Nitrogen-fixing trees in agroforestry systems: myths and realities

Abstract

The need to increase crop production on sustainable basis is very crucial in the tropics because of poor soil fertility as characterized by low nitrogen and phosphorus status. Agroforestry entails inclusion of woody perennial (trees and shrubs) in a diversified and sustainable land-use system. Use of nitrogen-fixing trees (NFT) in agroforestry systems is specifically to conserve the production potential of such systems due to the inherent ability of these trees and shrubs to improve the nutrient status of the soil. Appropriate manipulation and management of the microsymbiont and macrosymbiont enhances biological nitrogen fixation (BNF) in an agroforestry systems that incorporates NFTs as tree/shnlb components. TIlls paper highlights the technologies available for ensuring optimal exploitation of BNF in the agroforestry context and also points out some of the misconstructions about the nitrogen-fixing symbioses.