Trends of productivity of water in rain-fed agriculture (original) (raw)

In Sub-Saharan Africa, rain-fed agriculture is the dominant source of food production. It is likely to remain so for the foreseeable future. However, yields from rain-fed agriculture are often very low. But there is an enormous opportunity to raise crop yield of rain-fed agriculture especially by focusing on the aspect of increasing productivity of water. In order to formulate and adopt appropriate and adequate options for increasing productivity of water in rain-fed agriculture, there is a need to have an understanding of the trend of productivity of water in rain-fed agriculture. In this paper, an analysis of the trend of productivity of water (PW) for five crops cultivated under rain-fed conditions in Mbarali District, Mbeya Region, Tanzania, was carried out using secondary data. The crops included maize, sorghum, beans, potato, and groundnut. The PW (eta) for maize, sorghum, potato, beans and groundnut had peak values of 0.49kg/m 3 in 1993/94, 0.47 kg/m 3 in 1994/95, 3.07kg/m 3 in 1993/94, 0.33kg/m 3 in 1996/97, and 0.20kg/m 3 in 1994/95 cropping seasons, respectively. Evapotranspiration deficit caused by either mid cropping-season dry spell or early cessation of rainfall and low rainfall utilization efficiency were the primary drivers of the PW in rain-fed agriculture in the area.