Role of native shrubs of the Sahel in mitigating water and nutrient stresses of agricultural crops

Abstract:

In the semi arid zone of the Sahel native woody shrubs are present in many farmers’ fields. The native density of these shrubs is fairly low at around 200 to 300 individuals per hectare. An ongoing study in the Peanut Basin, Senegal has shown a vast improvement in crop yields when annual food crops are planted with the shrub Guiera senegalensis, especially in years of low or irregular precipitation. Shrubs in field plots established in 2003 where a rotation of peanuts and millet are grown are planted at a much higher density of 1500-1830 individuals per hectare. In order to increase the density of shrubs on the landscape, the shrubs must be cultivated. We monitored soil moisture, soil temperature, and growth of recently transplanted individuals at a field station in Thies, Senegal.This study seeks to determine the growth characteristics and water use of young shrubs in order to inform possible future plantations of the shrubs in a more intensely managed agroecosystem. If this technique of intercropping is to be expanded we must not exceed the carrying capacity of the landscape. In vulnerable ecosystems where natural resources are scarce and farming inputs are low, we must work to determine ways of exploiting the adaptation of local agroecosystems to increase the sustainability of agriculture in the region.