ABSTRACT

Aubreville (1949) was the first to popularise the term desertification to describe the process as well as the event of changing productive land into a desert. Since then, the term has presented a conceptual and descriptive dilemma to scientists, and it was not until recently at the 1992 United Nations Conference on Environment and Development that a working definition was discussed, negotiated, and accepted. Consequently, desertification is now defined as land degradation in arid, semi-arid and dry sub-humid areas, resulting from various factors, including climatic variations and human activities. The phenomenon assumes different forms, and is induced by several factors. Some of the factors are human-induced, which predispose land to degradation: deforestation, over-grazing, and inappropriate agricultural activities (slash and burn, reduced fallow period, soil nutrient mining). The combined effects of these factors is the removal of soil vegetative cover, soil physical and chemical impoverization, a decline in productivity and a light to moderate degree of degradation. In addition, they expose the soil to the action of wind which completes and aggravates degradation to strong and extreme levels (UNEP/ISRIC/GLASOD, 1990).