Soil erosion, land degradation and social transition : geoecological analysis of a semi-arid tropical region, Kenya

During the thirty years since the achievement of independence in many African countries, Kenya has been prominent as an apparent exception to the widespread political instability, social disturbance, environmental degradation, famine and desertification which have afflicted so many parts of the continent. To a large extent this has been achieved because of the high productivity of fertile soils in the humid highlands which form some 25 per cent of the country. Until very recently this has been sufficient to sustain nearly 80 per cent of the Kenyan population, which still has an annual growth rate near 4 per cent, amongst the highest in the world. Land use pressure in the highlands has become intense leading to subdivision of arid into non-viable units, and expansion onto steeply sloping lands of lower fertility and high erosion hazard. The highlands cannot sustain significantly higher population, so accommodation of future population growth must depend on significantly increased utilization of the 75 per cent of the country which is arid or semi-arid