Access to irrigation reduces the risk of crop failure, encouraging the adoption of higher-yielding varieties of food crops, diversification into higher-value cash crops, application of fertilisers and pest management, and intensification of farm labour and practices (Van Koppen et al., According to the World Development Report 2008 (World Bank, 2007), irrigated land does not exceed 4% of total agricultural land in Sub-Saharan Africa, compared with 29% in East Asia and 39% in South Asia. In areas where farmers mostly rely on rain-fed agriculture, water availability is one of the most binding constraints on agricultural production.