The semi-arid zones of the world are fragile ecosystems which are being sub stantially modified by the activities of mankind. Increasing human populations have resulted in greater demands on semi-arid zones for providing human susten ance and the possibility that this may enhance desertification is a grave concern. These zones are harsh habitats for humans. The famines that resulted from drought during the late 1960's and the 1970's in the African Sahel illustrated the unreliability of present agricultural systems in this zone. Large fluctuations in ag ricultural production have occurred in semi-arid zones of Australia, North Ameri ca, and the Soviet Union due to periodic droughts, even though considerable ag ricultural technology has been devoted to agricultural development in these zones. The challenge to mankind is to manage these different semi-arid zones so that pro ductivity is increased and stabilized, and environmental deterioration is decreased. Irrigation can be used to increase and stabilize agricultural production in semi-arid zones as discussed in Volume 5 of this series, Arid Zone Irrigation. The present volume, Agriculture in Semi-Arid Environments, focuses on dryland farming in semi-arid zones, and is relevant to the large areas of the world where rainfall is limiting and where water is not available for irrigation. This volume is designed to assist agricultural development in these areas and consists of reviews and analyses of available information by scientists working in Africa, Australia, and at the U ni versity of California.

Klappentext

The semi-arid zones of the world are fragile ecosystems which are being sub­ stantially modified by the activities of mankind. Increasing human populations have resulted in greater demands on semi-arid zones for providing human susten­ ance and the possibility that this may enhance desertification is a grave concern. These zones are harsh habitats for humans. The famines that resulted from drought during the late 1960's and the 1970's in the African Sahel illustrated the unreliability of present agricultural systems in this zone. Large fluctuations in ag­ ricultural production have occurred in semi-arid zones of Australia, North Ameri­ ca, and the Soviet Union due to periodic droughts, even though considerable ag­ ricultural technology has been devoted to agricultural development in these zones. The challenge to mankind is to manage these different semi-arid zones so that pro­ ductivity is increased and stabilized, and environmental deterioration is decreased. Irrigation can be used to increase and stabilize agricultural production in semi-arid zones as discussed in Volume 5 of this series, Arid Zone Irrigation. The present volume, Agriculture in Semi-Arid Environments, focuses on dryland farming in semi-arid zones, and is relevant to the large areas of the world where rainfall is limiting and where water is not available for irrigation. This volume is designed to assist agricultural development in these areas and consists of reviews and analyses of available information by scientists working in Africa, Australia, and at the U ni­ versity of California.

Inhalt
1 Ancient Agricultural Systems in Dry Regions.- 1.1 Introduction.- 1.2 The Beginnings of Agriculture.- 1.3 Ancient Agricultural Systems in Dry Regions of the Old World.- 1.4 Ancient Agricultural Systems in Dry Regions of the New World.- 1.5 Conclusions.- References.- 2 Development of Present Dryland Farming Systems.- 2.1 Introduction.- 2.2 Geographic Aspects of the World's Semi-Arid Tropics.- 2.3 Dryland Farming Systems in the Semi-Arid Tropics.- 2.4 Geographic Aspects of the World's Semi-Arid Mid-Latitude Lands (Steppe).- 2.5 Dryland Farming Systems in the Mid-Latitude Steppes.- 2.6 Perception of the Semi-Arid Environment.- 2.7 The Future of Dryland Farming Systems.- References.- 3 Semi-Arid Climates: Their Definition and Distribution.- 3.1 Introduction.- 3.2 Meteorological Factors Contributing to Aridity and Humidity.- 3.3 Defining Semi-Arid Regions.- 3.4 Thermal Regions of Semi-Arid Zones.- 3.5 Conclusions.- References.- 4 Agroclimatology Applied to Water Management in the Sudanian and Sahelian Zones of Africa.- 4.1 Introduction.- 4.2 Climatology and the Hydrologic Budget of Cropping Systems.- 4.3 Application of Agroclimatology to Agriculture in Senegal.- 4.4 Future Strategies.- References.- 5 Microbiological and Biochemical Aspects of Semi-Arid Agricultural Soils.- 5.1 Introduction.- 5.2 Microbial Ecology and Soil Physical Properties.- 5.3 Organic Matter.- 5.4 Mineral Nutrition of Plants.- 5.5 Future Directions for Research.- References.- 6 Crop Adaptation to Semi-Arid Environments.- 6.1 Introduction.- 6.2 Water as a Limiting Factor.- 6.3 Adaptive Attributes for Semi-Arid Environments.- 6.4 Developing Cultivars for Semi-Arid Environments.- 6.5 Future Strategies for Research.- References.- 7 Water Transport Through Soil, Plant, and Atmosphere.- 7.1 Introduction.-7.2 Components of the Soil-Plant-Atmosphere Continuum.- 7.3 Models of the Soil-Plant-Atmosphere Continuum.- 7.4 Conclusions.- References.- 8 Crop Management in Semi-Arid Environments.- 8.1 Introduction.- 8.2 Management Systems.- 8.3 Cultural Systems.- 8.4 Cropping Methods.- 8.5 Crop Selection.- 8.6 Planting Techniques.- 8.7 Crop Fertilization.- 8.8 Crop Rotation.- 8.9 Vertebrate Pest Control.- 8.10 Harvesting.- 8.11 Future Directions of Research.- References.- 9 Soil Management in Semi-Arid Environments.- 9.1 Introduction.- 9.2 Differing Responses of Soils to Tillage.- 9.3 Objectives of Soil Management.- 9.4 Tillage and Soil Water.- 9.5 Soil Fertility.- 9.6 Tillage and the Soil Microenvironment.- 9.7 Erosion Control.- References.- 10 Erosion and Its Control in Semi-Arid Regions.- 10.1 Introduction.- 10.2 Erosion by Water.- 10.3 Erosion by Wind.- 10.4 Erosion Control Measures.- References.- 11 Diseases and Nematode Pests in Semi-Arid West Africa.- 11.1 Introduction.- 11.2 Principles of Disease and Nematode Management.- 11.3 Diseases and Nematodes of Specific Food Crops.- 11.4 Future Directions for Research in Disease and Nematode Pest Control in Semi-Arid Africa.- References.- 12 Weed Control.- 12.1 Losses from Weeds.- 12.2 Weed Characteristics.- 12.3 Management of Weeds.- 12.4 Herbicides.- 12.5 Interaction of Weed Control and the Environment.- 12.6 Control of Specific Weeds.- 12.7 General Conclusions.- References.- 13 The Interaction Between Cultivation and Livestock Production in Semi-Arid Africa.- 13.1 Introduction.- 13.2 Linkages Between Crop and Livestock Production.- 13.3 Selected Cases of Cropping-Livestock Systems.- 13.4 Trends in Organization of Linkages.- 13.5 Conclusions.- References.- Taxonomic Index.