Indigenous Farmer-Managed Irrigation in Sonjo, Tanzania

Despite wide interest expressed in indigenous farmer-managed small-scale irrigation in Sub-Saharan Africa, there are relatively few studies of such systems. This paper offers a preliminary description of that practised by the Sonjo in northern Tanzania. Sonjo irrigation involves simple canals carrying water diverted by stone and brushwood dams from spring-fed streams and rivers. Land is irrigated on floodplain and piedmont slopes, and a wide variety of crops is now grown. There is an established system of water allocation. Sonjo irrigation is an example of hill-furrow irrigation of a kind occurring in several places in East Africa. Fuller information of the extent, organization, management and agronomy of these systems is vital as development initiatives are established which attempt to 'improve' or replicate 'indigenous knowledge' about irrigation.