Low-cost agroforestry technologies for climate change mitigation and adaptation in Sub-Saharan Africa: A review

Agroforestry encompasses a large set of techniques and practices that have the potential to improve farm productivity with minimum environmental impacts in the context of climate change mitigation and adaptation (CCMA). In this paper, we discuss the relevance of agroforestry technologies and practices for CCMA in Sub-Saharan Africa (SSA). We recorded 173 scholarly works and and reviewed 62. Our findings indicate that comprehensive and well-developed technologies are used in agroforestry systems in SSA. They can be classified into four main groups (intercropping, improved fallows, mulching and parkland) and seven sub-groups (relay cropping, hedgerow intercropping, rotational woodlots, coppicing fallows, farmer-managed regeneration, on-farm tree domestication through poly-propagation and mulching) based on factors including the origins and uses of the trees and the types of tree-crop association. Our review showed that the maximum positive effect of parkland agroforestry is obtained when tree density ranges from 20 to 40 tree/ha, indicating an increase in crop production of 915.9 kg/ha. Furthermore, overall, the returns to labour of techniques involving fertilizer trees outperform those for natural fallows by 17%. Agroforestry techniques contribute substantially to the REDD+ program, but the best techniques with the highest cost-benefit- ratio and a substantial CCMA effect appear to be the intercropping and improved fallow systems. However, we observed a lack of detailed context-specific economic, social and environmental costs for the different techniques. For effective and rational decision-making by farmers in their adoption of agroforestry, further research should focus on filling in the detailed economic, social and environmental costs of each technology in each specific context.