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Item Seeding depth effects on the performance of wheat and lupin seedlings under no-tillage : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science (Agricultural Machinery) at Massey University(Massey University, 1993) Hadfield, Anthony BarryThe effects of seeding depth on the emergence and performance of many crops under a wide range of cultivated soil types and conditions have been well researched. The same effects under a no-tillage system are not nearly so well covered in the literature and the validity of extrapolation of results between different tillage systems has been shown to be dubious at best. A field experiment was undertaken to compare the performance, in terms of various emergence parameters, of wheat (Triticum aestivum cv. Otane) and lupin (Lupinus angustifolius) sown at target depths of 20, 30, 50 and 70 mm into an untilled seedbed. A secondary aim was to assess the yield performance of wheat. The final factor involved was to assess the effect of the addition of disc scrapers to Cross Slot™ openers with respect to accuracy of seed placement. Emergence parameters assessed included total emergence, rates of emergence and time taken to attain both 5% and 95% emergence (of those seedlings that emerged). Results showed that lupin tended to be planted deeper than wheat at any given opener depth setting and that the addition of scrapers had little, if any, effect either on the sowing depth achieved or on the variability of seed placement, by the opener, around the mean. Scrapers appeared to have very little consequential effect on any of the performance parameters measured, under the conditions of this experiment. The emergence parameters showed a reasonable linear response to increasing seeding depth, especially so in the case of lupin. The variability of total wheat emergence, in particular, at different depths was high compared with lupin. Lupin demonstrated a much higher degree of sensitivity than wheat for almost all emergence parameters. The exception to this was for rates of emergence where relative changes with depth were similar for both species. Fertile tiller numbers decreased with increasing depth at all four depths for wheat. However a high degree of variability in the yield data meant that yield was reduced only at the deepest (70mm) seeding depth. Regression analysis of day-of-emergence as a function of seeding depth of a large number of individual seeds indicated that seeding depth accounted directly for approximately half of the factors affecting day-of-emergence of both wheat and lupin seedlings. These results can be used as a basis for specifying design parameters for seed-drills with respect to the accuracy of depth control mechanisms.Item Tillage-induced soil nitrous oxide fluxes from tow soils in the Manawatu : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Engineering, Institute of Technology and Engineering, Massey University, Palmerston North, New Zealand(Massey University, 2000) Akramkhanov, AkmalEnhanced greenhouse gas emissions of nitrous oxide (N₂O) induced by agricultural practices is believed to be the major anthropogenic source. Studies conducted in New Zealand generally from pasture suggest low N₂O emission, however, there is little information for arable farming systems. Therefore, there is a need for a site-specific assessment of the impact of tillage practices on N₂O fluxes. This paper evaluates tillage system and land use effects on N₂O emissions at two sites using a closed chamber technique. Sites included a Kairanga silt loam where maize/barley was grown continuously for either 17 (K17) or 34 (K34) years, with a conventional tillage system (Kairanga), and an Ohakea silt loam where winter oats and summer fodder maize was double-cropped for five years with conventional (CT) and no-tillage (NT) systems (Massey). At both sites permanent pasture (PP) soil was used as a control. Spatial measurements for all treatments at Massey site showed large inherent variations in N₂O fluxes (a mean CV=119%) which reflected natural soil heterogeneity, and perhaps the measurement technique used rather than the real differences due to the tillage and cropping systems evaluated. N₂O emissions measured from December 1998 to September 1999 from the PP were significantly lower (1.66 kg N₂O-N/ha/year) than the CT and NT plots at 9.20 and 12.00 kg N₂O-N/ha/year respectively. However, there were no differences in N₂O emission rates between the CT and NT treatments. Cumulative coefficient of variation (CV) of treatments ranged from 39 to 140%. Seedbed preparation using power-harrow which was done within few days of ploughing the CT plots reduced N₂O emissions by 65% within the first hour after power-harrowing. However. N₂O emission rates returned to the pre-power harrowing levels one month after power-harrowing. There was strong relationship between log-transformed values of soil moisture content (SMC) and N₂O emissions in all treatments. PP (r = 0.73), CT (r = 0.75) and NT (r = 0.86). Seasonal variation in N₂O emission from the PP was in the order of winter=autumn>summer. Although fluxes in the CT were higher in winter than in the autumn season, there were no differences between the summer and autumn data. Similar to the PP. the seasonal variations in N₂O emission in the NT treatment were in the order of winter>autumn=summer. The estimated annual N₂O emissions from the PP. K17 and K34 (calculated as the mean of all individual closed cover chamber measurements between November 1998 and September 1999) from Kairanga site were similar at 3.24, 3.42 and 2.37 kg N₂O-N/ha/year, respectively. There were large variations in N₂O emissions during the year with the mean flux rates ranging from 0.175 to 13.32, 0.175 to 16.91 and 0.088 to 30.05 kg N₂O-N/ha/year in the PP, K17 and K34 fields, respectively. Although overall comparison of treatment means did not show any discernible differences between management practices, there were signs that the K34 had lower emissions compared to the PP. N₂O fluxes from the K17 and PP field appeared to be influenced by SMC. There is clear indication that low or negligible emissions occur when gravimetric soil water content is less than 30% in the PP. Although N₂O fluxes did not follow the rainfall patterns in the K17 and PP, linear regression analyses indicated low but significant relationship r = 0.46 and 0.53 (0.72 when log-transformed), respectively. In the K34 field. SMC did not seem to govern fluxes which were especially apparent during wet months of April and May. The linear regression analysis using the measured data revealed no relationship (r = 0.12) between the SMC and N₂O fluxes in the K34 treatment. Seasonal grouping of monthly log-transformed N₂O emissions showed significant differences in all treatments. Summer season N₂O emissions in the PP were the lowest than other seasons whereas no discernible differences were observed among other seasons. Although N₂O fluxes during spring and summer were similar in the K17 field, they were significantly lower than the winter and higher than autumn fluxes. There were considerably higher emissions in summer than in autumn in the K34 but seasonal variation between winter and spring was less profound. Spatial variability in N₂O fluxes was large during the year with coefficients of variation (CV) ranging from 10 to 82%, 12 to 99% and 9 to 137% for the PP, K17 and K34 fields, respectively.Item Effect of cultivation on maize response to nitrogen fertilizer : a thesis presented in partial fulfillment of the requirements for the degree of Master in Applied Science in Soil Science, Institute of Natural Resources, Massey University, Palmerston North, New Zealand(Massey University, 2000) Munir, SulhadianaContinuous cultivation of arable soils results in the decline of 'soil quality' in terms of structural degradation and nutrient depletion. It decreases soil organic matter content, induces the leaching and gaseous losses of N through enhanced nitrification and denitrification, resulting in the depletion of nitrogen content of the soils. This will affect N availability, soil moisture retention, soil aeration and the activity of soil microorganisms. The objective of this study is to examine the effect of cultivation on the response of maize to N fertiliser. A glass house experiment was conducted using four soils. The soils included a permanent pasture soil and three maize / barley grown soils which have been cultivated for 6, 17 and 34 years. Maize plants were grown at six levels of N applied as urea (0 - 500 kg N/ha). The dry matter yield response to N application indicated higher maize growth for the pasture soil than for the cultivated soils at all levels of N application. Even at the highest level of N application (500 kg N/ha) the maize dry matter yield for the cultivated soil did not reach that for the unfertilised pasture soil. This indicates that N alone was not limiting the dry matter yield among the cultivated soils. It was hypothesised that the differences in the physical conditions among these soils may also be responsible for differences in dry matter yield. In the second experiment, pasture and the 34 year cultivated soils were incubated with poultry manure for eight weeks. The addition of poultry manure was to improve the physical conditions of the soil. A glasshouse experiment was then conducted to examine the effect of poultry manure addition on the growth of maize at five levels of N (0-400 kg N/ha) applied as urea. There was a clear visual indication of an improvement in the structure of the cultivated soil due to the incorporation of poultry manure. Addition of poultry manure increased the dry matter yields of maize plants both in the cultivated and the pasture soils. The dry matter yield of plants in the cultivated soils (in the presence of manure addition) was higher than the pasture soils at low levels of N application and similar yields were obtained at the higher rates of N application. Oxygen diffusion rate (ODR) values were higher for the pasture soil than the cultivated soil. The addition of poultry manure in the initial stages, however, decreased the ODR values in both soils which is attributed to the increased consumption of oxygen by the easily decomposable organic carbon in the poultry manure. With increasing time after incubation the ODR values slowly increased in the poultry manure treated soils indicating an improvement in soil structure. The study clearly demonstrated that the impact of cultivation on maize yield was partly due to poor soil physical conditions.Item The effects of tillage practices and cropping pattern on nonpoint source pollution and soil quality : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Engineering at Massey University(Massey University, 1997) Guo, PengSoil erosion is one of the most serious environmental problems facing world agriculture. In New Zealand, with the current low financial returns from pastoral-based farming, land which was previously unaffected by soil erosion is being intensively farmed and therefore becoming more susceptible to soil erosion and nonpoint source pollution. Adoption of soil resource management and agricultural practices that seek to conserve soil and water resources and minimise environmental degradation is attracting overwhelming interest among scientists and general public. Therefore, the main objective of this study was to assess the effects of selected tillage practices on soil physical properties, soil and water runoff, and water quality under selected cropping pattern. Experiments were conducted on a Ohakea silt loam comparing crop production (barley and oats double crop rotation) using conventional tillage (MP), no-tillage (NT), and pasture (P) (as a control treatment) and assess their impact on erosion and selected soil properties. It was expected that this relatively heavy soil type would be sensitive to cultivation management systems and was therefore suitable for a comparison of tillage methods. The treatments were arranged in a randomised complete block (RCB) design with four blocks of three treatments. In the field experiment, soil bulk density, water content, infiltrability, penetration resistance and earthworm populations were measured during two cropping seasons after barley and oats crops harvest in March and August 1996 respectively. Generally, these soil properties were significantly (P≤ 0.05) affected by tillage practices. Soil water content, infiltrability, and earthworm populations were similar in the NT and P treatments, but significantly higher than those found in the MP treatment. Conversely, soil bulk density at 0 - 50 mm depth was in the order of MP > NT > P. In the laboratory experiment, soil and water runoff, leachate volume, pH and nutrient losses from soil erosion were measured under a rainfall simulator. "Rainfall" intensity used was at an average application rate of 50 mm/hr for one hour, simulating a rainstorm. Mean data from the two experiments suggested that the surface water runoff and soil sediment in runoff were higher in the MP treatment than in the NT and P treatments, and were in the order of MP > NT = P and in a ratio of 4:1:1 and 30:1:1 respectively. Conversely, the volumes of water leachate were higher for the NT and P treatments than for the MP treatment, and in a ratio of 4:1:1 respectively. Soil pH from both water runoff and leachate was at an average of 7.4 and 7.2 respectively, but not different among the three treatments. Nutrient losses in surface water runoff were found to be significantly higher (P≤ 0.05) in the MP treatment (N=1.45 mg/m2, P=1.02 mg/m2, and K=8.3 mg/m2) than those with the NT (N=0.76 mg/m2, P=0.65 mg/m2, and K=6.8 mg/m2). Nutrient losses from NT and pasture treatments were similar. One year's data including two cropping seasons indicate that conventional tillage practices can result in high surface runoff and sediment loss and adversely affect runoff water quality. Such tillage practices are likely to lead to unsustainable land resource management and decreasing crop yields. On the other hand, conservation tillage practices such as no-tillage and continuous pasture cover reduced soil and water erosion, improved soil physical properties and runoff water quality, and conserved land resources leading to enhanced land productivity and agricultural sustainability.Item Wind erosion in Hawke's Bay : the influence of soil aggregate size and cultivation management on sediment flux : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Applied Science (Natural Resource Management) at Massey University(Massey University, 2000) Eastwood, Callum RThe influence of soil aggregate size and cultivation management on sediment flux of two Hawke's Bay soils was investigated. Hawke's Bay Regional Council initiated, and partially funded, the project after they identified wind erosion as a significant land management issue in their region. Wind erosion was simulated on Pakipaki sandy loam (Typic Sandy Recent Soil) and Takapau silt loam (Typic Orthic Allophanic Soil) soil types using a portable wind tunnel. Three different cultivation treatments were applied to research sites on each soil, with eight replicates of each treatment positioned via a split-plot, randomised block trial design. Treatments were designed to produce a range of soil aggregate size distributions. A minimum tillage treatment was also simulated. At each plot, surface (10 mm depth) soil samples were collected for gravimetric moisture content, soil aggregate size and aggregate stability tests. Surface roughness and vegetative cover were measured only on Takapau plots. The Takapau silt loam plots were very susceptible to aggregate breakdown under cultivation, with only a quarter of soil aggregates over 0.85 mm in size after one pass with the cultivator. Two additional passes did not cause a significant change in aggregate size. Minimum tillage on the Takapau plots lead to markedly lower mean sediment flux rates (0.2 gm -1s-1) compared to one pass with a cultivator (3.4 gm-1s-1). The Pakipaki sandy loam exhibited higher resistance to aggregate breakdown compared to Takapau silt loam. After one pass of the cultivator 50 percent of aggregates measured were over 0.85 mm in size, reducing to 45 and 43.3 percent after two and three passes respectively. Data collected from Pakipaki plots suggest decreasing soil aggregate size leads to increasing erosion rates. The relationship was not significant (P<0.05) primarily due to a high variance in results within treatments. Minimum tillage on the Pakipaki sandy loam also resulted in considerably lower mean sediment flux (0.03 gm-1s-1) than the least cultivated plots (1.8 gm-1s-1). The results highlighted some important implications for cultivation management in Hawke's Bay. Use of conventional cultivation techniques on Takapau silt loam soils should be avoided due to the high risk of aggregate breakdown and the subsequent wind erosion risk. Minimum or no-tillage with maximum retention of vegetative residue is the most appropriate for continued arable farming on such soils. In comparison, soil structural characteristics of the Pakipaki sandy loam soil allow for greater manipulation of aggregate size through cultivation However, the sediment flux measured off Pakipaki plots indicates other wind erosion control techniques, such as windbreaks and stubble retention, should be utilised in conjunction w ith maintenance of large aggregate size to adequately control soil wind erosion.Item An analysis of the effects of field-soil disturbance treatments on arbuscular mycorrhizal fungi : a thesis presented in partial fulfilment of the requirements for the degree of Master of Sciences in Plant Biology, Massey University(Massey University, 2001) Graves, Donald WayneIn soil and root ecosystems the partitioning of carbon is ubiquitously affected by interactions with heterotrophic rhizosphere micro organisms, including the potentially mutually beneficial (+,+) arbuscular mycorrhizal (AM) fungi. However, the existence and sustainable management of AM fungi is threatened by prolonged and or intensive disturbances of soil. Therefore this study set out to explore the relationships between plants, soil fungi and soil disturbance treatments. A containerised bioassay of maize seedlings was used to assess root inhabitation of arbuscular mycorrhizal fungi from samples of Manawatu silt loam pasture field soils, methods were adapted from Brundrett et al (1996). Development of a rapid method to visualise the AM fungal inhabited maize seedling roots was enhanced by an alternative light source on an Olympus SZIII dissection microscope. A 100W-equivalent fluorescent light tube produced less heat, but provided approximately five-fold more illumination than the original 20W Olympus incandescent light bulb. It was found that propagation of maize seedlings during mid to late winter and greenhouse environments with relatively limited light day-length and irradiance levels may have resulted in 'parasitic' (+,-) soil-fungal interactions, or reduced growth of maize seedling plant biomass. Soil fungal parasitism of plant growth was attributed to mutual competition (-,-) for carbon photosynthate resources shared between soil fungi and plant host symbionts. In addition, a Venn-diagram model is proposed with three entities depicting fungal and plant population interactions that include mutual costs and benefits derived from bidirectional exchange of mineral and carbon nutrients as follows; mutualism and protocooperation (+,+); neutralism (0,0); and competition (-,-). Intersecting sets of these entities depict a three-way continuum of population interactions; parasitism or predation (+,-), and prey or host escape (-,+); amensalism (0,- or -,0); and commensalism (0,+ or +,0).Item A study of tillage mechanisms in relation to soil properties and crop growth : a thesis presented in partial fulfillment of the requirements for the degree of Master of Agricultural Science in Agricultural Mechanisation at Massey University(Massey University, 1975) Hughes, Keith AndrewThree tillage systems were compared over the 1973-74 spring-summer season on two trial sites. One trial site was tilled and left to fallow over the winter, while the other was left in pasture. The three tillage systems studied were:- 1. traditional plough/disc/harrow 2. direct-drilling or chemical tillage 3. rotary-cultivation. There were no significant differences between treatmens in the subsequent establishment and yield of dry matter of a crop of chou moellier on the trial site which had been left to fallow. On the non-fallowed site, direct-drilling resuited in a significantly lower number of plants compared to the other tillage treatments. Despite this, dry matter yields were highest on the direct-drilled plots and lowest in the rotavated treatment. Soil which had been direct-drilled remained the most stable as determined by wet-sieving of soil samples. Soil stability under the rotavated treatment appeared to decrease to a greater extent than under ploughing as the length of time out of pasture increased. Dry-sieving of samples showed the same effect. The rotary cultivation treatment resulted in the greatest proportion of soil in the smaller aggregate size fraction (less than diameter 1.676mm). Differences between tillage treatments were also observed in soil resistance as measured by a penetrometer, and resistance to wheel compaction between the non-tilled and the two mechanically tilled treatments. In general the ploughed and rotary-cultivated soil required a lower penetrometer force than the undisturbed direct-drilled profile. On the tracked areas, increase in penetrating force of the two mechanically tilled plots was on average 12 times the increase on the direct-drilled plots. It is probable that soil moisture levels were not affected by cultivation treatment. Differences which occurred, particularly in the non-fallowed trial, were thought to have been an effect of differences in plant density-soil water loss increasing with plant density. Data from the two trials showed that total fuel consumption for direct-drilled and rotary cultivated treatments to be 9.7 and 1.9 times respectively, less than the traditional ploughing treatment. This did not include the fuel requirements of weed control, which varied between treatments.Item Effect of method of tillage on loss of carbon from soils : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Soil Science at Massey University, Palmerston North, New Zealand(Massey University, 2012) Ghatohra, Amandeep SinghSoils represent the largest terrestrial carbon (C) pool. Different tillage practices have been shown to result in variable losses of soil C. Among these, No-tillage is regarded as an effective management practice for conserving SOC and reducing soil CO2 emissions. Overseas research shows that No-tillage practice could reduce CO2 emissions by approximately 3 Mg CO2 ha-1yr-1. Quantitative information comparing soil CO2 emissions with No-tillage and conventional tillage is limited in New Zealand. Furthermore, little quantitative information is available on the effect of soil and climatic conditions in modifying these emissions. This Ph.D. study evaluated the potential for Cross Slot® No-tillage cultivation to reduce CO2 emissions from cropped soils in New Zealand conditions. A series of preliminary experiments were conducted to establish a suitable chamber method to collect and measure CO2 emissions from soil. The alkali trap method was selected for use in traditionally cultivated agricultural soils. Another experiment was conducted to test whether pressure fluctuations caused by wind velocity differentially influence soil CO2 emissions from conventionally and Cross Slot® No-tillage cultivated soils. Carbon dioxide emissions from conventionally cultivated soils rapidly equilibrated to the onset of lower (negative) pressure, whereas CO2 emissions from No-tillage soils took longer to equilibrate. Experiments on the potential savings of soil C with Cross Slot® No-tillage cultivation (NT) compared to simulated tillage, measured in the laboratory showed reduced (between 113 and 393 kg CO2-C ha-1) CO2 losses in three out of four soils. This reduction in CO2 losses was further verified with measurements made for one of the soils at a field site during autumn and summer seasons. Overall the results of field studies suggest that Cross Slot® No-tillage cultivation reduced ~3.0 Mg CO2 ha-1 compared with rotary tillage for combined autumn and summer sowings i.e. two cultivations. A subsequent laboratory incubation study assessed CO2 loss with different levels of residue addition to the four soils used in the previous laboratory and field experiments. A number of labile C fractions extracted from these soils were measured in an attempt to predict CO2 losses. These did not show any relationship with the CO2 respired during the incubation period. It was, therefore, not possible to develop a soil test to predict CO2 losses using these extractions. Modelling laboratory CO2 respiration data for predicting the CO2 losses from conventional and No-tillage soils was explored using relationships between short-term CO2 respired and total CO2 loss. The model developed from laboratory incubations was further improved with parameterising the soil temperature and moisture effects. The temperature and moisture sensitive model was used to predict the CO2 emissions measured during the summer season. The model precisely predicted the amount of C lost from No-tillage soils but the amount predicted for rotary tilled soils was 30 per cent less than the amount of C that was lost in the field. Moreover, the model predicted C loss was higher for the No-tillage soils than the rotary tilled soils which was contradictory to the findings from the field study. Therefore, further work is required as the data obtained during this Ph.D. study was insufficient to provide, or develop a model that could be used to predict CO2 loss from conventional and No-tillage cultivation in New Zealand soils.Item The effects of drill coulter designs on soil physical properties and plant responses in untilled seedbeds : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy at Massey University, Palmerston North, New Zealand(Massey University, 1978) Mai, Tran VanDuring the process of direct drilling different shaped drill coulters have been observed to create different micro-environments at the seed zone. This study has been to examine possible changes in soil structure and the state of soil compaction around the groove, which in turn might affect root penetration. Several methods and pieces of equipment were developed to investigate the influence on the soil of two contrasting coulter shapes. These were the commercially-available triple disc coulter and an experimental chisel coulter. To measure soil bulk density in the drilled groove zone, a small core sampler was designed and tested. Soil strength was assessed using a modified multi-point penetrometer which could be inserted vertically into the soil or normal to the groove walls. The instantaneous and permanent soil pressure zone of influence around the groove, which was created by the passing of the coulters, was monitored using a liquid-filled tube with a terminal diaphragm and a minipressure transducer. Macroscopic visual assessment of the compaction of soil at the seed level was undertaken using a freezing sampling technique which facilitated thin section subsamples to be studied by photographic techniques. In addition, 3 mm3 subsamples were taken directly from the grooves for electron microscopy study. Supplementary measurements included draft force and the coulter-passage-disturbance-zone at the soil surface using a load cell and a displacement transducer respectively. Wheat and lupin seeds were sown to study the effects of soil changes on root growth of a fibrous and tap root system. The data suggested that the triple disc coulter tended to compact well-defined zones around the groove while the chisel coulter produced no apparent compaction. Such soil compaction in a moist silt loam of initial bulk density less than 1.1g/cc did not result in any apparent differences in plant root responses between the two coulter types. In a drier, harder soil however (greater than 1.32g/cc) there appeared to be a clear disadvantage from use of the triple disc coulter in this respect. With lupin, root growth was restricted and deformed from use of the latter coulter, while in the case of wheat, seedling emergence was restricted in comparison with the chisel coulter. Smearing was found on the groove wall in moist soil with the triple disc coulter but the experiments were not able to show any mechanical restriction to root and plant development arising from the smear. In the field conditions, in contrast to the laboratory conditions (where seedling performance and root growth were better with the chisel coulter in almost all of the tested conditions except with moist and loose soil where it was equivalent to the triple disc) any localised compaction of soil by the triple disc coulter (particularly at and near the base of the groove) appeared to be compensated by other factors (weather, earthworms etc.) during the plant's full growth cycle. Compaction and mechanical impedance in isolation did not appear to be solely responsible for the root and plant growth responses. A physiological study of soil moisture transport process and soil water vapour availability in the seed zone should therefore be the subject of further studies.Item 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(Massey University, 2006) Viegas, Edmunda da Silva SoaresThe prospects of sustainable crop production technologies in East Timor were discerned 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 discussion on the aspects of agricultural mechanization and technological change and their socioeconomic ramifications on food security. Empirical data from tillage trials, established both in East Timor and New Zealand, were gathered and discussed in the quest for a better understanding of tillage effects on soil structure and crop production environment. The agro-climatic zones of East Timor provide a well-defined set of ecological boundaries upon which further collaborative research work can be developed. Given land resources as one of the major capital investments in agriculture development, the drive towards improvement and technical change in agriculture should be directed in a balanced combination, whenever appropriate, between technologies of land-saving (hybrid seeds, irrigation, and drainage) or labour-saving (mechanization, herbicides, varieties and cropping techniques) characteristics. Moreover, the justification for acquiring 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 dissemination, therefore, will have to shift from communication to education. Experimental results of this study on the effects of tillage, and no-tillage in Particular as a form of conservation tillage, on the edaphic changes affecting cropping environment generally concur with the findings known in the literature. Organic carbon levels are generally restored with cropping in East Timor. In addition, soil bulk density and crop grain and biomass yield were not affected by tillage treatments. Soil compaction was significantly affected by tillage as shown by data from the Palmerston North experiment. Soil aggregate stability in the 0-10 cm topsoil was similar under all the tillage treatments. Manual tillage (MT) had the greatest number of soil aggregates on sieve after a 30-minute wet-sieving (68.3%) followed by no-tillage (NT) (65.1), permanent pasture (PP) (62.6) and conventional tillage (CT) (56.5). Similarly, the top 0-10 cm soil under MT had significantly larger macroporosity (16.4%) than CT (9.23), NT (11.5), and PP (10.6). MT and CT significantly reduced the total C whereas N levels were significantly decreased by tillage (CT, MT and NT) compared to permanent pasture at the top 0-10 cm soil layer. Barley grain and biomass were unaffected by tillage whereas potato tuber yield and biomass were significantly less under no-tillage. Conventional tillage significantly increased water runoff but produced less leachate compared to no-till and permanent pasture. Total soil sediment loss was significantly lower under PP (95.8 kg/ha) and NT (132.9) compared to CT (3556.7) and MT (4652.2). pH of water runoff was significantly reduced under tillage treatments compared to that from permanent pasture whereas nitrogen losses were unaffected. There are at least four major public policy components that will play vital roles in the development of sustainable crop production technologies in East Timor: (i) Agricultural research and development (ii) Agricultural extension (iii) International and regional networking (iv) Shift of policy focus. The policy approach needs to be decentralized 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) Integrated Farming Systems (ii) Soil tillage and erosion (iii) Applied science and technology. The last component may cover disciplines such as: food policy analysis, farm machinery selection and testing, soil testing and mapping, land evaluation and GIs, 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 initiatives.