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Item The influence of cultural practices on soil organic matter, soil biomass size and nitrogen leaching : a thesis presented in partial fulfilment of the requirements for the degree of Master of Agricultural Science (Agricultural Environmental Science) at Massey University, New Zealand(Massey University, 1994) Mapfumo, PhillimonThe effects of bare fallow, cultivation and nitrogen application on soil organic matter, soil biomass and nitrogen leaching were compared against the backgrounds of permanent grass pasture and grass/clover pasture. Cultivated plots were dug annually to a depth of 15cm. All plots received an annual dressing of 300kg ha·1 of Potassic Super. The Nitrogen treatment was applied as two equal applications of 100kg ha·1 Calcium Ammonium Nitrate in November and December each year. The results indicated that both bare fallowing and cultivation reduced soil organic matter and soil microbial biomass. The use of N-fertilizer did not promote either the soil organic matter or soil microbial biomass; this is contrary to the general finding. Legume nitrogen was found to leach as readily as the applied nitrogen and hence posed an environmental threat to groundwater quality. In all cultural practices the largest concentration of nitrate nitrogen (NO3-N) was observed at the 50 - 100m depth, below the root zone. Vertical movement of groundwater was estimated at lm year·1 This confirmed the concern of possible groundwater pollution by nitrate nitrogen from agricultural activities.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 Inrteractions [sic] between farm effluent application methods, tillage practices and soil nutrients : a thesis presented in partial fulfilment of the requirements for the degree of Master of Applied Science in Agricultural Engineering at Massey University, Palmerston North, New Zealand(Massey University, 1998) Hoang, SonLand disposal of liquid effluent has benefits for the environment and is economically viable. Firstly, it can reduce nutrient levels from wastes polluting waterways. Secondly, the land application of effluent has been the most common treatment method because it can provide some necessary nutrients for plant growth. In New Zealand, land application of farm liquid effluent is a common method for disposing agricultural wastes. However, there is little comparative information about nutrient recycling in soils treated with effluent using surface application or subsurface injection. A field trial was conducted to examine the effect of tillage on the transformation of nutrient added through dairyshed effluent. Liquid effluent was either injected at 10 cm depth or broadcast on the surface at the Massey University long-term tillage experiments which include permanent pasture, and crops sown with no-till and conventional tillage as main treatments. In the first experiment, raw dairyshed liquid effluent was applied in August 1997 at the rate of 120 m 3 ha -1 (30 kg N ha -1 equivalent). This was considered as a low rate of application. In the second experiment starting in December 1997, the application was at the rate of 600 m 3 ha -1 (150 kg N ha -1 ). At this rate, although the hydraulic loading was considered as a high rate, the nutrient loading was considered optimum. Soil samples were collected before application, after one week, one month, and two months of application, at two depths: 0-10 cm and 10-20 cm and the samples were analysed for total N, total P, NO 3 - , NH 4 + , exchangeable K, available Olsen-P. Throughout the experiments, interactions between nutrient status, methods of application and different tillage practices were analysed. In the case of injection method, soil samples were taken both in the centre of the injected row and 10cm horizontally away from the centre of row. At the low rate of application (first experiment), soil nitrogen and phosphorus status did not change significantly for up to two months after application. Soil ammonium concentration reduced immediately after one week then reduced slowly. Nitrate concentration reduced slowly during the first month and significantly reduced during the second month after application. Exchangeable K and Olsen-P were not significantly different among treatments. At the high rate of application (second experiment), levels of soil nitrogen and phosphorus reduced slightly after two months of application. Nitrate concentration in the soil increased in the first month, but steadily reduced during the second month. On the other hand, ammonium concentration reduced gradually over a period of two months. Ammonium in injected plots was higher than that in the broadcast plots. Pasture retained more ammonium concentration compared with no-till and conventional tillage plots. Moreover, nitrate content in the injection plots was similar to that in the broadcast. This may be related to low rainfall during the experiment period that may have restricted the denitrification and reduced nitrate losses through leaching. Generally, there was higher content of exchangeable K and available P in soil which resulted from effluent application. Method of effluent application had no effects on K and P concentrations. Overall, there was an increase in nutrients in soil after application of liquid effluent, especially at the topsoil. There was a greater retention of nutrients in no-till soil than the conventionally tilled soil. Subsoil injection of effluent allowed higher level of nutrient retention than the surface broadcast method. This may be due to reduced nitrogen losses caused by volatilization of ammonium.Item An evaluation of the Land and Environment Planning toolkit for advancing soil and nutrient management in hill country and steepland farm systems : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Soil Science at Massey University, Manawatu, New Zealand(Massey University, 2013) Synge, KateThe Land and Environment Planning toolkit recently re-launched (December 2012) by Beef + Lamb NZ is a package developed to assist the sector with resource and business planning. The toolkit has three levels, from an introductory (Level 1) through to more advanced Levels 2 and 3, each providing a step-by-step guide to assess farmers’ with on-farm land and environment issues and includes a framework to address the management of these issues. To date the evaluation of the toolkit has been very limited. It has not been critiqued as a tool for advancing sustainable nutrient management. In this study a multi-disciplinary approach was taken using both quantitative and qualitative methods, including a case study and interactive workshops, to determine the utility and value of each of the three levels of the Beef + Lamb NZ Land and Environment Planning Toolkit (LEP) for advancing nutrient management. The research included a case study (farm interview) and interactive workshops, to determine the utility and efficacy of each of the three levels of the LEP toolkit and whether they progressively add the elements, flexibility and rigour necessary to address the current and future drivers that will shape sustainable nutrient management (SNM) for hill country and steepland farm systems. Primary data was collected during the fieldwork and interviews on the case farm, and during the LEP workshop meetings and immediately following through interviews. Data was analysed separately against each of the three key drivers identified in the literature review (freedom to operate, nutrient use efficiency and ability to demonstrate sustainability) using a framework developed as part of the study. Data collected as part of the analysis of the utility of each level of the toolkit was coded and grouped according to the degree the information obtained assisted in addressing the elements identified in each of the three driver identified for advancing soil nutrient management. The research findings concluded that the introductory (1a and 1b) levels of the toolkit proved useful as a desktop investigation that allowed the identification of factors influencing environmental issues, but offered little assistance in developing tailored solutions. The research findings recommend that Level 1 is used as an introductory package, with a pathway to Level 2 built into the initial conversation. Levels 2 and 3 proved more useful in advancing nutrient management by assisting with resource mapping and planning, but it was Level 3 that provided the most utility for addressing all the drivers of sustainable nutrient management (i.e. Freedom to operate, nutrient use efficiency and demonstrated sustainability). This was largely through the use of a highly detailed and comprehensive analysis and review of the farm’s resources, nutrient budgets, strengths and weakness analysis for the LUC classes identified for the farm and greater level of interaction between the farmer and the land use experts. Although it was highlighted that the Level 3 evaluation might not be comprehensive enough to achieve further growth or deal with the issues at hand, further investigation into the land resources and the linkages between nutrients and the landscape is required. The findings of this research will give an indication of the utility of the toolkit, and identify, if necessary where modifications can be made to improve utility and reporting, not just for the farmer but also for the Sheep and Beef sector. The findings from this research also supported the use of the LEP toolkit as a stepwise approach, and find that any programme (LEP Level 1, 2 and 3) needs to be simple enough for the lower end of farmers to buy in and not be intimidated, whilst providing a framework for a natural progression of stages for the farmers to continually improve through the completion for each level of the toolkit, as well as a final level that has sufficient rigour to produce a robust defendable nutrient management tool. Several recommendations for the future development for the LEP toolkit are made. Investigate the possibility of combining Level 1 (1a and 1b) with Level 2 as a single exercise. Within the same workshop, Level 1 would be used as an introductory step to the completion of the Level 2 farm plan. Greater integration of the Level 3 with other farm planning tools has the potential to extract greater value from the information collected and analysis as part of the process of developing the plan, but also the opportunity to better integrate resource management into the business planning cycle. An integrated farm planning tool would increase the utility of the toolkit by allowing the SNM issues to be considered alongside all the other drivers influencing the business. The addition of these proposed modifications for the toolkit would not only be of benefit for the farmer undertaking the LEP toolkit evaluation but also for continuing to extend the overall knowledge of the industry and Sheep and Beef sector as we move into a more environmentally aware and agriculturally sustainable future.Item Nutrient management plans and their influence on the farm management practices of dairy farmers : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Environmental Management, Massey University, Palmerston North(Massey University, 2013) Neal, GavinNutrient Management Plans (NMPs) are a relatively recent innovation in the New Zealand dairy industry, however due to their growing use in regional council policy, and initiatives such as the Dairying and Clean Streams Accord (2003), it is likely that NMPs will become mandatory for the diary industry in the near future. There is currently limited information on the use and benefits of NMPs in the New Zealand context, and how dairy farm management practices have been influenced by the introduction of NMPs. The main objective of this research was to investigate how the introduction of an NMP has influenced the farm management practices of dairy farmers. This was achieved through the use of two case studies within the Waikato and Otago regions. These regions have contrasting approaches to nutrient management; The Waikato Regional Council has incorporated the use of NMPs in regional policy and has supported a number of community initiatives regarding nutrient management. In comparison, at the time of the research, the Otago Regional Council, while stating that they promoted the adoption of nutrient management practices, had no current policy requiring NMPs. Results indicated that the degree of NMP uptake varied amongst farmers, depending on a variety of influences with regards to the farmer’s own unique goals, circumstances and opinions. It was also found that while the reasons for NMP introduction varied amongst the farmers interviewed, the overall influences of NMPs on farm management practices were similar across both cases. The key influences of NMPs on farm management practices were; the increased precision and efficiency of fertiliser application, an increased appreciation and use of effluent as a nutrient source, and the identification and manipulation of other factors such as the effects of bought in feed and stock movement on nutrient flows on the farm. There was a perceived lack of ongoing support and education for farmers regarding NMPs. This contributed to a general distrust amongst farmers of NMPs, in turn affecting their opinions, and uptake of NMPs. Furthermore NMPs were not being used to their full potential by the majority of farmers who participated in this research. The greater the involvement and support offered by the regional council and industry, the greater the trust and cooperation amongst the particular farmers with the relevant regional council and industry representatives. Overall, while this research has found that NMPs do provide benefits to farmer’s management practices, further support and ongoing education is required to ensure NMPs are accepted and used to their full potential by dairy farmers.Item Developing sustainable soil fertility in southern Shan State of Myanmar : 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, 2001) Tin Maung AyeLiterature review and a farm survey results indicated that the productive capacity of the Red Earths and Yellow Earths (Acrisols in FAO/UNESCO system) in Southern Shan State, Myanmar, continues to decline as poor, near-subsistence, farmers usually fallow-crop these soils and are unable, for economic reasons, to provide the necessary fertilisers and crop management strategies that could improve and maintain soil fertility. This thesis reports on investigations undertaken to determine ways in which the fertility of these soils can be improved in an economical and sustainable manner. A preliminary soil survey confirmed that soils of the Southern Shan State study area had low soil P status, low pH, low SOM (low reserves of N, P and S) and low base saturation, which are likely constraints to crop production on these marginal soils. A farmers' survey indicated farmers were aware of the P availability and soil acidity problems, however, they use low levels of N, P, K fertilisers, green manure and liming material because their economic margins were insufficient to buy expensive P fertilisers and liming materials. Preliminary glasshouse trials were conducted to establish the key soil fertility constraints. These trials included testing the P responsiveness of crops (pigeon pea (Cajanus cajan), rice bean (Vigna umbellata) and upland rice (Oryza sativa L)), the influence of liming materials on legume growth (black gram (Vigna mungo), cowpea (vigna unguriculata), kidney bean (Phaseolus vulgaris), lentil bean (Culinaris lentil), pigeon pea, soybean (Glycine max), stylosanthes (Stylosanthes quyanensis)), and the effectiveness of green manures for building SOM and P reserves in the Red Earths and Yellow Earths. The glasshouse trials confirmed that low P status is the factor most limiting to crops particularly legumes grown in the Yellow Earths. Upland rice, however, did not respond to added P suggesting that upland rice may not be a suitable test plant for evaluating the relative P effectiveness of fertilisers in the Red Earths and Yellow Earths. This pot experiment with the upland rice trial also demonstrated that indigenous Myanmar phosphate rock (MPR) and Farmyard manure (FYM) were ineffective P sources for raising soil plant-available P in the short-term. Local dolomite, however, was an effective liming material and when added with P enhanced the nodule formation of pigeon pea. Laboratory incubation studies showed that incorporating organic amendments (FYM, pigeon pea and upland rice residues) into the Red Earths and Yellow Earths significantly increased soil organic C, improved soil pH buffering, increased the total P content and increased labile-P fractions that could be used for plant growth. The Walkley and Black organic C determination can be used as a suitable 'low tech', portable method for the determination of organic C to monitor soil organic matter levels. Based on the results from the preliminary glasshouse trials, field trials were designed to establish relationships between P fertiliser form, application rate and soil P test levels for maize (Zea mays) and legumes (rice bean and black gram) grown in a Yellow Earth. In soils with initial Olsen-P values of approximately 8 kg P kg-1 soil, two maize field trials consistently indicated that near maximum yield (90%) of maize can be obtained by application of water-soluble P fertiliser (Triple superphosphate, TSP) at 40 to 50 kg P ha-1 in year one and reapplication of TSP at 25 kg P ha-1 in year two. Phosphate supplied as FYM, Tithonia diversifolia, Chinese partially acidulated phosphate rock (CPAPR) and Sechura reactive phosphate rock (SPR) were agronomically less effective as short-term P sources for maize than TSP, with TSP substitution ratio of 0.1, 0.17, 0.61 and 0.07 respectively at an application of 40 kg P ha-1 rate. A legume-wheat rotation field trial showed that rice bean (the legume) yield was significantly increased by the application of TSP at 40 kg P ha-1 plus local dolomite. Subsequently, rice bean plots fertilised with 40 kg P ha-1 as TSP produced the largest wheat grain yields in the Yellow Earth. In all trials the Olsen-P test was a suitable soil P test for providing an index of plant-available P. Olsen-P values at which optimum crop growth occurred (90% maximum yield) ranged between 30 to 40 mg P kg-1 in the Red Earths and Yellow Earths, depending on the season, plant age when harvested and crop grown. Use of the sulphuric acid acidulated CPAPR and elemental S (S°) with SPR confirmed that plant growth in the Yellow Earths was very responsive to sulphur application. Chinese PAPR can be used as a cost-effective P and S fertiliser to increase the crop yield in these Red Earths and Yellow Earths, particularly where S is also deficient. Use of local dolomite (2.5 t ha-1) in the field trials caused significant increases in soil pH in the first season and in the legume-wheat trials resulted in increases in legume yield. The research findings on soil P testing, alternative P sources and liming materials presented in this thesis are discussed in terms of the role they might have in the establishment of sustainable agriculture practice in Southern Shan State, Myanmar. Future research directions that should be taken to realise the productivity of these soils and farming systems are also discussed.