Thesis (Ph. D.)--University of California, Santa Cruz, 2002. / Typescript. Includes bibliographical references (leaves 241-268).

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The challenge to overcome hunger remains one of the most serious confrontations facing humanity today. The threat of starvation is most serious in Africa, where an estimated 33% (138 million) of the population, mainly women and children, suffer from malnutrition. An estimated 680 million people, representing about two thirds of the rural poor, keep livestock, confirming the importance of livestock to their livelihoods. Understanding a live stock system requires description and analysis of its various components and their functional inter-relationships (the systemâs functioning), rather than the description of livestock production alone. Therefore, the purpose of this study was to analyse the se relationships which are best understood by evaluating the various flows among system components as well as farmersâ management decisions. Farms vary in their resource endowments and in the family circumstances of the owners, with various resource flows and external interactions at the farm level. The biophysical, socio-economic and human elements of a farm are interdependent, and can be analysed as a system from various points of view. The challenges experienced in conducting diagnostic livestock studies are often attributed to the specific characteristics of livestock keeping. Taking cognisance of each farmerâs unique environment and context is central to the framework of farming systems research. No single component of smallholder farms in developing countries has as much potential as ruminant animals to address simultaneously the inter-related factors of under-nutrition, poverty and environmental decline that prevent people from improving their livelihoods. In mixed farming systems, as a result of the interplay among farm families, animals, crops and social systems, the roles and contributions of animals to smallholder agriculture are complex. The projected increased demand for livestock products could result in far-reaching changes in the structure of smallholder livestock production. Livestock never interact with natural resources in isolation, but people as livestock managers play a deciding role and are affected by biophysical, economic, social and policy factors. In this context, an integrated approach to natural resource management is required. Eighty-six smallholder cattle farmers in the Nzhelele District of the Limpopo Province of South Africa were surveyed. The farmers owned between one and 67 cattle, with an average of 10.3 head of cattle per household. The average age at first calving was 34.3 months. The rates of calving, weaning, calf mortality, herd mortality and offtake were 49.4%, 34.2%, 26.1%, 15.6% and 7.8% respectively. Contrary to the situation in many other regions of Southern Africa, commercial enterprise, not social prestige, constituted the main reason for farming with cattle. A marked complimentarity in resource-use i.e. crop residues as animal forage, has been demonstrated. Family size is the single most important factor among all variables studied (farm size, grazing land area, cultivated area and maize production area) that influences herd size for cattle and goats. The most important factor limiting the amount of land cultivated and the area used for maize production is farm size. Farm size has no relationship to the number of cattle or goats owned, as livestock predominantly depend on communal grazing. Animal traction supported by family labour, played a prominent role in land cultivation, due to the small farm size. Empirical studies and reviews from Eastern (Kenya) and Southern (South Africa) Africa has been used to construct a policy framework to guide livestock development in these two regions. Five overarching, integrated elements have been identified. These include food production and security, capacity strengthening for livestock research, livestock and the environment, health and genetics and marketing of livestock and livestock products. The framework that emerges is complex, due to the dramatically increasing demand for livestock products and, as a result, the farreaching changes in the structure of smallholder livestock production. To promote the development of smallholder farmers, different policy options must be assessed and evaluated, bearing in mind the farmersâ likely responses. New policies must include food production and security, capacity strengthening for livestock research, livestock and the environment, health and genetics and marketing of livestock and livestock products. An attempt has been made to translate these into complex, multi-disciplinary and multi-sectoral policy frameworks.

Thesis (M. Env. St.)--University of Adelaide, Mawson Graduate Centre for Environmental Studies, 1993? / Includes bibliographical references (leaves 172-185).

Thesis (M.A.--Urban and Environmental Policy)--Tufts University, 1992. / Cover title. "November 1992." Includes bibliographical references (p. 85-88).

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Orientador: Leonardo Fernandes Fraceto / Banca: Hudson Wallace Pereira de Carvalho / Banca: Daniel Junior de Andrade / Banca: Halley Caixeta de Oliveira / Banca: Marystela Ferreira / Resumo: Os artrópodes tem sido uma das principais causas de perdas agrícolas em todo o mundo. Só no Brasil essas perdas podem chegar a 7,7 % ao ano. A utilização extensiva de pesticidas sintéticos tem sido a principal forma de controle deste tipo de praga, no entanto, os efeitos adversos destes compostos tanto para o meio ambiente quanto para a saúde humana tem motivado a busca por alternativas menos impactantes. Neste contexto, diversos mecanismos estão sendo estudados a fim de minimizar estes danos, como por exemplo, o desenvolvimento de sistemas de liberação modificada, utilizando polímeros biodegradáveis e proteínas. Aliado a isto, a utilização de pesticidas botânicos também tem demostrado potencialidade para o combate a essas pragas, devido aos menores impactos causados por esses produtos de origem natural. Portanto, o presente trabalho apresenta o desenvolvimento (preparo e caracterização) de sistemas nanocarreadores produzidos a partir dos polímeros quitosana e goma arábica e da proteína zeína para os compostos botânicos (geraniol, citronelal, eugenol e cinamaldeído), bem como, os potenciais efeitos cito e fitotóxicos destes sistemas. Ademais foram também realizados ensaios de atividade biológica destes sistemas em pragas agrícolas (mosca-branca, ácaro-rajado e lagarta falsamedideira). Os compostos botânicos apresentaram elevada eficiência de encapsulação em ambos os sistemas carreadores, sendo que os sistemas foram capazes de proteger os compostos contra uma degradação premat... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Arthropods have been a major cause of agricultural losses worldwide. Only in Brazil can these losses reach 7.7% per year. The extensive use of synthetic pesticides has been the main form of control of this type of pest, however, the adverse effects of these compounds for both the environment and human health have motivated the search for less impactful alternatives. In this context, several mechanisms are being studied in order to minimize these damages, such as the development of modified release systems using biodegradable polymers and proteins. In addition to this, the use of botanical pesticides has also shown potential for combating these pests, due to the lower impacts caused by these products of natural origin. Therefore, the present work showed the development (preparation and characterization) of nanocarrier systems produced from chitosan and gum arabic polymers and zein protein for the botanical compounds (geraniol, citronellal, eugenol and cinnamaldehyde), as well as the potential effects and phytotoxic systems. In addition, tests of the biological activity of these systems on agricultural pests (whitefly, two-spotted spider mite and soybean looper) were also carried out. The botanical compounds showed high encapsulation efficiency in both carrier systems, and the systems were able to protect the compounds against premature degradation and also against ultraviolet radiation. The phyto and cytotoxicity results showed that encapsulation decreased the toxic effect of ... (Complete abstract click electronic access below) / Doutor

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Thesis (M. Com. (Agr.)) -- Lincoln University, 2009. / Also available via the World Wide Web.

Small-scale, conservation-based agrarianism provides a model for sustainable human habitation within heterogeneous landscapes. Thoreau's Transcendentalism and the historical roots of American Agrarianism are explored as influences for wilderness preservation and the New Agrarian movement. Idealizing a distant wilderness too often means overlooking the ecological and socio-economic environment where people live. Middle landscapes between nature and culture, or between wilderness and cities, can either increase or reduce ecological and social functioning within the landscape matrix. Managing middle landscapes by agrarian principles helps move both nature and culture towards ecological, economic, and social sustainability. This thesis ends with a discussion of agrarian themes, such as supporting decentralized local economies and increasing community connectivity, applied in urban, rural, and wilderness landscapes.