Paul L.G. Vlek – författare

This book provides a synthesis of the key issues and challenges facing agriculture and food production in Southern Africa. Southern Africa is facing numerous challenges from diverse issues such as agricultural transformations, growing populations, urbanization and climate change. These challenges place great pressure on food security, agriculture, water availability and other natural resources, as well as impacting biodiversity. Drawing on case studies from Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe, the chapters in this book consider these challenges from an interdisciplinary perspective, covering key areas in constraints to production, the most important building blocks of good farming practices, and established and emerging technologies. This book will be a valuable support for informing new policies and processes aimed at improving food production and security and developing sustainable agriculture in Southern Africa. This informative volume will be key reading for those interested in agricultural science, African studies, rural studies, development studies and sustainability. It will also be a valuable resource for policymakers, governmental and nongovernmental organizations, and agricultural practitioners.This title has been made available as Open Access under a Creative Commons Attribution-Non Commercial-No Derivatives (CCBY-NC-ND) license and can be accessed here: https://www.taylorfrancis.com/books/e/9780429401701

This book provides a synthesis of the key issues and challenges facing agriculture and food production in Southern Africa. Southern Africa is facing numerous challenges from diverse issues such as agricultural transformations, growing populations, urbanization and climate change. These challenges place great pressure on food security, agriculture, water availability and other natural resources, as well as impacting biodiversity. Drawing on case studies from Lesotho, Malawi, Mozambique, Namibia, South Africa, Swaziland, Tanzania, Zambia and Zimbabwe, the chapters in this book consider these challenges from an interdisciplinary perspective, covering key areas in constraints to production, the most important building blocks of good farming practices, and established and emerging technologies. This book will be a valuable support for informing new policies and processes aimed at improving food production and security and developing sustainable agriculture in Southern Africa. This informative volume will be key reading for those interested in agricultural science, African studies, rural studies, development studies and sustainability. It will also be a valuable resource for policymakers, governmental and nongovernmental organizations, and agricultural practitioners.This title has been made available as Open Access under a Creative Commons Attribution-Non Commercial-No Derivatives (CCBY-NC-ND) license and can be accessed here: https://www.taylorfrancis.com/books/e/9780429401701

Soil organic matter is a reservoir for plant nutrients, it provides water-holding capacity, stabilizes soil structure against compaction and erosion, and thus determines soil productivity. All agriculture to some degree depends on soil organic matter. It has long been known that soil organic matter declines when land is taken into cultivation, and that the productivity of new agricultural land is governed by fertility contributions from decomposing natural organic matter. The expansion of agriculture to ever new and more fragile lands, particularly in tropical and developing regions, causes environmental degradation with local effects on soil quality, regional effects on landscape integrity and water quality, and global effects on carbon cycles and the atmosphere. Rates of soil organic matter loss, equilibrium levels under different land use, and management options for stabilizing or reversing losses have been documented for temperate ecosystems. This has provided options not only for improved fertility management and lowered inputs but also for mitigation of greenhouse gas emissions.The understanding of processes governing organic matter in the tropics is documented in this book, and critical gaps in knowledge and management are explored for a readership of resource scientists, economists and advanced students.

Production from tropical agricultural systems will need to increase to satisfy the rising food demand of an increasing population coupled with changes in consumption patterns. At the same time, the agricultural sector is a significant source of greenhouse gases (GHG) in many developing countries, which can be attributed mainly to land-use change and methane emissions from rice and livestock. But how can we reconcile less GHG emissions from tropical agricultural systems while increasing productivity?Due to the interactive nature of these issues, this book is compiled of articles on natural resource management, as well as the socio-economic aspects of GHG mitigation. The scope of mitigation options in tropical agriculture is discussed for three different activities: (a) agroforestry; (b) rice-based production systems; (c) pasture/animal husbandry.Agronomic solutions alone will not be sufficient, as the institutional and economic frameworks within which farmers operate dictate whether a recommended agronomic management practice is acceptable. The prevention of deforestation, and the re-forestation of degraded land, could become key elements to national climate protection programs of some developing countries. Alternative management practices in rice-based and pasture systems may offer win-win options to reduce emissions and improve resource-use efficiencies.

Land-use change is one of the main drivers of many environmental change processes. It influences the basic resources of land use, including the soil. Its impact on soil often occurs so creepingly that land managers hardly contemplate initiating ameliorative or counterbalance measures. Poor land management has degraded vast amounts of land, reduced our ability to produce enough food, and is a major threat to rural livelihoods in many developing countries. To date, there has been no single unifying volume that addresses the multifaceted impacts of land use on soils. This book has responded to this challenge by bringing together renowned academics and policy experts to analyze the patterns, driving factors and proximate causes, and the socioeconomic impacts of soil degradation. Policy measures to prevent irreversible degradation and rehabilitate degraded soils are also identified.

The mission of the International Fertilizer Development Center is to increase food production through the improvement of fertilizers and fertilizer practices for the developing countries with special emphasis on tropical and subtropical agriculture. The principal aim is to ensure that fertilizer technology is not a limiting factor to food production in those regions. Although the full extent to which deficiency of micronutrients hampers food production is yet un­ known, there is ample evidence that problem areas exist and more will be identified as crop production is intensified and marginal lands are exploited. Therefore, it seems fully appropriate at this time that IFDC, as an international organization, take a leadership role in developing micronutrient fertilizer technology appropriate for the tropics and subtropics. The gravity of micronutrient deficiency as a limiting factor to crop pro­ duction varies from crop to crop and from soil to soil. The effects may range from slight yield reductions to complete crop failure. While the economic impact of omitting micronutrients in seriously affected areas (e.g., Zn in Brazilian Cerrado) is convincing, it is difficult to estimate the yearly loss in crop production due to unsuspected micronutrient deficiency. Active soil and crop testing programs in regions with advanced agricultural systems are aimed at recognizing micronutrients as a limiting plant nutrient in time to allow corrective measures and prevent yield loss. Successful micronutrient monitoring systems are generally limited to developed economies or to developing economies producing export cash crops.

Proceedings of a Symposium, held in Lome, Togo, March 25-28, 1985

Soil organic matter is a reservoir for plant nutrients, provides water-holding capacity, stabilizes soil structure against compaction and erosion, and thus determines soil productivity. All agriculture to some degree depends on soil organic matter. It has long been known that soil organic matter declines when land is taken into cultivation, and that the productivity of new agricultural land is governed by fertility contributions from decomposing natural organic matter. The expansion of agriculture to ever new and more fragile lands, particularly in tropical and developing regions, causes environmental degradation with local effects on soil quality, regional effects on landscape integrity and water quality, and global effects on carbon cycles and the atmosphere. This book summarizes current knowledge of the properties and dynamics of soil organic matter in the tropics, its role in determining soil quality, its stability and turnover, and the options for management in the context of tropical landuse systems, for a readership of resource scientists, economists and advanced students. Maintenance of organic matter is critical for preventing land degradation. Case studies and practical applications are therefore an important part of the book, as are the exploration of future directions in research and management.

Production from tropical agricultural systems will need to increase to satisfy the rising food demand of an increasing population coupled with changes in consumption patterns. At the same time, the agricultural sector is a significant source of greenhouse gases (GHG) in many developing countries, which can be attributed mainly to land-use change and methane emissions from rice and livestock. But how can we reconcile less GHG emissions from tropical agricultural systems while increasing productivity?Due to the interactive nature of these issues, this book is compiled of articles on natural resource management, as well as the socio-economic aspects of GHG mitigation. The scope of mitigation options in tropical agriculture is discussed for three different activities: (a) agroforestry; (b) rice-based production systems; (c) pasture/animal husbandry.Agronomic solutions alone will not be sufficient, as the institutional and economic frameworks within which farmers operate dictate whether a recommended agronomic management practice is acceptable. The prevention of deforestation, and the re-forestation of degraded land, could become key elements to national climate protection programs of some developing countries. Alternative management practices in rice-based and pasture systems may offer win-win options to reduce emissions and improve resource-use efficiencies.

Land-use change is one of the main drivers of many environmental change processes. It influences the basic resources of land use, including the soil. Its impact on soil often occurs so creepingly that land managers hardly contemplate initiating ameliorative or counterbalance measures. Poor land management has degraded vast amounts of land, reduced our ability to produce enough food, and is a major threat to rural livelihoods in many developing countries. To date, there has been no single unifying volume that addresses the multifaceted impacts of land use on soils. This book has responded to this challenge by bringing together renowned academics and policy experts to analyze the patterns, driving factors and proximate causes, and the socioeconomic impacts of soil degradation. Policy measures to prevent irreversible degradation and rehabilitate degraded soils are also identified.

Food security, one of the basic human rights, seems to be ever eluding the people of sub-Saharan Africa. With each occurrence of crop failure, agriculturalists around the world reawaken to the challenge of ensuring sta­ ble, adequate food production in the tropical African environments. The International Fertilizer Development Center (IFDC), with its mandate of alleviating food shortages through judicial use of fertilizers, formulated a program to study fertilizer use strategies for sub-Saharan Africa. With gener­ ous financial assistance from the International Fund for Agricultural Devel­ opment (IFAD), IFDC, in collaboration with the International Crop Re­ search Institute for the Semi-Arid Tropics (ICRISAT) and the International Institute for Tropical Agriculture (IIT A), initiated a research project aimed at assessing means to remedy soil nutrient deficiencies that constrain food production in the humid, subhumid, and semiarid tropics of Africa. The results of this project were summarized during a workshop held in Togo, March 25-28, 1985; the proceedings of that meetings are found in this vol­ ume. The project established collaboration with numerous national programs that were responsible for much of the data collection. The data presented in Chapters 6 and 9 include much of this information. We wish to acknowledge the contribution of the individual scientists, J.T. Ambe, F. Ganry, M. Gaoh, M. Issaka, J. Kiazolu, J. Kikafunde-Twine, K. Kpomblekou, F. Lompo, H.