Adaptive Irrigation Scheduling for Smallholder Farms Using Low-Cost Soil Sensors

Smallholder farms in sub-Saharan Africa face growing water stress from irregular
rainfall, yet most irrigation decisions are still made by intuition. This study
evaluates a low-cost, sensor-guided irrigation schedule against conventional
practice across twelve smallholder plots in Anambra State, Nigeria, over a single
dry-season cropping cycle. Using capacitive soil-moisture sensors and a simple
threshold controller, the sensor-guided group reduced total water application by
27% while maintaining equivalent yield. We discuss the cost model, sensor drift
over the season, and the practical barriers to adoption. The results suggest that
sub-US$40 sensor kits can deliver meaningful water savings without specialised
training, offering a scalable path to climate-resilient smallholder agriculture.