The interactive effects of rainfall, nutrient supply and defoliation on the herbage yields of Sahelian rangelands in north-east Mali
In the Sahelian rangelands biomass production is constrained by soil moisture in the drier (100-250 mm) parts and by soil nutrients in the wetter parts. Similarly, for a given Sahelian range, nutrient deficiency would be more prominent in good than in poor rainfall years. To test this hypothesis, fertiliser trials were carried out at sites distributed along the bioclimatic gradient in the Gourma (Mali) over contrasting rainfall years between 1988 and 1992.