Development of a Smart Irrigation Controller Using Soil Moisture Sensing and GSM Alerts for Farmers in Kogi State

Inefficient irrigation practices among smallholder farmers in Kogi State, North Central Nigeria, lead to both water wastage and crop loss through both over-watering and under-watering. This project developed a smart irrigation controller that automates water pump operation based on real-time soil moisture readings and sends SMS alerts to farmers via GSM. Two capacitive soil moisture sensors (v1.2) were buried at 10 cm and 30 cm depths in a test farm plot. An Arduino Uno microcontroller compared sensor readings against configurable dry and wet threshold values and activated a relay-controlled 0.5 HP submersible pump accordingly. A SIM800L GSM module sent SMS notifications to the farmer's phone for each pump activation, deactivation, and sensor fault condition. An RTC module enabled scheduled override irrigation for early morning watering regardless of soil moisture status. The system was field-tested over 21 days at a tomato demonstration farm in Lokoja LGA. Pump activation accuracy aligned with actual soil dryness conditions in 91.3 percent of measurements, validated by gravimetric soil moisture analysis. Estimated water usage reduction compared to fixed-schedule manual irrigation was 34.7 percent. Crop health visual assessment showed comparable outcomes to conventionally irrigated control plots. System power consumption averaged 2.1W in monitoring mode and 210W during pump operation. Total component cost was 24,500 naira. The study recommends incorporating weather API data for rain prediction to further reduce unnecessary irrigation activations.

Keywords: smart irrigation, soil moisture sensor, GSM alert, precision agriculture, Kogi State