Soil degradation is a major global problem, the effects of which may be felt most strongly in developing countries where large proportions of the population reap their livelihoods directly from the soil. In this review, I will focus on soil degradation in Africa, where declines in crop productivity have been linked to hunger and poverty. While the reality of hunger in Africa is not questionable, the nature and extent of soil degradation, and the role it plays in the vicious cycle of poverty, is still under debate.

Across Africa, a large percentage of the population depended on subsistence farming at the end of the last century. Livelihoods are diversifying and urbanization is on the rise, but in the near term, soils in Africa must sustain a largely subsistence population. Actually, sustainable soils should meet the needs of present populations without preventing future generations from meeting their needs.

In order to reverse soil degradation, it is critical to understand the factors that affect the stability and resilience of soils. Soils can be altered physically, chemically, or biologically as the result of natural processes. Eventually, soil itself forms over a thousand years through physical and chemical weathering of rocks.  Wind erosion shifts the dunes in sparsely vegetated deserts, and transports dust to other continents. Humans, however, are accelerating many of these natural processes, causing the degradation of soils. 

Physical degradation can occur when excessive soil cultivation breaks down soil aggregates; thus rapidly decomposing organic matter, loosening the soil in excess and making it vulnerable to wind and water erosion. Cultivation on steep slopes, clearing of vegetation, and poorly managed grazing are the primary factors accelerating soil erosion in Africa. High rates of topsoil loss contribute to downstream sedimentation and degradation of local and regional water bodies.

The other thing is tenure system which often determines how land is managed and used and thus is often implicated as a primary driver of degradation. For those who have tenure, policies that raise the farm gate prices of commodities are critical means for encouraging good land management strategies since they provide farmers with both resources and incentives. Smallholder farmers in Africa often operate at the economic margin where agricultural investments are a lower household priority than school fees, or medical treatment costs.

As I conclude, farmer wealth and ethnicity often determines whether soil degradation can be addressed on the farm. Wealthier farmers, who have more access to resources, are better equipped to cope with soil degradation. Therefore, land management strategies will only be successful if they can adapt to future demands for food and other ecosystem services. Future efforts should be addressing soil degradation in a way that leads to changes in soil ecosystem services, and what land management strategies make systems resilient and, thus, more sustainable.