In the past few decades there has been growing concern about the exhaustibility of non-renewable soil resources in
developing countries in the tropics to meet the needs of present and future generations. Land degradation is a major problem
in many parts of the tropics, including subsaharan Africa, mainly owing to overexploitation of vegetation and soil resources
and adoption of inappropiate farming methods. The challenge is to increase the sustainable agricultural productivity of the
land with acceptable inputs to meet increasing human needs, while maintaining the soil resource base and minimising
environmental degradation. One technology that can meet this need for rainfed upland farming with low external chemical
inputs is the alley cropping system. This technology integrates trees and shrubs in spatial zonal arrangements with food crops
in the production system. The presence of woody species in the alley cropping production system has been shown to
contribute to (1) nutrient recycling, (2) reduction in soil nutrient leaching losses, (3) stimulation of higher soil fauna1
activities, (4) soil erosion control, (5) soil fertility improvement and (6) sustained levels of crop production. These
experiences can be utilised in developing sustainable and environmentally friendly agroforestry systems.