Development of a cost-effective, photovoltaic-powered drip irrigation system for increased water resource management on smallholder farms in Sub-Saharan Africa

Introducing irrigation on farms in Sub-Saharan Africa (SSA) has been shown to have positive impacts on food security, nutrition, and poverty reduction. Drip irrigation in particular has a positive impact on water resource management. Here we introduce our work on the design of a photovoltaic (PV)-powered drip irrigation system for use on smallholder farms in SSA. As this is a highly cost-sensitive market, we compare the estimated costs of drip irrigation systems to those of PV-powered impact sprinkler systems similar to ones currently in use in the area. We use technical and ethnographic factors to present an argument for the design of a PV-powered drip irrigation system that could save up to 70% of water compared to that of a PV-powered sprinkler irrigation system. We present a model that calculates the energetics of delivering water plus the capital costs of irrigation equipment including commercially available sprinklers, PV panels, and cost-saving innovative drip technology designed previously by our research team. The model, informed by interviews with market stakeholders and SSA farmers, estimates energy used in irrigation systems given a number of characteristics about a farm, including field area, borehole depth, irrigation time per day, crop water requirement, and pump efficiency. Initial results predict PV-powered drip irrigation systems to be at least 73% and 84% less expensive than impact sprinkler systems for two representative horticultural farms of 0.5 ha and 1 ha, respectively, each with 20m deep boreholes. Our results also highlight the impact that could come from helping farmers operate on optimal irrigation schedules, incorporating data from inexpensive soil moisture sensors and local weather stations combined with a smarter pumping system, reducing a common tendency to overwater one's farm. These initial findings suggest that PV-powered drip irrigation systems have the strong potential to expand irrigation in SSA while promoting better water resource management.