Thesis (doctoral)--Swedish University of Agricultural Sciences, 2000. / Includes bibliographical references.

Please read the abstract in the section, 00front of this document / Dissertation (M Inst Agrar (Land-Use Planning))--University of Pretoria, 2008. / Agricultural Economics, Extension and Rural Development / MInst Agrar / Unrestricted

Thesis (M.Sc. Agriculture (Pasture Science)) -- University of Limpopo, 2021 / Finger millet (Eleusine coracana) is believed to be adapted to the arid and semi-arid regions, highly tolerant to pests, diseases and drought. It has the potential to produce a high forage biomass with fewer inputs under good production practices. The aim of the study was to evaluate the potential of finger millet as a fodder crop on the Pietersburg Plateau under rainfed and irrigation conditions, planted in rows and broadcast. The study was conducted for two consecutive seasons (2017 and 2018) at the Syferkuil Experimental Farm (SEF), University of Limpopo. Treatments consisted of two watering treatments (irrigation and rainfed) and two planting methods (broadcast and row planting). Seeding rate was 10 kg ha-1 with the inter row spacing of 25 cm. Irrigation had a significant effect on the dry matter production of finger millet (P ≤ 0.05). During 2017 growing season, under rainfed condition, the crop experienced zero production due to low rainfall. The total dry matter production of finger millet under rainfed conditions in 2018 was 3371 kg ha-1 for row planting and 3770 kg ha-1 for broadcasting. The dry matter production of finger millet under irrigation and row planting was 5318 kg ha-1 compared to 3371 kg ha-1 produced under row planting in the rainfed conditions. Broadcasting under irrigation produced 4890 kg ha-1 whereas broadcasting under rainfed conditions yielded 3770 kg ha-1. Planting method had no significant effect on the dry matter production of finger millet (P ≤ 0.05). The total dry matter production in 2017 was 5668 kg ha-1 and 5122 kg ha 1 under row planting and broadcast respectively, 2018 season produced the total dry matter production of 5122 kg ha-1 under row planting and 4892 kg ha-1 under broadcast. Finger millet planted under rainfed in rows had the CP% of 14.76 and 16.87% when broadcasted. In all the treatments CP% was higher than 10%. The ADF% was 33.02% under rainfed conditions and it ranged between 30.99% and 31.53% in 2017 and 2018 for row planting under irrigation. Finger millet can be considered an alternative fodder crop for livestock farmers in the Pietersburg Plateau

Please read the abstract in the 00front part of this document Copyright 2004, University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. Please cite as follows: Bayu, W 2004, Growth, development and yield responses of sorghum to water deficit stress, nitrogen fertilizer, organic fertilizer, and planting density, PhD thesis, University of Pretoria, Pretoria, viewed yymmdd < http://upetd.up.ac.za/thesis/available/etd-09202006-093510 / > / Thesis (PhD (Agronomy))--University of Pretoria, 2004. / Plant Production and Soil Science / unrestricted

Historical ecology is an emerging and interdisciplinary field that seeks to explain the changes in ecosystems over time through a synthesis of information derived from human records and biological data. The methods in historical ecology cover a wide range of temporal and spatial scales. However, methods for the more recent past (about 200 years) are largely limited to the human archive and dendrochronological evidence which can be subject to human bias, limited in spatial extent or not appropriate for non-forested systems. There is a need to explore new methods by which biological data can be used to understand historic vegetation and disturbance regimes over the recent past especially in arid ecosystem types. Soil phytolith analysis has the potential to provide much needed information regarding historical conditions in both areas. Phytoliths are structures formed in plants through deposition and accumulation of silica within and around cell walls that are released from plants and preserved in sediments long after death and decay of plant material. The City of Rocks National Reserve in southern Idaho was an excellent place to develop new methods in historical ecology because the human records of historic environmental conditions were so rich. There were two overarching and interconnected objectives for this dissertation research. The first was to reconstruct an ecological history of the City of Rocks National Reserve from the period of overland emigration to present. The second objective was to explore the utility of soil phytolith analysis for inferring vegetation and disturbance regime change over the recent past by testing its sensitivity to record known changes. I employed modern analogue studies, a multi-core approach and detailed core analysis to test for known changes through analysis of extraction weights, relative abundance of phytolith assemblages, microscopic charcoal and burned (darkened) phytoliths. My results showed that this combination of history and soil phytolith analysis would be a useful approach for inferring vegetation changes (e.g. increases in introduced grasses) and disturbances (e.g. fire) in ecological histories.

Diss. (sammanfattning). Umeå : Sveriges lantbruksuniv. / Härtill 5 uppsatser.

Thesis (M.Sc. Agriculture (Soil Science)) -- University of Limpopo, 2022 / Soil health support crop production and answer to its sustainability and renewability. This study involved the use of under explored legumes in South Africa, Limpopo under maizelegume intercropping systems as a strategy to mitigate soil quality deterioration. The study was conducted at University of Limpopo (Syferkuil) and University of Venda (UNIVEN) Experimental farms during 2020/2021. A split plot experiment, with the main factor comprised of water regimes (irrigation and rainfed) and second main factor included cropping systems (Intercropping and monocropping). Five treatments comprised of 3 monocrops (Maize, Chickpea, and Mungbean) and 2 intercrops (maize-chickpea and maize-mungbean) replicated three times. Data collected from the soil before planting and after maturity were pH, Electrical conductivity (EC), particle size, bulk density, aggregate stability, organic matter (OM), organic carbon (OC), phosphorus (P), ammonium (NH4-N), nitrate (NO3—N), soil active carbon (SAC), and potentially mineralizable nitrogen (PMN). Plant parameters collected during vegetative and flowering stage included plant height, chlorophyll content, plant vigour, and leaf area index. All data was subjected to descriptive statistics and analysis of variance using GenStat software. Significant effect (p<0.05) was observed between treatments on soil pH (KCl), OM, organic carbon (OC), and ammonium (NH4) at Syferkuil Farm. Also, interaction between water regimes and cropping systems affected NH4 and pH (KCl). Cropping systems had significant effect (p<0.01) on pH (H2O), OM, OC, P, NH4, and NO3 at UNIVEN. Interaction between water regimes and cropping systems affected (p<0.01) pH (H2O), P but no significant effect was observed on OC, NH4, and NO3. Cropping systems and interaction at both locations did not affect particle size, bulk density, aggregate stability, EC, SAC, and PMN. Pure stands of maize and legumes had greater plant height, plant vigour, and chlorophyll content whereas intercrops had greater LAI. The results at both locations revealed that legume intercropping systems improved soil health variables without posing negative feedbacks and hence can be used to boost soil functioning. Keywords: Soil health, maize-legume intercropping, soil quality / National Research Foundation (NRF)

Thesis (Ph.D. (Geography)) -- University of Limpopo, 2020 / Agriculture in South Africa, particularly in the summer rainfall areas, faces the challenge of optimal crop production in the face of climate change. Climate change scenarios for South Africa have been predicted to have a negative impact on agriculture particularly in the summer rainfall areas because of its dependence on climate variables. Within the context of the South African agricultural sector, it has become important to identify who and what is most vulnerable to impacts of climate change, so that support for adaptation can be targeted appropriately. The aim of this study was to assess the hazard of climate change in relation to the production of selected dryland crops, namely: sunflower, soybean, and groundnut in the summer rainfall areas and to model their vulnerability and response to climate change as well as to develop coping and adaptation strategies. A survey of 800 farmers was carried out in three agro-ecological zones of Limpopo and Free State. The population was purposively selected and were present for focus group discussions and questionnaire administration. Questions on agronomic practices, cost of production, climate change impact on productivity, coping and adaptation methods used in the face of climate change were asked. The response showed that farm production was not at the optimum, not only because of the influence of climate but as a result of the poor agronomic practices by the farmers. Following a factor analysis, 70% of the decline in crop yield was attributed to poor farming decisions. A further look at climatic factors affecting farmers indicated that frost with a 0.989 loading was the most climate extreme affecting most of the farmers. In order to buffer the effects of climate change, the farmers undertook various changes in their farm management and also received some support from the various governmental and non-governmental institutions. It was however, found that though there were policies in place for farmer support, such supports were not administered in a timely fashion and some support types were not adequate for the farmers. A correlation between the number of supports received and yields showed an increase in yield for farmers who received more than one type of support and with such variations evident across the agroecological zones. Physical modelling was conducted to model crop suitability based on downscaled data from the Special Report on Emissions Scenarios A2, (SRES A2) for the time periods centred on 2020, 2050 and 2080. The results showed areas which were not suitable for either soybean, sunflower or groundnut production in the future over time with some areas gaining and losing under different farm input regimes. To establish the effects of climate change on yield, a field experiment was carried out for two consecutive seasons and the results obtained were used to feed the AquaCrop crop simulation model to model the effects of climate change on yield under different management conditions.The results obtained from the survey, field experiments and climate indices guided the development of vulnerability indicators in a spatial manner. Using the socioeconomic and biophysical results, the vulnerability of the summer rainfall area was calculated. The results showed that areas in Limpopo, North West, Eastern Cape, and Northern Cape were the most vulnerable. Based on the types of adaptation options employed by farmers which included a change in planting dates, employing support from institutions, other sources of income, farming practices and recommendations for future adaptation, various scenarios were run in a crop simulation model to determine the cropping regimes suitable for the study area. Options included technology, on-farm management, out of farm management, human and social factors. The results indicated that coping and adaptation measures are place specific and the effects of a climate extreme are felt differently by different farming communities and farmers in the same community. It is hence recommended that the government in its policies towards alleviating the risk of farmers to climate change should look at site-specific options and not a one model fits all. Farmers should also play a role in enhancing their adaptive capacity as well. It is only when barriers are bridged and a proper network of communication established alongside resource provision, will there be a change in farmer’s attitude toward implementing suggested adaptation options. / University of Limpopo VLIR-IUC

Many agricultural communities have developed in Utah since the first settlement, but many no longer exist today. Some of these early communities experienced a "boom and bust," while others struggled for several years and were eventually abandoned. Johns Valley is a good example of these historic communities, as it experienced rapid growth and times of success and prosperity, yet it struggled and was eventually abandoned. The situation in Johns Valley, from its early settlement to its demise, demonstrates the hope of the people who settled there and their efforts to make Johns Valley a productive and successful area. History also shows the growth of the area and the development of communities, with schools, churches, businesses, and other institutions - as was the case with most historic agricultural communities of Utah. Despite the hope and hard work, these agricultural communities could not overcome the environment, or other factors that led to their demise. Dry farming was the main source of economic activity in Johns Valley and farmers had to rely upon adequate precipitation for crop growth. Dry farming is a technique often practiced in drier climates where irrigation is not readily available. Such areas do not have adequate precipitation in a single year, but in consecutive years there is often sufficient moisture for crop production. The main objective in dry farming is to maintain the soil in such a way that the soil will absorb and retain as much water as possible. The primary technique of dry farming is to allow the soil to remain fallow every other year. This practice allows the soil to store up water for two years so that there will be sufficient water for one year of crops. Regardless of the hope and efforts of the farmers in Johns Valley, they too could not overcome the environment. Annual precipitation was often insufficient for dry farming in Johns Valley. Also, the erratic nature of the precipitation added to the downfall of farming activity in the valley, as adequate precipitation could not be relied upon from year to year or from month to month. Additionally, with Johns Valley being located 7,500 feet above mean sea level, the growing season was often too short to adequately allow crops to mature and produce a good yield. Other factors perhaps added to the discouragement of the people of Johns Valley, but the insufficient and erratic nature of the precipitation, coupled with the short growing season, were major factors in the abandonment of the area. The people of the valley voted to leave the area and sell their land and farms to the federal government.

Maize is the most grown crop by the farmers in Jozini. Therefore, the main objective of the study was to assess the economic impact of climate change on maize production under different farming systems in Jozini Municipality in KwaZulu Natal (KZN). The study was looking at the smallholder farmers producing maize under dryland and irrigation system. A total of 100 farmers were selected for the study (40 from dry-land and 60 from irrigating farmers). Cluster and random sampling procedures were used to select the sample. Questionnaires were used for the collection of primary data, from the respondents (maize farmers). Data was analysed using descriptive statistics (frequency, percentages), gross margin, regression analysis and the Ricardian model. Data for computing gross margins and net revenue was taken from the on-farm trials. Gross margin was used on regression analysis and the net revenue was used on the Ricardian modelThe results of the regression analysis indicated that land size, farmer’s experience to farming, level of education, use of fertiliser, use of irrigation and the yield obtained were significant and have a positive relationship with farmers gross margin. The results of the Ricardian model indicated that climate change affects both farming systems, but farmers that are producing under dryland are the most affected farmers because they rely more on climate variables especially rainfall for their production. So a change in climate variables affects maize farmers’ productivity and thus affecting farmers’ gross margin and net revenue. The study recommends that the farmers must use irrigation in order to support maize production even in the absence of rainfall. Farmers must also adapt to the short growing season so that they will be able to produce even in the presence of climate change.