Why promote improved fallows as a climate-smart agroforestry technology in Sub-Saharan Africa?
This review (PDF) in the journal Sustainability provides an overview of how improved fallows (an agroforestry technology consisting of planting mainly legume tree/shrub species in rotation with cultivated crops) may achieve the goals of climate-smart agriculture in Sub-Saharan Africa (SSA). Through this, it assesses the trade-offs and synergies of how specific agroforestry technologies or practices achieve the three pillars of climate-smart agriculture; mitigation, adaptation and productivity. The review showed that improved fallow systems have real potential to contribute to food security and climate change mitigation and adaptation in SSA. Under proper management, improved fallows can increase maize yields to about 6 t ha−1, which is comparable to conventional maize yields under fertilization. This is attributed to improved soil fertility and nutrient use efficiency. Improved fallows increase soil carbon sequestration and reduce greenhouse emissions. Further, as a multiple output land use system, improved fallows may increase fodder availability during dry periods and provide substantial biomass for charcoal production. These livelihood options may become important financial safety nets during off seasons or in the event of crop failures. This notwithstanding, the adoption of improved fallows is mainly in Southern and Eastern Africa. Land tenure issues, lack of social capital, and improved germplasm and accessions of fallow species have been cited as constraints to scaling up. However, development of seed orchards, nursery development, and the willingness of policy makers to create a policy environment that addresses market failures and alleviates disincentives should improve adoption and future scaling up.