The potential benefits of agroforestry in the Sahel and other semi-arid regions

Abstract

This article summarises results of three related studies. The first study is a synthesis and analysis of available knowledge on woody plants in semi-arid regions with an emphasis on the Sahel region, investigating the potential ‘added value’ of woody plants to improve nutrient and water availability for agricultural crop and pasture production goals. The other two are field studies aimed to validate key issues identified by the synthesis study, through measurements on the influences of woody plants on water and nutrient availability, and investigations of the relationship between soil organic matter quantity and quality and the recovery rate of nitrogen and phosphorus from fertilisers. The field studies support the conclusion that processes leading to an added value of woody plants in agroforestry systems are mainly related to reduced losses of water and nutrients. Such added values are therefore lowest where they are most needed, in resource-poor environments. Specific farmers goals, agroecological and socio-economic conditions have to be taken into account to make optimal use of the potentials of agroforestry. The potential benefits of agroforestry systems are mainly in terms of the improved efficiency of nutrient inputs than as an alternative for fertilisers. This has major implications for design and management of agroforestry systems. © 1997 Elsevier Science B.V.