Status and trends in land degradation in Africa

There is insufficient data on the extent, severity and trend of land degradation in Africa. Through a four steps approach, which is based on the identification of a pillar layer (FAO problem soils map) and the combination of dynamic factors (human activities, livestock, climate) to determine risk factors, the current paper aims at providing quantitative data on the status and trend of land degradation at agro-ecological and main river basin levels. The results revealed that: (i) "hot spots" of land degradation are largely predominant at continental level, compare to the "bright spots" of very low to low degradation; (ii) there is an increasing trend of severity and extend of land degradation from the humid zones of the Congo and Zambezi basins (24 to 29%) to the dry areas of the Nile, Niger and lake Chad basins (78 to 86%); (iii) the interrelation and cumulative effects of water and wind erosion are also increasing along these agro ecological zones. The study also stressed on the high spatial variability in the extent and trend of degradation process according to the various agro-ecological zones and river basins. This variability could be strongly linked to soils behaviour and level of resistance, to the quality of their surrounding environment as well as to the impact of investments for conservation of natural resources and for better land care.