ABSTRACT
Food security in Africa, and especially in sub-Saharan Africa, is one of our most crucial challenges, which is why the United Nations has classi‹ed it as the ‹rst target of Objective 1 of the Millennium Development Goals. The rate of population growth is higher in sub-Saharan Africa than in any other region of the world (FAO, 1998). According to UN evaluations (1997), this population is likely to double in the next 25 years. In order to reduce poverty and hunger, agricultural production will need to increase considerably through sustainable management of soil fertility. Soil fertility is limited by the availability of arable soils, the use of mineral fertilizers, the restoration of soil fertility, water management, and climatic variability. Traditional systems of soil management depend on the use of long periods of fallow land intended to maintain soil fertility, but unfortunately this does not work for Africa due to its high population density. Assessment of available land surface in Africa indicates that there is between 0.28 and 0.52 ha of cultivated land per capita (Fischer and Heilig, 1997). Due to the lack of available land, fallow soils must be put back into agricultural production, and fertility falls, making the land more vulnerable to erosion.
