Thesis (M.A. in agricultural economics)--Washington State University, August 2006. / Includes bibliographical references.

Thesis (doctoral)--Universität, Hohenheim, 2006. / Includes bibliographical references (p. 187-199).

Arid and semi-arid regions have increasingly become the subject of much research and debate by scientists. By their very nature, these regions characteristically exhibit extremes which complicate the implementation of effective management strategies that ensure sustainable productivity and economic output. Namibia is one such region where low and highly variable rainfall conditions and fluctuating productivity pose a challenge to managers of commercial livestock enterprises, / who seek to optimise economic benefits while controlling the negative effect on herd production and income of unpredictable and unfavourable climatic events. Various management approaches are proposed as a means of exploiting periods of abundant productivity and so optimising income from herd production, while controlling for the effects of drought conditions. To analyse the effects of these various offtake strategies, a rainfall-driven plant-herbivore simulation model is used. The model comprises components simul~tihg vegetation and herbivore dynamics. The vegetation component incorporates soil moisture and nutrient allocation to plant parts. The herbivore dynamics sub-model comprises age and sex classes, population dynamics and animal energy requirements which govern accumulated fat reserves. The model is adapted to account for climatic and vegetation attributes specific to Namibia. An economic component including a seasonal monthly price structure is developed, and a dynamic feedback governing management decisions is incorporated. The much debated issue of whether to maintain a constant stocking rate or to track climatic variation by employing a variable stocking level is investigated, with the performance of management strategies incorporating these approaches ranked according to various factors, including annual returns, associated risk and annual stock mortality. The economic consequences of the timing of offtake are investigated, with the simulation of management strategies that implement destocking in the face of anticipated drought conditions. A dynamic projection of expected income allows the impact of forecasting potential economic gains on decision-making to be analysed. Results indicate that the performance of management strategies is not as dependent on climatic and seasonal price variability as was originally expected, with the application of a constant stocking level proving to be the most favourable strategy in terms of economic gain and variability of income. Tracking climatic variation by adapting stocking levels does not provide the improvement in economic returns from a livestock production system that was anticipated, although this approach is successful in effecting a significant reduction in annual stock mortality. Further results show the sensitivity of income to the long-term average stocking level characterising the management strategies investigated, as well as to the elasticity of the underlying price structure. The results of this study indicate that the implementation of management strategies designed to track climatic variation does not offer significant economic advantages over the application of a constant stocking approach. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 2001.

A large proportion of the world's land surface is covered by semi-arid grasslands, and they provide an important source of income as a grazing resource. A more comprehensive understanding of these complex ecosystems is vital for the effective management of rangelands, as it will lead to an increased and more sustainable economic output. Herbivores modify the spatial pattern of vegetation distribution and their response to spatially heterogeneous forage resources affects their performance. The spatial aspect of herbivory is often ignored although it is a necessary component of understanding grazing dynamics and the factors affecting herbivore condition. A spatial model is developed which incorporates vegetation and animal dynamics and the interactions between these two components. The effect of different spatial foraging strategies on animal performance and vegetation was investigated. Model results were compared with the output of a non-spatial model to assess the importance of spatially explicit modelling in the context of monitoring animal performance. The relative significance of a number of aspects relating to spatial grazing and animal condition was explored. The results from this research show that significant differences in output are obtained from spatial versus non-spatial models. While the purpose of a model will determine its nature, the results imply that in certain contexts, a spatial model is essential for accurate results and insight. The results also indicated that foraging strategies have a large affect on herbivore condition and that spatially explicit models are necessary in the context of investigating the effect of foraging strategies on animal performance. Various aspects that significantly affected animal condition were highlighted and are useful in directing future investigations into grazing dynamics. It is difficult to conduct field studies under spatially and temporally variable conditions where the interactions between vegetation and herbivores are so complex. In the light of this, modelling was found to be an effective tool that can be used in investigating and revealing important dynamics of semi-arid grazing systems. / Thesis (M.Sc.)-University of Natal, Pietermaritzburg, 1999.

Bibliography: p. 219-237.

The objective of this study is to develop a model to evaluate the economic feasibility of biofuels production, and in particular to isolate the variables crucial to feasibility. The model constructed to define these variables is unique in its ability to accommodate a variety of plants and to integrate all portions of the production process; it was tested on a case study of a Euphorbia lathyris industry. The model minimizes costs of production to determine the best configuration for the industry. Total cost equals the sum of costs incurred in each segment of the process: growth, harvest, transport, and extraction. The solution is determined through a non-linear transportation- transshipment algorithm which describes production as a series of nodes and links. Specific application of the model was analysis of E. lathyris biofuel production in Arizona. Simulations were run examining the sensitivity of biocrude cost to changes in input parameters. Conclusions are summarized as follows. * No change in any single element can reduce final cost sufficiently to enable competitive production in the near future. * The major factor necessary to bring cost into range is improvement in biological yield. Two components of equal importance are tonnage produced per acre and percentage extractables recovered in processing. * Lowering cropping costs provided the most effective improvements of economic inputs. Perennial crops significantly reduced farm costs. * Transportation costs outweighed economies of scale in extraction; extractor location close to crops is more efficient than centralized. The cost minimization model was successfully used to isolate the critical factors for an E. lathyris industry in an arid region. Results determine that this industry would not be competitive in Arizona without dramatic improvements in yields and moderate changes in a combination of input costs. Viability is critically dependent on improvements in tonnage yield produced per acre and percent extractables recovered.

This dissertation presents a case study of agricultural land use patterns and marketing aspects in the Taif region of Saudi Arabia. This area is one of importance to the overall agricultural future of Saudi Arabia, being a major producer of fruits, vegetables and dates in the Kingdom. In recent years, increases in personal income associated with oil production in the Kingdom have created significant changes in the types of crops grown as well as the way of life of the small farmer. These changes include the following: (1) Because better paying jobs and an enhanced lifestyle are luring farmers to the large urban areas, fewer workers are available for labor on the farms. (2) Large government subsidies have created a situation where the small farmer finds it no longer profitable to grow cereal crops as he traditionally did. (3) A lack of adequate refrigerated trucks and an increase in salinity in groundwater has caused farmers near the market centers of Makkah and Jeddah to cut fruit trees and replant with vegetables that can withstand more saline water and can be transported to the nearby markets more easily than those framers living in the farther areas of the region. What the author concludes is that increased attention to the problems of the small farmer in the region is necessary so that food supplies will be maintained to feed a growing population and so that self-sufficiency can be achieved. Additional support by the government in the way of subsidies and loans and more programs to educate farmers in marketing techniques and improved farm methods and management must be developed. And finally, the farmers should work together, sharing information and resources for the common good of all small farmers in the region.

This dissertation is based upon a research project designed to identify and evaluate alternative agricultural systems which are applicable to the arid environment of Saudi Arabia within a multiobjective context. The four systems are: traditional; conventional; aridity-oriented; and, controlled environment. These systems differ in their utilization of basic resources, the the amount and type of food they produce, the profits they generate and their compatibility with Saudi Arabian social traditions. Thus, the environmental and sociological consequences of their implementation were considered along with production and economic aspects. The procedure for evaluating the alternative agricultural systems is a computer program called ESAP (Evaluation and Sensitivity Analysis Program) which uses multi-attribute theory as an aid to decision making. Computations to determine the extent of that achievement are essentially a weighting of the variables identified as subdivisions of the goals. Decision makers are also required to give the relative values to the variables, and to select a particular utility function which describes the relationship between value and utility. The values assigned to each variable are usually presented as a range to express the users' uncertainty. Six consultants (five university professors plus the author) with varying professional backgrounds and knowledge of Saudi Arabian conditions were used as individual and collective decision makers to evaluate the four agricultural systems and their combinations. The procedure resulted in grouping these ten different alternatives (four systems plus combinations of any two) into three independent classes: I, Il and III. The grouping was based upon obtaining a clear distinction in overall score between the classes. The grouping into classes resulted in the aridity-oriented agricultural system being the only alternative in Class I. The consultants felt that this system offered the most favorable tradeoff between the economic benefits and the social and environmental factors. In general, the study indicated that the protection of natural resources and the maintenance of cultural factors should be given significant influence along with the economic factors in evaluating a particular plan of action. In utilizing such a procedure, the need for additional data and research became very evident, if there is to be better allocation of the Kingdom's agricultural resources.

China's Minqin Oasis once welcomed traders along the ancient Silk Road with rivers, lakes, and lush forests, yet today the region's farmland and grassland are increasingly being engulfed by the sands of the Gobi Desert. The severity of this incremental catastrophe for a declining population of 300,000 residents has brought forth a host of recent water policies to include agronomic water conservation through plastic mulch use, computerized regulation and pricing of groundwater, and water diversions from the Yellow River. This study uses a multi-disciplinary and mixed methods approach to better understand farmer perspectives on why they implement certain water and land use practices in agriculture. The world's farmers currently use the majority of the world's available freshwater and arable land. Modern agriculture and its continued intensification also lead to increases in petroleum based inputs such as agrochemicals and agricultural plastics (plasticulture). Despite the large of impact of the decisions made by the world's farmers on natural resources, little research to date has sought to better understand farmers' perceptions and decision-making processes. Plastic film mulch is a technology that has existed since the 1940's and it has been used in places such as rural China for over five decades. This technology conserves a considerable amount of irrigation water and it increases harvests, however, use of plastic for mulch causes waste disposal problems and is an expenditure of petroleum through plastic manufacturing. Without a fundamental understanding of why farmers perceive plastic mulch to be valuable to their households and communities, we may not fully grasp why its global application continues to increase year after year. Moreover, a focused study of plastic mulch use at the local level may also allow researchers and entrepreneurs to develop a suitable alternative mulch that does not consume non-renewable resources or result in detrimental plastic waste after its utility has been exhausted. This study uses household level interviews, surveys, and participant observation to better understand why Minqin County farmers in rural China continue to use plastic mulch and how it may influence their standard of living. / Graduation date: 2013

Contemporary conservation and development understanding in both policy and academic circles espouses that natural resources have a significant contribution to the livelihoods of local people and that knowledge of this can better foster conservation policies that are consistent with livelihood and ecological needs. This thesis is based on research conducted in the southern Kalahari region, South Africa among the San and Mier communities bordering Kgalagadi Transfrontier Park. It looks at the importance of natural resources to the San and Mier community groups and ascertains the extent of resource use and its value within broader livelihood portfolios. It also focuses on the cultural values of natural resources and interactions among institutions and actors and how these shape natural resource governance and livelihood outcomes. Overall, natural resources represent an important livelihood source contributing up to 32 % and 9 % of the total income of the San and Mier respectively or up to 46 % and 23 % if livestock incomes are included. However, the dependence on, diversification patterns and distribution of natural resource income vary substantially between and within the two communities. With regards to the cultural values attached to natural resources by the San and Mier, the findings show that these arise from an incredibly diverse and sometimes conflicting array of values that punctuate the two communities’ way of life and they are inextricably linked to resource use. Lastly, governance of natural resources in the co-managed Park and communitymanaged resettlement farms is characterised by complex institutional arrangements, compounded by the existence of multiple actors that have multiple and sometimes conflicting objectives – as shaped by different meanings and interpretations of natural resources. Heightened inter- and intra-community conflicts are common, notably resource use conflicts between the San and Mier and between the San ‘modernist’ and ‘traditionalist’ groups. This demonstrates that the communities’ livelihood dynamics in general and the dependence on natural resources in particular, are closely linked with ecological, economic and social factors including history, culture and present livelihood needs. By exploring the social-environment interactions, the study highlights the complexities and diversity of resource use for livelihoods that should be taken into consideration for both conservation and development policy interventions and research. The main argument of the study is that the contribution of natural resources to local livelihood portfolios in co- and community-managed areas, can be better understood through a consideration of cultural dynamics and institutional arrangements since these condition natural resource access, value and use.