Thesis (MSc.(Pasture Science)--University of Pretoria, 2007. / Includes summary. Includes bibliographical references. Available on the Internet via the World Wide Web.

Thesis (M.S.)--Oregon State University, 2005. / Printout. Includes bibliographical references. Also available on the World Wide Web.

Please read the abstract in the section 00front of this document / Dissertation (M Inst Agrar (Pasture Science))--University of Pretoria, 2001. / Plant Production and Soil Science / unrestricted

Thesis (M.S.)--University of Montana, 2007. / Title from title screen. Description based on contents viewed Oct. 24, 2008. Includes bibliographical references (p. 81-86).

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

Graduation date: 1998

Indigenous agroforestry systems, or the intentional use of trees and livestock in croplands, have a long history in the West African Sahel. In many locations, they have long contributed to food security and climate change resilience. But a century or more of cash cropping and use of modern agricultural inputs and tools has meant that no such agroforestry systems remain intact, and many are extinct, including in west-central Senegal, where the Serer historic mixed farming and pastoral strategies previously provided resilience to cyclical droughts and colonial-era agricultural and economic change but are now neither intact nor extinct. This study examines the current state of Serer agroecosystems, considering who uses what elements of the old systems, who has introduced what elements of nonindigenous farming systems, and whether this combination of local and imported farming systems is a coherent and sustainable fusion, or an incoherent pastiche leading toward agrarian collapse. I argue that, depending on how farmers integrate new models with the technical and cultural elements of the old system, a coherent fusion may result, with positive implications for sustainability, climate change adaptation, soil replenishment, crop yield, and livelihood resilience. This mixed-methods study draws upon literature from cultural ecology, agroecology, socioecological resilience, and history to interpret farmers’ accounts of changing agrarian practices. The study links ethnographic findings to empirical analysis of soil conditions and land use change. With these tools, my research sheds new light on the evolving role of local techniques and knowledge in the struggle to maintain agricultural productivity, as Sahelian communities confront soil fertility depletion, food insecurity, and climate change. The study finds that farming communities in this region can strengthen their livelihood resilience and enhance crop yields if they update elements of the well-adapted historic farming system, employ new techniques and tools, and in the process, forge coherent farming systems that still make cultural sense to farmers. / 10000-01-01

Communities in the Sahel region are confronted with problems such as depletion of soil fertility, food insecurity, and climate change, which exacerbate poverty and malnutrition for the inhabitants. The farmlands in Toukar, Senegal, are rapidly denuded of native trees, mainly Acacia albida, that provide myriad benefits. Agroforestry systems, or the intentional use of trees in croplands, have become a potential vehicle to transform the capacities of subsistence farmers to achieve food security. The purpose of this study is to determine farmers' attitudes about agroforestry, who seems to practice it and support it, who is unsure about its values, and who seems opposed to it. I find that farmers who practice a more intact historic version of the Serer farming system are the most supportive of agroforestry and tend to be wealthier, while people who are seemingly more modern are less likely to adopt it and tend to be poorer.

O objetivo do presente trabalho foi de analisar a viabilidade econômica de sistemas agroflorestais (SAFs) em dois ecossistemas amazônicos (terra firme e várzea) próximo a Manaus/AM. A amostra utilizada foi constituída por 21 módulos agroflorestais: 13 localizados em áreas de terra firme, no município de Manacapuru/AM; e, 08 localizados na margem direita do rio Solimões, em áreas de várzea. Os dados foram coletados via uso de questionários apropriados, visando a caracterização da amostra e para o estudo econômico proposto. Os preços dos produtos agrícolas cobrem um período de 23 anos (1980-2002) e foram fornecidos pela Secretaria Municipal de Abastecimento Mercados e Feiras (SEMAF) e Secretaria Municipal de Abastecimento e Produção Rural (SEPROR). Os padrões de variação estacional dos preços foram estimados pelo método da média geométrica móvel centralizada. A avaliação econômica das culturas perenes e semiperenes foi feita utilizando os seguintes indicadores: Valor Presente Líquido (VPL); Taxa Interna de Retorno (TIR); Relação Benefício Custo (RB/C); e, Valor Esperado da Terra (VET). Os resultados obtidos mostraram que os SAFs estudados apresentaram viabilidade econômica para a pratica nos dois ecossistemas, sendo que as áreas de terra firme são mais estáveis que as áreas de várzea. / The objective of this study was the estimation of the economic viability of Agroforestry Systems (SAFs) in two Amazon ecosystems ("terra firme" and "varzeas") near Manaus/AM. The sample used had 21 observations of farmers adopting SAFs: 13 located in areas of "Terra Firme" in the Manacapuru/AM municipality; and, 8 located on the right margin of "Solimões" River, in "varzea" area. The data was collected using a properly developed questionnaire, to determine the profile of the sample and to do the economic evaluation. Selected agricultural prices, covering a period of 23 years (1980 - 2002) were collected from the Secretaria Municipal de abastecimento Mercados e Feiras (SEMAF) and Secretaria Municipal de Abastecimento e Produção Rural (SEPROR). The patterns of seasonal price variation were estimated using the centralized geometrical moving average method. The economic evaluation of SAFs was estimated using the following indicators: Net Present Value; Internal Rate of Return; Benefit-Cost Ratio; and, Expected Land Value. The results obtained indicate that the SAFs in the sample studied were economic viable on both ecosystems, and they are more profitable in "Terra Firme" than in the "Varzeas".

A crescente demanda por recursos naturais e a conseqüente perda de qualidade e quantidade dos mesmos, indica a necessidade do desenvolvimento de alternativas, nas diversas áreas do conhecimento e das atividades humanas. No caso dos agroecossistemas, as práticas convencionais provocaram ao longo do tempo a degradação do solo e dos recursos hídricos, a perda da biodiversidade e a desestruturação dos ecossistemas, que culminaram em desequilíbrios globais de balanço hídrico e temperatura. O presente estudo visa analisar o potencial de utilização de Sistemas Agroflorestais (SAFs). SAFs são práticas de manejo da terra há muito tempo conhecidas, que associam, deliberadamente, árvores com culturas agrícolas temporárias, permanentes e/ou animais simultaneamente ou sucedendo-se temporalmente no espaço; obtendo os benefícios de proteção ambiental e de produção proporcionados pelas árvores. Para a realização do estudo foram utilizadas as bases cartográficas digitalizadas das características ambientais (solo, topografia, hidrologia e clima) do município e as mesmas foram sobrepostas através do Sistema de Informação Geográfica (SIG). As características ambientais de São Carlos, indicam a necessidade da adoção de sistemas de produção sustentáveis, capazes de conservar a qualidade e a quantidade do solo e dos recursos hídricos disponíveis, bem como sua biodiversidade, por isso apresenta grande aptidão para a utilização dos SAFs e uma ampla variedade de espécies com potencial de uso. A prioridade de adoção de SAFs é para áreas degradadas e subutilizadas, áreas de preservação ambiental e adjacentes, reservas legais e áreas suscetíveis à erosão. Sugere-se novos estudos, em campo, para comprovação dos resultados teóricos obtidos. / Growing demand for natural resources and the consequent losses on their quality and quantity indicates that it is necessary to develop alternatives for knowledge as well as for human activities. In the case of agroecosystems, conventional practices stimulated, at the same time, depletion of soil, water resources, loss of biodiversity and ecosystem disorganization, that takes to global unbalances on water and temperature. The aim of this study was to analize the potencial for utilization of Agroforestry Systems (AFSs) in São Carlos, SP. AFSs are land management practices known since long time ago. AFSs consist in association of trees with another activities (such as temporary/permanent agricultural species and/or animals), simultaneously or succeeding temporally on space. The trees used in this practice provide benefits like production and environmental protection. In this study, it was used local environmental features - soil, topography, hidrology and climate - represented on digital cartographic bases. They were overlaid by Geographic Information Systems (GIS). São Carlos environmental features indicate the necessity of adoption of sustainable production systems, enabling to conserve soil and water resources quality and quantity as well as the biodiversity. Therefore, São Carlos presents vocation for Agroforestry Systems utilization, with wide species variety that presents potencial use. Priority areas for AFSs implementation are those degraded and underutilized ones, environmental preservation areas and surroundings, as well as soils with high susceptible of erosion. It is suggested new studies with a practical approach aiming the confirmation of theoretical results obtained.