The potentials and limitations of agroforestry for improving livestock production and soil fertility in southern Africa

Abstract

Drawing upon a wealth of research information available for the southern African subcontinent, the potential and limitations of agroforestry for improving animal production and soil fertility are discussed. Agroforestry is reputed to incorporate essential components of sustainability and self-sufficiency into some agricultural systems. Evidence is given that agroforestry, by providing shade in pastoral systems, thereby reduces heat stress in livestock and increases animal performance and overall productivity. A wide range of agroforestry trees provide forage with high crude protein and Iow fibre contents, making them a source of home-grown and cheaply available supplements for poor quality roughage feed stuffs such as cereal crop residues. Evidence is presented that browsing on such trees improves feed intake, animal performance and overall utilisation efficiency of poor quality roughage. However, in some leguminous trees, the presence of tanniferous compounds could cause depression of dry matter and nitrogen digestion in the rumen. Due to the inherent Iow soil fertility of major areas of the southern African subcontinent, and to the rapidly increasing population pressures, systems of agricultural production that combine the use of leguminous shrubs and trees to recycle nutrients of importance are discussed. Evidence is given that several agroforestry technologies, e.g. improved fallows, relay cropping, hedgerow inter cropping and tree biomass transfer, can improve soil fertility and sustain crop yields