Some general charscteristics of farming in a tropical environment; Shifting cultivation systems; Fallow systems; Ley systems; Systems with permanent upland cultivation; Systems with arable irrigation farming; Systems with perennial crops; Grazing systems; General tendences in the development of tropical farm systems.

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.

This book introduces state-of-the-art approaches, methods and research, focusing on smart management of rainwater. In addition, it provides an overview of projects from across the world, illustrating how rainwater-smart management has been implemented in drylands. Focusing on the scientific perspective it demonstrates how rural dryland agriculture can be improved. It also documents the wealth of rainwater-smart know-how available today, and replicates and transfers results to other countries and regions, to encourage cross-sector interactions among various stakeholders, such as practitioners from governmental and public organisations, policy- and decision-makers, and teaching staff from academic scientific institutions. The contributors showcase vital lessons learned from research, field projects and best-practice examples. They address the integrated use of rainwater harvesting management with landscape restoration practices and water-, and climate-smart agriculture for food security and poverty alleviation in arid and semi-arid areas. Original research, combined with the contributors’ synthetic approach, lays a foundation for new concepts and ideas. Through case studies and research reports, the book discusses all the relevant issues necessary for the comprehensive analysis and successful implementation of the technologies in rainwater management. Highlighting the working principles and technical recommendations with regard to cost-efficient rainwater-smart solutions, it is of interest to practitioners. It is also a valuable resource for academic specialists, professionals and students, since many development agencies are funding rainwater harvesting for irrigation purposes.

While a good grasp of the many separate aspects of agriculture is important, it is equally essential for all those involved in agriculture to understand the functioning of the farming system as a whole and how it can be best managed. It is necessary to re-assess and understand rain-fed farming systems around the world and to find ways to improve the selection, design and operation of such systems for long term productivity, profitability and sustainability. The components of the system must operate together efficiently; yet many of the relationships and interactions are not clearly understood. Appreciation of these matters and how they are affected by external influences or inputs are important for decision making and for achieving desirable outcomes for the farm as a whole. This book analyses common rain-fed farming systems and defines the principles and practices important to their effective functioning and management.