Maintaining the natural resource base over time in dryland areas of the tropics (which cover the arid, semi-arid, and subhumid regions) requires that desertification and land degradation be controlled. Because of their areal importance, on a global scale, their potential for food and wood production, and their vulnerability, the semi-arid regions, in particular of Africa, are of special importance. The book contains the proceedings of a SCOPE (Scientific Committee on Problems of the Environment) workshop held between 15-19 November 1993, in Dakar, Senegal. It presents 30 papers which bring together experiences of physical and social scientists from Francophone, Anglophone and Lusophone countries who have been working on land issues in Africa. The first section of the book is made up of 11 papers which discuss sustainable management of the biological, physical and chemical fertility. In the second section five papers examine the measures being taken against erosion in rural Africa and what new approaches are currently being introduced. Section three contains three papers which analyse the sustainable management of irrigated lands. The fourth section (11 papers) focuses on the sustainable management of cultivation, agropastoral and agroforestry systems. Finally four discussion groups make policy recommendations and determine the research priorities for sustainable land management systems. (CAB Abstracts)