Potential use of forage-legume intercropping technologies to adapt to climate-change impacts on mixed crop-livestock systems in Africa : a review

Abstract

This paper summarizes effects of forage-legume intercropping on grain and fodder yield, land equivalent ratio, residual soil fertility, disease and insect pest reduction in mixed crop-livestock systems in Africa. In particular, it discusses the potential benefit of forage-legume intercropping in improving productivity, resource use efficiency and resilience of the system under climate change, which enhances adaptation to climate change and possibly provides the co-benefit of reducing greenhouse gases in sub-Saharan Africa. Research undertaken in Africa demonstrates that intercropping forage legumes with cereals improves overall yield and soil fertility, and reduces the risk of crop failure owing to rainfall variability, diseases, weeds and pests. When the forage from intercropped legumes is provided to animals it improves the digestibility of poor-quality feed, animal performance and efficiency of roughage feed utilization by ruminants. Additional role that legumes may play include lowering erosion and the loss of organic matter, reducing nitrogen leaching and carbon losses, and promoting carbon sequestration. Nitrogen fixed by legumes is safer than nitrogen from inorganic fertilizers. Despite the many benefits of forage legume intercropping the current adoption rate in sub-Saharan Africa is very low. Future research aimed at selection of compatible varieties, appropriate plant geometry and temporal arrangement of the various intercrops under different locations and management scenarios, as well as minimizing the confounding effects of water, soil, light, microclimate, and seeds could enhance adoption of the technology in Africa.