Technical validation of the Predictive Optimal Water and Energy Irrigation (POWEIr) controller for solar-powered drip irrigation

Abstract

To feed the growing population, agriculture production must be intensified using existing resources. Sustainable agriculture intensification is particularly important in low and middle income countries (LMICs), which disproportionately experience food insecurity. This study evaluates the performance of a precision irrigation controller for solar-powered drip irrigation (SPDI) under real-world operating conditions. SPDI has the potential to increase water use efficiency and reduce fossil fuel use for irrigation. Precision irrigation technology could lower SPDI operating costs and enable sustainable irrigation practices among farmers with varied expertise. Despite these benefits, the adoption of SPDI and precision irrigation is limited in LMICs due to high investment costs and system complexity. Previous work proposed the Predictive Optimal Water and Energy Irrigation (POWEIr) controller as a precision irrigation solution that could meet the needs of farmers in resource-constrained contexts. This study quantifies the POWEIr controller performance in terms of water and energy savings, irrigation reliability, and system cost. The controller reduced water and energy use compared to typical farmer practice by up to 44% and 43%, respectively, while maintaining crop yield over three growing seasons. The controller used solar power for irrigation, but relied on a buffer battery to execute irrigation schedules. A yield loss sensitivity analysis found that increasing the controller’s use of solar energy by about 40% would have been sufficient to reliably irrigate with solar alone. These results suggest that the POWEIr controller could enable reliable, low-cost SPDI systems, and if adopted, could make sustainable irrigation practices more accessible to farmers in LMICs.