African Soil Erosion and Desertification are some of the key challenges facing the continent which remains almost unresolved for years. Until recently, there was widespread consensus among scientists and policy makers that African soils were threatened by ill-advised traditional farming methods that increased soil erosion and desertification (the process in which soil dries out until almost no vegetation grows on it). Policy documents used limited, often flawed case studies to produce continent-wide generalizations in which worst-case scenarios were too often presented as typical. In reality, the nature and extent of soil erosion and desertification varies greatly throughout Africa and much of it is unrelated to human activity. For example, savanna regions are subject to wind erosion in the dry season, which is the primary cause of soil erosion in arid and semiarid environments.
The Sahel, a semiarid savanna region located to the south of the Sahara, experienced a severe drought from the late 1960s to the early 1970s. In reaction, Western scholars propagated a popular view that the Sahara was expanding year by year, relentlessly enveloping once-productive land. Further research has shown that, while soil degradation was confirmed in some areas, in many parts of the Sahel there was little evidence of degradation, and none of steady desert expansion. During the colonial era, the perception of imminent crisis led to policy initiatives designed to preserve the soil. Colonial administrators attempted to control the perceived problem of erosion by enforcing restrictions on herding and agriculture, restricting the use of fire to clear land for agriculture, and installing grass and stone barriers along slope contours. These measures were generally resented by the local African population, and they had little impact on erosion rates. Similarly, attempts to control desertification through policies such as planting shelter belts of trees and restricting nomadic herding have had limited effect.
Scientific research has demonstrated that indigenous African farming and herding practices are much less harmful to the soil than was formerly believed. Methods such as retaining farmland trees, growing crops on ridges, and inter-planting different crops densely in a single field significantly reduce soil erosion. On the other hand, modern cultivation methods—involving the use of mechanical equipment, row cropping, and weed control with herbicides—greatly increase the risk of soil loss. Similarly, problems of soil erosion and degradation are greater in areas with fenced cattle ranches than in places where traditional livestock practices are followed, with animals grazing less intensively over a very large area. African Soil Erosion and Desertification have often resulted in certain species migrating to what could be considered suitable areas within the continent.