Can african agrarian systems carry on rapidly increasing populations ? To contribute to this debate, a model has been built at the village level in the cotton zone and is used in a recursive way. The maximum of the available information on the zone has been incorporated. Simulations show a crucial threshold when fallow desappear and when it is necessary to combine different techniques for a better management of the soils and of the organic matter ; doing so, a permanent regime could be reach with four times more people but with half the revenue.
