons ha-1 (alfalfa , 
buckwheat (Fagopyrum esculentum) ,  rice by-products) ,  can g ive weed reduction 
and increase rice yield by 70 and 20 %, respectively (Khanh et al . ,  2005). It was 
further postu lated that legumes, and other a l lelopath ic crops, can be usefu l as 
natural herbicides. 
In lowland areas, the growing conditions requ i red for rice are entirely d ifferent from 
those requ i red for legumes. Rice is grown best under puddled and reduced 
conditions whi le legumes require unpuddled and oxid ised conditions. The two 
cond itions are associated with large differences in  physical ,  chemical and biological 
properties of the soi l  (Adisarwanto et al . ,  1 996) .  Mohanty et al . (2004) suggest that 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 32 
puddl ing only to the required level wi l l  deteriorate the soil physical conditions less as 
compared to more intense puddl ing .  The unpuddled direct seeded rice maintai ned 
the soil in a better physical condition but the yield was significantly lower in relation 
to the pudd led ones. Simi lar results concern ing yield were reported by Kirchhof et 
al. (2000) where puddl ing had no significant  effect on post-rice mungbean and 
peanut production but increasing puddl ing intensity tended to reduce soybean yie ld .  
A study by Cass et a l .  (1 994) ind icated that a rotation of rice-soybean over a period 
of 21 years, deteriorated the soi l structural quality ,  and thus  it was u nsustainable .  
Instead , they suggested that a rotation of rice and grass fal low would probably 
restore the soi l structure to a favou rable state. The inclusion of a green manure crop 
such as Sesbania rostrata berm in the rice-rice cropping system either du ring fal low 
and/or i ntercrop can be benefic ial .  The results of a study by Ramesh and 
Chandrasekaran (2004) revealed that there was a gradual bu i ld-up of SOC when 
S. rostrata was inc luded and in situ i ncorporated at flowering stage as a basic 
means of improving soil q ual ity i n  a rice-rice cropping system . A study i n  northeast 
Thai land revealed that annual appl ications of 1 500 kg ha-1 of leaf l i tter from d ifferent 
local ly grown shrubs for five seasons resulted i n  increases i n  rainfed rice grain yield 
in  1 997 of between 20 and 26% above the no-leaf l itter control . The analysis for 
Eastern Austra l ia ,  by contrast, ind icated that after five wheat and two legume/fal low 
crops, negative N balances of up to -303 kg ha- 1 were calcu lated for the treatments 
where wheat stubble was not retained and bare fal low leys were used (Whitbread et 
a l . ,  2003) .  
I n  the humid tropics, where soils are main ly acidic, rotation of acid-tolerant crops 
such as upland rice and cowpea under no-ti l lage practice was recommended by 
Ben ites and Ofori ( 1 993) .  This was viewed as part of solution addressing the 
problems associated with shifting cultivation in  transition to continuous cultivation .  I n  
the mounta ins of northern Vietnam, attempts were made to promote d irect sowin g  
upland rice i n  a dead mulch i n  the quest for a lternatives to slash-and-burn systems ,  
with promising pre l iminary results (Husson et  al . ,  200 1 ) .  A study i n  the western 
semi-arid zone of Mexico, looking at ways to increase the water availabil ity for 
rainfed maize production ,  found the merits of d irect seed ing maize i nto residue  
mu lch with an increase in  infi ltration rates of  up to 10  times the traditional ti l lage .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 33 
The avai lable water increased by 30% during the crop cycle (Scopel and Findel ing , 
200 1 ) .  Zero-ti l lage practices are being introduced in South Asia with in  the rotational 
rice-wheat farming systems that dominate large areas of northern I ndia, parts of 
Pakistan and Bangladesh, and the terai ( lowland) in Nepal (Uphoff, 2004) .  The 
i nternational rice-wheat system within the context of a sustainable agriculture 
emphasizing the prospects of no-ti l lage has been discussed at large by Lal et a l .  
(2004) .  
New Zealand has quite a long experience in pasture production since its export 
income is heavily dependent on animal products . Efforts have been made in either 
renewal or renovation of the existing pasture lands. Surface reseeding of poor 
pastures on steep land by aerial methods and resowing of pastures into crop 
rotations on flatter land using cultivation have become common practice in  
temperate New Zealand (Choudhary and Baker, 1 994) .  Traditional ly, this has been 
achieved by using conventional means of ti l lage prior to grass seed ing. In recent 
decades, however, d irect dri l l i ng has gained many adherents due to its advantages .  
Al ien ( 1 981 ) and Baker et a l .  ( 1 996), i n  their publ ications partly discussed the 
advantages of d irect-dri l l ing with regard to pasture renewal and renovation and 
provided some practical gu idel ines as wel l .  
Two major attractions of d i rect-dri l l ing related to pasture were that ( i) the whole 
process of renewal is more rapid and streamlined and ( i i )  the consolidation of the 
surface is not affected , so that shortly after the new seeds have been sufficiently 
establ ished, the old grass can be grazed (Al ien , 1 98 1 ) . The New Zealand pattern of 
using a pasture-crop rotation on mixed cropping farms means that the renewal or 
restoration of pasture without cultivation is an integral part of the total low energy 
input system .  The advent of glyphosate in particular has had a major impact on 
pasture renovation programs (Choudhary and Baker, 1 994). Apart from that, a 
number of pasture seed d ri l ls commercially available such as 'Cross Slot'TM and 
'Original Baker Boot'TM, provide favourable soi l microenvironments and are suitable 
for operations in contouring and trash-free pastu reland (Choudhary and Baker, 
1 993). Attempts were also made to promote ecological ly sound techniques such as 
triple disc dri l l  and strip seeder d ri l l .  A study conducted by Lowther  et a l .  ( 1 996) 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 34 
demonstrated the agronomic superiority of the strip seeder d i rect dri l l  for pasture 
establ ishment. 
Schipper and Sparl ing (2000) conducted a test in New Zealand covering a standard 
set of 1 6  primary indicators at 29 sites (0-1 0 cm depth) across n ine soi l great 
groups representing indigenous forest, plantation forest, pastures, and crops. The 
results revealed that pasture soi ls  were less acid ic (pH 5 .3-6.9)  than forest soi ls ,  but 
with more avai lable P (5 . 5-43.0 �g cm-3) ,  h igher total C (30 .7-1 4 1 . 5  mg cm-3 ) ,  total 
N (2 .7-9 .0  mg cm-3) ,  and minera l izable N (68-1 75 �g cm-3) . The physical cond ition 
was simi lar to forest soi ls .  Cropped soi l on the other hand , had low total C (20-34 
mg cm-3) ,  microbial C (1 60-956 �g cm-3) ,  respiration (0 .29-1 .33 �g C cm-3 h- 1 ) ,  and 
total avai lable water (6.7-30. 1  % v/v) ,  but h igh pH (5 .8-7 .2) ,  Olsen P ( 1 1 .2-1 99 �g 
cm-3) ,  and bulk density (0.96-1 . 3  g cm-3) .  In an earlier study Sparl ing et al . ( 1 992) 
reported that the re-establ ishment of pasture caused a more rapid recovery in  
microbial biomass C than tota l C ,  and increased the proportion of organic C 
comprised of microbial C .  However, recovery of the total organic and microbial C 
pools and aggregate stabil ity was very variable, and after 4 years of pasture none of 
the sites under study had re-establ ished the levels found under permanent pastu re . 
They concluded that the previous cropping h istory of these soi ls before being 
returned to pasture ,  rather than the organ ic  or microbial C content, appeared to be 
of greater importance in contro l l ing the aggregate stabi l ity characterist ics.  
An overseas study, investigating crop-pasture rotation (CPR) with NT reported that 
chisel ing or paraplough ing can al leviate plough-pans inherited by NT from previous 
CT; but higher soi l  strength at the soil surface under NT contributes to better forage 
uti l ization under grazing . Soil organic carbon (SOC) content i n  continuous cropping 
(CC) decreased with CT, and was maintained with NT only if grain was harvested . 
I n  CC systems with harvested forage, SOC decreased even with NT. CPR with NT 
maintained or i ncreased the orig inal SOC content. I t  was concluded that both CC 
and CPR were sustainable from the soil qual ity and productivity standpoints. 
However, compared with CC, CPR was a more economically and cl imatical ly 
buffered system due to h igher diversity, and more environmentally sustainable since 
fuel and agrochemicals usage is reduced approximately 50% (Garcia-Prechac et 
al . ,  2004) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 35 
2 .  Crop yield performance 
As far as crop yields are concerned , it is d ifficu lt to establish clear and major 
advantages of no-ti l lage, since the results to date have been variable over d ifferent 
soi l types, seasonal cond itions and types of management. Long-term trials 
undertaken in  Western Austral ia concluded that conservation t i l lage,  after some 
in it ial problems, performed well on the heavier soi ls but was less successful on l ight 
sandy soi ls .  On average ,  conservation t i l lage practices out yielded conventional 
practice over an eight year period (Conacher and Conacher, 1 986) .  The increased 
yields under no-t i l lage practices were also confi rmed by other overseas studies 
(Dickson and Ritch ie ,  1 996,  Barber et al . ,  1 996) .  Janson ( 1 984) ,  i nvestigating 
intensive arable cropping in  two different soil types under direct-dri l l ing (DD) and 
conventional ti l lage (CT) in New Zealand concluded that rel iabi l ity in crop yield 
under d i rect-dri l l ing on l ight free-drain ing soi ls was easier to achieve . By contrast, 
on the heavy, slow-draining soi ls ,  despite the greater problems imposed by DD,  the 
yield comparabi l i ty with CT was achieved relatively quickly. 
A study in north-western Turkey, examin ing the effects of three ti l lage systems on 
the properties of clay-loam soil (Eutric Vertisol )  planted with winter wheat ( Triticum 
aestivum L . )  reported that i ncreasing organ ic carbon (OC) and total N and 
decreasing bulk density (BD) and penetration resistance (PR) under reduced ti l lage 
(single disking / RT) increased grain yield to 4.6 t ha-\ fol lowed by mouldboard 
t i l lage (MT) and double d isking (DD) at 4 .4 and 4 .2 t ha-1 , respectively, accord ing to 
the 2-year mean (Ozpinar and Cay, 2006) .  A 3-year experiment was conducted 
under d ryland conditions to determine the influence of conventional and 
conservation ti l lage systems on grain yield and yield components of a winter wheat 
cu ltivar on a clay loam soi l  (Vertic Calcixerepts) in  the northwest region of I ran 
(Hemmat and Eskandari , 2006). The ti l lage treatments were conventional ti l lage 
(CT: mould board plow + disk), reduced ti l lage (RT: chisel plow + disk), m in imum ti l l  
(MT:  sweep plow) , and no-ti l l  (NTss and NTtr: with standing stubble and total residue ,  
respectively), and the mean grain yield over three seasons was 1 .0 t ha-1 for CT, 
1 .3 t ha-1 for RT, 1 . 1 t ha-1 for MT, 1 .2 t ha-1 for NTss and 1 .4 t ha-1 for NTtr. 
Contrasting yield results were found in other stud ies, which resulted from 
conservation ti l lage. Hughes et a l .  ( 1 992) in  a study on a 1 0-year maize/oats 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 36 
rotation i n  a fine si lt loam soil found lower maize forage yields under reduced t i l lage 
as compared to fu l ly ti l led seedbeds. Two reduced ti l lage treatments (min imum 
ti l lage and no-ti l lage) gave depressed maize yields i n  7 years out of  1 0. A major 
reason for this was l ikely to be d ifferences in  p lant popu lations. Seedl ing 
establ ishment was often low and variable i n  no-ti l led crops. The winter-grown oats 
showed no statistical differences among treatments .  Reduced yields under no­
t i l lage practices were also found by Acharya and Sharma ( 1 994) in a study on 
maize/wheat rotation.  Variable yield results were also reported by Lindwal l  et a l .  
( 1 994)  on continuous wheat, wheat-fal low, and wheat-barley-fal low rotations 
superimposed by conventional and no-ti l lage. 
Research evidence suggests that t i l lage practices do not always have a d irect 
impact on crop yield which is generally a result of i nteractions of a number of factors 
apart from ti l lage such as ferti l izer and crop rotation . The study by Kel ley and 
Sweeney (2005) in  the eastern Great Pla ins demonstrated that t i l lage effects on 
grain yield were smaller than othe r  treatment factors, averaging 3 .23 t ha-1 for RT 
and 3.06 t ha-1 for NT. Plant N uptake responses indicated that g rain yield 
differences were primari ly related to greater immobi l ization of both ferti l izer and soi l 
N fol lowing grain sorghum,  compared with soybean ,  and to better uti l ization of 
subsurface-knifed N than surface-broadcast N .  The authors concluded that wheat 
yield potential was more strongly i nfluenced by previous crop, ferti l izer N rate , and N 
placement method than t i l lage system . 
Another study i n  south-eastern Nebraska reported that corn and soybean produced 
less grain with greater summer temperatures whi le corn yield increased with less 
spring and more summer rainfa l l  (Wi lhelm and Wortmann ,  2004) .  They further 
described that ti l lage and rotation practices affected corn grain yield ; but only 
rotation affected soybean yield. I t  was concluded that the benefit of rotation for 
soybean grain yield did not vary with weather conditions. Seasonal temperature and 
rainfal l  patterns influenced the effects of t i l lage and rotation on corn yield . I n  
contrast , for soybean ,  only the pattern of  temperature influenced the effect of  t i l lage 
on yield . Another study, investigating the agronomic performance of spring barley 
(Hordeum vulgare L . ) ,  sown into conventional ly t i l led (CT) seedbeds with double­
disk dri l ls  or into standing stubble with several types of no-ti l l  (NT) d ri l ls (hoe, single 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 37 
d isk, and notched cou lter), reported that early season seed-zone temperatu res were 
cooler under NT, but seed-zone water was sl ightly higher with CT. Low spike 
density consistently occurred i n  a wide row spacing (406 mm) NT dri l l  treatment, 
and the h ighest overal l  yields were obta ined with NT dri l ls  with rows spaced 255 
mm or less (Sch i l l inger et aI . , 1 999). They concluded that no-ti l l  spring sowing into 
und isturbed standing stubble (2 .4-5 .2 t ha- 1 ) can p roduce grain yields equal to or 
exceeding those under CT and can provide environmental and potential soi l  qual ity 
benefits for low-precipitation dryland farming areas in the in land Pacific Northwest. 
A recent study concluded that long-term mean d ry matter corn yields were not 
affected by ti l lage and residue practices during the course of this study; rather 
cl imatic-related differences seemed to have a greater influence on the variation in 
dry matter yields (Dam et al . ,  2005). 
Despite the contrad icting resu lts cited above , it can be said that, usual ly, g iven 
adequate soil water, favourable precip itation , good drainage, reasonable soi l  ferti l i ty 
and good weed control , crop yields under conservation t i l lage can be equal to or 
higher than under conventional systems.  Concern ing sustainabi l i ty, whi lst yield and 
short-term economic differences between these ti l lage systems may not be al l  that 
g reat, this needs to be weighed against some obvious advantages, particu larly in  
the more fragi le or degraded agricultura l  a reas. 
3 .  Energy efficiency 
Uri ( 1 999) studied the relationship between energy use and the adoption of 
conservation ti l lage i n  the Un ited States using cointegration techn iques. The results 
showed that whi le the real price of crude oi l ,  the proxy used for the price of energy, 
does not affect the rate of adoption of conservation t i l lage, it does impact the extent 
to wh ich it is  used over the period of 1 963-1 997. The pol icy impl ications a re that the 
price of energy can be used to promote the adoption of conservation t i l lage through 
a fairly SUbstantia l  i ncrease in real energy price .  
The results of a study in Canada showed that the total energy i nput per  un it o f  land 
was lowest for the traditiona l  fal low-wheat (F-W) rotation (3482 MJ ha - 1 ) ,  
intermediate (4470 MJ ha-1 ) for N- and P-fertil ized fallow-wheat-wheat (F-W-W) and 
h ighest for N - and P-fert i l ized continuous wheat (71 00 MJ Ha- 1 ) .  Metabolizable 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 38 
energy output on the other hand , displayed simi lar response patterns as total 
energy input reflecting the h igher total annual  grain yields as cropping intensity 
increased . The energy output averaged 1 2639 MJ ha-1 for F-W, 1 464 1 MJ ha-1 for 
F-W-W and 1 7764 MJ ha-1 for continuous wheat. I n  contrast, the energy output to 
input ratios and the quantity of wheat produced uniC 1 of energy input decreased 
with cropping i ntensity. The average energy output to input ratio for F-W was 3 .6, or 
262 kg of wheat GJ-1 of energy input ,  whi le those for F-W-W and continuous wheat 
were 3 .3  and 2.6 ,  or 240 and 1 9 1 kg of wheat GJ-1 of energy input, respectively. It 
was concluded that rotations that incl uded flax or cereal forage crops had the lowest 
energy efficiencies (Zentner et a l . ,  1 989). 
In a recent study, Zentner et al .  (2004) postulated that the use of conservation 
t i l lage management enhanced overal l  energy use efficiency for the mixed rotations, 
but not for the monocu lture cereal rotation . They concluded that adopting d iversifi ed 
crop rotations, together with min imum and zero ti l lage management practices wi l l  
enhance non-renewable energy use efficiency of annual grain production in th is 
sub-humid region . Low-input systems in wh ich ti l lage and/or herbicides were 
reduced but not e l im inated were more efficient in converting energy into yield than 
h igh- input systems,  provided that other inputs substituted for reduced inputs (e .g .  
mechanical inputs instead of chemical inputs) were used in moderation . Thus, most 
alternative methods of weed control (e.g . reduced herbicide and ti l lage i nputs) a re 
more energy efficient than conventional weed control practices (e .g .  broadcast 
appl ication of herbicides at recommended rates) (Clements et al . ,  1 995). 
Modern agricu l tu ral  systems,  despite being efficient in  terms of human time and 
labour, are highly inefficient from an overal l  energetic point of view as five to ten 
times of fuel energy are required to produce a single un it food energy (Toky and 
Ramakrishnan , 1 982) .  Comparing energy input : output ratio at a vi l lage ecosystem 
level in north-eastern I nd ia ,  M ish ra and Ramakrishnan ( 1 982) reported that the 
energetic efficiency (output : input ratio)  of jhum i n  5 ha of land worked out at 7 :53 
and that of val ley cultivation on 2 ha of land at 40 : 1 4. I n  a d ifferent study Toky and 
Ramakrishnan ( 1 982) concluded that jhum and val ley agricultural systems are more 
efficient from the energy viewpoint, with h igher output-input ratios compared with 
terrace cultivation ,  which is least efficient due to heavy ferti l iser input requirements. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass p roduction 1 39 
5.2.5 T i l lage Effects on Selected S o i l  P roperties 
A large volume of i nformation can be found in l iterature on the effects of t i l lage 
practices on soi l  properties under various soi l types, cropping regimes and cl imatic 
conditions. Soi l  structure is dynamic and i n  almost al l  soi l s  changes with time or 
rainfa l l  after t i l lage. The structure may col lapse progressively and surface crusts or 
seals may form especial ly on soi ls  with low stabi l ity resu lt ing from low contents of 
clay or organic matter. A crust i s  often a barrier to water infi ltration and can be a 
cause of ponding and run-off (Dexter, 1 997) .  Moreover, the specific effects of 
various ti l lage operations also vary. Thus,  effects of changes in soil properties due  
to t i l lage must be  interpreted differently for regions ,  local ities with i n  a region , and  
often for soi ls  on a farm , when they differ appreciably in  d rainage, texture , depth , 
and topographic characteristics. 
Wel l-developed soils have a good balance between voids and particles and have a 
h igh water storage capacity; accord ingly, these types of soils offer the most 
favourable cond itions for crop growth . They are a lso less susceptib le to erosion . 
Ti l lage,  i n  various practices, is  primari ly defined as the mechan ical manipulation of 
the soil structure aimed at improving soi l  conditions affecting crop production (H i l le l ,  
1 980) .  Studies have indicated that soi ls  which have long been continuously d irect 
dri l led are different to conventional ly cu ltivated soi ls in a number of ways . A 
description of the main d ifferences between soi ls under these two ti l lage systems 
has been made by McLaren and Cameron ( 1 996 ) .  However, because of the many 
factors i nvolved and the complexity of interactions encompassed , the t i l lage 
investigations must necessari ly be long-term undertakings. In some situations, 
variabi l ity is such that a long run of experiments is necessary to determine a clear 
and consistent resu lt. 
Ti l lage and practices that change the organic matter content of soi l  are foremost 
amongst the many practices that influence soil structure (Kay and Munkholm ,  
2004) .  Some studies suggest t i l lage to have greater impact on  soil propert ies and 
on crop yie ld than crop residue management (Bescansa et a l . ,  2006). Nonetheless, 
the importance of the management and the maintenance of a stable soi l  structure 
under cropping regimes and ti l lage practices has been the subject of many studies. 
The results of some studies related to changes in selected soi l  physical and 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 40 
chemical properties are d iscussed . These include soil penetration resistance,  soil 
compaction and density, soi l aggregate stabi l ity ,  soi l porosity and hydrau l ic 
properties, total C and N,  Olsen P, and so i l  pH (H20). The d iscussion wi l l  a lso cover 
the effects of these soi l  properties on crop and b iomass production .  
1 .  Soi l penetration resistance 
There are several soil factors infl uencing penetration resistance. These , accord ing 
to Bradford ( 1 986), i nclude matric potential (or water content) ,  bu lk  density, soi l 
compressibi l ity, soil strength parameters , and soil structure .  The changes in such 
soi l compaction affecting properties induced by ti l lage systems are of the most 
concern of many studies. 
Lampurlanes and Cantero-Martfnez (2003) ,  comparing soi ls  under subsoil t i l lage 
(ST), min imum ti l lage (MT) , and no-ti l lage (NT) cropped with barley (Hordeum 
vulgare L . )  found larger penetration resistance under NT than in ST and MT. 
However, root length density profiles sometimes showed greater values for NT than 
for the other ti l lage systems,  reveal ing a good soi l condition for root growth under 
NT. The results confirm the findings of earlier studies by Bra im et al .  ( 1 992) and 
Home et al. ( 1 992) .  The former study concluded that with in  the topsoil (0-230 mm)  
of  the d i rect dri l led treatments, resistances to cone penetrometer were 7 - 9 times 
greater than those of the ploughed soils. While the latter study, investigating 
maize/oats rotation in a si lt loam under fu l l-ti l lage, min imum ti l lage, and zero-ti l lage 
found that penetration resistance was substantial ly lower in the fu l l  t i l lage compared 
to the other two treatments. Pasture plots gave the greater penetration resistance. 
S imi lar results were reported by recent  studies (Fabrizzi et a l . ,  2005, Govaerts et 
a l . ,  2006, Katsvai ro et al . ,  2002, Ozpinar and Cay, 2006). 
Contrasting resu lts, however, were found by Sidiras et al . (200 1 ) .  The penetration 
resistance (PR) was measured together with other physical properties and root 
system performance at growth stages 5 ,  9 and 1 6  of the Feekes scale under winter 
barley .  The results showed that in CT plots , PR was 1 .75 MPa at growth stage 5 ,  
1 .87 MPa at  growth stage 9 and 2 .02 MPa at  growth stage 1 6 . I n  MT plots, the 
respective values for PR were 1 .28,  1 .70 and 1 .94 MPa and in NT plots, which had 
the lowest PR, the values were 1 .27,  1 .52 and 1 .70 MPa, respectively. Karamanos 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 41 
et al. (2004) also reported a significantly lower penetration resistance 2-3 months 
after sowing in the no-t i l led plots after being in it ial ly h igher. 
2. Soil bu lk  density 
Bulk density, Pb, the ratio of the mass of dry sol ids to the bulk volume of the soi l ,  is 
not invariant for a given soi l .  It varies with structural cond ition of the soi l ,  particu larly 
that related to packing. For th is reason it is often used as a measure of soil structure 
(Blake and Hartge, 1 986) .  A review of the usefu lness of relative bulk density values 
in studies of soil structure and compaction was presented by Hakansson and Lipiec 
(2000) .  Damage to soil physical structures under continuous ti l lage (plough ing and 
d isking in particular), reduction of soi l  porosity, compaction and pulverisation by 
mach ines and stock , and cultivation of very wet to dry soi ls ,  all contri bute to 
increases i n  bu lk density (Conacher and Conacher, 1 986) .  Th is consequently leads 
to the soi l suffering effects such as increased resistance to mechanical cultivation , 
incurring g reater wear and tear of parts and increased fuel consumption ;  impedance 
to root penetration ; reduced water infi ltration ; increased waterlogging and surface 
water runoff, and accelerated erosion . 
Numerous stud ies have so far investigated changes in soil properties affected by 
t i l lage practices ,  inclusively bu lk density. A recent study in the Indian Hima layas' 
clay loam soil found the values of soil bulk density under zero-ti l lage (ZT) to be 
higher in 0-75 mm soil depth compared to soi ls under min imum ti l lage (MT) and 
conventional t i l lage (CT). At the depths below, however, the bulk density under ZT 
were e ither simi lar or lower than those of the other two treatments (Bhattacharyya et 
a l . , 2006). It was reported in another recent study that bulk density was affected by 
ti l lage practices, but on ly with in the top 1 0  cm soi l  layer (Dam et a l . ,  2005) .  The 
study concluded that both conventional ti l lage (CT) and reduced-t i l lage (RT) 
reduced bu lk density relative to no-ti l lage (NT) over a period of 1 1  years. Simi lar 
resu lts were reported by Bescansa et a l .  (2006) .  The study found the soi l  bu lk 
density at 0 - 1 5  and 1 5  - 30 cm soil depth to be significantly higher under 
conservation ti l lage practices (no-ti l lage,  no-ti l lage with stubble burn ing ,  and 
reduced ch isel ploughing) than that under the mouldboard plough treatment (MT). 
An exception was found under the reduced ti l lage (RT) at the 0 - 15 cm soi l  where 
the BD value was sim ilar with the one under MT. 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 42 
Wet cultivation for rice cropping poses significant chal lenges with regards to soil 
compaction and its effects on the post-rice crop. According to McOonald et a l .  
(2006) ,  puddl ing ,  as a management scheme for rice, is typical ly considered 
advantageous for maxim iz ing resource ava i labi l ity and yield . However, some 
experimental find ings suggest a conflict between edaphic  conditions created by th i s  
establ ishment techn ique and  the  performance of subsequent non-rice crops l ike 
wheat. Kukal and Aggarwal (2003) reported that increase in puddl ing intensity from 
medium to i ntensive ,  significantly increased bulk density from 1 .63 to 1 .67 Mg m-3 
in  1 6-1 8 cm and from 1 .6 1  to 1 .66 Mg m -3 in  1 8-20 cm soi l  layers . I n  normal­
puddled plots , the average bu lk density of 1 4-20 cm soil layers was significantly 
h igher ( 1 .74 Mg m-3) than that of shallow pudd led plots ( 1 .57 Mg m-3) at the end of 
3 years of study. Simi lar trends were observed in the case of soil penetration 
resistance. Despite favoured more soi l wetness at harvest, h igher i ntensity of 
puddl ing caused larger crack d imensions ( length , width and depth) than unpuddled 
and low intensity puddled soils according to a study by Mohanty et al. (2004). 
In a recent study by Ozpinar and Cay (2006) ,  i nvestigating the effects of t i l lage 
systems on the qual ity and crop productivity of a clay-loam soi l in  semi-arid north­
western Turkey, bulk density (BD) was found significantly lower under rototi l l i ng with 
one d isking (RT) at both 0-1 0 and 1 0-20 cm depths with 1 .24 and 1 .32 Mg cm -3 , 
respectively, when compared to MT (mouldboard plough fol lowed by two d iskings) 
treatment. At the 20-30 cm , however, MT provided the highest BD, at 
1 .49 Mg cm-3 . I n  the second year of the study, double d isking (DD) had the lowest 
BD  at all depths fol lowed by RT and MT. Studies by Bra im et a l .  ( 1 992) and Unger 
( 1 996), contrastingly, found that bulk density was not sign ificantly affected by t i l lage 
practices. These contradicting results may reflect the specificities of the 
circumstances and the nature of each study,  primari ly related to site characteristics , 
cropping regimes involved,  and the timing and duration of the tria ls .  
3 .  Soi l compaction and density 
Surface compaction may be created as a result of either traffic and/or treading when 
the soil is too wet or through  the excessive use of ti l lage implements (Al ien , 1 98 1 , 
B riggs and Courtney, 1 985, Robinson et al . ,  1 994) and could be reflected by the 
degree of penetration resistance and bulk density ,  two parameters largely used to 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 1 43 
assess compaction (Tarawal ly et a I . ,  2004) .  Soi l structural degradation by 
compaction alters soil pore architecture ,  and when the volume, d imension and 
configuration of soil pores are affected , mass and energy movement in the soil 
envi ronment suffer the same fate (Lipiec and Hakansson , 2000). Soi l compaction 
usual ly alters some basic soil properties such as pore volume, pore size distribution , 
macropore continuity, and soil strength . This, i n  turn , have a large infl uence on 
e longation of plant roots, and on storage and movement of water, air and heat in the 
soi l (Hakansson and Voorhees, 1 998). 
Research data from Hungary showed that annual d isking and plowing causes 
subsoi l compaction at the depth of ti l lage with in 3 years and that the compacted 
layer expanded both in surface and deeper layers after the 5th year. Soil qual ity 
deterioration by ti l lage-pans was improved by subsoi l i ng and maintained by d irect 
d ri l l ing and planting soi l- loosening catch crops (Birkas et aI . ,  2004) .  This confirms 
earl ier studies cited by Al ien ( 1 981 ) which found that fol lowing ploughing to 25-30 
cm subsequent wheel traffic caused very large recompaction effects through the 
depth of cu ltivation . I n  contrast, where di rect dri l l ing is adopted the soi l  rapidly bui lds 
up  to an equi l ibrium level of reformation of aggregates and i t  then has a high 
enough strength to resist further compaction . However, Hakansson and Voorhees 
( 1 998) concluded from their research that compaction effects tend to accumu late 
and be more persistent under reduced ti l lage than in a system with plough ing .  
Accord ing to this source these cond itions may sti l l  be adequate for clay soi ls due to 
improved continuity of macropore system .  I n  contrast, for un loosened sandy soils 
the compaction effects usual ly accumu late with l itt le natural a l leviation.  
Consequently , compaction may prevent continuous use of reduced ti l lage or d i rect 
d ri l l ing ,  especial ly for sandy soi ls .  
Repeated ti l lage at the same depth may result i n  the formation of a p low pan,  a soil 
layer of increased bulk density and strength j ust below the tilth layer (Briggs and 
Courtney, 1 985, Robinson et aI . ,  1 994) .  Consequences are that in wet periods 
plants may suffer from water logging in the root zone;  and during dry periods the 
shal low depth of the roots may mean that they are unable to exploit water reserves 
deeper in the soi l and may suffer from moistu re deficiencies. In short, compaction of 
soils adversely affects crop performance by l imit ing the availabi l ity of soil oxygen,  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 144 
restricting root penetration , and reducing the abi l ity of roots to take up  water and 
nutrients (Robinson et a l . ,  1 994, Conacher and Conacher, 1 986 ,  Hakansson and 
Voorhees , 1 998). 
Compaction ,  as described above , alters many soi l  physical characteristics . 
However, despite the effected changes in physical properties, a recent study 
discovered that m icrobial measures were either unaffected by compaction or 
showed inconsistent i ncreases (e.g . ,  fungal hyphae, C use, total phosphol ip id ester­
l inked fatty acids (PLFA)) across sampl ing periods and soil types under study. It was 
found that soil strength values, ranging from 75 to 3800 kPa (no to severe 
compaction) ,  were unrelated to either microbial respiration or biomass. The resu lts 
show broad tolerance of microbial communities from contrasting soi l  textures to 
compaction , and ind icate a poor l ink between physical and biological indices of soil 
health (Shestak and Busse , 2005). 
In a recent l i terature review on the nature, causes and possib le solutions to soi l 
compaction in agriculture ,  Hamza and Anderson (2005) offered the fol lowing  
practical techn iques: (a) reducing pressure on  soil either by decreasing axle load 
and/or increasing the contact area of wheels and tracked vehicles with the soi l ;  (b )  
working soi l and a l lowing grazing at  optimal soil moisture; (c )  reducing the number 
of passes by farm machinery and the i ntensity and frequency of grazing ;  (d ) 
confin ing traffic to certain areas of the field (controlled traffic) ;  (e) increasing soi l  
organic matter through retention of crop and pasture residues; (f) removing soi l 
compaction by deep ripping in the presence of an aggregating agent; (g) crop 
rotations that i nclude plants with deep, strong taproots ; ( h )  maintenance of an  
appropriate base saturation ratio and complete nutrition to meet crop requ i rements 
to help the soi l/crop system to resist harmful external stresses . 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 45 
4 .  Soil aggregate stabi l ity 
Soil structure can be characterized through measurable ind icators such as 
aggregate stabi l ity, bu lk density, and soil penetrabi l ity (Kemper and Rosenau , 1 986 , 
Hi l le l ,  1 998) .  Soi l aggregation effects on soil physical and chemical properties of 
structured soi ls  have been reviewed at length by Horn et a/. ( 1 994) .  Kemper and 
Rosenau ( 1 986) defined aggregate as a g roup of primary particles that adhere to 
each other more strongly than to other surrounding soi l  particles. The stabil i ty of 
aggregates is measured as a function of whether the cohesive force between 
particles withstands the appl ied disruptive force. Most frequently, th is concept is  
appl ied in  relation to the destructive action of water (H i l le l ,  1 998,  Kay and 
Munkholm ,  2004) .  This is  probably the ma in  reason for using the wet-sieving  
procedure to determine the water-stable aggregates (WSA) and mean weight 
d iameter (MWD) of a given sample of soil as suggested by Yoder ( 1 936) and 
Kemper and Rosenau (1 986). A study in Lond rina ,  state of Parana, Brazil found 
sign ificantly h igher indices of MWD, geometric mean d iameter (GM D), and 
aggregate stabi l ity (AS%) in soi ls under no-ti l lage than those under conventional 
t i l lage treatments (Castro Fi lho et a l . ,  2002) .  A recent research by Primorad ian et al. 
(2005), however, suggests the use of the non-l inear fractal d imension Onl to be 
more appropriate to quantify the aggregate stabi l i ty induced by t i l lage treatments 
compared with mean-weight d iameter Omw and geometric mean d iameter Dgm of 
aggregates. 
Apart from the d isruptive force of water and wind causing erosion , the clearing of 
natural vegetation , loss of organic matter, repeated t i l lage, excessive working 
speeds, passage of  heavy machinery and trampl ing by stock a l l  contribute to a 
reduction in the number and size of stable aggregates in the soil (Conacher and 
Conacher, 1 986) .  By any measure ,  however, the degree of aggregation is a t ime­
variable property, as aggregates form, d is integrate , and re-form period ica l ly (H il le l ,  
1 998). I n  other words, Lal ( 1 998) stated that agricu lturally stable soils are dynamic 
and always change in response to management and weather. A recent study by 
Valmis et a l .  (2005) proposed a model to predict interril erosion which takes in to 
account the aggregate instabil ity index, P. The proposed equation to describe the 
interri l l  erosion rate (�=0.939 ,P<0 .00 1 ) is as fol low: 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass p roduction 1 46 
E;==0 .628 � St1 3 eO 0967130 where St represents the tangent of the slope angle ,  and 130 
represents the maximum rainfal l  i ntensity in 30 min .  After val idating the model with 
i ndependent data , they concluded that the model predicted interri l l  erosion wel l  
(Ff2=0.766, P<0 .00 1 ) . 
I ntensive cultivation can cause excessive breakdown of soil aggregates. An early 
study has shown the decrease in aggregate water stabil it ies after 1 0  years of 
continuous maize/oats rotation in  a si lt loam to be the greatest in  the fu lly ti l led plots 
as compared to the no-ti l led plots (Home et al . ,  1 992) .  This is confirmed by recent  
studies indicating the prevalence of  more stable aggregates in  less mechanical ly 
d isturbed soi ls prior to cultivation as it is the case under no-ti l lage or reduced ti l lage 
than in soi ls under conventional ti l lage practices (Zotarel l i  et al . ,  2005, Wright and 
Hons,  2005a , Valmis et a l . ,  2005 ,  Eynard et al . ,  2005) .  At two agricultural 
experiment s ites (Passo Fundo and Londrina) in southern Brazi l , Zotarel l i  et a l .  
(2005) found  that CT decreased the proportion of the largest macroaggregate class 
(>2000 JLm) by approximately 1 0% in comparison with NT management, and there 
was a corresponding increase in  the proportion of the 53- to 250 t-'m aggregate 
class. They also reported that the mean weight diameter (MWO) of the aggregates 
was on average 0 .5  mm greater under NT compared with CT, and was also greater 
(approximately 0 .2 mm) under more d iverse rotations, which included a leguminous 
green-manure crop, in comparison with continuous wheat-soybean .  The study by 
Castro Fi lho (2002) ,  experimenting with two planting systems (conventional-ti l lage 
(CT) and no-ti l lage (NT), under three crop rotations (soybean/wheat/soybean 
(S/W/S) ,  ma ize/wheat/maize (M/W/M) and soybean/wheat/maize (S/w/M)) ,  found  
that no-ti l lage system had the best aggregation indices for the 0-20 cm layer due  to 
the increase in the organic carbon content. The greatest quantities of organic 
carbon were found in the 2 mm aggregate size class. The study concluded that soi l  
aggregate stabi l ity indices were not affected by the crop rotations. 
A d ifferent study by Wright and Hons (2005a) reported that no-ti l lage increased the 
proportion of >2-mm and 250-l'm to 2-mm macroaggregate fractions in soi l  
compared with CT. At the 0-5 cm depth , NT increased SOC compared with CT by 
1 58% i n  macroaggregate fractions but on ly 40% in <250 I'm fractions. They further 
indicated that long-term impacts of NT included a greater proportion of 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 47 
macroaggregates and increased C and N sequestration , but impacts were 
dependent on crop species and varied with soil depth . A simi lar study confirmed that 
the loss of aggregate stabi l ity in cultivated soi ls was associated with organic C loss 
(Eynard et a l . ,  2005). Their study suggests that most structural characteristics 
developed u nder til led systems persisted after 6-1 6 years of no-ti l l . At the sites 
stud ied by Zotarel l i  et al. (2005 )  the total organic C and N in the 0-5 cm depth 
interval , decreased i n  order native vegetation (NV) > NT > conventional t i l lage (CT). 
S imi larly, i n  the study of Sasal et al. (2006) aggregates were 30% more stable in 
zero ti l lage (ZT) than under conventional p loughing (CP) in  the top at 0 .05 m due to 
a 2 1  % increase in  organic matter. 
Franzluebbers and Arshad ( 1 996) reported the d istribution of water-stable 
aggregates (WSA) to be only secondari ly affected by ti l lage.  The primary effect was 
due to the clay content. Comparing two soi ls  with different textures, th is study also 
concluded that at a depth of 0 - 50 mm,  macroaggregation (> 0 .25 mm) was found 
significantly h igher under no-ti l lage than u nder conventional  ti l lage in  coarse­
textured soi ls ,  but simi lar, less or not significant in fine-textured soi ls. Simi lar resu lts 
were also reported by Beare et aJ. ( 1 994). Th is study found that at the 0 - 50 mm 
soi l depth the total sand-free C and N were significantly h igher in  al l  WSA of no­
ti l lage than  of conventional ti l lage. 
These stud ies, in genera l ,  confirm that no-ti l lage causes less damage to soil 
structu re . Also, the greatest WSA found at the topsoil under NT is bel ieved to be 
closely associated with more organic matter retained at this specific soil layer as 
compared to conventional  t i l lage. 
5 .  Soi l porosity 
Agricultura l  management affects pore-size d istribution as wel l  as pore continu ity and 
tortuosity. Traffic reduces macroporosity and t i l lage mechanica l ly breaks pore 
continu ity and h inders biopore formation (Boersma and Kooistra , 1 994) .  Pores are 
of d ifferent size , shape and continuity and these characteristics influence the 
infi ltration ,  storage and drainage of water, the movement and d istribution of gases, 
and the ease of penetration of soil by growing roots (Kay and VandenBygaart ,  
2002). Porosity i s  expressed as the ratio or percent of voids or pores to the total 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 48 
volume of soi l ,  and in  the case of most ferti le mineral soi ls ,  it takes up about 50 
percent of the volume (Wolf and Snyder, 2003 p. 84) .  
Effective porosity of the soi l  is largely determined by  macropores (Ahuja et al . ,  
1 989) which i s  closely related to saturated hydraul ic conductivity as it reflects the 
percentage of total pores that are open to infiltration during a rain event (Azooz et 
a l . ,  1 996) .  Effective porosity or macroporosity (0e) is approximately equal to 
porosity minus volumetric soi l  water content at the field capacity (Aimru n  et a l . , 
2004) .  The volume fraction of total porosity with pores <7 .5 I-'m in d iameter are 
classified as effective pores for reta in ing plant avai lable water. In contrast, the 
volume fractions of total porosity with pores > 1 50 I-'m i n  diameter are effective pores 
for d ra inage of water freely with gravity (Azooz et al . ,  1 996). A review by Kay and 
VandenBygaart (2002) ind icates that the introduction of NT can result i n  the loss of 
porosity ,  most consistently evident after 1 5  years and is general ly l imited to depths 
of 5-20 cm . There is, however, some evidence that the porosity in the top 5 cm of 
the profi le  may be greater under NT.  They also concl uded that regardless of depth 
stratigraphy, morphology and time ,  there is general ly an increase in pores 1 00-
500 J1m d iameter when soils  under CT were converted to NT or min imum ti l lage. 
Research by Eynard at al. (2004) ,  studying the effects of no-ti l l , conventional-ti l l  
(ti l l ) ,  and grasslands (grass) on porosity and pore size d istribution of two soi ls  in  
eight locations i n  central South Dakota confirmed that soi l  porosity and very fine 
pore-size d istribution were affected by management systems,  most evidently in the 
surface horizons (0-0 .30 m) .  Total pore space decreased in cu ltivated soi ls when 
compared with grasslands while no-ti l lage increased total soi l porosity relative to 
t i l lage between the 0 .05- and the 0 .30-m depth below the surface .  It was d iscovered 
that more very fine macropores ( 1 - to 0 .050-mm diam . )  and ,  in particular, more 
tubular very fine macropores ( indicating g reater biologica l  activity) were observed in  
grass than in cultivated soi ls ,  and more i n  no-t i l l  than i n  ti l led soi ls. A simi lar study by 
Bhattacharyya et  a l .  (2006)  in the Indian H imalayas found that the average values 
of the volume fraction of total porosity with pores <7 .5 I-'m in d iameter (effective 
pores for retain ing plant avai lable water) were 0 .557, 0 .636 and 0.628 m3 m-3 under 
conventional t i l lage (CT), m in imum ti l lage (MT) and zero-ti l lage (ZT) ,  respectively. I n  
contrast, the average values o f  the volume fraction of total porosity with pores 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 49 
> 1 50 I'm in diameter (pores drain ing freely with gravity) were 0 . 1 24, 0 .096 and 
0 .095 m3 m-3 , respectively under CT, MT and ZT. 
Greater knowledge of intra-aggregate porosity modifications by ti l lage conveys new 
information for identifying additional hydrologic, ion retention , and aggregate stabi l ity 
responses to specific  management practices (Park and Smucker, 2005). Overal l ,  
porosity i s  important because i t  influences: ( i )  the amount of air present i n  the soi l ,  
( i i )  the rapid ity with which spent a i r  rich i n  CO2 can be  exchanged for a i r  rich in  O2 , 
( i i i )  the amount of water held by a soi l ,  ( iv) the rapidity with which water infiltrates a 
soi l ,  and (v) how quickly excess water can be d rained (Wolf and Snyder, 2003) .  The 
hydraul ic aspects of porosity related to ti l lage are briefly discussed in the following 
section . 
6 .  Soil hydraul ic properties 
Under agricultural land use , the properties of the macropore network are governed 
by the appl ied management and ti l lage system (Wahl et al . ,  2004) .  Ti l lage 
operations affect hydraul ic conductivities in  contrasting ways. Ti l lage, especia l ly 
ploughing, creates macropores that cause saturated and near-saturated hydraul ic 
conductivities to i ncrease considerably, but a lso d isrupts pore continu ities that 
reduce hydraul ic conductivities between plow layers and subsoils (Fuentes et a l . ,  
2004). Conservation ti l lage in particular, preserves soil water and th is has been the 
main reason for its rapid d issemination in rainfed agriculture in semiarid climates 
(Bescansa et al . ,  2006). Because plough ing is min im ized under conservation ti l lage 
there are more continuous macropores and other preferential paths reach ing 
d i rectly from the soil surface deep i nto the subsoi l .  Conventional ti l lage destroys the 
structure of the surface soi ls ,  mixing the p lough layer and covering the macropore's 
connection to the surface . These macropores are capable of i ncreaSing the 
infi ltration of water and d issolved chemicals (Andre in i  and Steenhu is ,  1 990 , Green 
et al . ,  2003). 
Infi ltration i nto soi ls is strongly correlated with macroporosity. (Wah l  et aI . ,  2004). 
Chan and Mead ( 1 989), assessing the effect of d ifferent ti l lage practices ( i .e .  
conventional t i l lage and d i rect dri l l i ng) and pasture conditions on the infi ltration and 
d istribution of infi ltrated rai n  water in  an Austral ian Alfisol , reported that the h ighest 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 1 50 
density of macropores and the h ighest percentage of transmitting macropores were 
found in the permanent pasture .  Conventional cultivation for 4 years , by contrast, 
completely disrupted this macropore structure, thus decreased the macroporosity . 
This ,  in  turn , i ncreased run-off by reducing channel ing flow and changed the 
pathway of water movement resu lting in  increased leaching of the soil solution .  
Conversely, the study found that the macropore system was intact under d i rect 
dri l l i ng .  Recently, Fuentes et a l .  (2004) ,  i n  a simi lar study, reported that hydraul ic 
conductivities in  the natural prairie (NP) were about one order of magn itude larger 
than in  the cultivated soils .  In NT, saturated hydraul ic conductivities in  the top 5 cm 
of soi ls were significantly larger than in  CT. No-ti l l  and CT soi ls had simi lar near­
saturated hydraul ic conductivities, indicating that even 27 yr of continuous NT cou ld 
not restore the original hydraul ic properties of the soi l .  Restoration of orig inal 
hydraul ic properties in cultivated former prairie soi ls may take considerably longer. 
The study by Bescansa et a/. (2006) ,  at the end of 5 years of management on a clay 
loam calcic soi l (Calcic Haploxerept) in semiarid northern Spai n ,  compari ng water 
retention under d ifferent ti l lage and mulch ing management, found that avai lable 
water capacity (AWC) was greater with no-ti l lage (NT) than with reduced ti l lage (RT) 
and mouldboard plough (MT).  H igher soi l  water content (SWC) under conservation 
t i l lage systems (NT, NT with stubble burn ing ,  and RT) than under MT was attributed 
main ly to greater AWC and to the mulch ing effect of crop residues. A study in the 
Ind ian Himalayas reported that saturated hydraul ic conductivity values in a l l  the 
studied soil depths were significantly greater under zero t i l lage (ZT) than those 
under conventional ti l lage (CT) (range from 300 to 344 mm day- 1 ) .  The observed Ks 
values at 0-75 mm soi l  depth under ZT were significantly h igher than those 
computed under CT at all the suction levels, except at -1 0 ,  - 1 00 and -400 kPa 
suction . Investigating the effects of crop rotations on hydraul ic properties they 
stated that soybean-pea (S-P) rotation recorded sign ificantly h igher Ks values than 
those under soybean-wheat (S-W) and soybean-Ientil (Lens culinaris) (S-L) 
rotations up to -40 kPa suction . It was concluded that the interaction effects of 
t i l lage and crop rotations affecting the Ks values were found sign ificant at a l l  the soil 
water suctions. Both S-L and S-P rotations resulted in better soil water retention 
and transmission properties under ZT (Bhattacharyya et a l . , 2006). 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES:  Impacts on crop and biomass production 1 51 
Saturated hydraul ic conductivity (Ks) i s  an important soil physical property, 
especially for determin ing infiltration rate, i rrigation practice , drainage design ,  runoff, 
groundwater recharge and in simulating leach ing and other agricultural and 
hydrological processes (Aimrun et a I . ,  2004). The research of Park and Smucker 
(2005) measu red Ks of multiple aggregate fractions from two soil types subjected to 
conventional t i l lage (CT) , no t i l lage (NT), and native forest (NF) .  They found that 
long-term CT reduced intraaggregate porosities and Ks within macroaggregates, of 
the same size fraction , from both the Hoytvi l le si lty clay loam and Wooster silt loam 
soil types. Values for Ks of NF aggregates,  5 .0  x 1 0-5 cm S-1 , were reduced 50-fold 
by long-term CT treatments of the Hoytvi l le series. The Ks values through Wooster 
aggregates from NF ,  1 6 .0 x 1 0-5 cm S-1 , were reduced 80-fold by long-term CT 
treatments .  The Ks values through NF  and NT aggregates were positively correlated 
with their intraaggregate porosities (fi2 = 0 .84 for NF and R2 = 0 .45 for NT at P < 
0 .005) (Park and Smucker, 2005) .  
Chan and Mead ( 1 989) ,  studying water movement and macroporosity usi ng a 
rainfall s imulator under different t i l lage practices, found an evident decrease in  
macropore density and continu ity under  conventional cultivation . Simi larly, La l  and 
Vandoren ( 1 990) also reported higher cumulative infi ltration and infi l tration rate 
under no-t i l lage treatment than mouldboard plough and chisel plough treatments. 
Later, Benjamin ( 1 993) also found that no-ti l lage had a better impact on hydrau l ic 
conductivity. Many researchers have reported that saturated hydraul ic conductivity 
(Ks) and unsaturated hydraul ic conductivity (Kunsat) were sign ificantly and positively 
affected by zero-ti l lage (ZT) owing to either greater continuity of pores (Benjamin ,  
1 993) or  to water flow through a very few large pores (Al lmaras et  al . ,  1 982) or more 
depth (Ehlers, 1 977). The inconsistent resu lts of soil physical and hydraul ic 
properties under d ifferent t i l lage systems may be related to the transitory nature of 
soi l structure after ti l lage, site h istory, i n itial and final water content ,  the t ime of 
sampling and the extent of soi l  d isturbances (Azooz and Arshad , 1 996). 
The soil water retention function defines the relationship between water content and 
soil matric potentia l ,  and is an important hydraul ic p roperty necessary to study water 
flow and chemical  movement i n  unsaturated soils (Wang et a l . ,  2005). Soi l-water 
retention function is generally described in the form soi l -water characteristic curve 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 52 
(SWCC). Tarawal ly et al. (2004) used SWCC to calculate pore size d istribution and 
classify them into three pore size categories on the basis of their hydrau l ic 
functioning :  >50 I'm (f>50 /Jm) ,  50-0 .5 I'm (f50-0 .5 /Jm) and <0.5 I-'m (f<0 5 IJm) .  The 
greatest compaction levels were attained i n  the Fs (water content at saturation ) and 
Fc (field capacity)  soi l water treatments ,  and a s ignificant contribution to compaction 
was attributed to the existing soi l water states under which the soil compaction was 
accompl ished. For certain soils however, the d ifferential water capacity defined as 
do/dh is h igher from field data than from laboratory data in the range of low soi l ­
water matric potentials (Pachepsky et al . ,  200 1 ) .  
Suction properties constitute a key element for the functional representation of 
unsaturated flow conditions (Kunsat) . These are usual ly shown by the water 
characteristic curve , which g ives the relationsh ip between volumetric water content 
(theta (8) )  and matric suction (psi ( If)) .  The water characteristic curve used in th is 
study fol lows the closed-equation first forwarded by van Genuchten ( 1 980) as 
fol lows: 
fJ I .  t · )  ' l  .. . u , rl l  /. (H .. · ) . 
Where 0 is the volumetric water content, .l!' i s  the matric potential , and Or and Os are 
the residual and saturated volumetric water contents, respectively. The er, rn, and n 
are fitting parameters ,  which control a portion of the S-shape soi l shrinkage curve. 
The results of the studies mentioned above wi l l  be elaborated whi le d igesting the 
find ings of th is research later i n  th is chapter. I n  addition , the discussion wi l l  be 
complemented by a separate study on soil and nutrient loss through runoff and 
leaching under a s imulated rainfa l l ,  presented i n  the next chapter. I n  short, it can be 
suggested that these infi ltration and hydraul ic conductivity studies show that 
although no-ti l l  soi ls may have h igh bu lk densities and penetration resistance, they 
seem to have enhanced water conductivities enhancing water conservation and 
plant growth . 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 53 
7 .  Soi l organic matter and chemical properties 
M i l ler and Donahue ( 1 990) described the importance of soil organic matter (SOM)  
emphasizing its close relationsh ips with the other soi l  parameters previously 
d iscussed as a "very important and active portion of the soi l .  It is  the n itrogen  
reservoir; i t  furnishes large portions of the soi l phosphorus and  sulphur; it protects 
soils against erosion ; it suppl ies the cementing substances for desirable 
aggregation formation ;  and it loosens up the soi l  to provide better aeration and 
water movement" .  A review on soi l structure degradation with special reference to 
organic matter depletion and ti l lage was thorough ly presented by Kay and 
Munkholm (2004) .  Earl ier publ ication by Kay and VandenBygaart (2002) d iscussed 
the depth stratification of porosity and organic matter due to conservation ti l lage. 
Total soil organic matter concentration is a critical edaphic factor in dryland 
agroecosystem productivity which is partly controlled by crop biomass input v ia 
residues and roots . For smallholder farmers i n  fragi le lands, multip le benefits cou ld 
accrue as a result of management practices to re-establish soi l carbon content lost 
because of land use changes or management practices that are not sustainable 
(Tieszen et a l . ,  2004). Under rainfed conditions, reduced soil organic matter can 
decrease the effective util ization of l im ited precipitation by decreasing infi ltration and 
hydraul ic conductivity and increasing runoff and erosion (Shukla and Lal ,  2005). 
Wolf and Snyder (2003 ) stated that one of the surest ways to increase SOM is by 
means of conservation ti l lage through the combined effects of (i ) lower amount of 
soi l  02 which slows down the decomposition of organic matter by microbial activity 
thus al lowing SOM to accumulate, ( i i )  large proportion of residue on the soi l  surface, 
which reduces the amount of OM in close contact with soi l microorganisms that can 
qu ickly decompose it, (i i i )  the greater amount of surface residue general ly reduces 
erosion which is responsible for considerable SOM losses through water run-off. In 
genera l ,  agricultural  practices for the purpose of increasing SOC must either 
increase organic matter inputs to the soil , decrease decomposition of soil organic 
matter (SOM) and oxidation of SOC, or a combination thereof (West and Post, 
2002) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 54 
I n  a study on pasture and maize cropping fol lowing pasture conversion at four  
d ifferent soi ls  i n  Manawatu , New Zealand ,  Sparl ing et al. ( 1 992) found a marked 
decl ine i n  both organic C and m icrobial C under continuous cultivation fol lowing 
conversion from pasture. Another  study by Aslam ( 1 998) found greater amounts of 
microbial biomass C ,  N,  and P i n  the no-ti l led plots than conventional ly t i l led plots . 
Significant d ifferences were found main ly at the 0 - 50 mm soi l  surface. The study, 
which spanned two cropping seasons with continuous conventional ti l lage, resulted 
i n  a significant decl ine i n  soi l  biological status and organic matter. A simi lar 
influence on soi l  b iological status was found between no-ti l lage treatment and the 
adjacent permanent pasture control treatment. Simi lar resu lts were reported by 
studies from other parts of New Zealand (Beare et al . ,  1 994, Haynes, 1 999,  
Haynes, 2000) and from overseas (Cam pbell et  a l . ,  1 996, D iekow et al . ,  2005) .  
Recent studies i n  the humid subtropical regions indicate that long-term no-ti l l  
legume-based cropping systems and N ferti l isation improved soi l C and N stocks of 
previously cultivated land to the original stocks of native grassland (Diekow et al . ,  
2005). General ly their findings suggested that with i ncreasing time under pasture, 
soi l organic content increased.  By contrast, intensive cu ltivation mainly caused 
organic carbon decl ine partly due to enhanced decomposition of the existing  
organic matter by  t i l lage . 
The benefits of conservation ti l lage appear to increase with t ime, evidently as the 
i ncrease i n  soi l  organic matter (SOM) reduces erosion and i mproves soil structure 
(Wolf and Snyder, 2003 p. 228) .  A study by Koch and Stockfisch (2006) ind icates 
that after 7-9 years of conservation t i l lage, SOC and soi l n itrogen (SN) were 
concentrated i n  the top 1 0  cm layer of the soil which can undergo a substantial loss 
by one plough ing operation . The study revealed that at the 0-30 cm soi l  depth , 
losses of 0 .26 kg m-2 SOC and 0 .046 kg m-2 SN occurred with in 1 -6 months after 
ploughing ,  accounting for 4 and 7% of the total in itial masses, respectively. After 
1 .5-2.5  years after ploughing,  losses from the 0-45 cm depth accounted for 6% and 
1 0% of the i n it ial total mass of SOC and SN, respectively. An earl ier study by 
Rhoton (2000) reported s imi lar results. With i n  4 yr, no-t i l l  (NT) resulted in 
statistical ly s ignificant (P ::;0 .05)  differences compared to conventional t i l lage (CT). 
The surface 2 .5  cm of the NT treatments had h igher levels of SOM ,  exchangeable 
Ca, and extractable P, Mn ,  and Zn ,  but lower extractable K, Fe, and Cu and there 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 55 
were no noticeable ti l lage effects on exchangeable Mg and pH .  Rhoton concluded 
that the d ifferences in soi l  properties between ti l lage treatments were essential ly 
independent of crop and were control led by relative amounts of SOM and clay, and 
the extent to which these properties change with time.  The study reiterated that NT 
practices can improve several ferti l ity and erodib i l ity-related properties of this soil 
with i n  4 yr, and enhance its susta inabi l ity. 
The studies described above general ly suggest an improvement in soil qual ity thus 
ensuring agricultural sustainabi l ity through the SOM enhancing practices of 
conservation t i l lage management. 
5.2.6 C o n c l u d i n g  re marks 
Numerous studies suggest soi l  t i l lage plays an important role in agricu ltural 
sustainabi l ity .  It i nfluences crop yields through its effects on soi l properties that 
regulate nutrient and water supply, competition with pests , and co-restrictive 
biophysical and socio-economic constraints . Appropriate ti l lage methods differ 
among soi ls ,  crops, and cl imatic regions, and the choice depends on a range of 
interacting factors. Til lage,  or lack of t i l lage as is the case for the no-t i l lage 
agricu ltural  production systems, in combination with the appl ication of 
agrichemicals ,  is the one farming variable that most d i rectly impacts our 
envi ronment. It can greatly alter the soi l  physical ,  chemica l ,  and biological 
properties lead ing to changes in crop productivity and the qual ity of the envi ronment 
(Dick, 1 997) .  
The l i terature also reveals the prevalence of soi l  degradation in many agricu ltural 
production and agroecology systems. To avert further degradation ,  the soil 
productivity balance must be shifted from degrad ing processes to conserving 
processes , and more urgently, in the fragi le eco-regions and marginal lands of the 
tropics .  Conservation ti l lage is one of the soil conserving practices recogn ised 
world-wide.  However, it is a lso recogn ised that there is no single ti l lage system that 
can be widely used for d iverse soi l and climatic cond itions .  
The u ltimate goal of th is review is  to stimulate research interest and d iscussion on 
the impact of t i l lage on the environment quality. The issue of environment and 
especial ly soil qual ity is  as paramount to advanced and soi l  r ich cou ntries as to 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 56 
developing countries with fragi le tropical land such as East Timor. Whi le research 
work and supporting resources are general ly largely ava i lable in the former category 
of countries that is not the case for the latter. Due to l im ited capital and human 
resou rces i n  developing countries, government-funded research projects are too 
often single discip l ined studies using a top-down approach with inadequate farmer 
involvement. 
For the two countries most related to this present study, and especial ly to East 
Timor ,  it i s  recommended , fol lowing Will cocks and Twomlow ( 1 993) for southern 
Africa's case, that ti l lage research and development should g ive increased attention 
to: ( i )  understanding farmer constraints to rel iable rainfed crop production systems 
and identifying existing and potential technology supply systems available to local 
farmers through a multidiscip l inary approach ; ( i i )  creating interim systems that are 
susta inable with existing resources and selective external information and 
technological input; ( i i i ) establ ishing long-term ti l lage and agricultural production 
systems that conserve energy (labour and draught power) , water and soi l  
resou rces. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES : Impacts on crop and biomass production 1 57 
5.3 RESEARCH METHODOLOGIES 
5.3 . 1  EXP E R I M E N T  1 
5.3 . 1 . 1 Experimental S ite 
The first experiment was in a farmer's field in an outlying area of Di l i ,  the capital city 
of East Timor. The plots were part of a rice fie ld from which rice had been harvested 
prior to the research . The soi l  type was a vertisol with 1 4:51  :35 and 1 3:48:39 sand : 
si l t :  loam texture ratio in the top 0-1 0 cm topsoi l  and 1 0-20 cm subsoi l ,  respectively. 
5 .3 . 1 .2 Experimental Design 
1 .  Treatments 
Three soil mechanical treatments,  in very modest modes, were employed in this 
experiment on 8-1 4  June 2002, as fol low: 
(i) Conventional Ti l lage (CT) 
Ti l lage was done by a hand tractor with mouldboard plough fol lowed a week 
later by a single pass of a rol ler to break up clods and level the surface. The 
ti l lage depth was between 1 5-20 cm range. 
( i i )  Manual Ti l lage (MT) 
The inversion of soi l  was done manual ly using hoes as common tools for seed 
bed preparation .  The depth of the manual ti l lage was in the range of 1 0  - 1 5  
cm. The breaking of soil clods was also done manual ly with hoes and wooden 
blocks and  soil was level led using steel forks. 
( i i i )  No-ti l lage (NT) 
Under this treatment, the soi l  was left intact and soil d isturbance was kept 
min imal at the clearing of vegetation .  Due to the unavailabi l ity of herbicide, the 
vegetation inside the plots was manual ly cut, sun d ried , and later burnt. 
2 .  Experimental design and lay-out 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 58 
Due to cond itions of the farmer's rice field and the lack of water for i rrigation , the 
establ ishment of a proper experimental design was not possible .  It was aimed at the 
in itial plann ing stage to set up the experimental lay-out in  Figure 5 . 1  i n  three 
d ifferent farmer fields, thus  regarding each block as a repl icate. However, due to 
seasonal constraints beyond the control of research management, th is plan could 
not be material ized and the treatments, therefore , could not be external ly repl icated . 
Unl ike in  conventional designs, six smal l rice field p lots , close to a tertiary traditional 
i rrigation cana l ,  were purposively chosen .  The plot size was, on average, 1 0  x 1 5  m2 
each . In  addition , sub-samples or i nternal repl icates as shown in Figure 5 . 1  were 
used for statistical purpose . 
C 
T 
CT 
NT 
III � 
MT 
� I " I rngatlon cana 
Mungbeans 
Corn 
CT=Convenlional Tillage 
MT= Manual Tillage 
NT = No-Tillage 
Figure 5 . 1  Schematic lay-out of the experimental plots at the Di l i  Site 
3 .  Soi l sampl ing 
The soil sampl ing was carried out on 8 June 2002 prior to the soil preparation,  for 
two different purposes, as described below: 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 59 
a. Bulk density and water content 
Thin wal led cyl indrical alumin ium samplers, 48 mm in  internal d iameter and 50 mm 
in  length , were used to sample soi l for bulk density measurement , for each 50 mm 
layer of  the soil down to 200 mm depth . The sampler was manual ly driven i nto the 
soil and the soil core removed with care to preserve its volume. The same soi l  core 
was used to determine soi l water content of the respective soi l  layers. The soi l 
water content was gravimetrical ly measu red. I n  the absence of proper laboratory 
equipment, rudimentary oven and scale for the drying and weigh ing of soi l  samples, 
respectively ,  were used . 
b. Soil chemical analysis 
A half spade amount of soil was taken from 0-1 00 mm and 1 00-200 mm soi l depth 
from four  points i n  each p lot and bulked . The soil samples were firmly wrapped and 
sent to a laboratory in West T imor, Indonesia for further processing prior to the 
chemical analysis .  Soi l pH , organic C ,  total N, P ,  and K were measured before and 
after cropping,  for 0 - 1 00 and 1 00 - 200 mm soi l depths. 
4. Crop establ ishment 
Commercial  corn and mungbeans were obta ined from the local market for the 
purpose of this study. Both corn and mungbeans were planted manual ly in each 
treated plot fol lowing the farmer's usual technique on 1 5  June 2002. No pre-planting 
ferti l izer was appl ied . In mid-season ,  however, NPK ferti l izer was evenly broadcast 
in the plots. 
5 .  Soi l analysis 
Soi l pH was determined by using a pH electrode meter. Total organ ic carbon 
determination was done by ash (dry combustion)  system .  Total N content  was 
determined by using the Kjeldhal method whi le P content was determined by using 
the Olsen method . K was measured by using the NH40AC-AAS method . Soi l  
texture was determined by Pipette method . 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 60 
6.  Crop and biomass production 
a. Crop yield and biomass 
Crop biomass was measured at m id  cropping season by cutt ing the sampled crops 
at the base close to soil surface , at random from 1 x1 m2 each plot on 1 2  Ju ly 2002.  
The resultant biomass was sun dried (oven not avai lable) and dry matter weighed . 
Plant height and root length from crop samples were also measured . Corn and 
mungbeans gra in yield were assessed by taking 1 0  crop harvest samples at 
maturity on 28 September 2002 . The grain was manual ly threshed , cleaned , and 
weighed . 
b. Weed dry matter 
Weed biomass were determined by col lecting weed samples on weed and 
mungbeans plots on 15 Ju ly 2002 . Weed samples of 1 m2 were cut  at  the base and 
later sun d ried and weighed for calculation of the total weed biomass. 
5.3.2 EXPE RIM E N T  2 
5.3 .2.1  Experim e ntal S ite 
The experiment was conducted in a permanent pasture field at Massey Un iversity's 
Pasture and Crop Research Unit (Mogin ie Block), Palmerston North , New Zealand .  
The un it occupies 2 7  ha of upper terrace land on H ighway 57. The soil type was 
Tokomaru si lt loam with an average pH of 5 .9  (Awan ,  1 989) .  A smal l  part of the 
pasture was converted to cropping for the purpose of the t i l lage trial with the slope 
ranging from 1 1  to 20°. Unl ike in  New Zealand where steep agricultural  lands are 
developed with pasture and trees , SUbsistence farmers in countries such as East 
Timor sti l l  extensively use steep land for cultivation . 
5.3.2.2 Experimental Design 
1 .  Main treatments 
Three soi l  mechan ical treatments were used in this study, as described below: 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 6 1 
( i )  Conventional Ti l lage (CT) 
This treatment involved a primary t i l lage with a mouldboard plough fol lowed by  
a single pass of rol ler to break up  clods and level the surface . Secondary t i l lage 
was done after two weeks by two passes of power harrowing  for seedbed 
preparation . 
( i i )  Manual Ti l lage (MT) 
The inversion of soil was done manual ly by the use of shovels .  I n itial ly a hoe 
was deemed the appropriate tool for this treatment, recognizing its common use 
by farmers elsewhere in  the develop ing countries. However, this option was 
later found incompatible with the fie ld conditions where the topsoil was heavi ly  
covered by dense pasture grass roots making i t  difficult for the hoe to penetrate .  
( i i i )  No-ti l lage (NT) 
This involved no soi l and residue inversion at a l l ,  and the surface soi l was left 
intact. Approximately two weeks prior to seeding, weeds were control led with 4 
I/ha of Roundup (360 g/I glyphosate) mixed with 1 I/ha Versati l l  (300 9/1 
clopyral id ) .  Seeding was conducted by d irect seeding with an Aitchinson seed 
dri l l .  
( iv) Permanent pasture (PP) 
The plots were surrounded by a large area of permanent pasture (PP) fie lds 
that were considered as a control treatment during the measurement of some 
experimental parameters with in  th is study. This was an undisturbed soi l with 
permanent pasture grass cover [ryegrass (Lolium perene L . )  with clover 
( Trifolium repens L . )) .  
2 .  Sub-plot treatments 
( i )  Two crops were used i n  th is study namely potato ( var. /lam Hardy) and barley 
(var. Fleet). 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 62 
( i i )  Two weeding approaches were employed as sub-plot treatments. Half of the 
plots were weeded and the other half were left unweeded during the course of 
the study. 
3 .  Experimental design and lay-out 
The plots were arranged in a spl it-plot design with three ti l lage treatments being i n  
the main plots and two crops (potato and barley) and weed (weeded and 
unweeded ) treatments as sub-plots . The main and sub-plots were placed 
completely randomly (ReB) into four separate blocks and located at three d ifferent  
field slopes . Four repl ications of  each main and sub-treatment were considered 
necessary to account for any variation due to field condit ions. Thus, a total of 48 
plots were used in the trial . 
Each plot size was 5 m long and 3 m wide (one dri l l  width is 2.4 m) with a qu ite 
large headland for machinery operation on both sides of the field . The lay-out of the 
plots is shown in F igure 5 .2 .  
4 .  Soil sampling 
There were separate soi l  samples for the different measurements required in th is 
study. S ince the soil samples have to represent the field condition and reflect the 
variation with in the area of study, considerable number, size , and methods of 
sampl ing were taken into account. Therefore, the specific sampl ing method used for 
each measurement is described below: 
8. Bulk density 
Sampl ing for bu lk density measurement was taken for each 50 mm layer of the soil 
down to 300 mm depth .  Th in  walled cyl indrical a lumin ium samplers, 48 mm in 
internal d iameter and 50 mm i n  length , were used . Each sampler was driven i nto 
the soil manually and the soil core carefu lly removed to preserve a known volume of 
the sample as it existed in  situ . 
Six soil samples were taken from each plot at d ifferent depths: 0-50, 50-1 00, 1 00-
1 50 ,  1 50-200,  200-250, and 250-300 mm.  The samples were weighed , oven-dried 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 63 
at 1 05°C overn ight, and reweighed. Bulk density was calculated as the ratio of the 
oven-dry mass of soi l  to the bu lk volume (g cm-3) of the sample.  
Bu lk  density was measured on 1 2  March 2004 , after the crops had been harvested , 
and i n  the first week of April 2004 , after the second measurement of soi l penetration 
resistance. Sl ightly bigger soi l corers were used during the second measurement as 
a check and balance measure against the standard corer used in the first 
measurement. 
MT MT MT MT CT 
Bw Puw Buw Pw Buw 
1 2 3 4 5 
MT MT MT MT NT 
Pw Buw Puw Bw Pw 
1 3  1 4  1 5  1 6  1 7  
NT NT NT NT CT 
Bw Puw Buw Pw Buw 
25 26 27 28 29 
CT CT CT CT MT 
Buw Pw Bw Puw Bw 
37 38 39 40 4 1  
Lay-out 
R ep 
CT CT CT NT NT NT NT 
Pw Bw Puw Bw Puw Buw Pw 
6 7 8 9 1 0  1 1  1 2  
R 2 ep. 
NT 
Buw 
1 8  
R 
CT 
Pw 
30 
R 
MT 
Puw 
42 
NT NT CT CT CT CT 
Puw Bw Pw Buw Puw Bw 
1 9  20 21  22 23 24 
ep 3 
CT CT MT MT MT MT 
Bw Puw Bw Puw Buw Pw 
3 1  32 33 34 35 36 
ep 4 
MT MT NT NT NT NT 
Buw Pw Bw Puw Buw Pw 
43 44 45 46 47 48 
Legend: 
Main Plots: CT = Conventional Ti l lage; 
MT = Manual Ti l lage; 
NT = No-Til lage; 
Sub-Plots: Pw = Potato Weeded ; 
Puw = Potato Unweeded; 
Bw = Barley Weeded; 
Buw = Barley Unweeded 
Figure 5.2 Schematic lay-out of the experimental plots at the Palmerston North Site 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 64 
b. Soil water content 
Samples for bulk density were a lso used for volumetric water content measurement. 
I n  this case ,  water content for six soil layers of 50 mm each from the 300 mm top 
soil were recorded . Sampl ing at d ifferent soi l  layers from the above were used at 
the time samples for aggregation stabil ity measurement were extracted i .e .  one 
sample for each layer of 0 - 1 00 mm , 1 00 - 200 mm ,  and 200 - 300 mm.  
Soi l  samples a t  appropriate depths from each plot were col lected at d ifferent times, 
corresponding to the sampl ing for bulk density, aggregate stabi l ity , hydraul ic 
conductivity ,  and soil moisture release analyses / porosity measurement. The 
samples were weighed ,  oven-dried at 1 050 C overnight, and reweighed . Both 
volumetric and gravimetric water content was determined from the change of 
volume / mass after oven-dry ing .  Volumetric soil water content was also assessed 
in the field during the growing season by Time Domain Reflectometry (TOR). 
c. Hydraulic conductivity 
Alumin ium sampling l iners of 98 mm internal diameter were used to col lect soil 
samples for both saturated and unsaturated hydraul ic conductivity measurement. 
L iners were l ightly greased on the inside to assist in a sealing the soi l/l iner contact. 
The collection of samples was done by hand carving the l iner into the soil (F igure .  
5 .3)  at  0 - 1 00 mm and 1 00 - 200 mm soil depths .  This is  a time consuming 
method but produces excel lent samples under most conditions encountered. It is 
especially suitable where the soil is  unavoidably d ry ,  i s  very dense, contains roots 
or is i naccessible to vehicles (Dando, 2004) .  
d. Soil moisture releasel soil porosity measurement 
For the purpose of low tension analysis i .e .  up to 1 0  kPa suction leve l ,  the same soil 
cores for hydraul ic conductivity were used . After the low tension analyses had been 
completed , a smaller sampling l iner was used to extract one small sample from 
each big soi l core for further analysis using h igh tension . The h igh suction level 
employed in th is study was 1 00 kPa, needed for the estimation of readi ly avai lable 
water. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 65 
e. Aggregate stability 
Spade sl ices of soil from two depths (0-1 00 mm and 1 00-200 mm) were removed 
from each plot. Air-dried samples from the sl ices were then sieved through a nest of 
sieves to obtain aggregate with the d iameter sizes between 2 to 4 mm.  These 2 - 4 
mm aggregate samples were used to determine the aggregate stabi l i ty by means of 
wet-sieving analysis. Soil samples were also taken for organ ic C and N analysis as 
these were suggested by many studies to have close relationship with soil structural 
stabi l ity . 
F igure 5 .3 Core samples being taken in the field for hydrau l ic conductivity 
measurement 
5 .  Crop establ ishment 
- Potato and Barley 
Potato (Solanum tuberosum L . )  and barley (Hordeum vulgare L . )  were planted on 
the 1 8th of November 2003 (Figure 5 .4) .  lIam Hardy was the potato variety chosen 
because it is  an all purpose potato suitable for most end uses especial ly mash ing 
and baking.  It is a yel low skinned white f1eshed potato , fu l l  flavoured , tend i ng 
towards being floury .  The planting was 25 cm in row spacing and 75 cm between 
rows . 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 66 
Barley was chosen as an above ground crop in contrast to the tubers of the potato. 
The barley seed rate was 1 35 kg/ha and was planted by dri l l ing into CT and NT 
plots with the dri l l  width of 2 .40 m .  The space between rows was 1 5  cm. The 
planting in the MT plots was done by placing the barley seeds manual ly into the 
hand-dug rows with the seed requirements of 1 2 .6 g/row. 
Figure 5.4 Potato and barley growth at the mid-cropping season (6/1 /04) 
5.3.2 .3 Field Measu rements 
The key soi l ind icators measu red in the field were : (a) soi l penetration resistance, 
(b) soil bu lk density, (c) soi l water content, (d) crop and biomass yield , and (e) weed 
population and d ry matter. 
1 .  Penetration resistance 
A Bush® record ing cone penetrometer (Mark 1 model 1 979) with 1 2 .2 mm cone 
diameter was used to measure soi l penetration resistance in each plot to a depth of 
300 mm (Figure 5.5) .  Data were reported as the maximum force recorded as the 
cone passed through each 2 mm soi l  layer (for the top 200 mm topsoi l )  and each 
50-mm soil layer at the 200 - 300 mm soi l depth . The locations were chosen at 
random and the penetrometer was pushed into the soi l by hand at a constant rate 
(Viegas and Choudhary, 2002). Measurements of soil penetration resistance were 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 67 
done twice. The first measurement was on 6 January 2004, at approximately mid­
cropping season . This time was considered appropriate in order to examine the soi l  
conditions several weeks after cu ltivation . The  second measurement was done 
more than two months later, on 22 March 2004, after al l  the crops were harvested 
and the plots left und isturbed . 
Figure 5.5 Soil penetration resistance measurement 
2. Crop and biomass yield 
Barley grain and biomass yield were assessed by taking crop samples at maturity 
from a 2 x 1 m row on 1 7  February 2004. Plants were cut at the base close to soi l 
surface , at random from each plot .  The grain was manual ly threshed and cleaned 
using a fan ,  moisture content determined , and net barley gra in weight adjusted and 
calcu lated . The resultant biomass was oven-dried at 1 05° C and dry matter 
weighed . 
Simi larly, potato tuber yield was measured by col lecting 8 crop samples (from 2 x 1 
m row) on 26 February 2004 . The tubers were manual ly dug ,  stored,  and later 
washed . The clean potatoes were then weighed and sorted into three major size 
categories. The biomass yield was assessed by using s imi lar procedure to the 
barley biomass. 
Chapter 5 - TILLAGE AND EDAPHIC  CHANGES: I mpacts on crop and biomass p roduction 1 68 
3 .  Weed population and dry matter 
Weed biomass were determined by collecting weed samples on weeded potato and 
barley plots on 5 January 2004. Weed samples of 1 m2 were cut at the base and 
later weighed to determine the wet weight. The samples were then manual ly sorted 
and identified to estimate the approximate population and d istribution in each plot. 
They were later oven-dried and weighed for calculation of the total weed biomass. 
Weed population in the unweeded plots was simi lar to those in the weeded plots 
based on observation . However, the determination of weed biomass on unweeded 
plots was on ly  done on the potato plots on 9 March 2004 . Strong wind prior to that 
t ime caused severe lodging to the barley crops , making it d ifficult to assess the 
weed population.  
5.3.2.4 Laboratory Measu rements 
1 .  Aggregate stabi l ity 
Wet-sieving analysis to determine aggregate water stabi l ity was carried out on 2 .0  -
4 . 0  mm aggregates using the method of Gradwell ( 1 972) .  This is basically a 
modification of Yoder's method described by Kemper and Rosenau ( 1 986). 
The main apparatus used in th is method is the wet sieving tank. I t  i s  approximately 
35 cm wide x 45 cm long x 30 cm deep (Figure 5 .6) .  S ix stacks of 1 3  cm sieves 
were carried in a frame which moved up and down a d istance of 3 cm, thi rty times a 
m inute . Each sieve stack comprised three sieves stacked from top to bottom with 
apertures of 2 .0 ,  1 .0 ,  and 0 .5  mm respectively (Dando, 1 999). 
Samples were a ir-dried soon after sampl ing .  The larger clods were broken down by 
hand and the whole sample p laced i nto shallow trays and a ir-dried .  Once air-dry, 
the samples were mechanical ly sieved to extract aggregates between 2-4 mm in 
d iameter (Figure 5 .7) . Samples of 2-4 mm were analysed soon after a ir-drying. The 
aggregates were placed on the top sieves which were then moved up and down 
u nder water and the proportion of crumbs remain ing on the s ieves after the 30 
minute period being a measure of stabi l ity. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 69 
Figure 5 .6 Wet-sieving tank 
Figure 5 .7 Sieving for the extraction of 2 - 4 mm soil aggregates 
2. Soi l  hydrau l ic conductivity 
a. Saturated hydraulic conductivity (K sat.) 
The 98 mm core soil samples had the top 1 0  mm of soil picked out (cavity) to 
expose natural fractures between peds and to produce a soi l  surface as undisturbed 
as possib le .  Samples were slowly saturated in a water bath . When saturated , the 
cores were placed on a drain ing grid and a pool of water maintained in the cavity 
(F igure 5 .8a) .  The rate of water moving through the soi l was measured . Once a 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and b iomass production 1 70 
constant rate was reached for an individual  sample it was recorded and reported i n  
m/s (Dando, 2004) .  
b. Unsaturated hydraulic conductivity (K-40) 
Soi l  samples in 99 mm cores were placed on a Buchner funnel capable of creating 
a tension of between -0 . 1  and -1 . 0  kPa to control drainage of the soil .  A d isc 
permeameter (tension permeameter, suction perm ea meter) was placed on top of 
the core to supply water from a reservoir at a tension equal to that set on the 
Buchner funnel (Figure 5 .8b) .  The rate of water moving through the soil (hydraul ic 
conductivity) was measured . The unsaturated rate was recorded once a constant 
rate was reached for an ind ividual sample .  Rates were reported in m/s and mm/hr 
(Dando, 2004) .  
3 .  Soi l porosity 
The determination of soi l porosity was carried out using the same soil cores 
previously used for hydraul ic conductivity measurement. After the unsatutared 
hydrau l ic conductivity measurements were completed , the soil cores were then 
subjected to h igher suction levels under the moisture release analysis. The results 
obta ined from each suction level were further used to calcu late tota l ,  macro, and 
m icro-porosity for each soi l  core (Gradwel l ,  1 972) .  At the same time, soi l  moisture 
content, particle and bulk densities at different suction levels were a lso calculated . 
4 .  Soi l  pH, total C and N, and Olsen P analysis 
Soi l pH ,  total C and N were measured at once . Soil pH was determined by using a 
pH  e lectrode meter. Soil organic carbon content and total N were measured using a 
Laboratory Equipment Corporation (Leco) h igh-frequency induction furnace 
(Blakemore et a l . ,  1 987). The P content was determined by using the Olsen 
method . The measurements were done on sub-samples taken from a ir-dried soi l  
col lected from each plot. Samples were col lected from three depths, 0-1 00 ,  1 00-
200, and 200-300 mm, from each plot after the crops were harvested , and from the 
adjacent pasture fields on 27 March 2004. Soi l from each plot was bulked before 
sub-sampl ing .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 7 1 
(a) (b) 
F igure 5.8 Measurement of (a) saturated and (b) unsaturated hydraul ic conductivity 
5 . 3 . 3  STATISTICAL ANALY S I S  
The analysis of a l l  data obtained dur ing th is study was performed using the General 
L ineal Model (GLM) procedure of SAS (Statistical Analysis System)(SAS, 2002) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 72 
5.4 RESULTS 
5.4.1 Experiment 1 (Oil i ,  East Timor) 
1 .  Soil chemical indicators 
Table 5 . 1  presents the results of soi l chemical  analysis under corn and mungbeans 
affected by d ifferent ti l lage treatments. Comparing before and after cropping,  the 
average pH of two soil layers (0-1 0 and 1 0-20 cm) was reduced after the plants 
were harvested under all the treatments except under NT where an increase of 
average pH  was noticed both under corn and mungbean crops. Total organic 
carbon measurement was undetected (near zero) before the cropping but showed 
some increase after the corn and mungbeans were harvested , with the h ighest 
carbon figure ( 1 .52%) found under no-ti l l  corn treatment. Total N ,  l i ke the organic C,  
showed a sl ight increase after cropping with the exception of soi ls  under MT 
mungbeans where organ ic carbon decreased . 
Table 5 . 1  Selected soil chemical indicators as affected by ti l lage and cropping 
management (CT=conventional t i l lage, MT=manual ti l lage, NT=No-
ti l lage) before (BC) and after (AC) cropping 
C-org . N-tot. P K 
Treat. Soil pH (%) (%) (ppm) (me/100 g) layer 
BC AC BC  AC BC AC BC AC BC AC 
c 0-1 0  8.36 7 .55 1 .0 1  0.27 0 .23 1 1 0 78 .54 8 .8 1  1 .30 Cl! aJ 1- .0  u g>  1 0-20 8 .03 7 .64 0 .81  0.02 0.32 73.2 20.09 23.60 0 .79 ::l Aver. 8.20 7.60 0.91 0. 1 5  0.28 91 .6 49.32 16.21 1 .05 E 
0-1 0  7 .78 7 .4 1  1 .72 0 .23 0 . 1 5 307 . 7  95.37 3 1 .37 1 .2 1  
I- E 1 0-20 7 .79 7 .85 0.65 0 .23 0 .50 262 .9 93 .96 25.79 0.97 u 0 '-' 
Aver. 7.79 7.63 1 .1 9  0.23 0.33 285.3 94.67 28.58 1 .09 
0-1 0  7 .39 7 .39 2 .03 0.02 0 . 1 9  1 87 .3  88.07 29 .37  0.82 
I- E z 8 1 0-20 7 .35 7 .76 1 .0 1  0 .02 0 .06 1 6 1 . 7  1 7. 33 44.23 1 . 1 2  
Aver. 7.37 7 .58 1 .52 0.02 0 . 13  174.5 52.7 36.80 0.97 
c 0-1 0  7.09 7.35 1 .22 0 .01  0.28 64.4 67.32 42.00 2 .42 Cl! 1- 25  1 0-20 7 .20 7.48 0 .25 Z Ol  c 0. 1 9  0. 1 5  65.7 40 . 54 44 .6 1  0.58 ::l 
Aver. 7.15  7.42 0.74 0 . 10  0 .22 65.05 53.93 43.31 1 .50 E 
0-1 0  7 . 1 8  7 .35 1 .25  0 . 1 8  0 .09 1 46 .7 28.08 64 .60 1 .47 
I- E 1 0-20 7 .07 7 .43 0.86 0 .02 0 .24 1 91 . 5  27.04 73.65 1 . 1 3  � 0 '-' 
Aver. 7.1 3 7 .39 1 .06 0 . 10  0.1 7 169.1 27.56 69.1 3 1 .30 
c:: 0-1 0  7 .03 7 .35 1 .39 0 . 1 2  0 .07 1 50 .2 89 .25 20.86 1 .42 Cl! 1- 25  1 0-20 7 .23 7 .55 0 .67 0 . 1 2  0 . 1 1 1 47 .2  53 .46 26. 1 1  1 . 1 1  � g> ::l Aver. 7.1 3 7.45 1 .03 0 . 12  0.09 148.7 71 .36 23.49 1 .27 E 
BC= soil sampled on June 8, 2002; AC= soil sampled on early October 2002 
Chapter 5 - TILLAGE AND EOAPHIC CHANGES: Impacts on crop and biomass production 1 73 
2 .  Soi l bu lk  density and water content 
The results show that there was no signifi cant d ifference in bulk density for soi ls 
under cUltivation (CT and MT) compared with those in  the unti"ed plots (NT). 
Simi larly, i nsignificant resu lts were also found for soil water content under al l the 
ti l lage treatments (Table 5 .2) .  
Table 5.2 Soi l  bu lk density and water content under different ti l lage and cropping 
regimes (CT=conventional t i l lage, MT=manual ti l lage, NT=No-ti l lage) 
Parameters 
Soil bu lk  density (g cm-3) 
Soil water content (%) 
n .s. = not significant 
3 .  Crop and biomass production 
CT 
1 .25 a 
28 .33 a 
Treatments 
MT 
1 .25 a 
3 1 .58 a 
NT 
1 .2 1  a 
34.63 a 
LSDo.05 
n .s. 
n .s. 
Maize height and root length , mungbeans root length , and maize and mungbeans 
wet and dry matter was not affected by the ti l lage treatments. Significant differences 
were only observed on mungbeans plant height and weed population on maize 
plots . Mungbeans height was significantly h igher under the MT treatment as 
compared to the CT and NT treatments. A significantly higher weed b iomass , not 
unexpectedly, was found on the NT plots compared to cultivated plots (CT and MT) .  
Table 5 .3  Selected crops and weed indicators durin g  development stage 
(CT=conventional t i l lage , MT=manual til lage , NT=No-ti"age) 
Plant height Root length Weed biomass Crop wet matter Crop dry 
Treat. (mm)  (mm)  ( kg/ha OM)  ( kg/ha) matter (kg/ha) 
Maize Mbeans Maize Mbeans Maize Mbeans Maize M beans Maize M beans e10ts e10ts 
CT 533 .3 a 282.2 b 1 37 .8  a 1 42.4 a 745.6 b 800.2 a 2900 a 1 283.3a 606.9 a 28 1 .2 a 
MT  588.9  a 3 1 0. 6  a 1 24.4 a 1 1 0. 6  a 898.4 b 434.2 a 2400 a 1 800 a 5 1 7. 5  a 322.4 a 
NT 467.2 a 280.0 b 1 1 8 .9 a 97 .2 a 2 1 16 .9a 953.4 a 1 0 1 6 .7a 1 1 83.3a 302 5 a 274.5 a 
LSDo.o5 n.s. 27.72 n.s.  n .s .  1 069.4 n .s. n .s .  n .s .  n .s .  n .s .  
Values followed by the same letter in each column  are not significantly d ifferent (P<O.05), n .s .  = not 
significant 
The crop yield measurement resu lts ind icated significantly h igher maize and cob 
yields under CT and MT treatments compared to NT treatment. Mungbeans gra in 
and husk yield on the other hand,  were unaffected by ti l lage treatment. 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: I mpacts on crop and biomass production 1 74 
Table 5.4 Crop yield and by-products on 
MT=manual ti l lage, NT=No-ti l lage) 
1 2/1 0102 (CT=conventional ti l lage, 
Treatment __ -,--_M_a_iz....::e-,(>.....:..
U-,-h_a )'--=-____ ----::-M--"--un..'->gL-b_e....;,.a_n-'-s ...J...(
U_h....::a..L) __ _ 
Grain Cobs Grain Husk 
CT 
MT 
NT 
LSDo.o5 
1 8.5 a 5 .0  a 1 .8 a 0 .77 a 
1 5 . 1  a 4 .6 a 2 .0 a 0 .83a 
6.4 b 1 .7 b  1 .2 a  0 .52 a 
6.5 1 .7 n . s .  n .s. 
Values followed by the same letter in each column are not significantly different (P<O .05), n.s . = not 
significant 
5.4.2 Experi m e nt 2 (Palmerston N o rt h ,  New Zeal a n d )  
1 . Penetration resistance 
The first measurement was taken on the 6th of January 2004 , at the middle of the 
potato and barley-cropping season . There was a signifi cantly h igher soil resistance 
in the PP and NT plots compared to MT and CT plots at soil layers down to 1 8  cm 
(Table 5 .5 ) .  No significant d ifferences were found among all the treatments at 20-30 
cm soil layer. Almost sim i lar readings were observed at al l depths between the NT  
and  PP  plots with only a significantly lower value found  in the top 2 cm of  the NT  
plots. A significantly low resistance to penetration was found down to 1 2  cm soil 
profi le depth under the MT treatment compared to the CT treatment. This is the 
depth that ind icated the average hoeing depth under the MT treatment whereas 
under the CT the ploughing depth was deeper. 
There was a clear indication of the development of a loose ti lth depth or  rooting 
zone under the CT treatment down to 1 8  to 20 cm soi l  depth . From this point 
downwards (20-30 cm soi l  layer), the effects of t i l lage implements were not 
noticeable as shown by the simi larities i n  soi l strength between the ti l led plots (eT 
and MT treatments) and unti l led ones (NT and PP treatments) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 75 
Table 5.5 Effects of ti l lage practices and cropping regime on soil penetration 
resistance (MPa) (measu red on 6th January 2004) (CT=conventiona l  
t i l lage, MT=manual t i l lage , NT=No-t i l lage,  PP=Permanent pasture) 
Soil Depth Treatments LSDo.05 
(cm) eT MT NT pp 
2 1 . 58 be 1 .37 e 1 .85 ab 2 . 1 2  a 0.39 
4 2 . 1 9  a 1 .59 b 2 .45 a 2 .55 a 0 .42 
6 2 .30 b 1 . 58 c 2 .68 a 2 .66 a 0 .33 
8 2 .34 b 1 .59 e 2 .67 a 2 .66 a 0 .27 
1 0  2 .28 b 1 .66 e 2 .57 a 2 .55 a 0 .23 
1 2  2.20 b 1 .86 c 2 .43 a 2 .46 a 0 .20 
1 4  2 . 1 1 b 2 .05 b 2 .33 a 2 .44 a 0 .22 
1 6  2 . 1 3  b 2 .24 ab 2 .33 ab 2 .47 a 0 .27 
1 8  2 .26 b 2 .40 ab 2 .48 ab 2 .59 a 0 .30 
20 2 .56 a 2 .57 a 2 .79 a 2 .75 a n .s .  
25 3.25 a 3 . 1 4  a 3 .34 a 3 .25 a n .s .  
30 3 . 1 9  a 3 .42 a 3 . 1 6  a 3 .46 a n .s .  
Values fol lowed by  the same letter in each row are not sign ificantly different (P<O.05), n .s. = not 
significant 
The regression analyses (Fig. 5 .9)  showed that the increase in soi l  penetration 
resistance was l inearly correlated with the increase in soi l  depth under a l l  the 
treatments ,  the relationship was strongest for MT (R2 = 0 .96) and moderate under 
other treatments (CT: R2 = 0 .69; PP: R2 = 0.66; and NT: R2 = 0 .55) .  
The second soi l  penetration measurement was undertaken on 27 March 2004 , after 
the soil was left undisturbed under potato and barley crops (Table 5.6) .  In the top 2 
cm soil layer there was no sign ificant difference among al l  the treatments .  The top 
0- 1 0  cm soil layer under the CT treatment had been compacted to an extent s imi lar 
to that under the NT and PP treatments . With i n  th is layer, the MT treatment 
produced significantly lower resistance compared to the other treatments . Below the 
0-1 0  cm soil layer, however, a m ixed pattern was observed . In contrast to the layer 
above , the resistance under the CT and pp were reduced whi le the penetration 
resistance under the NT remained the h ighest. On the other hand,  the MT treatment 
produced significantly lower resistance in the 1 2  - 1 4  cm soi l layer. Beyond this 
layer, however, the resu lts show no significant difference among the CT, MT, and 
PP treatments. 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: I mpacts on crop and biomass production 1 76 
eT 
3.00 · � 
2.00 � 
1 4.00 
• Y = 0 .0448x + 1 .7494 
� :: � _  , _ 
� 
_
_
_ R�= 0.�24
_ _  _ 
o 5 10 1 5  20 25 30 35 1 4.00 
3.00 
2.00 
1 .00 -
0.00 . 
Soildept h ( cm) 
NI 
. -
J • • • • • • • • 
• y = 0.0341x + 2. 1 1 99 
R' = 0.5501 
o 5 10 1 5  20 25 30 35 
Solldepth(cmj 
3.00 -
2.00 -
1 .00 -
MT 
y " 0.0758x + 1 .0799 
R2 = 0.9639 
1 4.00 
0.00 ---��----�---j 
1 4.00 
3.00 
2.00 
1 .00 
0.00 
o 5 10 1 5  20 25 30 35 
SOlldepth{cm) 
pp 
t J 
• • • • • • • • • 
y = 0.0348x + 2.1852 
R' = 0.6642 
o 5 10 15 20 25 30 35 
Soi ldept h (cm) 
Figure 5 .9 Regression analysis between soi l  depth (cm) and soi l penetration 
resistance (MPa) under the CT (conventional t i l lage) ,  MT (manual 
ti l lage), NT (no-ti l lage) and pp (Permanent pasture) treatments 
measured during early summer potato and barley growing season 2003 
Table 5 .6 Effects of ti l lage practices and cro�ping regime on soi l  penetration 
resistance (MPa) (measured on 271 March 2004) (CT=conventional 
t i l lage, MT=manual t i l lage , NT=No-ti l lage, PP=Permanent pasture) 
Soil Depth Treatments LSDo o5 
(cm) eT MT NT pp 
2 1 .92 a 1 .52 a 1 .67 a 1 .89 a n . s  
4 2 . 1 0  a 1 .52 b 1 .94 ab 2 .09 a 0 .45 
6 2 . 1 4 a 1 .39 b 2 . 1 7  a 2 . 07 a 0.43 
8 2 .08 a 1 .22 b 2 .24 a 2 .04 a 0 .35 
1 0  1 .96 a 1 . 1 8  b 2 . 1 8  a 1 .94 a 0 .30 
1 2  1 .85 b 1 .24 c 2 .09 a 1 .82 b 0 .23 
1 4  1 .72 b 1 .37 c 1 .94 a 1 .72 ab 0 .22 
1 6  1 .67 b 1 .48 b 1 .90 a 1 .65 b 0 .22 
1 8  1 . 73 b 1 .59 b 1 .98 a 1 . 7 1  b 0 .23 
20 1 .78 ab 1 . 75 b 2 . 1 1  a 1 .82 ab 0 .36 
25 2 . 1 4 b 2 . 1 2  b 2 .57 a 2 .23  ab 0 .35 
30 2 .33 b 2 .24 b 2 .70 a 2 .36 b 0 . 32 
Values followed by the same letter i n  each row are not significantly different ( P<O.05); n .s. = not 
sign ificant 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 1 77 
1 3.00 
2.50 
2.00 
1 .50 
1 .00 
0.50 
0.00 
CT 
So,l depl h(cm) 
NT 
• J 
_ . . . . . . . . • 
y = 0.024x + 1 .7954 
R' = 0.5099 
o 5 10 15  20 25 30 35 
Solldapth l crn)  
MT 1 2.50 
2.00 ' �. • 
1 .50 < • • • • • • • 1 .00 < Y = 0.03 1x  + 1 . 1 258 
0.50 . R' = 0.6052 
0.00 ---��------
o 5 1 0  1 5  20 25 30 35 
Soildepth jcm)  
pp 
• • 2.00 • • • • • 
• • • • • 1 .50 
1 2.50 -
1 .00 -
0.50 < 
0.00 -
y = 0.0072x + 1 .8972 
R2 = 0.0144 
(no clear relationship) 
o 5 10 15 20 25 30 35 
SOll dept h ( cm) 
Figure 5 . 1 0  Regression analysis between soi l depth (cm) and soi l penetration 
resistance (MPa)  under the CT (conventional ti l lage), MT (manua l  
ti l lage), NT (no-ti l lage )  and pp (Permanent pasture) treatments 
measured after potato and barley harvest 2004 
Soi l resistance tended to i ncrease in the lower layers under al l the treatments after 
a period of more than two months. Another observation from the second set of 
measurements in the MP plots was the decrease in soil resistance observed at the 
depths below 20 cm. This suggests the characterization of another differing soi l 
horizon just below the cultivated layer. Regression analysis results demonstrated no 
clear trend between soi l depth and soil penetration resistance under MP whereas a 
l inear regression was found under PP and NT (Figure 5 . 1 0) .  
2 .  Soi l bu lk density 
The resul ts show simi lar densities of soi l in  the 0-5 cm topsoil under al l  the 
treatments (Table 5.7) .  A clear pattern is observed where soi l bu lk density 
i ncreased with the increase of soi l depth especial ly below 20 cm depth . The soi ls i n  
the unt i l led plots (NT and  PP) showed a consistently h igher soi l bu l k  density 
compared to those from the t i l led p lots (CT and MT). CT and MT show almost 
s imi lar soi l  densities in al l  depths except at 5-1 0  cm soil layer where the soil bu lk  
density is  s ignificantly h igher under CT.  S imi la rly, the soi ls under NT and PP 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 78 
treatments show no significant differences throughout the soi l  profi le .  On average ,  
however, the soi ls under MT had a significantly lower bu lk  density a t  0-30 cm depth 
compared to the soi ls  under the other treatments. 
Table 5.7 Effects of ti l lage practices and cropping regime on soi l  bulk density 
(gcm-3) measured on 1 ih March 2004 (CT=conventional t i l lage , 
MT=manual ti l lage, NT=No-ti l lage, PP=Permanent pasture) 
Soil Depth Treatments 
(cm) CT MT NT pp LSDo o5 
5 1 .22 a 1 .26 a 1 .2 1  a 1 .2 1  a n . s  
1 0  1 .20 b 1 . 1 4  c 1 .25 ab 1 .28 a 0 .06 
1 5  1 . 1 9  ab 1 .05 b 1 .30 a 1 .27 a 0 . 1 6  
20 1 . 1 8  b 1 .22 ab 1 .29 a 1 .23 ab 0 . 1 0  
25 1 .34 a 1 .25 ab 1 .3 1  ab 1 .20 b 0 . 1 2  
30 1 .44 a 1 .36 a 1 .49 a 1 .33 a n .s .  
Average 1 .26 ab 1 .21  b 1 .3 1  a 1 .25 ab 0 .07 
Values fol lowed by the same letter in each row are not significantly d ifferent (P<O.05) 
The second measurement was done using a 98 mm internal diameter corer at two 
soi l depths ,  0-1 0 and 1 0-20 cm (Table 5 .8) .  There was a significantly h igher soil 
bu lk density under the CT compared to the others in  the 0-1 0  cm soi l layer. In the 
layer below, however, the soil bulk densities were s imi lar. On average ,  CT soi ls  
were sign ificantly more compacted than the soils under MT and pp (P<0 .05) but ,  
ins ignificantly different with soils under NT at 0-20 cm depth . 
Table 5.8 Effects of ti l lage practices and cropping regime on soi l  bu lk density 
(gcm-3 ) measured on Apri l 2004 (CT=conventional til lage, MT=manual 
t i l lage, NT=No-ti l lage, PP=Permanent pasture) 
Soil Depth Treatments 
(cm) 
0-1 0 
1 0-20 
Average 
CT 
1 .23 a 
1 . 1 8  a 
1 .2 1  a 
MT 
1 . 1 1  b 
1 . 1 6  a 
1 . 1 4  b 
NT 
1 . 1 2  b 
1 .25 a 
1 . 1 9  ab 
pp 
1 .07 b 
1 . 1 6  a 
1 . 1 0  b 
LSDo.o5 
0 .06 
n .s .  
0 .07 
Values fol lowed by the same letter in each row are not significantly d ifferent (P<O.05); n .s .  = not 
significant 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 79 
3 .  Soil Water Properties 
a. Low tension (L T) Moisture Release Analysis 
The moisture release analysis using low tension shows that permanent pasture 
(PP) soi ls had consistently a sign ificantly h igher field capacity and water content at 
the 0-1 0  cm depth under all levels of suction (0 kPa, 5 kPa ,  and 1 0  kPa) compared 
with the soi ls under the other treatments (Table 5 .9) .  On the contrary, among all the 
soil treatments, MT produced the lowest level of field capacity while CT had the 
lowest water content at saturation .  At the 5 kPa and 1 0  kPa suction leve l ,  a mixed 
water content result was observed between CT and MT, however they were 
general ly s imi lar .  The NT produced sign ificantly lower soi l  water content compared 
to PP at 5 kPa and 1 0  kPa suction but general ly h igher or similar results compared 
to CT and MT. 
Table 5 .9 Ti l lage effects on soi l  water properties at 0 - 1 0  cm topsoil (measured 
using Low Tension Moisture Release Analysis) (CT=conventional t i l lage , 
MT=manual ti l lage, NT=No-ti l lage, PP=Permanent pasture) 
Til lage Field Water content 
Treatment capacity at saturation at 5 kPa at 1 0  kPa 
(%) %w/w %v/v %w/w %v/v %w/w %v/v 
CT 4 1 . 1 bc 43.0 b 52.9 b 35 .5 c 43.6 b 33 .5 c 4 1 . 1  cb 
MT 38.6 c 51 .3 a 56.9 a 36.5 bc 40.5 c 34 .7 bc 38.6 c 
NT 42.8 b 50 .5  a 56.5 a 40.3 b 45.0 b 38.2 b 42.8 b 
pp 46. 1  a 54.8 a 58.5 a 44.9 a 47.9 a 43.2 a 46 . 1  a 
LSDo o5 2 .8 4.8 2.2 4 . 1  2 . 7  3 .9 2 .8 
Values followed by the same letter i n  each column are not sign ificantly different (P<0.05) 
Table 5. 1 0  Ti l lage effects on soil water properties at 1 0  - 20 cm subsoil (measured 
using Low Tension Moisture Release Analysis) (CT=conventional t i l lage, 
MT=manual t i l lage, NT=No-ti l lage, PP=Permanent pasture) 
Field Water content Til lage capacity at saturation at 5 kPa at 1 0  kPa Treatment (%) %w/w %v/v %w/w %v/v %w/w %v/v 
CT 4 1 . 1  a 46 .9 a 54 .6 a 37 . 1  a 43 .5 a 35. 1 a 4 1 . 1  a 
MT 37.8 c 48. 1 a 55.5 a 34.3 ab  39 .7  c 32.6 ab 37.8 c 
NT 39.0 bc 42 .0 a 52 .5 a 32.9 b 4 1 .0 bc 3 1 . 3  b 39.0 bc 
pp 40.3 ab 48.2 a 55.6 a 37.0 a 42.7 ab 34. 9 ab 40.3 ab 
LSDo.05 1 .5 n.s . n . s. 4.0 2 . 1  3 .6 1 .5 
Values followed by the same letter i n  each column are not significantly d ifferent (P<0.05) ,  n .s .  = not 
sign ificant 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 80 
At the 1 0-20 cm soi l  depth , the CT, interestingly, produced the h ighest field capacity 
and water content at 5 and 1 0  kPa suction levels although i nsign ificantly different 
with pp treatment (Table 5 . 1 0) .  Water content at saturation (0 kPa) was simi lar 
u nder al l the treatments. MT and CT have general ly simi lar values of field capacity 
and water content at a l l  levels of water suction . 
b. High tension (HT) Moisture Release Analysis 
The high tension ana lysis on soils from 0-1 0 cm depth shows that PP, l ike in  the low 
tension analysis results described earl ier, had the highest fie ld  capacity and water 
content at al l  suction levels (Table 5 . 1 1 ) . MT had the lowest fie ld capacity but 
showed no significant differences with CT and NT.  NT had s imi larities with pp i n  
field capacity and volumetric water content ( 1 0  and 1 00 kPa suction) but sign ificant 
d ifferences in g ravimetric water content (0 ,  1 0 , and 1 00 kPa suction ) and volumetric 
water content at satu ration (0 kPa suction) .  CT and MT shared many simi larities 
except for gravimetric water content (0 and 1 0  kPa suction ) and volumetric water 
content at 0 kPa suction . Readi ly avai lable water (RAW) was not affected by ti l lage 
and pasture treatments as no sign ifi cant d ifferences were found .  
Table 5. 1 1  Ti l lage effects on  soi l water properties at 0 - 10  cm topsoil (measured 
using High Tension Moisture Release Analysis) (CT=conventional ti l lage ,  
MT=manual ti l lage, NT=No-ti l lage, PP=Permanent pasture ,  RAW=read i ly  
avai lable water) 
RAW Water content 
Field 10 - at saturation at 1 0  kPa at 1 00 kPa Til lage 100 
Treatment capacity kPa (%) (%) %w/w %v/v %w/w %v/v %w/w %v/v 
CT 39.3 b 9.3 a 40.7  e 5 1 . 5  e 31 .0 e 39.3 b 23.7 b 30.0 b 
MT 39.0 b 8.6 a 47.4 ab 55 .0  ab 33.6 b 39.0 b 26.2 b 30.4 b 
NT 40.2 ab 8.4 a 43.7 be 53.0 be 33.2 be 40.2 ab 26.3 b 3 1 .8 ab 
pp 42.1  a 6.6 a 48.8 a 55.6 a 38.9 a 42 .1  a 3 1 . 1  a 35.5 a 
LSDo.05 2 .4 n .s .  4.2  2 .4 2 .3  2 .4  3 .6  4 . 1  
Values followed by the same letter in each column are not significantly d ifferent (P<0.05) . n .s .  = not 
Sign ificant 
At 1 0-20 cm soil depth , the ti l lage and pasture treatments in genera l ,  did not have 
any significant impact on the field capacity and soi l water content (Table 5 . 1 2). This 
was shown by the simi larities among the values under al l  the treatments except 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 81 
volumetric water content under MT at 1 0  kPa and field capacity which had 
s ignificantly lower values compared to the other soi l  treatments. 
Table 5. 1 2  Til lage effects on soil water properties at 1 0  - 20 cm subsoi l  (measured 
by High Tension Moisture Release Analysis) (CT=conventional ti l lage ,  
MT=manual ti l lage, NT=No-ti l lage, PP=Permanent pasture , 
RAW=readi ly ava i lable water) 
RAW Water content 
Field 10 - at saturation at 1 0kPa at 1 00 kPa Ti l lage capacity 1 00 Treatment kPa (%) (%) %w/w %v/v %w/w %v/v %w/w %v/v 
CT 39.7 a 9.0 a 44 . 1  a 52.9 a 32.8 a 39.7 a 25.5 a 30.7 a 
MT 37.8  b 8.9 a 43.1  a 52.8 a 30.8 a 37.8 b 23.6 a 28.9 a 
NT 38.4 ab 9.5 a 39.5 a 50.7 a 29.9 a 38 .4 ab 22.5 a 29.0 a 
pp 38.5 ab 9.6 a 42.2 a 52.3 a 3 1 .0 a 38.5 ab 23.3 a 28.9 a 
LSDo o5 1 .3 n . s  n .s .  n .s .  n . s .  1 .3 n.s.  n .s .  
Values followed by the same letter in each column are not significantly different (P<0.05), n .s .  = not 
significant 
4 .  Temporal volumetric soi l  water content (TOR measurement) 
Table 5 . 1 3  shows that MT had the lowest volumetric water content at both depths 
(0-1 5 and 1 5-30 cm) over the course of the experiment, from late spring 2003 to late 
summer 2004 . Usual ly the soi ls under NT had the h ighest volumetric water content. 
There were, however, three instances when CT had h igher water content value than 
NT, on 27/1 1 /03 (0-1 5 cm soi l  depth) ,  1 2/1 2/03 ( 1 5-30 cm), and 23/02/04 (0-1 5 cm) .  
Table 5 . 1 3  Temporal volumetric soi l  water content by TDR measurement (CT= 
conventional t i l lage, MT=manual ti l lage, NT=No-ti l lage) 
Dates 
Soil Soil 
Treat Depth 20/1 1 /03 27/1 1 /03 1 2/1 2/03 610 1 104 23/02/04 Aver. St Dev. 
eT 0 - 1 5  30 . 1  39 .2 37 .3 1 8 . 7  27.6 30 .7  9 .5  15  - 30  28.5 35.0 36.8 20.0 27.8 29 .9 7 .6  
MT 0 - 1 5  27.0 33.9 33.9 1 7 .5  28 .5  28 .5  7 . 7  15  - 30 27.0 33 .8 34.3  1 8 .7  28 .5 28.8 7 .2  
NT 0 - 1 5  32.6 39 . 1  38 .5  24.6 24 .6 3 1 .7 8 .2  15  - 30  29.4 37.7 36.7 24.0 29.4 3 1 .9 6 .5  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 1 82 
The temporal variation of soil volumetric water content i n  the 0-1 5 cm topsoil is  
clearly demonstrated by a sharp decrease i n  water content around mid summer i n  
January 2005, down from a range of 33 . 1  - 39.2 % i n  late November 2003 to 1 7.5 -
24 .6 i n  early January 2004.  A sl ight i ncrease in soil water content was noticed 
towards the end of summer 2005 .  S imi lar trends were observed for the 1 5-30 cm 
soil layer. 
5 .  Soil Aggregate Stabi l ity 
At the 0-1 0 cm soi l depth , the remain ing aggregates in the sieve after 30 m inutes 
wet-sieving were general ly simi lar for a l l  the treatments (Table 5. 1 4) .  
Table 5 . 1 4  Effects of ti l lage practices on soil water-stable aggregates of the 0-1 0  cm 
soi l  layer us ing 30 minutes wet-sieving ( % ) (CT=conventional t i l lage, 
MT=manual t i l lage, NT=No-ti l lage,  PP=Permanent pasture, 
MWD=mean weight diameter) 
Soil A9..9..re9..ate Size MWD 
Treatment >2 mm 1 -2 mm 0 .5 - 1  mm  <0.5mm (mm) 
eT 25 .2  a 1 9 .3  b 1 2 .2  a 43.5 a 1 .2 
MT 35 .2  a 24. 5  a 8 .7  b 3 1 .7  a 1 .6 
NT 36.9 a 1 8 . 7  b 9.4 b 34.9  a 1 .6 
pp 29 .6 a 20 .7 ab 1 2 .2  a 37.4 a 1 .4 
LSDo.o5 n . s .  4 .3 2 . 1  n .s .  
Values followed by  the same letter i n  each col umn are not significantly different (P<O.05) , n . s .  = not 
sign ificant 
Significant d ifferences were observed at the 0 .5  - 1 mm aggregate size range 
where soi ls under CT and pp had significantly h igher stabi l ity compared to those 
under MT and NT. In addition ,  differences also existed in the 1 -2 mm aggregate 
size range where CT, NT, and pp soi ls had sign ificantly lower stabi l i ty compared to 
the MT soi ls .  The MT and NT soi ls had greater mean weight d iameter (MWD) of 
aggregates remain ing on sieve after 30 m inute wet-sieving ( 1 . 6  mm)  as compared 
to 1 .2 and 1 .4 mm for soi ls under CT and PP, respectively. 
Overa l l ,  the MT had the greatest number of aggregates on  s ieve after the 30 minute 
wet-sieving (68.3%) fol lowed by NT (65 . 1  %) ,  pp (62.6%) and CT (56.52%) .  
S imi larly with the <0.5 mm aggregates (soi l loss by  water) i t  can be  assumed that 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 83 
the d ifferences i n  cumulative aggregates on sieve were also not statistical l y  
s ignificant. 
Soils from 1 0-20 cm depth exhibited a d ifferent picture compared to the 0-1 0 cm 
depth soi ls  particularly in  regards to the >2 mm and <0.5 mm aggregate size ranges 
(Table 5 . 1 5) .  The CT and NT produced s ignifi cantly more >2 mm stable aggregates 
compared to pp (P<0 .05) ,  but statistical ly s imi lar amounts compared with MT. I n  
the 1 -2 mm aggregate size range, MT produced significantly h igher amounts of 
stable aggregates compared to CT and pp (P<0 .05) ,  but not d ifferent amounts from 
NT. No signifi cant d ifferences were observed among treatments on the 0 .5  - 1 mm 
aggregate size range.  pp had sign ificantly more unstable soi ls  « 0 .5  mm aggregate 
size) compared to NT and MT (P<0.05), but simi lar amounts with CT after 30 
minute wet-sieving . NT had the greatest MWD of soil aggregates of 1 .02 mm 
followed by CT (0 .94 mm), MT (0 .92 mm) ,  and pp (0.72 mm).  
Table 5 . 1 5  Effects of ti l lage practices on soi l  water-stable aggregates of the 1 0-20 
cm soil layer using 30 minutes wet-sieving (%) (CT=conventional ti l lage, 
MT=manual t i l lage, NT=No-ti l lage, PP=Permanent pasture , 
MWD=mean weight d iameter) 
Soil Aggregate Size MWD 
Treatment (mm) 
>2 mm 1 -2 mm 0 .5-1  mm <0.5mm 
eT 1 5 .9  a 1 5 .5 b 1 2 . 1  a 56.5 ab 0 .94 
MT 1 3 .5 ab 1 8 . 7  a 1 3 .6 a 54.2 b 0 .92 
NT 1 7 .6 a 1 7 . 7  ab 1 2 .5  a 52 . 3  b 1 .02 
pp 7 .8  b 1 5 . 1  b 1 4 . 1  a 63 . 1  a 0 .72 
LSDo 05 7 . 1  3 . 1  n .s .  7 .8  
Values followed by the same letter in each column are not sign ificantly d ifferent (P<O.05); n.s.=not 
significant 
Cumulatively, NT had the largest number of stable aggregates (47.7%) fol lowed by 
MT (45.8%),  CT (45 .5%), and pp with 36.9% . The statistical d ifferences followed 
the case of <0 .5 mm aggregate size range described in Table 5 . 14 .  
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 84 
6 .  Soil Porosity 
a. Low tension (L T) Moisture Release Analysis 
Soi l porosity was determined by using moisture release analysis and th is resulted in 
the series of porosity related parameters in Table 5. 1 6  for 0-1 0 cm soil depth . Total 
porosity and void ratio were sign ificantly lower under eT treatment compared with 
the other three treatments . MT on the other hand , had sign ificantly more 
macroporosity, soi l  air capacity, and air-fi l led porosity (at 5 and 1 0  kPa) but less 
water-fi l led porosity (at 5 and 1 0  kPa) compared to the other treatments. Pore size 
distribution (60 - 30 mu) was insign ificantly affected by t i l lage and pasture 
treatments. 
Table 5 . 1 6  Soil porosity and related parameters in the 0- 1 0  cm topsoi l as affected 
by t i l lage and pasture management (measured using Low Tension 
Moisture Release Analysis) (CT=conventional ti l lage , MT=manual t i l lage ,  
NT=No-ti l lage , PP=Permanent pasture , PSD=Pore size distribution , 
AFP=Air-fi l led porosity, WFP=Water-fi l led porosity) 
Total Macro Soil air PSD Void AFP @ AFP @ WFP @ WFP @ Treat. porosity porosity capacity 60 - 30 ratio 5 kPa 1 0  kPa 5 kPa 10 kPa (%} (%} (%} mu (%} (%} (%} (%} (%} 
CT 52.9 b 9.23b 1 1 .7 b 4 .7 a 1 . 1 b 9.2 b 1 1 .7 b 82.6 a 77.9 a 
MT 56.9 a 1 6 .4 a 1 8 .3 a 3.4 a 1 .3 a 1 6 .4 a 1 8 .3 a 71 .3 b 67.9 b 
NT 56 .5 a 1 1 .5 b 1 3 .7 b 4 .0 a 1 .3 a 1 1 .5 b 1 3 .7 b 79.7 a 75.7 a 
pp 58.5 a 1 0 .6 b 1 2 .4 b 3 .0 a 1 .4 a 1 0 .6 b 1 2 .4 b 81 .8  a 78.8 a 
LSDo.o5 2.2 2.6 3 . 1  n .s .  0. 1 2  2.6 3 . 1 1  4 . 3  5.2 
Values followed by the same letter in  each column are not significantly d ifferent (P<O.05), n.s. = not 
significant 
NT and PP appeared to have s imi lar impacts on soi l  porosity and its related 
parameters in the top 10 cm soil as ind icated by statistical ly simi lar values across a l l  
the measurements. Total porosity, pore size distribution (60 - 30 mu) ,  and void ratio 
seemed unaffected by the soil treatments as no significant differences were found in 
the 1 0-20 cm soil layer as shown in Table 5 . 1 7 .  Simi lar with the layer above, MT 
appeared to have significantly h igher macroporosity, soi l a i r  capacity,  and a i r-fi l led 
porosity (at 5 and 1 0  kPa) but less water fi l led porosity (at 5 and 1 0  kPa) compared 
to the other treatments. PP and NT shared simi lar soil porosity characteristics as no 
s ignificant d ifferences were found comparatively between the two (Table 5 . 1 7 ) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 85 
Table 5 . 1 7  Soil porosity and related parameters in the 1 0-20 cm subsoil as affected 
by ti l lage and pasture management (measured using Low Tension 
Moisture Release Analysis) (CT=conventional t i l lage, MT=manual 
ti l lage, NT=No-ti l lage, PP=Permanent pasture ,  PSD=Pore size 
d istribution, AFP=Ai r-fi l led porosity, WFP=Water-fi l led porosity) 
Treat. 
eT 
MT 
NT 
pp 
LSDo 05 
Total 
porosity 
(%) 
54.6 a 
55.5 a 
52.2 a 
55.6 a 
n .s .  
Macro 
porosity 
(%) 
1 1 . 1 b 
1 5 .9 a 
1 1 .2 b 
1 3 .0 ab 
4 .6 
Soil air 
capacity 
(%) 
1 3 .5  ab 
1 7 .8 a 
1 3.3  b 
1 5 .4 ab 
4 .3  
PSD 
60 - 30 
mu (%) 
4 .5 a 
3 .4 a 
3.9 a 
4 .3 a 
n .s .  
Void 
ratio 
1 .22 a 
1 .25 a 
1 .09 a 
1 .25 a 
n .s .  
AFP @ 
5 kPa 
(%) 
1 1 .1 b 
1 5 .9 a 
1 1 .2 b 
13 .0  ab 
4.6  
AFP @ 
1 0  kPa 
(%) 
1 3 .5 ab 
1 7.8  a 
1 3.3 b 
1 5.4 ab 
4.3 
WFP @ 
5 kPa 
(%) 
80. 1  a 
71 .5  b 
78.6 a 
76.7 ab 
7.0 
WFP @ 
1 0  kPa 
(%) 
75.6 a 
68. 1  b 
74.7 a 
72.4 ab 
6.1  
Values fol lowed by the same letter in each column are not significantly different (P<O.05), n .s .  = not 
s ign ificant 
b. High tension (HT) Moisture Release AnalYSis 
Moisture release analysis using h igh tension resulted in a qu i te different set of 
porosity parameters to the analysis using low tension . In the 0-1 0  cm soil depth , 
pore size d istribution (30 - 3 mu) ,  a i r-fi l led porosity (at 1 0  and 1 00 kPa) ,  and water­
fi l led porosity (at 1 0  kPa) were not affected by the t i l lage and pasture treatments 
(Table 5 . 1 8) .  pp had higher total porosity and void ratio than other treatments, and 
was sign ificantly h igher compared to CT and NT treatments. In  addition,  pp also 
had a sign ificantly higher water-fi l led porosity compared with MT, whi le showing 
s imi larities with CT and NT treatments . Bulk density determi ned using h igh tension 
moisture release analysis ,  un l ike in the previous measurements , was sign ificantly 
h igher under CT compared to others, while the lowest value was found under PP. 
The results for the 1 0-20 cm soi l  depth showed that the t i l lage and pasture 
treatments d id not have significant effects on the soil porosity and related 
parameters (Table 5 . 1 9) .  
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 86 
Table 5 . 1 8 Soil porosity and related parameters at the 0-1 0 cm topsoi l  as affected 
by ti l lage and pasture management (measured using H igh Tension 
Moisture Release Analysis) (CT=conventional ti l lage, MT=manual t i l lage, 
NT=No-ti l lage , PP=Permanent pasture, PSD=Pore size distribution , 
AFP=Air-fi l led porosity, WFP=Water-fil led porosity) 
Bu lk Total PSD AFP@ AFP@ Void WFP@ WFP@ Treat. densit¥, porosity 30-3 1 0  kPa 1 00 kPa ratio 1 0  kPa 1 00 kPa (Mgm- ) (%) mu (%)  (% )  (%)  (%) (%) 
CT 1 .30 a 51 .5 c 9 .3  a 1 2 .2 a 2 1 .5  a 1 .06 c 76.4 a 58.4 ab 
MT 1 . 1 9  bc 55 .0 ab 8.6 a 16 .0 a 24 .6 a 1 .22 ab 70 .9 a 55.3 b 
NT 1 . 23 b 53.0 bc 8.4 a 1 2 .8 a 21 . 2  a 1 . 1 3  bc 76.0 a 60 . 1  ab 
pp 1 . 1 6  c 55.6 a 6 .6 a 1 3.5 a 20. 1 a 1 .26 a 75.9 a 63.9 a 
LSDo o5 0.06 2.4 n .s .  n .s .  n .s .  0. 1 1  n .s .  8 .5 
Values followed by the same letter in each column are not s ignificantly d ifferent (P<0.05) , n .s .  = not 
significant 
Table 5 . 1 9  Soil porosity and related parameters at the 1 0-20 cm subsoil as affected 
by ti l lage and pasture management (measured using H igh Tension 
Moisture Release Analysis) (CT=conventional ti l lage, MT=manual 
ti l lage, NT=No-ti l lage , PP=Permanent pasture ,  PSD=Pore size 
d istribution , AFP=Air-fi l led porosity, WFP=Water-fi l led porosity) 
Bulk Total PSD AFP@ AFP@ WFP@ WFP Void @ 1 00 Treat. densit¥, porosity 30-3 1 0  kPa 1 00 kPa ratio 1 0  kPa kPa (Mgm- ) (%) mu (%)  (%) (%)  (%)  (%) 
CT 1 .22 a 52.9 a 9 .0 a 1 3.2 a 22.2 a 1 . 1  a 75 .5 a 58.2 a 
MT 1 .23 a 52.8 a 8 .9  a 14 .9  a 23.8 a 1 . 1  a 7 1 .8 a 54.9 a 
NT 1 .29 a 50.7 a 9 .5  a 1 2 .2 a 2 1 . 7  a 1 .0 a 76.0 a 57 .2 a 
pp 1 .24 a 52.3 a 9 .6 a 1 3 .9 a 23.4 a 1 . 1  a 73.6 a 55 .3 a 
LSDo.o5 n .s .  n .s. n .s .  n .s. n . s. n .s .  n .s .  n .s .  
n .s .  = not significant 
7. Hydrau l ic Conductivity 
The soil hydraul ic conductivity measurements at the end of the cropping season 
were inconclusive, due primari ly to the high level of variation among the repl icates 
in each treatment as indicated by the h igh LSDo.o5 values. Thus Table 5 .20 below 
shows that both saturated and unsaturated hydraul ic conductivity were simi lar under 
al l  the treatments except for the hydraul ic conductivity at 1 0-20 cm soil depth which 
appeared to be significantly h igher under MT treatment compared to the others. 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 87 
Table 5 .20 Saturated and unsaturated hydrau l ic conductivity of soi l layers under 
d ifferent t i l lage and pasture management (CT= conventiona l  ti l lage , 
MT=manual ti l lage , NT=No-t i l lage, PP=Permanent pasture) 
Ti l lage Ksat Kunsat 
Treatments 0 - 1 0 1 0  - 20 0 - 1 0 1 0  - 20 
cm cm cm cm 
CT 562.8 a 1 32 .0 b 45.0 a 38 . 1  a 
MT 747 .4 a 454 .2 a 56.3 a 59 .5  a 
NT 334.6 a 61 . 1  b 24 .3  a 39.4 a 
pp 376.5 a 86 .6 b 1 6 .4 a 42 .8  a 
LSDo o5 n .s. 258. 1  n .s .  n .s .  
Values followed by  the same letter in each column are not significantly d ifferent (P<0 .05) , n .s. = not 
s ignificant 
8. Chemical Properties 
The soil chemical analysis  for selected macro nutrients showed that the treatments 
had few significant effects on the nutrients especial ly for Olsen P in both 0-1 0  and 
1 0-20 cm soil depths, and total C and total N in the 1 0-20 cm soil layer wh ich 
showed no statistical differences among treatments (Table 5 .21 ) .  The percentage of 
tota l carbon i n  the 0- 1 0  cm soil layer found under the PP treatment was s imi lar  with 
that under NT, but sign ificantly higher compared with those u nder MT and CT 
treatments. Likewise, total n itrogen at the 0-1 0 cm topsoi l was sim ilar under PP, NT 
and MT but the CT treatment p roduced s ignificantly lower total N compared to the 
other  treatments . 
Table 5 .21  Ti l lage effects on soi l chemical properties (CT= conventional t i l lage, 
MT=manual t i l lage, NT=No-ti l lage, PP=Permanent pasture) 
Ti llage Total C (%) Total N (%) Olsen P (ugP/g soi l )  
Treatment 0-1 0  10-20 0- 10 10-20 0-10  10-20 
CT 2 . 14  c 1 .95 a 0.25 b 0. 1 6  a 26.67 a 2 1 . 79 a 
MT 2 .34 bc 1 .79 a 0 .27 ab 0 . 1 5  a 39.29 a 1 7.02 a 
NT 2.48 ab 1 . 76 a 0.27 ab 0. 1 6  a 52 .26 a 1 7. 50 a 
pp 2 .70 a 1 .74 a 0.28 a 0 . 1 5 a 51 .43 a 65.7 1 a 
LSDo.05 0.31  n .S .  0 .03 n .s .  n .s. n .s .  
Values followed by the same letter in each column are not significantly d ifferent (P<0.05) , n .s .  = not 
s ignificant 
When extrapolated to an area basis the statistical differences no longer existed 
although a general ly simi lar trend was present (Table 5 .22) .  
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 88 
Table 5 .22 Total C ,  total N (tlha) ,  and CN ratio at the top 0-1 0 cm soil affected by 
ti l lage treatments and pasture management (CT=conventional t i l lage , 
MT=manual ti l lage, NT=no-ti l lage, PP=permanent pasture) 
Treatments 
CT 
MT 
NT 
pp 
LSDo os 
n . s. = not Sign ificant 
9 .  Crop and biomass yield 
C 
26.24 
25.99 
27.74 
28.92 
n .s. 
N CN ratio 
3 .05 8 .6 
2 .94 8 .8 
3 .06 9 . 1  
3 .03 9 .5  
n .s 
The potato tuber and above ground biomass yield was significantly lower under the 
NT  treatment, both i n  the weeded and unweeded p lots, compared to those from the 
t i l led (CT and MT) plots (Table  5 .23). 
Table 5.23 Potato tuber and biomass yield (tlha )  under d ifferent t i l lage treatments 
(CT= conventional t i l lage ,  MT=manual t i l lage, NT=No-ti l lage) 
Ti l lage Potato Yield Potato B iomass OM 
treatments Weeded plots Unweeded Weeded plots Unweeded 
plots plots 
CT 46.58 a 44 .08 a 3 . 99 ab 4 .59 a 
MT 5 1 .03 a 43 .38 a 4 .54 a 4 .40 a 
NT 28. 1 3  b 28.40 b 2 .67 b 1 .80 b 
LSOo os 1 2 .51  1 0.37 1 .58 1 .40 
Values followed by the same letter in each column are not Significantly different (P<O.05) 
An exception was found i n  potato b iomass from unweeded plots where the lowest 
yie ld under NT treatment was insignificantly d ifferent with that from the CT treatment. 
In contrast to the potato, the barley gra in  and b iomass production under a l l  the 
treatments were found to be statistical ly sim i lar, both in the weeded and unweeded 
p lots (Table 5.24) .  
The weed biomass as expected was greater i n  the cultivated p lots than the unti l led 
plots (NT) (Table 5.25). An exception was the manual ly t i l led (MT) and unweeded 
potato plots, two months after the first assessment, where the weed biomass showed 
no significant d ifferences with those under the CT and NT treatments. As mentioned 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 89 
earl ier, the assessment of weeds i n  the unweeded barley plots was not possible due 
to a storm wind which caused damage to the already mature crops. 
Table 5 .24 Barley grain and biomass yield (Uha)  u nder d i fferent t i l lage treatments 
(CT= conventional ti l lage, MT=manual t i l lage, NT=No-ti l lage) 
Ti l lage 
treatments 
CT 
MT 
NT 
LSDo o5 
Barley grain 
Weeded plots Unweeded 
4.85 a 
5 .02 a 
5 .07 a 
n .s .  
plots 
4 .55 a 
4 .76 a 
4 .38 a 
n .s .  
Barley biomass OM 
Weeded plots Unweeded 
5 .84 a 
5 .97 a 
5 .82 a 
n .s. 
plots 
5 .33 a 
5.78 a 
5.67 a 
n .s .  
n .s .  = not significant 
Table 5 .25 Weed biomass on potato and barley plots (Uha) (CT= conventional 
ti l lage, MT=manual t i l lage, NT=No-ti l lage) 
Ti l lage 
treatments 
CT 
MT 
NT 
LS00 05 
Weeded p lots (5/ 1 /04) 
Potato Barley 
0.78 b 0 .77 b 
1 .08 b 0 .93 b 
2 .67 a 2 .42 a 
0.67 0 .73 
Unweeded plots (9/3/04) 
Potato 
1 . 1 3  b 
1 .4 1  ab 
1 .95 a 
0.57 
Values fol lowed by the same letter in each column are not sign ificantly different (P<O.05) 
Visual observation suggested that conventional and manual  ti l l  plots contained more 
erect ,  d icot weeds, most evident in  the form of black n ight shade, compared to 
grass weeds.  On the other hand ,  the NT p lots were mostly dominated by clover as 
shown in Table 5 .26 .  Basical ly, clover and black n ight shade were the most 
d istinctive types of weed characterizing the effects of t i l led and unti l led treatments, 
respectively, i n  the experimental plots. There were, however, some other weeds 
which appeared only in  minor quantities . 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: I mpacts on crop and biomass production 1 90 
Table 5.26 Distribution of 1 0  most evident weeds* i n  the unweeded potato plots (%) 
(CT=conventional ti l lage, MT=manual ti l lage, NT=no-ti l lage) 
Weed 
Clover (Trifolium repens) 
Ryegrass (Lolium perenne) 
Black n ight shade (Solanum nigrum) 
Broad leaved dock (Rumex obtusifolius) 
Broad leaved planta in  (Plantago major) 
Fathen (Chenopodium album) 
Hawksbeard (Crepis capillaries) 
Hawkbit (Leontodon taraxacoides) 
Scarlet p impernel (Anagallis aNensis) 
Wil low weed (Polygon urn persicaria) 
CT 
8 .0  
70 .5  
9 .5  
5 .6  
5 .2  
0 .5  
0 .7  
1 00 
Ti l lage Treatments 
MT 
7 .0 
5 .0 
48.4 
6.0 
4.0 
1 1 .2 
6 .0 
1 2 .4  
1 00 
NT 
57.0 
9 .5  
8 .5  
2 .5  
1 0 .0 
1 2 .5 
1 00 
* Weeds were hand sorted and identified from samples collected from each plot. F igures were 
calculated from the percentage of the weight of a deSignated weed in the sampled weed population 
in each plot. Some plots contained small (to negl igible) amounts of weeds such as: cal iforn ian 
th istle (Cirsium arvense) , hairy buttercup (Ranunculus sardous), pennyroyal (mentha pulegium L . ) ,  
and creeping cudweed (Euchiton involucratus) . 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 9 1  
5.5 DISCUSSION 
5.5.1 I ntro d u cti o n  
This section endeavours to synthesize the find ings of th is study and relate them 
with those obta ined under simi lar conditions elsewhere supported by ti l lage 
research data from d ifferent agro-ecosystems and cl imatic conditions. The impacts 
of ti l lage, as has been stated before, are site and crop-specific .  The analysis i s  
pursued i n  a manner to avoid the incl ination to overlook contrasting d ifferences i n  
the nature of two experimental agro-ecosystem sett ings of th is  study and of those of 
the research data sources cited i n  the d iscussion and to generalize or simpl ify the 
issues related to soi l  and environmental degradation due to ti l lage.  The issues are 
i ndeed complex, and th is research analysis is ,  nevertheless, aimed at contributin g  
to a better understanding  of the issues and to hopeful ly suggest some useful 
i nsights for a viable ti l lage research and agricultural  development and pol icy design  
in East Timor and ,  to a certain extent, New Zealand . 
5.5 .2 Soil  c o m p action : penetratio n  res i sta nce a nd b u l k  d e n s ity 
The soil compaction due to ti l lage and traffic is  reflected by the degree of 
penetration res istance and bu lk density, two parameters largely used to assess 
compaction (Tarawally et al . ,  2004) .  
1 .  Penetration resistance 
The results of the first penetration resistance (PR) measurement presented in Table 
5.5 .  clearly ind icated that the recently cultivated soils i n  the CT and MT p lots were, 
not unexpectedly,  significantly less compacted than the soi ls  under the NT and PP 
treatments. Down to 1 2  cm soil depth , MT caused the least resistance to 
penetration , which was most probably due to MT soi ls  having larger total porosi ty ,  
comparatively to CT ,  and  qu ite surpris ing ly to NT as  wel l ,  as ind icated by  total 
porosity val ues in Tables 5 . 1 2  and 5 . 1 4  for the topsoi l 0- 1 0  cm . In compacted soi ls ,  
accord ing to Gajri et  al . (2002) ,  total porosity decreases largely at the expense of 
macropres, whi le  loosening has the opposite effect. Soi l moisture content and bu lk  
density may have contributed as wel l  to d ifferences in penetration resistance among 
treatments ,  particularly for the CT and MT, as suggested by Eh lers et al .  ( 1 983) .  
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: I mpacts on crop and biomass production 1 92 
Soil moisture i n  some soi ls, however, does not always have a relationshi p  with 
penetration resistance (Govaerts et a l . ,  2006). Field assessment of volumetric water 
content with TOR around the t ime of the first PR measu rement, i nd icated MT to 
have on average lower volumetric water content in the 0-1 5  and 1 5-30 cm soil 
layers compared to the other treatments (refer to Table 5 . 1 3) .  Despite having less 
moisture content in these two respective layers, hydraul ic conductivity figures under 
MT (Table 5.20) suggest that water may have infi ltrated and was probably stored i n  
deeper subsoi l  layers. 
S igns of compaction were evident at the second measurement two months later 
(Table 5.6) .  PR values of soi ls under CT, in contrast with the first measurement ,  
i ncreased and became statist ically simi lar with the soi ls of  NT and PP treatments . 
This confirms earl ier findings by Guo et aJ. ( 1 999) .  I n  a 5-year t i l lage experiment on 
a si lt loam , the PR measured one week after winter oats were sown was about 
twice as much in the two top layers (0-5 and 5- 1 0  cm) in the PP and NT plots as i n  
the CT plots conventionally ti l led with mouldboard plough (Viegas and Choudhary , 
2002). However, six months later, after the oats were grazed and the field left fallow 
du ring spring ,  soi ls in the CT were more compacted than the other  two treatments 
especially in  the 0-20 cm soi l depth . 
The PR values for MT were demonstrably lower than those under the other  
treatments, well below the threshold PR of  2 MPa that has been indicated to affect 
root growth (Fabrizzi et al . ,  2005). This contrasts with the find ings of Osunbitan et 
a l .  (2005) i n  N igeria ,  who found h igh soi l PR u nder manual t i l lage (MT) treatment 
and conventional t i l lage (plough-plough / PP and plough harrow / PH). The increase 
in penetration resistance with the increase in soil depth as i ndicated by the 
regression analysis (clearly demonstrated by Figure 5 . 1 0) has also been previously 
suggested (Ozpinar and Cay, 2006, Viegas and Choudhary, 2002). This  may be 
attributed to the soi l  structure below the cultivated soi l horizon being different, 
affected by conditions such as low soil water status ,  total porosity, and a ir-fi l led 
porosity ,  but h igh mechanical impedance and bulk density. It is  rare to find  a loose 
subsoi l (Hakansson and Voorhees, 1 998) ,  however, there are reports indicating 
compaction i n  subsoil (Logsdon et a I . ,  1 992, Hakansson and Reeder, 1 994). 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 93 
A sl ight decrease was noticeable when comparing the PR values of the first 
measurement with that of the second ,  especial ly under CT, NT and PP treatments. 
Soi ls became softer over a period of more two months which was probably due to 
the rainfal l  du ring the experimental period . Although situated in a steep landscape, 
water through infi ltration and percolation with i n  the p lots may have reached the 
subsoil layers and have been stored . The seasonal volumetric water content results 
d iscussed i n  the next sUb-section wi l l  confirm the water status i n  these subso i l  
layers. 
2 .  Soi l bu lk  density 
Soi l bu lk density (BD) data from the first experiment i n  Di l i  showed no effects of 
t i l lage treatment (Table 5 .2 ) .  However, using proper laboratory means, BD results 
from the second experiment demonstrated a s imi lar trend to that of PR, and more 
obvious was the increase of BD with i ncrease of soil depth . There were at least two 
sets of BD data, usi ng d ifferent sizes of soil corer. The first measurement, taken 
approx. 2 weeks prior to the second PR readings, using  a standard 50 mm d iameter 
corer, showed that the top 5 cm of soi l under all treatments was of the same degree 
of compaction ,  indicated by simi lar BD values (Table 5 .7). Th is agreed with the PR 
values measured two weeks later which showed statistical ly s imi lar values for the 
top 2 cm in al l  soi l .  On average , of six values from 0 - 30 cm depth , MT and NT soil 
had significantly the lowest and the h ighest BD, respectively, whi le BD of CT and 
PP soi ls were in the middle range . 
Bu lk  density is not invariant for a g iven soi l  because it changes according to 
structural condition of the soil (Blake and Hartge,  1 986) and most changes in soil 
physical environment are mediated through bu lk density (Gajri et al . ,  2002). The 
second BD measurement was done one month after the first one, using a 1 00 mm  
diameter corer (Table 5 .8) .  The resu lts demonstrated that, for the 0 - 20 cm soil 
depth , CT had the h ighest soil BD fol lowed by NT, whi le MT and PP had the lowest. 
With regards to soil BD u nder MT, however, contrasting resu lts were obtained in  
N igeria (Osunbitan et  al . ,  2005) .  Soil BD was assessed every week after cultivation 
for eight weeks and it was found that manual ly ti l led (MT) soi ls had a BD between 
that of soi ls u nder NT and the ti l led soi l s  (PP and PH) . The d ifferences i n  the effects 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 1 94 
of the two manual t i l lage (MT) experiments may derive from the d ifferent methods of 
manual  ti l l i ng used , with a shovel in experiment 2 of the present study and a hoe in 
the case of Osunb itan et a l .  (2005) experiment. Other reasons may be attributed to 
the subjective nature of the human power involved i n  doing the t i l l ing and the 
different characteristics of soi l types used in the respective studies.  
H igh  soi l  BD  under zero-ti l lage or no-ti l lage has been confi rmed by recent studies 
(Bescansa et a l . ,  2006, Bhattacharyya et a l . ,  2006). The high bulk density found i n  
the NT plots was an indication of h igher soil density and lower total porosity, 
especia l ly at the subsoil layers (refer to Tables 5 . 1 7  and 5 . 1 9 ) ,  relatively compared 
to the other treatments . A separate study by Karamanos et a l .  (2004) reported bu lk 
density and penetration resistance were i n i tia l ly h igher i n  the no-ti l led plots, but they 
became significantly lower after 2-3 months from sowing .  Despite this, NT had a 
comparatively h igh volumetric water content compared to other treatments, i n  0-1 5 
and 1 5-30 cm soi l layers as reflected by TOR assessment results in  Tab le 5. 1 3 , 
except for the last reading on 23/02/04 . Early stud ies also suggest that even though 
soi l bu lk  density was greater for no-ti l l  systems compared with ti l led systems in the 
experimental fields of Sauer et al .  ( 1 990) ,  Home et a l .  ( 1 992) ,  Karlen et a l .  ( 1 994) 
and Hussain et a l .  ( 1 998) ,  water retention and i nfi ltration for the no-ti l l  soils were as 
great or greater than for the ti l led soi ls. 
5 .5.3 S oi l  water p roperties 
1 .  Field capacity 
The experimental results indicated significant effects of t i l lage treatment on soil fie ld 
capacity (Fc) ,  in both the 0 - 1 0  and 1 0  - 20 cm soi l layers (Table  5.9 and 5 . 1 0 ) .  
F ie ld  capacity results , both at  low and h igh tension moisture release (MR), for both 
soil layers , ind icated that NT and pp soil held more water compared to MT and CT, 
implying that NT and pp soi l had better infi ltration or less runs off. These results 
correspond with the soi l  water content at various suction leve ls ,  and agree with Gajri 
et a l .  (2002) who suggest that i ncreased porosity associated with a decrease in bu lk 
density increases the amount of water held at  h igh soi l  water potentials and 
decreases the amount he ld at  lower potentials. 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 95 
2 .  Water content and readi ly avai lable water (RAW) 
Water content was unaffected by ti l lage treatment during the Di l i  experiment (Table 
5 .2) .  In the absence of proper laboratory equipment, and due to the use of 
rud imentary oven and scale for the drying and weighing of soil samples , 
respectively, this resu lt may not reflect the true fie ld conditions. The results from 
experiment 2 ,  however, showed that water content (WC),  s imi lar to the field 
capacity, was affected by ti l lage treatments especially in the top 0 - 1 0  cm soil layer 
(refer to Tables 5.9 and 5 . 1 1 ) . PP, not unexpectedly, had significantly h igher soil 
water content at al l  potentia ls ,  gravimetric and volumetric ,  general ly  followed by NT 
(Table 5 .9 ) .  Down in the 1 0-20 cm soi l layer, on ly low tension MR analysis detected 
sign ificant d ifferences in WC d ue to ti l lage, whereas under h igh tension MR water 
properties under al l  the treatments appeared simi lar, except for small d ifferences in  
fie ld capacity. 
Based on low tension moisture release analysis, NT usual ly had greater water 
content at 0- 1 0  cm than CT and MT (Table 5 .9) ,  whi le at the 1 0-20 CT usual ly had a 
h igher WC (Table 5 . 1 0). The results agree with those reported by Karamanos et a l .  
(2004) .  The higher water retention of the NT plots than the CT and MT plots cou ld 
be attributed to, apart from WFP, the i ncreased surface residue under NT resulting 
in  a significantly h igh organic matter under th i s  treatment. As shown later in  Table 
5 . 1 7, NT produced a significantly h igher total organic C at the 0-1 0 cm topsoi l ,  
compared especial ly with CT. Simi lar reasons were argued by Fuentes et al .  (2004) .  
Another possible explanation i s  that water loss through evapotranspiration in the NT 
plots was inh ibited by the h igh amount of residue left on the surface, thus al lowing 
h igher conservation of soi l  moisture in the root zone .  
The water retention at low suction levels (5  and 10  kPa) i n  the top 0-1 0  cm topsoi l  
was simi lar to the findings of Osunbitan et a l .  (2005) whose study also involved 
manual t i l lage (MT). Simi larities i ncluded NT retain ing the greatest amount of water, 
especial ly at 50, 1 00 ,  and 1 50 kPa suction , and MT soil the least amount of water. 
Their study also suggested conventional t i l led soil had signifi cantly h igher field 
capacity (approx. at 4.5 kPa suction) compared to the manual and unt i l led soi ls .  
They observed ti l lage operations significantly decreased the water hold ing capacity 
of the sandy loam soi l  used . In a clay loam calcic soil (Calcic Haploxerept) in 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 96 
semiarid northern Spain ,  Bescansa et al. (2006) found h igher soi l  water content 
under conservation ti l lage systems (NT, NTSB and RT) than under tillage with 
mouldboard plough .  This was mainly attributable to greater avai lable water content 
(AWC) and to the mu lching effect of crop residues. Early studies by Karlen et al. 
( 1 994) and Hussain et al .  ( 1 998) also reported NT to have more water fi l led and 
residual pores compared to conventionally t i l led soi ls due to the presence of more 
soil residue on the soil surface, which improved i nfi ltration , decreased runoff, and 
restricted evaporation . 
Despite differences in Fc and WC, the soil mechan ical treatments had no influence 
on the amount of water readi ly avai lable (RAW) to plants. F ind ings by Tarawal ly 
(2004) suggested that the use of field capacity water content as the upper l imit of 
plant avai lable soi l water was considered inappropriate for compacted soi ls .  
3 .  TOR soi l fie ld volumetric water content 
Soil under NT and CT had h igher volumetric water content compared to MT in 0 -
1 5  and 1 5  - 30 cm soil layers (Table 5 . 1 3) .  This was probably due to sign ificantly 
h igher water-fi l led porosity under NT and CT as d iscussed later in th is chapter. 
Despite having h igher total macroporosity, MT produced fewer water-fi l led pores 
and lower field capacity . The precipitation cou ld have all infi ltrated through the 
macropores down to subsoi l  layers ,  a point confi rmed by the h igher saturated and 
unsaturated hydrau l ic conductivity values in soi ls under MT than those under CT 
and NT. The find ings of Osunbitan et a l .  (2005) also suggested MT soi ls have the 
h ighest hydrau l ic  conductivity, after NT, compared to soils under conventional t i l lage 
using plough-plough (PP) and plough-harrow (PH ) sequence. Hydraul ic conductivity 
experiment resu lts wi l l  be further d iscussed later in th is chapter. 
5.5.4 Soi l  a g g reg ate sta bi l ity a n d  MWD 
The stabi l ity of aggregates is measured as a function of whether the cohesive force 
between particles withstands the appl ied d isruptive force , and most frequently, the 
destructive action of water (Hi l le l ,  1 998) .  CT, PP,  NT, and MT had simi lar topsoi l  
loss (Table 5 . 1 4) .  In the 1 0-20 cm soil layer, the losses were also simi lar among 
ti l lage treatments (CT, NT, and MT) (Table 5 . 1 5) .  A significant loss, however, was 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 97 
observed on soil from the adjacent permanent pasture (PP) plots from the 1 0-20 cm 
layer. 
The short-term nature of the experiments may have contributed to these results .  
The find ings of a t i l lage tria l  i n  a si lt loam , establ ished over 5 years , compari ng 
mouldboard plough (MP), no-t i l lage (NT), and permanent pasture (PP) ,  clearly 
demonstrated enhanced soil structural stabi l ity (Viegas and Choudhary, 2002) .  I n  
the top 0-1 0 topsoi l  for example,  the results ind icated that the loss of soil aggregate 
< 0 .5  mm  was in the decreasing order of MP>NT>PP with nominal values of 73 .8 ,  
29 .2 ,  and 24.8 % ,  respectively. A simi lar pattern as the topsoi l  also occurred for the 
subsoi l .  Previous work using soil in the Manawatu region , New Zealand reported by 
Horne et al. ( 1 992) and Sparl ing et a l .  ( 1 992) suggested simi lar soi l stabi l ity trends. 
Haynes ( 1 999) ,  working on a Wakanui  s i lt loam (Udic Dystrochrept; USDA) in the 
Canterbury region of New Zealand ,  also found aggregation stabi l ity to be h igher 
under long-term permanent pasture and zero ti l led annual grass , than long-term 
arable cropping and conventional ly cultivated annual grass. 
While Horne et a l .  ( 1 992) found on ly smal l  d ifferences in organic carbon content 
between treatments in the 0-20 cm soi l  depth ,  Watts and Dexter ( 1 997) us ing a 
s imulated ti l lage found an increase in water stable aggregates with increase i n  soi l  
organic carbon. F indings of the latter study appeared to confirm earl ier data 
reported by Sparl ing et a l .  ( 1 992). Their results suggested a strong relationship 
between the proportion of water-stable macroaggregates and microbial C,  much 
stronger than that between macroaggregate stabi l ity and organic C .  A recent study 
by Mikha and Rice (2004) reported that no-ti l lage (NT) and manure (M) a lone each 
significantly i ncreased soil aggregation and aggregate-associated C and N ;  
however, NT  and M together further improved soi l  aggregation and aggregate­
protected C and N .  
5 . 5 . 5  Soil  porosity 
1 . Total porosity 
I ntensive ti l lage affected pore structure i n  the topsoi l  resulti ng i n  a significantly lower 
total porosity under CT compared to the other treatments based on both low and 
high moisture release tension analyses (refer to Tables 5 . 1 6  and 5 . 1 8) .  This result 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 1 98 
confi rmed the find ings of ti l lage research that suggest the improvement i n  soi l pore 
size distribution and continuity under no- and min imum-ti l lage systems 
(Bhattacharyya et a l . ,  2006 , Eynard et a l . ,  2004) .  I ncreased total porosity under no­
ti l lage, as wel l  as under MT in th is study,  may have had a positive impact on the 
movement and retention of solutes, chemical  processes ,  aeration , erosion , and 
biological activity suggested by Park and Smucker (2005) .  The effects of ti l lage on 
total porosity in the soil layer below the topsoil were not as statistical ly comparable 
as those of the topsoi l (refer to Tables 5 . 1 7  and 5. 1 9). In  can be assumed that 
differences in soi l porosity between ti l lage systems were mainly confi ned to the top 
1 0  cm soi l ,  or surface 0-8-cm soil depth i n  the case of previous work by Carter 
( 1 988). 
2 .  Macroporosity, a ir-fi l led porosity. water-fi l led porosity 
Topsoi l macroporosity was significantly i ncreased i n  the manual ly ti l led (MT) plots 
compared to soi l under other treatments (Table 5 . 1 6) .  Conversely, CT had the 
lowest macroporosity. Channels near the surface under the ti l led systems (CT) were 
not as continuous,  p robably owing to the destructive nature of t i l lage (Heard et al . ,  
1 988). Park and Smucker (2005) found no  response of Ksat to porosity change i n  CT 
aggregates ind icating that there were no increases in the effective i nterconnected 
porosities with i n  CT aggregates. A macroporosity of between 8 to 1 0% (v/v) wou ld  
maintain adequate soil permeabil ity (Carter, 1 988) .  
It can be noted , from the related parameters, that the macroporosity under MT, as 
shown by the supporting data , was probably largely contributed by the h igh level of 
a i r  capacity and a ir-fi l led porosity (AFP) .  It can be assumed that a better aeration 
has taken place on the manual ly cultivated soi ls than other soi ls under study as 
AFP is most often used to evaluate soil aeration (Upiec and Hatano, 2003). AFP of 
< 1 0% (v/v) is regarded as critical for plant growth and that at a s imi lar AFP, the 
equivalent pore d iameter can be much smal ler in  compacted than in uncompacted 
soil (Upiec and Hatano, 2003) .  On the contrary, water-fi l led porosity (WFP)  made 
up the largest part of the total porosity in the cases of CT, NT, and PP as shown by 
generally h igher field capacity, water retention , and volumetric water content under 
these treatments compared to MT at the top 1 0  cm soi l (Table 5 . 1 6) .  I n  Carter's 
( 1 988) study, a close relationship (R2 = 0 .952) was found between water-fi l led 
Chapter 5 - TILLAGE AND EDAPH IC CHANGES: Impacts on crop and biomass production 1 99 
porosity and macroporosity and soi l water content, i ndicating that the volume of 
macropores should exceed 1 4% to provide  an optimum level of a ir-fi l led pore space. 
S imi lar  trends in  macroporosity, a ir- and water-fi l led porosity under a l l  the 
treatments were observed for the lower 1 0-20 soi l layer. 
3 .  Pore size d istribution and void ratio 
The d istribution of pore size was u naffected by the ti l l age methods (refer to Tables 
5 . 1 6  and 5 . 1 7) .  Void ratio was significantly reduced by CT in  the surface soil (Table 
5 . 1 6) ,  which indicated a greater degree of compaction in the CT soi l  than under NT 
and MT, i n  confirmation of the results for PR and BD. Pore size d istribution i s  a 
fundamental and h igh ly degradable soil property (Tarawally et al . ,  2004) .  
5 . 5 . 6  Hydra u l i c  cond uctivity 
The h igh saturated hydraul ic conductivity of the ti l led layer under CT and MT was 
because of the preponderance of large inter-aggregate macro-pores (Add iscott and 
Dexter, 1 994) .  La l  et  al .  ( 1 989) pointed out  that the i n itial infi ltration was significantly 
greater in  contin uous plough-ti l l  than i n  no-ti l l  treatments, apparently caused by h igh 
total porosity i n  the freshly ploughed p lots . The results of the current study,  
however, were not signifi cant due to a large coefficient variation . The coefficient of 
variation of soi l  hydraulic conductivity, which is often d ictated by the soil structural 
pores, ranged from 1 00 to 400% (Libard i et al . ,  1 980) ,  which suggests that the 
spatia l  variabi l ity of soil structura l  pores measured by using core- or block-sized 
samples was very large . As a resu lt, the size spectrum of large structural pores 
measured at several random locations by small sample sizes in a fie ld may not 
represent the spectrum of the entire fie ld . The h igh coefficient of variation of 
hydraul ic conductivity was also encountered by Cameira et al. (2003). 
Contrasting resu l ts were reported by Park and Smucker (2005) .  They reported 
increased Ks through bulk soils  and through  intra-aggregates in the NT management 
system suggesting greater d i ffusive exchange and possibly longer retention times of 
soi l  solutions .  Conversely,  much lower Ks was fou nd with i n  CT aggregates whi ch 
impl ied that d iffusive exchanges of nutrients might be l im ited to exterior regions of 
macroaggregates. Viegas and Choudhary (2002) ,  s imi larly, reported that the 
average infi l tration rate was in the order of M P<NT=PP. Other studies have 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 200 
suggested the earthworm channels are one of the factors contributing to the 
macropore continu ity improvement under NT (Aslam ,  1 998,  Guo et a l . ,  1 999). Chan 
and Mead ( 1 989) demonstrated that conventional ti l lage red uced macropore density 
as well as their  continu ity which caused infi l tration to be greatly hampered lead ing to 
sign ificantly h igher run-off. Simi larly, Lal and Vandoren ( 1 990) concluded that both 
the cumu lative infi ltration and infi ltration rates were somewhat h igher for no-ti l lage 
than mouldboard plough and chisel p lough treatments. Benjamin ( 1 993) suggested 
the no-ti l lage system to have 30 to 1 80% greater saturated hydrau l ic  conductivity 
than either the chisel plough or mou ldboard plough systems. 
5 . 5 . 7  C hem ica l p roperties 
1 .  Experiment 1 (DilL East Timor) 
Due to constraints mentioned earl ier in  the introduction , a proper experimenta l 
layout was not possible to implement, thus  no statistical analysis was performed to 
compare the d ifferent mechanical treatments employed i n  the field . The soil 
chemica l  and physical analysis revealed that soi ls  were vertiso l ,  main ly alka l ine, and 
composed largely of al l uvial si lt and clay. 
The plots were previously harvested with rice prior to the fie ld work . The level of 
organic carbon was negl ig ib le (content undetected ) ,  assuming all taken up during  
the earl ier rice cropping season . However, after about 4 months of maize and 
mungbeans cropping , the soi ls had regained some organic carbon (average range 
of 0 .74 - 1 .52 %). I n  add ition , total N also showed a modest i ncrease after the crops 
were harvested . In  contrast, the soil phosphorus (P) and potassium (K) were 
decreased after the field tria l .  
The resu lts were not unusual for soi ls  which have long been under intensive 
cultivation . Sustainable farming systems require that crop yields are stable through 
the maintenance of soil ferti l ity and the balance of nutrients i n  the system . Increases 
in soil C levels for example requ i re sustained periods of balanced ferti l ization and 
residue retention (Whitbread et a l . ,  2003) .  Whitbread et a l .  (2003) concluded that 
poor management of ferti l izers and crop residues, and excessive cultivation has 
also resu lted in large soi l ferti l ity losses in the gra in growing areas of Eastern 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 201  
Austral ia .  Cropping decreases C everywhere except where residue retention is h igh  
and  fal low crops are used . 
2 .  Experiment 2 (Palmerston North , New Zealand) 
a. Total C 
Ti l lage effects on total soi l  organic C were more evident i n  the 0-1 0 cm soil depth . 
The order i n  which the marked decl i ne i n  % total C l evel was observed was pp 2: 
NT 2: MT > CT (Table 5.2 1 ) .  These changes, however, were only sign ificant when 
calculated on the basis of percentage of total C and N out of the soi l samples thus i t  
may not reflect the real nutrient status on the site . When extrapolated to an area 
basis the statistical d ifferences no longer existed although a generally similar trend 
was present (Table 5.22) .  Considering the permanent pasture soi ls as control 
treatment, the reduction of total C after a short-term cUltivation was 1 0 . 1 ,  9 .3 ,  and 
4 . 1 %  under MT, CT, and NT,  respectively. The CN ratio was i n  the decreasing order 
of PP > NT > MT > CT. 
Total C losses from native soils and long-term pasture fol lowing cropping were a lso 
reported for s imi lar studies in New Zealand (Sparl i ng  et al . ,  1 992, Aslam et al . ,  
1 999, Haynes, 2000). I n  the 1 0-20 cm  soil layer, the total C level was lower than 
that of the upper layer and d istributed quite equally in al l plots as only i nsignificant 
d ifferences were noticed among the treatments .  
The h igh retention of  crop residue and less soi l d isturbance on the NT plots may 
have resulted i n  h igher % of C than i n  the ti l led treatments . A study by Zibi lske et a l .  
(2002) revealed that no-ti l l  resulted i n  g reater soil organic C i n  the top 4 cm of soi l ,  
where the organ ic C concentration was 58% greater than i n  the top 4 cm of the 
plough-ti l l  treatment. In the 4-8 cm depth , organ ic C was 1 5% greater than the 
plough-ti l l  contro l .  Beare et a l .  ( 1 994) and Campbell et a l .  ( 1 996) have also reported 
s imi lar results .  The former, comparing NT and CT reported that the whole-soil 
organic C was 1 8% higher in the NT (30 .7  mg C ha-1 ) than CT (26 . 1  mg C ha-1 ) .  I n  
the latter study, i t  was found that cropping frequency d id  not affect soil organ ic  C,  
but soil C content was greater under NT than under mechanical ly ti l led contin uous 
wheat (cont. W) and fal low-wheat (F-W) rotations .  The effects were apparent in the 
0- 1 5  cm soi l depth . According to Sparl ing et al. ( 1 992) ,  the marked organic C 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: I mpacts on crop and biomass production 202 
content decl ine in the cultivated soils  is caused main ly by the reduced organic 
matter inputs and the decomposition of existing organic matter enhanced by t i l lage. 
b. Total N 
Simi lar to the trend for % C i n  the top soi l ,  total N was significantly reduced by CT 
(Table 5 .2 1 ) .  According to Zibi lske et al. (2002) ,  ti l lage-induced changes in soil 
organic  N are often d i rectly related to changes in soi l organic C.  Usually, i ncreased 
use of N-ferti l izers i n  crop production has been accompanied by increased amounts 
of N compounds in the general soi l-water environment. However, th is was not the 
case in thi s  study as no ferti l izer was used . The reduction in total N, therefore ,  was 
main ly attributed to the uti l ization by crops .  At 1 0-20 cm soi l  depth , the total N was 
lower than for the topsoi l ,  and s imi larly to C, it was equal ly d istributed i n  a l l  p lots . 
This partly agrees with the results of Zibi lske et al . (2002) who suggest that both no­
t i l l  and ridge-t i l l  promoted greater concentrations of soil organic N at the soil 
surface , but it was uniformly d istributed with depth under plough ti l lage. 
The above results are in l ine with the study  of Biederbeck et a l .  ( 1 996) who found a 
h igher potential ly mineralizable N under zero-ti l lage compared to a conventional 
ti l lage system .  Their study also suggested that t i l lage depressed microb ial  
populations and the abil ity of the soi l  to m ineral ize C and N in the 0-5 cm soi l  layer. 
A close correlation between m icrobial b iomass N and anaerobic mineral izable N 
was proposed by Dalal et a l .  ( 1 991 ) ,  who also suggested that the former provide a 
labi le source of N i n  soi l .  The labi le fractions, as stated by Haynes ( 1 999) are 
important components of organic matter qual ity, which influence crop productivity. 
M ineral izable N for instance , can contribute greatly to crop N requ irements but also 
to leaching losses of nitrate to groundwater. 
For pasture in particular, the study of Haynes ( 1 999) demonstrated the positive 
effect that a short-term (5 years) pasture can have on soi l  organ ic matter quantity 
and quality and its attendant benefits on N ferti l izer and soi l structure. Their results 
also indicated that the particulate organic matter (POM) comprised a h igher 
percentage of total aggregate N in surface soi ls  of the NT than eT soi ls .  Campbel l  
et  al . ( 1 996) a lso reported total N to be h igher under NT than under ti l led systems i n  
continuous wheat and wheat-fal low rotations. 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 203 
c. Olsen P 
Conservation ti l lage resu lts in  the concentration of plant-avai lable P near the soil 
surface . The present short-term study, however, demonstrated no significant 
differences in Olsen P under the d ifferent ti l lage treatments, both in the 0-1 0  and 
1 0-20 cm soi l  depths (Table 5 .2 1 ) .  Essington and Howard (2000) found that total P 
d id  not vary with depth , but was greater i n  no-ti l lage (NT) than i n  d isc-ti l lage (OT) 
and increased with P rate . Mehl ich 3-P and Olsen-P were greatest in the surface 4 
cm and i n  the 60-kg P ha-1 p lots, with higher levels observed in NT plots. Because 
the impact of t i l lage was l im ited to a th i n ,  soil surface layer « 4  cm),  soil P-test rating 
would not be affected by ti l lage practice . They also suggested that improper 
col lection of soil samples from NT ( i .e . , too shal low) for P-testing may provide 
erroneous P-test resu lts and ferti l izer recommendations.  
5 . 5 . 8  Cro p  y i e l d  and b i omass prod u ction 
1 .  Experiment 1 (Oi l i, East Timor) 
Under modest experimental ci rcumstances, the crop and weed measurements 
general ly agreed with those a l ready known with respect to no-ti l lage cropping in  
comparison to conventional means of cu ltivation (refer to Table 5 .4 )  (Arshad et  aI . ,  
1 994, Fisk et a l . ,  200 1 , Mas and Verdu ,  2003 ,  Ozpinar, 2006). Maize and 
m ungbean height as wel l  as d ry matter, measured in the mid-cropping season , 
suggested a lower level of performance in the NT treatment. By contrast, weed 
population , not unexpectedly ,  was more abundant in the no-t i l l  p lots. These 
cond itions, however,  did not inh ibit the growth cond itions for both crops ,  result ing i n  
a general ly simi lar grain and by-product yie lds under a l l  the ti l lage treatments. 
2 .  Experiment 2 (Palmerston North , New Zealand) 
Potato tuber and biomass yield were signifi cantly reduced under no-ti l lage 
compared to CT and MT treatments (Table 5.23). Presumably this was due to the 
g reater soil compaction in NT which may have restricted growth of potato tubers 
and roots . The reduced yield in potato tuber and biomass in NT, however, were 
offset by the h igher amount of weed biomass dry matter (Table 5.25). Barley g rain 
and biomass yield , on the other hand, was simi lar for a l l  the treatments (Table 
Chapter 5 - TILLAGE AND EDAPH IC  CHANGES: Impacts on crop and biomass production 204 
5 .24). Better moisture conservation under NT may have promoted an equal ly better 
n utrient uptake for barley growth . 
Variable results with regards to crop and b iomass yie ld under no-t i l lage treatments 
have been widely reported . Hughes et a! . ( 1 992) found  a 1 0-year average of maize 
d ry matter to be significantly lower under zero ti l lage than ful ly tilled treatment. I n  a 
s imi lar  tria l ,  Ekeberg and Ri ley ( 1 996) reported a generally good performance of 
cereals and potatoes with shallow or m in imum ti l lage, and this was attributed to the 
favou rable soi l physical conditions, and to the successful control of weeds. Lower 
crop yields (Acharya and Sharma, 1 994) and variable results (Lindwal l  et a! . ,  1 994) 
were reported under no-t i l lage treatment as compared with conventional t i l lage 
systems. A recent report suggests that in genera l ,  NT, and in the second instance, 
m in imum ti l lage (MT) cons iderably improved plant water status, and hence fol iage 
growth and yield in  comparison with CT by mainta in ing h igher levels of soi l water 
and improving root growth . It was also concluded that manuring positively i nteracted 
with the reduced ti l lage practices for most soil and plant parameters (Karamanos et 
a l . , 2004) .  
I n  essence,  as far as crop yields are concerned ,  it is  d ifficu lt  to establ ish any clear 
and major advantage of no-ti l lage. However, in  genera l ,  given favourable conditions 
are met, such as adequate soi l water, sufficient rainfal l  and good drainage , 
reasonable soi l ferti l ity and good weed control , crop yields under conservation 
t i l lage can be equal to or h igher than under conventional ti l lage systems. 
5.6 C O N C L U D I N G  RE MARKS 
Despite being based on short-term experiments in both locations, the study 
provides empirical effects of ti l lage, and no-ti l lage in particular, on the edaphic 
changes affecting the plant growing environment. General ly, the findings concur  
with those already in the l iterature . Organic carbon levels are generally restored 
with cropping .  I n  addition ,  soi l bulk density and crop grain and biomass yield were 
not affected by til lage treatments. Soi l compaction was significantly affected by 
t i l lage as shown by data from the Palmerston North experiment. Soil aggregate 
stabi l ity in the 0-1 0 cm topsoil was simi lar under a l l  the ti l lage treatments. MT had 
the greatest number of soi l  aggregates on sieve after 30-mi nute wet-sieving (68 .3%) 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 205 
fol lowed by NT (65. 1 ) , pp (62 .6) and CT (56 .52) .  S imi la rly, top 0-1 0  cm soil under 
MT had significantly larger macroporosity ( 1 6 .4%) than CT (9 .23) ,  NT ( 1 1 .5) ,  and 
pp ( 1 0 .6) .  MT and CT significantly reduced the total C whereas N levels were 
significantly decreased by ti l lage (CT, MT and NT) compared to permanent pasture 
at the top 0-1 0  cm soil layer. Barley grain and biomass were u naffected by ti l lage 
whereas potato tuber and biomass were significantly less under no-ti l lage. 
Conventional t i l lage significantly i ncreased water runoff but less leachate compared 
to no-ti l l  and permanent pasture. Total soil sediment loss was significantly lower 
under pp (95 .8 kg/ha) and NT ( 1 32.9) compared to CT (3556 .7 )  and MT (4652 .2) .  
pH of water runoff was significantly reduced u nder ti l lage treatments compared to 
that from permanent pasture whereas n itrogen losses were unaffected .  
Whi le a large volume of research data i s  avai lable on long-term ti l lage research i n  
temperate climate regions i n  developed countries,  short-term experiments such as  
the present study, provide significant information to support agricultural pol i cy 
design i n  developing countries of the tropics, for the sound use of their fragi le soi l 
and scarce water resources. 
Chapter 5 - TILLAGE AND EDAPHIC CHANGES: Impacts on crop and biomass production 206 
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Q6 TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, 
� 
AND SOIL SEDIMENT AND NUTRIENT LOSSES 
6. 1 INTRODUCTION 
6 . 1 . 1  General backgro u n d  
I n  recent years, research on soi l  management has put increasing emphasis on 
improving soi l  qual ity, by promoting sensible soi l conservation practices, based on 
sound  management of soi ls ,  crops , and water (La l ,  2004) .  Tropical soi l 
management, in particular , is often concerned with soil management strategies, 
which improve the structure of the surface soi l  thereby making it less susceptible 
to activities of erosive agents ( Idowu , 2003) .  These practices and strategies aim 
to: ( i )  mainta in good soi l  structure, ( i i )  protect the soi l  surface by adequate crop 
and residue cover, and ( i i i )  use special  structural erosion control practices where 
necessary. The decline in  soil structure is increasingly seen as a form of soil 
degradation (Chan et al. , 2003) and is often related to land use and soi l/crop 
management practices. As has been discussed in the previous chapter, soil 
structure influences soil water movement and retention, erosion , crusting ,  nutrient 
recycl ing ,  root penetration and crop yield . External ities such as runoff, surface­
and ground-water pollution and CO2 emissions are infl uenced by soil structure 
(Bronick and Lal ,  2005), which in many respects, can be control l ed and mitigated 
by implementing proper ti l lage practices for crop production . 
I n  developing countries, i n  particular, soil t i l lage has predominantly been promoted 
through large scale mechanized land development and management schemes with 
the hope of increasing food production.  Accelerated soil erosion and the result ing 
soi l  degradation are among the reasons for the fai lure of these schemes, which 
often cause a rapid decline i n  soil ferti l ity and create vast tracts of barren and 
unproductive land in  areas that were once biological ly productive. This has been the 
case in  Thai land (Turkelboom et a l . ,  1 997), Nepal (Thapa and Paudel , 2002) ,  and 
China (Sheng and Liao, 1 997) ,  to mention a few cases. To assess the impacts of 
these practices, it is often time consuming, not to mention the h igh cost involved 
(Laflen and Roose, 1 998). Publ ic sector budgets are general ly largely al located to 
Chapter 6 - TILLAGE EFFECTS ON  WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 223 
AND NUTRIENT LOSSES 
production generating projects wh i le leaving i nsufficient fund  for research,  let alone, 
for long-term studies.  Under these circumstances, short-term study resu lts often 
provide useful information , and in many cases are the only rel iable sources to 
support decision making process. This short-term study, as part of a large academic 
pursu it ,  was designed to assess the impacts of soi l ti l lage on soi l erosion on h i ll 
slopes under simulated rainfal l  and laboratory condit ions. Given its s imulated 
condit ions, cautionary approach needs to be taken when extrapolating the results to 
the field conditions .  
6 . 1 .2 Scope and l i m itatio n s  
The ideal assessment of  soi l erosion processes is by  means of sett ing up  
experimental runoff plots i n  the field over a period du ring  which storm and rainfall 
with varied i ntensities occur. This method , however, is beyond the resource 
capabil ity of this research project. Obtained under a set of laboratory condit ions, the 
experimental results of this study, should therefore , be regarded as an estimative 
approach to the factual soi l erosion ,  and soil and nutrient losses. I n  addition , the 
impl ications may only be appl icable to areas with simi lar yet specific site 
characteristics where the study was conducted . Some lessons, however, cou ld be 
derived from this study and modified methods could be created and implemented to 
d ifferent agroecosystem conditions accordingly. 
6 . 1 . 3 O bjectives 
The objectives of this study were : 
1 .  To investigate the effects of d i fferent ti l lage practices on soi l erosion under a 
simulated rainfal l ,  
2 .  To measure soi l  and selected nutrient losses from sloped land affected by 
simulated rainfal l  i ntensity in  combination with prior ti l lage treatment. 
6 . 1 .4 Rai nfal l  sim u l ator 
Erosion research using rainfal l simulators has been cond ucted for more than 50 
years (Shelton et al . ,  1 985). E rosion deals with a complexity of interactions of 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOI L  SEDIMENT 224 
AND NUTRIENT LOSSES 
variables such as rai nfal l ,  soi l  characteristics, topography and t i l lage. For these to 
be well understood , more controlled conditions than those under natural rai nfal l  
need to be atta ined . This i s  basically the main logic for the design and development 
of the most recent rainfal l simulators. 
Desirable characteristics of a rainfal l  s imulator have been suggested by many 
stud ies (Moore et al . ,  1 983, Shelton et al . ,  1 985, Meyer, 1 994) ,  which can be 
summarized as fol lows: 
( i )  S imi larity to natural rai nfal l  in d rop size d istribution and fal l  velocity. 
( i i )  Most drops have a nearly vertical ang le of impact. 
( i i i )  Capabi l ity to reproduce rai nstorms with i ntens ity, duration , uniformity and 
continu ity which are of i nterest of any specific purpose. 
( iv) Appli cabi l ity to a research a rea sufficiently large to represent the treatments 
and conditions under i nvestigation .  
(v) Mobi l ity from one research site to another. 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 225 
AND NUTRIENT LOSSES 
6.2 SOIL DEGRADATION AND TILLAGE-INDUCED EROSION 
6.2.1 Introd uctio n  
Agriculture i n  semi-a rid areas suffers from strong annual variat ions both i n  crop 
yield and profitabi l ity; two factors that d i rectly depend on rainfal l volume and 
d istribution during the growing season (Sescansa et al . ,  2006). In  th is context and in 
the formation of a new conventional agriculture , it wi l l  be necessary to scruti nize 
current management systems to determine those practices that sustain  the soil 
resource and those that degrade it (Robinson et al . ,  1 994) .  
Soi l degradation is a resultant of a wide variety of interacting factors. S lum ( 1 998) 
suggested two types of soi l  degradation : ( i )  natural degradation  (without h uman 
interference) and ( i i )  soil degradation caused by anthropogenic activit ies, especially 
by the competition between the various types of land use. Lal ( 1 998) further 
specified the soil degradation by anthropogenic activities i nto : (a) industrial (b) 
urban ,  and (c) agricultura l .  A soi l is  agricultural ly degraded when its functions of 
d irect concern to human well-being ,  agricu ltura l  productivity and environmental 
regulatory capacity have been lost or reduced (Lal ,  1 998,  S lum , 1 998). I t  impl ies a 
decl ine i n  soi l 's inherent capacity to p roduce economic goods and perform 
envi ronmental regu latory functions, which is very much dependent on soi l  qual ity 
and relevant properties. Therefore , soil degradation involves adverse changes in i ts 
properties that l imit or reduce soi l 's capacity to perform the above mentioned 
functions. 
Agricu ltural productivity is  strongly influenced by management such as fert i l izer use, 
water management, and ti l lage methods. Resi l ient soils  are productive and respond 
positively to management whereas inappropriate management in  agriculture is often 
the main cause of soil degradation . The most severe form of agricultural 
degradation according to Lal ( 1 998) i s  that caused by accelerated erosion and 
nonpoint source pol lution. Key soi l  properties , such as soi l structure ,  soi l  organic 
carbon content, clay and clay minerals, and avai lable water capacity are ,  among 
others, properties being affected by these degradative mechanisms. The net effect 
would be the degradation of soil qual ity which i n  turn adversely affects the 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 226 
AND NUTR IENT LOSSES 
agriculture productivity and sustainabi l ity. However, judicious land use and choice of 
appropriate crop management systems would reverse these degradative trends. 
This  brief outlook of soi l  degradation complements the d iscussion in chapter  5 with 
descriptive l i terature analysis and experimental data emphasizing soi l erosion , 
particu larly t i l lage-induced erosion , and nonpoint source pol lution . 
6.2.2 Soil  ero s i o n  
Soi l  erosion is a serious threat to the qual ity of soi l ,  land ,  and water resources as a 
basis for a sustainable agricu lture and land use. The problem with erosion is found 
i n  i ts consequences. Problems and prospects associated with soi l  erosion by wind 
and water were reviewed at length by Lal ( 1 994). Although it is recogn ised as part 
of natura l  landscape-forming processes, it is  the extensive acceleration of the soil 
erosion processes induced by human act ivities that is of concern (Rose , 1 998). Soi l 
erosion , accelerated by human activities relative to natural rates ,  reduces crop 
productivity and causes soi l  damage resu lt ing i n  sediment transport and deposition 
(Pierce and Lal , 1 994) .  Deforestation ,  i n  part icular, can result i n  severe erosion 
patterns and erosion intensities which can lead to dramatic nutrient losses (Zheng 
et al . ,  2005, Fernandes et a l . ,  1 997) .  As has been d iscussed in the previous 
chapter, t i l lage has also been recogn ised as a cause of i ntense landscape 
modification and as a major source of soil erosion and redistribution along h i l lslopes 
(Alba et al . ,  2006, Zheng et a l . ,  2005), and remains the focus of continuous 
research covering a wide range of erosion aspects (among the recent ones: Fu et 
al . ,  2006, Kimaro et al . ,  2005, Van Muysen et a l . ,  2006 , Wu and Cheng, 2005). 
The susceptib i l ity of a soil to erosion , however, is  i nfluenced by d iverse factors. 
These i nclude physical and hydrologic,  chemical and mineralogica l ,  and biologica l  
and biochemica l  properties as wel l  as i ts  soi l profi le characteristics ( Lal ,  1 998) .  In  
regard to so i l  physical properties that affect the resistance of a soi l  to erosion ,  
texture , structure ,  water retention and transmission properties, and unconfi ned 
compressive and shear strength are the most relevant. S imota et a l .  (2005) further 
i nclude other protection parameters of specific relevance such as ston iness, organic 
matter, carbonate content, bu lk density, i n fi ltration rate, surface roughness, surface 
crusting ,  workabi l ity status ,  topsoi l  pu lverisation ,  subsoil compaction and 
Chapter 6 - TILLAGE EFFECTS ON  WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 227 
AND NUTRIENT LOSSES 
contamination risk. All these soil attributes must be considered in order to formulate 
sustainable agricu ltura l  management systems according to the characteristics of 
each particular site .  
The  importance o f  these p roperties has been reviewed , by  among others ,  Briggs 
and Courtney ( 1 985), Qui rk and Murray ( 1 99 1 ), and H il le l  ( 1 998) .  Moreover, the 
effects of agricultura l  activities such as ti l lage practices on these properties with 
respect to water runoff and soil losses are under research . Among the studies in the 
recent past include long-term ti l lage effects on physical properties of eroded soi ls 
(Hussain et al . ,  1 998), quantification (Montgomery et al . ,  1 999), assessment (Thapa 
et al . ,  1 999), and modell i ng  (Lobb and Kachanoski , 1 999) of soil t i l lage erosion and 
translocation . One of the main d i fficulties related to erosion control , however, is the 
rel iabi l ity and the precision of erosion assessment i n  terms of extension , magn itude,  
and rate of soi l  erosion and its economic and environmental consequences (La l ,  
1 998). Many studies have been undertaken for th is purpose . Laflen and Roose 
( 1 998) have suggested methodologies for assessment of soil degradation due to 
water erosion i ncluding measurement and estimation techn iques for both interri l and 
channel (ri l l  and gul ly) e rosion . Also mathematical models of water and wind erosion 
have been widely developed and reviewed (Nearing et al . ,  1 994, Skidmore ,  1 994 , 
Rose, 1 998) .  
Ti l lage-induced erosion has been widely studied across nations, with particular 
emphasis on mouldboard plough (Alba et al . ,  2006 ,  Heckrath et al . ,  2005, Kimaro et 
a l . ,  2005, Van Muysen et al . ,  2006) and manual hoeing/ti l lage (Zhang et al . ,  2004 , 
Kimaro et a l . ,  2005, de Rouw and Rajot, 2004, Turkelboom et aI . ,  1 999). Sim ilarly, a 
variety of d ifferent study methods on erosion patterns i n  the form of gu l ly erosion 
have been reported. Among these were erosion monitoring by the use of GPS (Wu 
and Cheng, 2005), erosion assessment with photogrammetric techn iques (Oaba et 
al. , 2003) ,  and erosion evaluation us ing 1 37Cs and 2 1 0Pb/1 37Cs ratio (Li et al. , 
2003). Likewise , some recent assessment reports on interril erosion have been 
establ ished ranging from using survey methodology (Bewket and Sterk, 2003) ,  to 
incorporat ing the soil instabi l ity index (Valmis et a I . ,  2005), to i nvestigating the 
effects of rai nfall i ntensity,  slope length , and gradient on runoff amount and 
pathways for in terri l l  erosion in ti l led fields (Chaplot and Le Bissonnais,  2003). 
Chapter 6 - TI LLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 228 
AND NUTRIENT LOSSES 
The determination of soil erosion and compaction and the ir  inter-relations requires 
detai led analysis as wel l  as inclusion of the mechanical and hydrological aspects in 
the defin ition of erosion prevention methods (Simota et a l . ,  2005) .  The Un iversal 
Soil Loss Equation (USLE), is  the empirical erosion model which has been used 
most widely for pred icting soi l erosion (Nearing et a I . ,  1 994). It is hai led as one of 
the most sign ificant developments in soil and water conservation in the 20th century 
(Flanagan et a l . ,  2003) .  The basic structu re of USLE is given by: 
A = RKLSCP 
where A is the computed soi l loss , R is the rainfal l-runoff erosivity factor, K is the 
soi l  erod ib i l ity factor, L is the s lope length factor, S is the slope steepness factor, C 
is the cover-management factor, and P is the supporting practices factor. Th is 
empirica l ly-based equation , derived from a large mass of field data , computes sheet 
and ri l l  erosion using values representing the four major factors affecting erosion .  
These factors are cl imate erosivity represented by R ,  soi l erod ib i l ity represented by 
K, topography represented by LS, and land use represented by CP (Renard et a l . ,  
1 994 , Flanagan et a l . ,  2003). Despite its wide acceptance , th is model has been 
shown to be ineffective when appl ied outside the range of cond itions for which it 
was developed . This has lead to the emergence of new models, among them the 
revised USLE (RUSLE) and the USDA-Water Erosion Pred iction Project (WEPP) 
models .  The latter, categorized by Nearing et al. ( 1 994) as physical ly-based 
models, are intended to represent synthesis of the i ndividual components which 
affect erosion , the complex interaction between various factors, and their spatial 
and temporal variabil ities. 
6.2.3 N o n point source pollution : soi l  and water q u al ity 
Sources of water pol lution are recognized as either of point or nonpoint orig in 
(Schwab et a/. , 1 996) .  Point sources i ncl ude animal feed lots, chemica l  dumpsites, 
storm dra in  and sewer outlets, acid mine outlets, and other identifiable points of 
orig in .  Nonpoint source (NPS) pol lution originates from d iffuse land areas that 
intermittently contribute pol lutants to surface and groundwater. Agriculture is the 
major cause of NPS pol lution , whereby storm runoff carries pesticides , particles of 
Chapter 6 - TI LLAGE EFFECTS ON WATER RUNOFF, LEACHATE,  AND SOIL SEDIMENT 229 
AND NUTRIENT LOSSES 
soi l ,  nutrients, and organic wastes.  I rrigation water return is also a nonpoint source 
pollutant, when it is saline and contains nutrients (Poincelot, 1 986) .  
Water qual i ty i s  determined by the presence of biolog ical, chemical , and physical 
contaminants. Biological contaminants resu lt from human and an imal wastes p lus 
some industria l  processes. Chemicals enter the water supply from industrial 
processes and agricultural use of fert i l izers and pesticides. Physical contaminants 
result from erosion and disposal of man-made objects (Schwab et a l . ,  1 996). The 
most troublesome agriculture pol lutants in  terms of soil qual ity are pesticides. 
Certain toxic wastes, if used as ferti l izers or organic amendments can also be 
harmfu l .  An area in need of research is whether the use of pesticides damages the 
soi l  ecosystem to the extent that the crop productivity is  lessened over a long period 
of time (Poincelot, 1 986). The lack of soil m ixing and heavy herbicide usage with 
no-ti l l  and m in imal ti l l  systems suggests a potential problem of NPS pol lution . 
Studies on NPS pol lution have been reviewed by L ine et al. ( 1 999) and reported at 
length by Overcash and Davidson ( 1 980) concern ing pesticides, pathogens, 
n itrogen and phosphorus, sed iment, and land use. S imi larly, Baker (1 980) has 
largely d iscussed the issue of agricultural areas as non point sources of pol l ution 
with data on loads and time-concentration trends for nutrients such as N and P, and 
pesticides in surface runoff from agricultu ral areas as affected by management 
practices such as cropping,  ti l lage, and chemical appl ication methods. More 
specifical ly on ti l lage impacts on groundwater qual ity, Logan et al. (1 987) ind icated 
a number of resource studies, covering aspects of soi l  physica l ,  chemica l ,  and 
biological processes as well as the fate and transport of appl ied pesticides and 
fert i l izers . 
Preventing or control l ing non point source pollution can accompl ish two purposes i .e .  
susta inabi l ity of an agricultural resource and reduction of  pollution (Poincelot, 1 986). 
However, it is technical ly d ifficult and costly to mon itor NPS pol lution.  Consequently, 
most economic instruments d i rected towards reducing this type of pollution have 
focused on circumventing the mon itoring problem by focusing on readi ly observable 
factors . In some developed economies, such instruments i nclude taxes or tradable 
perm its on inputs or other incentives to induce changes in farming practices. The 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF ,  LEACHATE, AND SOIL SEDIMENT 230 
AND NUTRIENT LOSSES 
latter may i nclude ferti l ization , manure spreading and t i l lage practices that are 
assumed to form strong l inkages to farm field runoffs (Romstad , 2003). 
Not surprisingly however, the chal lenges for NPS pollution and erosion control i n  
the developing countries are even greater, largely due  to the  lack of  social and 
economic instruments. The degree of severity of soi l  erosion and water runoff u nder 
tradit ional farming systems in these countries depends largely on the soi l ,  land-use 
i ntensity, rel ief and cultural practices adopted (La l ,  1 995), much of which has been 
previously d iscussed in chapter 2. Erosion and runoff are generally reduced if the 
fal low period is long enough to restore soil physical properties and increase the soil 
organ ic  matter content. 
6.2.4 S u rface water ru noff a n d  leachate 
Soil erosion research must be based on experimental results of some form as it 
i nvolves a complexity of interacting factors. Often ,  laboratory and field plots are 
used to obtain experimental data for predicting and evaluating soil erosion and 
sediment yield (Mutchler et a/. , 1 994). Empirical studies suggest that t i l lage systems 
that do not incorporate surface residue and amendments (conservation ti l lage) 
appear to be more vulnerable to soluble nutrient losses main ly in  surface runoff but 
also in subsurface drainage (due to macropore flow). In contrast, t i l lage practices 
that thoroughly m ix residue and amendments in the surface soil (conventional  
t i l lage) are more susceptible to sediment and sediment-bound nutrient losses (e .g .  
particulate P)  through surface water runoff (Zhao et al. , 200 1 ) .  I n  genera l ,  as 
reported by earl ier studies , surface amendments (Rao et a l . ,  1 998a, Rao et al . ,  
1 998b), watershed characteristics (Ship italo and Edwards, 1 998), and landscape 
features (Lobb and Kachanoski ,  1 999) are the lead ing factors contributing 
significantly to the differences of  soil erosion and runoff among ti l lage treatments . 
A 2-year experiment study by Myers and Wagger ( 1 996) on runoff and sed iment 
losses under conventional t i l lage (CT) for corn gra in  production ,  no-ti l lage gra in  
production (NTG) with surface residue, and no-t i l lage si lage production (NTS) 
without residue cover found sed iment losses in the order of NTG<NTS<CT and this 
was clearly associated with the residue cover. The study a lso suggested that the 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 231 
AND NUTRIENT LOSSES 
surface roughness that existed immediately after t i l lage operations in CT may have 
aided in more rainfal l  water catchment and infiltration leading to decreased surface 
water runoff. However, in the second event  each year, the runoff loss was doubled 
with eT suggesting that soi l  surface seal development had taken place , thus 
decreasing water retention and infi ltration . Under no-t i l lage systems on the other 
hand , as has been largely d iscussed in the previous chapter, a g radual 
accumulation of soi l  organ ic  matter and greater porosity develops in  the near­
surface zone contributing to enhanced aggregate stabi l ity at the soi l surface. Thus ,  
surface seal ing tendencies are d im in ished which promotes an  increase in infi ltration 
rates and reduced water runoff (Rhoton et  al. , 2002). 
A s imi lar study in the Nepalese h il ls reported that total annual soi l  loss from 
conventional and reduced ti l lage was 1 6 .6 and 1 1 . 1  Mg/ha ,  respectively, while the 
annual  sediment-associated nutrient losses were 1 88 kg QC/ha , 1 8 .8 kg N/ha ,  
< 1  kg P/ha and 3.8 kg K/ha  for conventional t i l lage and 1 26 kg QC/ha, 1 1 .8 kg 
N/ha ,  <1 kg P/ha and 2 .4 kg Klha for reduced t i l lage. The study also indicated the 
significantly h igher soil organic carbon and N losses under conventional ti l lage to be 
one of the major causes of ferti l i ty depletion in the region (Atreya et al. , 2006) .  
6 . 2 . 5  C o n c l ud i ng remarks 
It is important to account for risks of soi l qual ity degradation ,  particularly soil erosion 
and sediment-bound nutrient losses, when designing agricultural policies for long­
term susta inabi l ity. This is  particularly true given the great pressure that has always 
been laid on land-based activities to meet the food demands of the increased 
population in the developing countries and the importance to reconcile these two 
ends sustainably. Having d iscussed the ti l lage-induced aspects of soil erosion, the 
derived lessons for the dryland farming areas would be to: ( i) i ncrease the level of 
soil organic matter, ( i i )  red uce the ti l lage intensity, (H i )  follow the contour for t i l lage 
d i rection ,  ( iv)  d iversify the t i l lage implements, (v)  reduce the subsoil com paction and 
(vi ) consider the optimum soi l  workabi l ity as suggested by Simota et al. (2005) . 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 232 
AND NUTRI ENT LOSSES 
6.3 RESEARCH METHODOLOGIES 
6 . 3 . 1  Expe rimental S ite 
The experiment was carried out in  a laboratory at the Practical Teach ing Complex 
(PTC) of Massey University i n  Palmerston North ,  New Zealand. 
6 . 3 . 2  Soil  sam p l i n g  for run off and leachate m easure m e nt 
Due to t ime and resource l imitations the soil samples were purposively taken only 
from the unweeded potato sub-plots and from the adjacent permanent pastu re fields 
with a total number of 1 6  samples. A soi l sample size of 300 mm long x 200 mm 
wide x 1 50 mm deep was taken from each plot for th is purpose . The size was 
considered large enough to account for any variabi l ity in soil physical conditions on 
the one hand, which a lso al lowed ease of extraction and transportation to the 
laboratory with l ittle or no soil d isturbance on the other. The steel corers with the 
above size and 3 mm wall th ickness were installed manual ly i nto the soi l and the 
soil cores were then carefu l ly extracted avoiding soi l  d isturbance (Figure 6. 1 ) . 
Figure 6 . 1  A soil core soon after extraction from the field 
The bottom end of each soil core was cut flush with the end of the core and 
carefu l ly transported and placed into a laboratory at Massey Un iversity. Any 
vegetative cover at the top of the soil cores was cut level to a height of ± 1 5  mm 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 233 
AND NUTRIENT LOSSES 
before cores were placed for experimentation .  A rainfa l l  s imulator, under which , 
three soil cores were placed at a time ,  wi l l  be described in  the next section. Special  
equipment (F igure 6.2) was constructed to be attached to each soi l  core for the 
col lection and measurement of soi l  and water runoff and leach ate under the rainfa l l  
s imu lator (Guo et al. , 1 999). 
Figure 6.2 Schematic diagram of the apparatus special ly designed for runoff and 
leachate measurements (Guo et al. , 1 999) 
6 . 3 .3 Rainfal l  Simulator 
Massey University's I nstitute of Natural Resource , has developed a laboratory 
rainfa l l  s imulator based on the design of USDA-ARS demonstration rainfal l  
s imulator developed by Dr .  John Laflen at  the Oh io State University (Hairsine ,  
1 999). Th is portable rainfa l l  s imulator suits many purposes i n  soi l  and hydro logy 
research , especial ly studies related to soil erosion and soil and water qual ity . It 
consists of fan osci l lating spray nozzles which produce rainfal l  rates ,  drop sizes and 
drop velocities simi lar to natural rainfa l l .  Water is pumped from a reservoir  to the 
nozzles and excess water is confined and drained back to the reservoir by a roof 
canopy and a hose . This  tool can also simu late variable rainfal l  intensities by 
varying the time between sweeps. 
Chapter 6 - TI LLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 234 
AND NUTRIENT LOSSES 
As laboratory equ ipment, it has been designed specifical ly for laboratory research , 
as shown in Figure 6 .3 .  The experiments with this rai nfall s imu lator were l imited to 
evaluating three types of t i l lage and permanent pasture and their effects on soi l  and 
water runoff and leachate . The slope of approximately 20% incl ination in the field 
was a lso taken into account in the simu lation process. 
The target rainfal l  parameter used was intensity of ± 50 mm/hr. This is in 
accordance with Meyer ( 1 994) who suggested that rainfal l  intensities between 0.2 
and 2 mm/min  are usual ly of greatest importance. Intensities below and above th is 
range are not of major interest in soi l and hydrologic studies. 
Figure 6.3 A rainfa l l  simu lator developed by Massey University's Institute of Natural 
Resources 
6.3.4 Runoff, sediment and leachate m e a s u re ment 
The experiments were carried out twice starting on 25 March 2004, with the first 
being a pi lot experiment. The volume of water runoff was collected at ten-minute 
intervals .  The total volume of surface runoff was determined by adding al l  runoff 
samples thus collected . 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 235 
AND NUTR IENT LOSSES 
The volume of water-sediment mix for each sample was obtained from the surface 
water runoff. A part of the water-sed iment m ix was used to determine the amounts 
of soil sediment in  surface water runoff. The dry mass of sediment was determined 
after evaporating the water off in an oven at 1 05°C for 24 hours .  The sediment 
concentration i n  surface water runoff was determined by multiplying the mean mass 
of sediment by the mean volume of surface water runoff from each ten-minute 
interval .  
The water leachate was col lected in  a catching tray p laced immediately below the 
soi l  cores (refer to Figure 6.2) .  The leachate samples were collected at ten-minute 
intervals .  The sum of six collections over one hour was equivalent to the total 
volume of water leachate . 
6.3.5 p H  o f  ru n off and leachate 
The pH of surface water runoff and leachate was measured by using a Standard pH  
meter into surface runoff and leachate samples. 
6.3.6 N utrient concentration of ru noff and leachate 
The surface water runoff and leachate samples were chemical ly analyzed to 
determine the amount of n itrogen (N) losses . N was extracted and determined 
accord ing to Kurmies ( 1 972). 
6.3.7 Statistical Analysis 
The analysis of all data obtained during this study was performed using the Genera l  
Lineal Model (GLM) procedure of  SAS (Statistical Ana lysis System)(SAS , 2002) .  
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 236 
AND NUTRIENT LOSSES 
6.4 Resu lts 
6.4.1 Water ru n off 
Water runoff was substantial ly affected by cultivation. The results i n  Table 6 . 1  show 
that, after the first 1 0-minute i nterval , surface water runoff data started to show a 
significant variation between the cultivated soi ls  (CT and MT) and the u nti l led soi ls 
i n  the NT and pp  plots towards the end of one-hour period of observation .  A trend 
was observed from 20-minutes rainfal l  consistently through to 60-minutes, where 
manual and conventional ti l lage practices produced significantly h igher surface 
water runoff compared to no-ti l lage and permanent pasture . The results also show 
that there were no significant d ifferences between CT and MT as wel l  as between 
NT and PP. 
Table 6 . 1  Water runoff (ml) as affected by ti l lage and pasture management 
(measured u nder simulated rainfal l  on 25th March 2004) (CT= 
conventional t i l lage, MT=manual  t i l lage, NT=No-ti l lage,  PP=Permanent 
pasture ) 
Time Treatments (m in )  LSDo o5 
CT MT NT PP 
1 0  22.25 a 25.25 a 5 .05 a 1 7 .00 a n .s .  
20 1 2 1 .25 a 1 1 4 .75 a 5 . 1 3  b 52 .00 ab 91 .02 
30 240.00 a 202 .25 ab 1 8 .38 c 83.00 bc 1 31 . 74 
40 279 .75 a 286 .50 a 39.38 b 1 08.25 b 1 47 .9  
50  306.00 a 356.00 a 69.50 b 1 26.00 b 1 49 .34 
60 308.00 a 379.00 a 79.75 b 1 47.75 b 1 59 .57 
Values followed by the same letter in each row are not significantly different (P<O. 05); n.s. =not 
significant. 
An i ncreased trend overtime, based on 1 0-minute measurement, was observed . At 
the last 1 0-minute observation ,  almost 4 ml/min water runoff rate was observed 
under the MT treatment. MT treatment produced the h ighest ( 1 363.75 ml )  total 
water runoff during one-hour s imulated rainfal l fol lowed by CT ( 1 277.25), PP 
(534 .00), and NT (21 7 . 1 8) (F igure 6 .4 ) .  Consistent with the results of every ten­
minute i nterval measurement described above, it is clear that total water runoff were 
significantly reduced under NT and PP treatments compared to that from the 
cultivated soi ls under CT and MT. However, the variabi l ity among repl icates with in  
treatments was quite h igh as shown by the LSDs . 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE , AND SOIL SEDIMENT 237 
AND NUTRIENT LOSSES 
Total Surface Water Runoff Under Different 
Ti l lage Treatments 
1 600 �--------------------------------� 
1 400 
� 1 200 
E :; 1 000 
o 5 800 
a: � 600 
o 
I- 400 I 
200 
0 -"---
1 363.75 a 
Til lage Treatment 
Figure 6.4 Ti l lage effects on total surface water runoff under one-hour simulated 
rainfal l  
6.4.2 Water leachate 
The water leachate during the first 20 m inutes was simi lar under a l l  the treatments, 
but sign ificant d ifferences started to appear from 30 m inutes onwards (Table 6 .2) .  
At the end of the observation (60-minutes), NT and pp produced sign ificantly h igher 
leachate than CT and MT. The leachate from NT after one hour s imu lated rainfal l  
was approximately 5 and 4 t imes compared to that for MT and CT, respectively. 
Table 6 .2 Water leachate (ml )  every ten minutes as affected by t i l la�e and pasture 
management (measured under simulated rainfal l  on 251 March 2004) 
(CT= conventional t i l lage, MT=manual  t i l lage, NT=No-ti l lage, 
PP=Permanent pasture) 
Time 
(min)  
1 0  
20 
30 
40 
50 
60 
eT 
1 1 .50 a 
59.25 a 
99.75 b 
87 .00 b 
77 . 1 3  b 
74.25 be 
Treatments 
MT 
3 1 .00 a 
1 36.25 a 
1 42.25 ab 
94 .50 b 
7 1 .75 b 
58.50 c 
NT 
1 5 .00 a 
1 20.75 a 
242 .50 a 
292 .75 a 
320.25 a 
306 .50 a 
pp 
1 3 .38 a 
1 03 .00 a 
1 39 .50 ab 
1 69 .75 ab 
1 9 1 .50 b 
205.50 ab 
LSDo.05 
n .s .  
n .s .  
1 2 1 .0  
140.92 
1 22 .4 
1 32 .8  
Values followed by the same letter in each row are not Significantly different (P<O. 05); n.s. =not 
significant. 
Chapter 6 - TI LLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 238 
AND NUTRIENT LOSSES 
As expected , total water leachate was significantly greater under no-ti l lage, whereas 
leach ing in the CT and MT plots was lower (Figure 6.5) .  The leachate under 
permanent pasture was somewhat moderate , being i n  between that from the t i l l ed 
and unt i l led plots, but showed not significantly d ifferent from either of the 
treatments. 
Total Water Leachate U n d e r  D iffe re nt Ti l lag e 
Treatme nts 
1400�----------------------------------�
_ 1200 
E 
-; 1000 -Cl! ..c: 
� 800 (1) ...J 
� 600 -Cl! 
� 400 Cl! 
� 200 
o --'----
Tillage Treatment 
Figure 6 .5  Ti l lage effects on total water leachate under one-hour simulated rainfal l  
The leachate from each 1 0-minute observation during an hour increased unti l  30 
minutes under CT and MT then decl ined (Table 6 .2) .  Simi larly with NT, the leachate 
volume increased for 50 minutes then decl ined .  pp soi ls ,  in contrast, had an 
increased leachate volume per 1 0  m inutes during the one-hour measurement. 
6.4.3 S o i l  sed iment 
The measured soi l losses due to surface water runoff were i n  l ine with the amount 
of water runoff (Table 6. 1 ) . During the fi rst 1 O-minutes simu lated rainfa l l ,  MT had the 
greatest soil loss , estimated at 82 . 3  kg/ha,  fol lowed by CT (32 .3) ,  NT ( 1 2.45) ,  and 
pp (5 .49) (Table 6.3). A large i ncrease in soil loss was observed during the second 
1 0-minutes in CT and MT, and a lesser increase in pp whereas, in NT the soi l loss 
decreased (Table 6.3) .  
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 239 
AND NUTRIENT LOSSES 
After one-hour s imulated rainfa l l ,  the soi l  sediment loss from the manual ti l l age (MT) 
treatment was 70 and 47 times h igher than from the pp and NT treatments ,  
respectively (Table 6.3) .  There was no  d ifference i n  soi l  loss i n  one  hour between 
MT and CT, and between CT, NT and pp (Table 6.3) .  
Table 6.3 Estimated soil sediment losses (kg/ha) as affected by t i l lage and pasture 
management (measured under s imulated rainfa l l  on 25th March 2004) 
(CT= conventional t i l lage , MT=manual t i l lage, NT=No-ti l lage, 
PP=Permanent pasture ;  ANOVA was performed on log transformed data) 
Time Treatments LSDo.05 (min)  CT MT NT pp 
1 0  32 .3 82.3 1 2.45 5.49 
( 1 . 38)  ab ( 1 . 54) a (0 .99) ab (0.72) b 0.70 
20 2 1 0.6 279.4 5.59 1 0 .20 
(2 . 1 1 ) a (2.37) a (0 .69)  b (0.98) b 0 .53 
30 567 .7 628.6 8 .84 1 8 .95 
(2.6) a (2.68) a (0.84) b ( 1 .27) b 0 .58 
40 942.4  974.7 40.05 1 9.76 
(2.79) a (2.89) a ( 1 .28) b ( 1 .28) b 0 .75 
50 1 006.0 1 1 08.4 32.09 1 8.91  
(2.82) a (2.99) a ( 1 .23) b ( 1 .26) b 0 .70 
60 797.7 1 578.8 33.86 22 .48 
(2.77} a p.07) a ( 1 .231 b {1 .35} b 0 .69 
Values followed by the same letter in each row are not significantly different (P<O. 05); n.s. =not 
significant 
The total soi l  sediment losses were significantly greater under cultivated soi ls  (CT 
and MT) than until led (NT) and permanent pasture (PP) soi ls (Figure 6 .6) .  The 
magnitude of soi l  sediment loss was in the increasing order of PP (95 .79 Kg/Ha) > 
NT ( 1 32.87) > CT (3556.7)  > MT (4652 .2) .  The longer the period of rainfa l l ,  the 
greater was the amount of soi l  sed iment loss through surface water runoff. This  was 
particularly the case for cultivated soi ls  under CT and MT as indicated in earl ier 
presentations. 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 240 
AND NUTRIENT LOSSES 
Tota l Soi l Loss Effe cte d by T i l l a g e  Treatme nts u n d e r  O n e ­
Hour S i m u late d Ra i nfa l l  
5000 
4652.2 a 
4500 
4000 
la 3500 .=. 
Cl 
� 3000 
/I) /I) 0 2500 ...J 
'0 
2000 (J) 
'iii 
-0 1 500 I-
1 000 
500 
0 
1 32 .87 b 95.79 b 
Tillage Treatment 
Figure 6 .6  Ti l lage effects on total soi l loss under one-hour simu lated ra infal l  
(ANOVA was performed on log transformed data) 
6.4.4 S o i l  nutrie nts 
Water runoff pH under permanent pasture was significantly increased compared to 
other treatments while it was unaffected under ti l lage practices. Water leachate pH 
was simi lar under al l the treatments. There was no effect on ammonia and nitrate 
losses by any of the treatments (Table 6 .4) .  
Table 6.4 Til lage effects on soil water pH and n itrogen losses (CT= conventional 
ti l lage, MT=manual t i l lage, NT=No-ti l lage, PP=Permanent pasture) 
Ti l lage 
CT 
MT 
NT 
pp 
LSDo.05 
runoff 
7.25 b 
7 .24 b 
7 . 1 7  b 
7 .55 a 
0 .24 
pH  N as  NH4+ (ppm) N as N03- (ppm) 
ka�a� runoff ka�a� runoff ka�a� 
6 .95 a 0 .37 a 0 .30 a 0 .67 a 8 .40 a 
6 .94 a 1 .74 a 8. 1 9 a 0 .48 a 1 0 .77 a 
6 .9 1  a 0 .54 a 1 . 1 1  a 0 .64 a 6 .  1 8  a 
6 .75 a 0.68 a 0.65 a 0 .50 a 8 .98 a 
n .s n .s n .s .  n .s .  n .s .  
Values followed by the same letter in each column are not  significantly different (P<O.05); n.s. =not 
significant. 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 241 
AND NUTR IENT LOSSES 
6.5 Discussion 
6.5. 1 Water run off, soil sed i m e n t  and n utrien t  losses 
Soil t i l lage breaks up the soi l  surface and lowers the stabi l ity of soi l  aggregates and 
thus decreases the soi l 's resistance to detachment by raindrop impact or flowing 
water, and when rainfall exceeds the surface depression storage, t i l lage can lead to 
concentrated flow erosion (Turkelboom et a l . ,  1 999, Valmis et al . ,  2005). The resu lts 
clearly showed that conventional t i l lage (mouldboard plough and manual hoeing) 
produced more surface water runoff than no-ti l lage and permanent pasture. This 
concurs with results from overseas ti l lage and erosion studies, especial ly on manual 
hoe ing and mouldboard plough ing (Basic et al . ,  2004, Zhang et al . ,  2004 , 
Turkelboom et al . ,  1 999, Turkelboom et al . ,  1 997, de Rouw and Rajot, 2004, 
Osunbitan et al . ,  2005). 
The results of th is study, not surpris ingly, partial ly confirm those from other studies 
a lready avai lable i n  the l iterature. The point of i nterest, however, was that soi l  
structural damage, and the obvious causal differences among mechanical 
treatments employed, happened and were noticeable j ust over a period of one 
cropping season.  The results show that manual t i l lage (MT) resulted i n  the most 
serious short-term soi l  structural deterioration , as far as water erosion indicated by 
runoff and soil losses was concerned. This however, appears to contradict the 
aggregate stabi l i ty data d iscussed in Chapter 5 ,  which showed that MT, 
cumulatively, produced the most stable aggregates in the top 0-1 0  cm topsoi l  (refer 
to Figure 5. 1 5) .  Moreover, it also d isagrees with the porosity and hydraul ic 
conductivity data which ind icated i nsignificant d ifferences among treatments .  I n  
com bination with stronger soi l  aggregate stabil i ty ,  these soil properties could have, 
theoretical ly, led to MT producing s imi lar results, or even lower runoff and soi l  
losses compared to conventional ti l lage (eT) using mouldboard plough.  This 
d isparity is  a matter for further investigation . However, the penetration resistance 
data at the t ime the soil samples were col lected (Table 5 .6)  may offer some 
explanation . The soi ls under MT were less compacted in the few centimetres of the 
topsoi l ,  probably exposing more loose soi l particles susceptible to erosion . The 
s imulated degree of field slope (± 20°) could also have been a determin ing factor i n  
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 242 
AND NUTRIENT LOSSES 
decreasing water infi l tration , thus  producing a h igher amount of surface water and 
sediment runoff u nder MT. 
These empirical find ings about water runoff and sediment loss can be crucial  for 
cropping systems i n  the steeply sloped lands of the tropics, where farmers ,  under 
social and economic pressure, a re forced to farm on very marg ina l  soi ls of the hi l l  
s ides. Even with a superficia l  manual cultivation ,  the t i l lage translocation rates can 
be very h igh on the steepest slopes as was reported for the U luguru Mounta ins of 
Tanzania (Kimaro et al. , 2005). It was also presumed that manual t i l lage cou ld be 
responsible for the occurrence of most shal low soils observed on the steepest 
slopes and the accumulation of col l uvium beh ind grass barriers along contour 
bands. The calculated t i l lage erosion rates along contour bands  in the U luguru 
Mountains can reach values of up to 1 80 t ha - 1 per year for p lots of 8 .5  m length 
(Kimaro et al. , 2005) .  A s imi lar study i n  N iger recorded short-term soi l transport by 
means of saltation and creep and in the long-run by means of suspension (de Rouw 
and Rajot, 2004) . The former was reported as loose soi ls in the mobi le upper layers 
under manual cultivation being swept away during  storms causing the less fertile 
lower soil layers, often crusted , acid and very low in organ ic matter content, to come 
nearer to the surface . The latter, under prolonged cultivation , describes a condition 
where increased exposure to rainstorm reduces soi l  organic matter thus implying 
loss of soi l structure and subsequently less stable aggregates. Enhanced by wind 
erosion this condition eventual ly led to an extremely sandy top soi l  (de Rouw and 
Rajot, 2004) .  Also, Heckrath et al .  (2005) found that t i l lage translocation rates were 
strongly correlated with SOC contents, A-horizon depth , and P contents . This, in  
turn , had led to truncated soi l s  on shoulderslopes and deep, col luvial so i ls  on the 
foot- and toeslopes, substantia l ly affecting with in-field variabi l i ty of soi l properties. 
The erosional effects of mouldboard ploughing as opposed to no-ti l lage u nder th i s  
study general ly concur with those a lready known . A study by  Rhoton et a l .  (2002) 
reported runoff under conventional ti l lage (CT) and no-ti l lage (NT) treatments 
averaged 27 .8  and 1 6. 5  mm,  respectively, whi le soi l loss from CT treatments 
averaged 3 .9  t ha-1 and 0 for the NT. The decreased runoff u nder NT was due to 
the development of greater porosity i n  the near-surface zone attributable to 
enhanced aggregate stabi l ity at the soil surface , and d iminished surface sealing 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 243 
AND NUTRIENT LOSSES 
which promotes an i ncrease in infi ltration rates .  Choudhary et a l .  ( 1 997) comparing 
mould board plough (MP),  chisel plough (CP), and no-t i l l  (NT) also reported that soi l  
e rosion and surface runoff were markedly affected by t i l lage methods .  The order in 
which the runoff i ncreased was MP > CP > NT.  The reverse o rder was obtained for 
leachate. 
The n itrogen losses associated with runoff were insignificantly different, probably 
due the study being run only with i n  a short period of time . Atreya et a l . (2006), 
recorded annual nutrient losses in the Nepalese hi l ls associated with the eroded 
sediment that were 1 88 kg QC/ha ,  1 8 .8  kg N/ha, <1 kg P/ha and 3 .8  kg Klha for 
conventional t i l l  and 126 kg QC/ha , 1 1 .8 kg N/ha,  < 1  kg P/ha and 2.4 kg Klha for 
reduced ti l l .  An earl ier study by Guo et a l .  ( 1 999), s imi larly ,  reported significantly 
h igher amounts of sediment-bound  nutrient losses under conventional t i l lage (CT) 
than no-ti l lage (NT) by the amount of 1 .45 mg N .m-2 , 1 .02 mg P .m-2 , 8 . 3  mg K.m-2 
under CT and 0 .76 mg N .m-2, 0 .65 mg P .m-2 , and 6.8 mg K.m-2 under NT.  
6.5.2 Wate r leachate and n utri e nt l o sses 
Water leachate resu lts showed an inverse trend from those of water runoff. Greater 
water volume was transmitted down the soi l  profi le than as surface runoff under no­
ti l lage (NT) and pasture (PP) treatments comparative to the cultivated soils (eT and 
MT) .  S imi larly, Guo et al. ( 1 999) reported significantly h igher  amounts of water 
leachate under NT and PP than the mould board plough. Choudhary et al. ( 1 997) 
also reported water leachate to be markedly affected by moldboard plough (MP) ,  
chisel plough (CP)  and no-ti l lage (NT) treatments in the order of NT>CP>MP. Early 
find ings from both Guo et al. ( 1 999) and Lal ( 1 997) suggested that h igher nutrient 
losses were found in water leachate than water runoff. 
6.5.3 N o n-poi nt source pollution 
The runoff and leachate losses are a matter of concern i n  relation to non-point 
source pol lution as pinpointed earl ier i n  Chapter 5 .  The short-term ti l lage effects on 
nutrient losses through surface and leaching were not significant. However, a 3-year 
ti l lage experiment in Manawatu New Zealand by Guo et a l .  ( 1 999) ind icated that 
total N losses (in runoff and leachate) were significantly reduced with decreased 
Chapter 6 - TI LLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 244 
AND NUTRIENT LOSSES 
intensity of t i l lage. The N losses were 3.06,  7 .70, and 8.29 mg.m-2 u nder CT, NT, 
and PP, respectively. The losses under NT and PP derived largely from leaching .  
These results were confirmed later by Zhao et a l .  (2001 ) ,  i nvestigating the effects of 
ti l lage and nutrient source on water qual ity. It was revealed that sed iment, total P ,  
soluble P ,  and NH\-N losses mainly occurred i n  surface runoff and the NO-3-N 
losses primari ly occurred in subsurface ti le dra inage. Analyzing the combined 
surface and subsurface flow, the study fu rther ind icated that the mou ldboard plough 
(MP) treatment resu lted in nearly two times greater sediment loss than ridge ti l lage 
(RT) (P < 0.0 1 ) .  Ridge ti l lage with urea lost at least 1 1  t imes more NH+ 4-N than any 
other  treatment (P < 0.01 ) .  Ridge ti l lage with manure also had the most total and 
soluble P losses of al l  treatments (P < 0.0 1 ) . Similar find ings were made by Nissen 
and Wander (2003),  studying the management and soi l-qual ity effects on ferti l izer­
use efficiency and leaching .  Although total leached N was simi lar i n  al l cropping 
systems under study, increased macropore flow i n  NT cores led to g reater leach ing 
of ferti l izer N and less leach ing of soil-derived N ,  as well as g reater moisture stress 
and decreased plant N uptake. 
Contrasting resu lts, however, were found  in a s imi lar study by J iao et a l .  (2004) 
where d issolved N and dissolved P loads were not affected by t i l lage and were 
simi lar fol lowing corn (Zea mays L . )  in a continuous corn rotation , and soybean 
[Glycine Max (L . )  Merr. )] in  a soybean/corn rotation production .  The study revealed 
that soi ls receiving inorganic ferti l izer had a 70% greater nitrate (N03-N) load and 
48% less d issolved reactive P than soi ls  receiving organic ferti l izer (Jiao et al. , 
2004) .  This evidence suggests that ferti l izing soils with a combination of inorganic 
and organic ferti l izers might be a good way to reduce both N03-N and d issolved 
reactive P transport to water systems. The overall resu lts suggest that the leach ing 
of dissolved N and dissolved P compounds is influenced more by the type of 
fert i l izer appl ied than ti l lage or cropp ing practices. Simi larly, Zhu et a l .  (2003) 
reported that ti l lage had no effect on total leachate col lected during the 6-yr 
experiment by either pan (228 mm y(1 ) or wick (558 mm y(1 ) Iys imeters. Their study 
found that the flow-weighted NO-3-N concentrations and NO-3-N masses in 
leach ate were not significantly different between t i l led and NT, but increased with 
increasing N-rate (at 0, 1 00, and 200 kg N ha-\ flow-weighted NO-rN 
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF,  LEACHATE, AND SOIL SEDIMENT 245 
AND NUTRIENT LOSSES 
concentrations were 3.5, 8 .2 ,  and 23 .9  mg L-1 and NO-3-N masses were 1 7 , 39, and 
1 1 2 kg ha-1 y(1 , respectively) . They concluded that under their experimental 
cond itions ,  NT did not result in more NO-3 leaching than chisel-ti l lage over a 
multiyear period . 
6.6 Concl u d i ng remarks 
The experimental results show that conventional t i l lage practices cause more water 
and sediment erosion than no-ti l lage. Conventional t i l lage significantly increased 
water runoff but less leachate compared to no-ti l l  and permanent pasture .  Total soi l 
sed iment loss was significantly lower under pp (95 .8  kg/ha) and NT ( 1 32 .9)  
compared to CT (3556.7)  and MT (4652 .2) .  pH of water runoff was significantly 
reduced under ti l lage treatments compared to that from permanent pasture whereas 
n itrogen losses were unaffected . The results emphasize ti l lage as one of major 
contributing factors to erosion , as has been proven elsewhere, part icularly in  the 
undu lating to steep and fragi le lands .  
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 246 
AND NUTRIENT LOSSES 
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pp .  265-293. SWCS & St. Lucie Press, USA 
Thapa ,  B .  B. , Cassel ,  D .  K. & Garrity, D .  P. ( 1 999) Assessment of ti l lage erosion 
rates on steepland Oxisols in the humid tropics using granite rocks. Soil and 
Tillage Research, 51 , 233-243.  
Thapa , G .  B .  & Paudel , G .  S.  (2002) Farmland Degradation in the Mountains of 
Nepal : A Study of Watersheds 'With' and 'Without' External Intervention .  
Land Degradation & Development, 1 3, 479-493 . 
Turkelboom , F . ,  Poesen , J . ,  Ohler, I .  & Ongprasert, S .  ( 1 999) Reassessment of 
t i l lage erosion rates by manual t i l lage on steep s lopes i n  northern Thai land .  
Soil and Tillage Research, 51 , 245-259. 
Turkelboom, F. ,  Poesen ,  J . ,  Ohler ,  I . ,  Van Keer, K. , Ongprasert, S .  & Vlassak,  K .  
( 1 997) Assessment of ti l lage erosion rates on steep slopes i n  northern 
Thailand.  CATENA, 29, 29-44. 
Valmis ,  S . ,  D imoyiann is ,  D .  & Danalatos, N .  G. (2005) Assessing i nterri l l  erosion 
rate from soil aggregate instabi l i ty i ndex, rainfa l l  intensity and slope angle on 
cultivated soil s  in central Greece. Soil and Tillage Research, 80, 1 39-1 47 .  
Chapter 6 - TILLAGE EFFECTS ON WATER RUNOFF, LEACHATE, AND SOIL SEDIMENT 251  
AND NUTRIENT LOSSES 
Van Muysen , W. ,  Van Oost, K .  & Govers , G. (2006) Soil translocation result ing from 
mu lt iple passes of t i l lage under normal field operating condit ions. Soil and 
Tillage Research, 87, 2 1 8-230 .  
Wu,  Y. & Cheng , H .  (2005) Monitoring of gul ly erosion on the Loess Plateau of 
China using a global position ing system .  CA TENA, 63, 1 54-1 66. 
Zhang, J .  H . ,  Lobb, D. A. , L i ,  Y .  & Liu , G .  C.  (2004) Assessment of t i l lage 
translocation and ti l lage erosion by hoeing on the steep land i n  h i l ly areas of 
Sichuan ,  China. Soil and Tillage Research, 75, 99-1 07. 
Zhao, S .  L . ,  Gupta, S. C . ,  Hugg ins ,  D. R. & Moncrief, J. F. (200 1 ) Ti l lage and 
Nutrient Source Effects on Surface and Subsurface Water Quality at Corn 
Planting .  J Environ Qual, 30, 998- 1 008. 
Zheng , F . ,  He,  X . ,  Gao , X . ,  Zhang, C .-e . & Tang, K. (2005) Effects of erosion 
patterns on nutrient loss fol lowing deforestation on the Loess Plateau of 
China. Agriculture, Ecosystems & Environment, 1 08, 85-97. 
Zhu ,  Y. , Fox, R. H. & Toth , J .  D .  (2003) Ti l lage Effects on N itrate Leaching 
Measured by Pan and Wick Lysimeters. Soil Sci Sac Am J, 67,  1 5 1 7-1 523 . 
GENERAL DISCUSSION 
Impl ications of  Research Findings to East Timor 
Agricultural  Development 
7.1  I ntroduction 
This thesis has examined i ssues concerning sustainable crop production 
technologies in East T imor, using relevant case stud ies and experimental data. The 
objective has been to offer prospective long-term outcomes for the development of 
the country's largely rural and agriculture-base industry. The i ntroductory part of the 
thesis outl ines the research agenda, fol lowed by an overview of the agri cu ltural 
development in East Timor emphasizing the traditional  farmi ng and cropping 
systems. This analysis was further complemented with d iscussion of aspects of 
agricultural mechanization , and the staging of agricultural and technological change. 
The social  and economic ramifi cations and impl ications for food security are jointly 
considered in a food policy approach . Empiri cal data were gathered from 
experiments, attempted both in East Timor and New Zealand , on soil and water 
conservation through the comparison of d ifferent t i l lage practices. 
This chapter brings together al l the topics covered , h ighl ights the l inkages, and 
summarizes the main pol icy impl ications for East Timor's rural and agricultural 
development. Moreover, it sets u p  the l ikely agenda com ponents for future 
research , which , i n  the foreseeable time horizon , wi l l  be undertaken main ly by 
publ ic funding and i nstitutions. 
7.2 The traditional setting of agricultural  development 
One of the major debates of recent times has been focused on how best to lead a 
smooth and less social ly d isrupting transformation from a traditional social 
landscape towards a reasonable stage of modernization. In the context of East 
T imor, a variety of central ized pol icies have been trial led i n  the past, so often 
through uncoord inated boards and sporadic  developmental projects . After many 
decades to centuries, of both foreign occupation and negl igence, the social fabric 
remains that of an agrarian and backward looking society. The post- independence 
era brings about an opportun ity to start anew. Strategic action plans have been 
Chapter 7 - GENERAL D ISCUSSION: Impl ications of Research F indings to East Timor 253 
Agricultural Development 
designed and implemented , tailored at i ncreasing land and human resources 
productivity with the ult imate goal of al leviating hunger and poverty, sti l l  chronical ly 
experienced nationwide.  However, a cautionary approach and measures are equally 
necessary so as to avoid putting excessive pressure on scarce resources, thus 
degrading the environmental qual ity , as well as to use the avai lable resources 
effectively. 
On a more narrow scope, the basel ine for the d iscussion is based on the social 
environmental sphere, covering geographic and demographic features, and most 
essential ly the cultural mindset which governs almost the entire range of farming 
activities and rural l ives. I n  add ition ,  the legacies of the past, particularly deal ing 
with forced mass resettlements and the accompanied arbitrary and uncontrolled 
environment destruction, poses a tremendous chal lenge. Central to this specific 
setting , particularly i n  the context of East Timor and many other developing 
countries, is the common practice of shifting cultivation with the slash and burn 
method of land clearing . It continues to be the economic mainstay of upland 
communities in many developing countries worldwide, as suggested by Dendi et al. 
(2005) and Porro (2005) despite the introduction of technolog ical innovations. 
The increasing imbalance between the rural and urban economies is encourag ing 
urbanization . To reverse the current trend of mass movement to the u rban centres, 
l ivel ihood sources from farming and rural environments must be transformed so as 
to become attractive, productive , and l ucrative. Of major concern is that cond itions 
that helped susta in the shifting cultivation rotations with long fal lows for many 
generations in the past have largely vanished (Sunderl i n ,  1 997), exacerbated 
main ly by rapid population growth (Cramb, 1 993) ,  i ntensification of shifting 
cultivation (Arnason et al. , 1 982) ,  and publ ic pol icies to settle permanent agriculture 
and d iscourage the use of fal lows and fi res (Cairns and Garrity, 1 999) .  What publ ic 
pol icies fai led to address ,  or to address adequately, was to put i n  place a proper 
diagnostic framework of the trad itional farming system through an i ntegrated 
research approach and methodolog ies. This is particularly important for sh ifting 
cultivation effects as they are not isolated from the commun ity . Fuj isaka ( 1 994), for 
example, h igh l ights the importance of recognizing the constraints experienced by 
Chapter 7 - GENERAL DISCUSSION: Implications of Research Find ings to East Timor 254 
Agricultural Development 
farmers that underpin their rejection of researcher-driven solutions to the ir  
problems . 
A participatory, on-farm research approach to identify viable alternatives to shifting 
cultivation is requ ired (Hazel l and Wood , 2000, Astatke et al . ,  2003, Poudel et al . ,  
2000 , Sang inga et al . ,  2004) .  As recommended by Cairns and Garrity ( 1 999) ,  th i s  
process may i nvolve , but not be  l imited to, identification of promising ind igenous 
practices, characterization of the pract ices, val idation of the uti l ity of the pract ice for 
other communit ies, extrapolation to other locations ,  verification with key farmers , 
and wide-scale d issemination through wel l-resourced extension channels. The agro­
cl imatic zones of East Timor provide a wel l-defined set of ecological boundaries 
upon which further collaborative research work can be developed . 
Apart from the rice fields and coffee p lantations which ,  to some degree, have been 
touched by technolog ical waves in the past, large parts of the country, mainly h i l ly  
and mountainous, remain d istant from innovative actions .  The latter areas are a 
major concern of th is thesis ,  being in large part the l iving envi ronment of the rural 
population , practising traditional farming methods over many years. Case stud ies 
suggest that for many reasons beyond their  control , these rural farmers cannot 
adopt high labour and cash cost innovations. Therefore , it is relevant to suggest 
fol lowing F ij isaka ( 1 99 1 )  that intermed iate steps such as improved fal lows for these 
h i l ly and mountainous areas are needed prior to crop d iversification,  adoption of 
ag ro-forestry technologies, and sedentary agriculture. Other studies have also 
ind icated that wel l  managed alternative systems to shift ing cultivation can reduce 
soil structure deterioration, maintai n  soi l fert i l ity, and promote long-term productivity 
(Alegre and Casse l ,  1 996). 
7.3 Agricultural productivity:  managing technological change 
I t  is  argued that in  the context of the trad itional setti ng of East Timor that agricultural 
productivity, both in terms of human capital and land resources, should be 
enhanced and promoted . Given land resources are one of the major capital 
i nvestments in agricultu re development, the drive towards improvement and 
technical change in  agriculture should be d i rected in  a balanced comb ination ,  
Chapter 7 - GENERAL DISCUSSION :  Implications of Research Findings to East Timor 255 
Agricultural Development 
whenever appropriate, between technolog ies of land-saving (hybrid seeds ,  
i rrigation , and drainage) or labour-saving (mechanization , herbicides , varieties and 
cropping techniques) characteristics. Where shortage of labour exists, for example 
i n  rice-production areas such as Mal iana and Viqueque,  mechanization for seedbed 
preparation is deemed necessary. The same degree of mechanization may not be 
requ i red , or a different form of mechanization can be employed during the time of 
harvest where, the availabi l ity of labour i ncreases due to the less laborious nature of 
the work, and also because of the increased presence of fami ly labour for seasonal 
festivities . 
When weighing the merits of new innovations, farmers tend to make rational 
decisions (French and Schmidt, 1 985) and traditional farmers in  general , are 
efficient al locators of avai lable resources according to their knowledge of 
technology (Schultz, 1964). As Morris ( 1 985) points out, the justification for 
acqu i ring an improved technology for traditional farmers, to some extent, needs to 
conform to the features of their subsistence mode of farming . Thus the introduction  
of any external intervention to this subsistence setting ,  which causes d isequi l ibri um  
(Schultz, 1 964) ,  has to go  through a learn ing and experimentation phase. By doing 
this in a proper manner, the disruption of the traditional mechanisms can be kept 
min imal and a new equi l ibrium wil l  be achieved . Empirical evidence suggests that 
investment i n  human capital through education enhances early technology adoption  
and promotes greater productivity (Schultz, 1 964) .  The emphasis in  technology 
dissemination, therefore, wi l l  have to shift from communication to education .  
The arduous task ahead i s  to find best management practices to guide the 
technolog ical change, which in the case of subsistence and trad itional communit ies 
may imply cultural adaptations as wel l .  Given the role  of agricultural mechanization 
and i ts important social ramifications, mechanization pol icy becomes an important 
aspect of agricu ltural planning , as has been widely adopted and i mplemented 
worldwide (Clarke , 2000, Rijk, 1 989). For East Timor, a selective mechanization i s  
deemed appropriate , taking into account the traditional farmers' power constraints , 
and avoiding the wasteful and undesirable effects of over-mechanization ,  
particu larly labour d isplacement (Morris, 1 985, Schultz, 1 964) .  
Chapter 7 - GENERAL DISCUSSION: Imp lications of Research Findings to East Timor 256 
Agricultural Development 
7.4 Agricultural  productivity: food pol icy impl ications 
Questions arise on whether such technological innovations and cultural adaptations 
mentioned above should be d i rected to enhance productivity of  certain grain ,  tuber, 
root, staple food crops, or more oriented to cash crops to meet the food security 
needs of the whole population . Three d imensions of food security , namely food 
avai labi l ity ,  accessib i l ity, and uti l ization have been briefly h igh lighted (Chapter 4 ) .  
Because food security concerns primari ly the buying power of ord inary citizens, it i s  
i nseparable with poverty. Furthermore, poverty i n  turn , i s  a problem that can be  
solved only by  profitable and equitable economic development. I n  this context, a n  
appropriate domestic food pol icy may help reduce hunger and poverty. The 
importance of incorporation of the traditional food crops i nto the domestic food 
pol icy is emphasised . 
Literature studies strongly support the close l inkage between achieving food 
security and overcoming poverty. Tweeten ( 1 997) observed that because poverty is  
a function of  the level and d istribution of  national i ncome, food security cannot be  
separated from economic development. Because i t  embraces a much larger top ic  
than merely a crop production issue, i t  is  i n  the realm of  the government to design a 
food policy which encompasses al l the publ ic col lective efforts to influence the 
decision-making environment of food producers, food consumers, and food 
marketing agents (Timmer et al. , 1 983) .  These col lective actions cover a wide 
range of activities from research and extension , the provision of basic 
i nfrastructure, price i nterventions, to land legislation .  
The major issues i n  this regard , i nclude urbanization  and production demand i n  
urban centres, shortage of labour and the need for mechanization ,  and productivity 
growth as i nd icated above . Of these , productivity growth is the umbrella top ic ,  
which i n  the theme of th is thesis ,  covers the productivity of human capital and land 
resources, the two most s ignificant factors i n  agricultural development. Empi ri cal 
stud ies suggest that future productivity growth is l ikely to come from three ma in  
sources : agricultural research , technology transfer systems (extension and  
education) ,  and agricultural support pol icies (Morris and  Byerlee, 1 998) .  For East 
Timor, however, this thesis argues that it is worthwhi le to de-emphasize the 
Chapter 7 - GENERAL DISCUSSION: Implications of Research Find ings to East Timor 257 
Agricu ltura l  Development 
i ntroduction of the h igh yielding varieties (HYV's) seeds ,  al lowing more focus on the 
improvement of local seeds. 
7.5 Paradigm shift towards sustainabi l ity? 
Conservation has been the gu id ing principle ru l i ng the d iscussion of major topics i n  
th is thesis .  The basic phi losophy is that to sustain over t ime the agriculture sector of 
a country such as East Timor, it has to be productive and lucrative, actively 
generated by local human capital and selective imported expertise, while based on 
a jud icious and balanced use of its trad itional environmental resources (MAFP, 
2005). 
Any agricultural system to which the current trad itional system wi l l be transformed 
must be both sustainable and h ighly productive in the future if i t  is to feed the 
growing human population . For this twin chal lenge to be met Poincelot ( 1 986) 
recommended a new approach to agriculture and agricultural development that 
bu i lds on resource-conserving aspects of trad itional ,  local ,  and smal l-scale 
agriculture whi le  at the same time drawing on modern ecological knowledge and 
methods. It is empirically proven that trad itional agriculture, despite its market 
l im itations, can provide models and practices valuable i n  developing sustainable 
agriculture .  The mainstream approach to modernizing agriculture on  the other hand , 
apart from its successes promoted by scientific advances and technolog ical 
i nnovations, has led to dependency on external i nputs, e.g . seed , fert i l izer, 
pesticides, machinery and fossil fuels .  
I n  essence , ag ricultural practices tend to degrade the resource base and the 
challenge for modern agriculture is to min imize this degradation . East T imor, as a 
semi-arid region with low- input technology and resource-poor farmers working i n  a 
h igh ly unpredictable agro-cl imate is particu larly challenged i n  regards to protecting 
the natural resource base . In this context, sustainable agriculture is largely a 
function of, and frequently control led by, socioeconomic cond itions. 
The l i terature also reveals the prevalence of soi l degradation in many agricultural 
production and agroecology systems.  To avert further degradation ,  the soil 
productivity balance must be shifted from degradi ng processes to conserving 
Chapter 7 - GENERAL DISCUSSION:  Implications of Research Findings to East Timor 258 
Agricultural Development 
processes, and more urgently, i n  the fragi le eco-regions and marg inal lands of the 
tropics .  The issue of environment and especial ly soil qual ity is as paramount to 
advanced and soil rich countries as to developing countries with fragi le tropica l  land 
such as East Timor. Whi le research work and support ing resources are generally 
largely avai lable in the former category of countries that is not the case for the latter. 
Due to l imited capital and human resources i n  developing countries, government­
funded research projects are too often single d iscip l ined studies using a top-down 
approach with i nadequate farmer i nvolvement. 
7.6 Soil  and water conservation 
Soi l  and water are the largest resources required for agriculture and need to be 
managed sustainably. Literature and empirical studies also strongly suggest that 
conventional agriculture tends to deteriorate the soi l  and water quality comparatively 
to alternative agricultural practices such as d i rect dri l l  or min imum ti l lage (Chapter 
5) .  I n  the context of East Timor, an improved shifting cultivation practice i n  rotation 
with a better fal low system would guarantee better so i l  and water conservation (see 
Chapter 2) .  
It i s  also relevant to consider suggestions made by Wil l  cocks and Twomlow ( 1 993) 
that t i l lage research and development should give increased attentio n  to: ( i ) 
understanding farmer constraints to rel iable rainfed crop production systems and 
identifying existing and potential technology supply systems avai lable to local 
farmers through a multid i scip l inary approach; ( i i ) creating interim systems that are 
sustainable with existing resources and selective external information and 
technologica l  i nput; ( i i i )  establ ishing long-term ti l lage and agricultural p roduction 
systems that conserve energy (labour and draught power) , water and soil 
resources. 
Experimental results i n  this thesis on the effects of ti l lage and no-ti l lage, i n  
particular, on  the edaphic changes affecting the cropping environment generally 
concur with the findings in the l iterature. They also strongly support conventional 
t i l lage practices causing more water and sed iment erosion than no-ti l lage. It also 
emphasises t i l lage as one of major contribut ing factors to erosion ,  as has been 
Chapter 7 - GENERAL DISCUSSION: Impl ications of Research Findings to East Timor 259 
Agricultural Development 
proven elsewhere, particularly on the undulating to steep and fragi le lands. Despite 
being in the emerg ing phase, these short-term experimental results (Chapter 6)  
ind icate that ti l l age erosion could be  a major source of nutrient losses as wel l  as 
non-point pol lution affecting the soi l  and water qual ity i n  general .  
Whi le a large volume of research data are available on long-term ti l lage research i n  
temperate cl imates and developed countries, short-term experiments such as the 
present study, may well provide sign ificant information to support agricultural pol i cy 
design in  developing countries of the tropics for a sound use of their fragi le  soil and 
scarce water resources. 
7.7 Pol icy impl ications for East Timor agricultural development 
Despite the macro nature of hunger, poverty alleviation,  and environmental 
degradation depicted earl ier in the first chapter and the subsequent economic 
development measures to address these issues on a national scale there are at 
least four major publ ic pol icy components that wil l play vital roles: 
( i )  Agricultural research and development 
This is fundamental and constitutes the core of an agricu ltural and rural 
development system , being at this stage primari ly the role of the government. It 
a ims at researching and identifying farmers' constraints to i nnovation , 
opportun it ies for improvement, and offers solutions to social ly and economically 
beneficial development breakthroughs. Funds and related resources should be 
made avai lable for this purpose. 
( i i )  Agricultural extension and education 
H istorical ly, this has been under the provision of government, however, g iven 
the financial and bureaucracy shortfal ls ,  this trend has to be reversed , al lowing 
greater participation of the civi l  society, particularly the NGOs. In a sense, this 
is  l ikely to be a form of national or domestic networking to d isseminate 
technology information with a gradual emphasis shift from communication to 
education .  
Chapter 7 - GENERAL D ISCUSSION: Implications of Research Findings to East Timor 260 
Agricultural Development 
Education , or investment i n  human capital ,  is the key to any agricultural 
transformation (Schultz, 1 964) .  Therefore , the current agricultural schools i n  
Fu i loro, Natarbora, and Mal iana could wel l  be  gradual ly developed as centres of 
excel lence coupled by the natural ly well-resourced areas in which they are 
s ituated . 
( H i )  I nternational and regional networking 
A systematic agricultural and rural research development and extension 
framework should be put forward to the i nternational development partners' 
forum where key strateg ic development areas can be identified and viable 
channels are created through which exchange and transfer of technology and 
i nformation knowledge can occur continuously. This has been i nitiated , however 
areas of cooperation need to be redefined allowing projects to develop on  a 
more self-sustained fashion especially i n  the long-run basis. 
( iv)  Sh ift of pol icy focus 
Pol icy focus i n  agricultural development needs to be reoriented i n  two major 
ways: firstly, decentralized and broad-based orientation covering the most 
remote vi l lage and community centres. Secondly, conservation agricu lture as 
opposed to production agriculture aimed at securing an environmental ly 
friendly agriculture sector for generations to come. 
7.8 Agenda for future research 
A workable research agenda in the short to med ium term as fol low-up of this study 
may cover three major areas as fol lows: 
( i )  I ntegrated Farming Systems 
This is  primarily aimed at understanding the local and indigenous farming 
practices , ranging from rural technolog ies, farm i ng tools, energy balance, soi l 
fert i l ity management, crop and plant d iversity, weeds and pest control , to 
animal husbandry and forestry management. 
Chapter 7 - GENERAL DISCUSSION:  Implications of Research Findings to East Timor 261 
Agricultural Development 
( i i )  Soi l  ti l lage and erosion 
Ti l lage and erosion trials can be establ ished at specific sites, covering d ifferent 
soil types and cropping systems. This can be on local farms or on purposively 
establ ished sites. 
( i i i )  Appl ied science and technology 
Advanced and complex trials can be i n it iated under this scheme with projects 
such as: food pol icy analysis ,  farm machinery selection and testing ,  soil testing  
and mapping ,  land evaluation and G IS ,  b io-energy technologies, improved 
local seed varieties, adaptive fodder crops for i mproved grazing and pasture 
management, appropriate agro-forestry and soi l and water conservation  
technologies and  cash crop in itiatives. 
Chapter 7 - GENERAL DISCUSSION: Implications of Research Findings to East Timor 262 
Agricultural Development 
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