The Sahel is a climatic zone that stretches from the Atlantic Ocean to the Red Sea with a width of 400 km to 600 km from North to South and a rainfall ranging from 100 to 600 mm. This zone is characterised by sandy soils supporting thorny vegetation and a discontinuous layer of herbaceous species. Transhumance and nomadic grazing are the main forms of land uses although in some areas there are some rain fed and/or irrigated cropping systems.