Successful agroforestry requires an understanding of the complex relationship between trees, crops and soils. This book provides a review of both economic and biophysical aspects of soil use and research in agroforestry, with an emphasis on nutrient-poor forest and savanna soils. Key topics covered include the economics of soil fertility management, cycling of water, nutrients and organic matter, soil structure, and soil biological processes. The book combines synthetic overviews of research results and a review of methods used in research.