The observed water productivity (WP, kilograms of crop per cubic metre of rain) of cereals is very low in the Volta Basin: mean WP barely reaches 0.15 kg/m3 for maize (±0.05), with a mean yield of 1.25 t/ha (±0.58). We sought to explain these observations by using simulation modelling to develop a frequency analysis along a 9° transect on the meridian of Ouagadougou, that is about the whole gradient of rainfall in the basin. At both plot and basin scale, the model indicated that fertilizers would allow much higher yields and thus better WP.
Water International (2009) 34 (1) 104-118 [DOI: 10.1080/02508060802666336]
Yields and water productivity of rainfed grain crops in the Volta Basin, West Africa