Afforestation in Drylands of West Africa Rehabilitation of degraded croplands

Situation after 15 month. Photos: Florent Noulèkoun

January 08, 2020.  

The ongoing cropland degradation in West Africa, particularly in its dryland regions, is increasingly threatening food security, environmental health, and rural and urban livelihoods. This situation is exacerbated by the growing impacts of climate change. Afforestation with multipurpose tree species has been recognized worldwide as a low-cost and viable option to reverse land degradation in the face of climate change.

To confirm this approach for the semi-arid areas of West Africa and to assess the suitability of five multipurpose tree species for planting on degraded croplands, afforestation trials were conducted in the Sudano-Sahelian zone of Benin. The planted multipurpose tree species included the fast-growing Leucaena leucocephala Lam. (river tamarind), Moringa oleifera Lam. (drumstick), Jatropha curcas L. (physic nut) as well as slow-growing Anacardium occidentale L. (cashew) and Parkia biglobosa Jacq. (African locust bean).

Based on an assessment of survival rates and functional traits of saplings subjected to fertilization and supplemental irrigation treatments, the study revealed a variety of fast- and slow-growing species suitable for  afforestation in semi-arid Benin.

Climate-growth modeling analysis, considering risks for future afforestation efforts due to projected water deficits, showed that deep rooting might be an effective adaptive trait to enhance biomass growth in the changing environment. For the rehabilitation of degraded croplands in the West African drylands, the findings suggest the need for silvicultural management and a multi-species afforestation system integrating a diversity of species able to develop deep-penetrating root systems.