Development and performance evaluation of a low-cost sensor-based automated drip irrigation system for small-scale farming

Abstract

Small-scale farmers operating in water-scarce areas are frequently deprived of access to affordable and dependable irrigation scheduling technologies. To overcome this obstacle, a sensor-based automated drip irrigation system employing inexpensive components was developed and tested for small-scale farming purposes. The system features a microcontroller connected to in-house-developed NE555- based soil moisture and water-level sensors to enable irrigation as per the preset soil moisture limits without the need for internet connectivity. The system was evaluated in a laboratory setting using clay, sand, and loam soils that were compacted in PVC columns and irrigated through drip emitters. Volumetric soil moisture content, irrigation duration, and water application volumes were recorded and compared with those from a commercial reference sensor (MPM160). The results revealed that the newly developed system and the reference sensor were in strong agreement indicating root mean square error (RMSE), mean bias error (MBE) (1.90%, −0.69%; 5.2%, 1.90%) in clay soils, with no significant differences (p > 0.05) at irrigation start and termination, respectively. The NE555 sensor performed fairly in sandy loam (RMSE = 8.4%) at irrigation termination, but there was unreliability at low-moisture levels (MBE = −2.4%), and there were significant differences (p < 0.05) in sand due to the limitations of compaction and probe-soil contact. The irrigation durations were 18.9, 25.8, and 19.4 min on average, and the corresponding water volumes were 1280, 1073, and 896 mL for clay, sandy loam, and sand, respectively. In general, the system performed reliably in fine-textured soils and is an inexpensive sensor-based technology that operates offline, without internet connectivity and uses low-cost sensors and a microcontroller for irrigation scheduling. The system is expected to help the water sector.