Design and Construction of a Drip Irrigation Controller with Fertilizer Injection for Tomato Cultivation in Kaduna State

Tomato farming is one of the most commercially important agricultural activities in Kaduna State, North West Nigeria, yet yield inconsistencies due to poor water and nutrient management are common challenges among smallholder growers. This project presents the design and construction of an automated drip irrigation controller integrated with a fertilizer injection unit for precision crop nutrition management. An Arduino Mega microcontroller governs the irrigation schedule using a real-time clock module, activates solenoid valves for drip line water flow, and controls a small peristaltic pump that injects a pre-mixed liquid fertilizer concentrate into the irrigation water at a configurable injection ratio. A soil moisture sensor at root zone depth provides feedback to enable irrigation skipping when soil moisture is above the target threshold, conserving water. The system was deployed on a 0.5-hectare tomato plot in Kauru Local Government Area of Kaduna State during the 2023 dry season. Tomato yield from the irrigated and fertigated plot averaged 28 tonnes per hectare compared to 16 tonnes per hectare from a neighbouring plot under the same variety managed with furrow irrigation and broadcast fertilizer application. Water consumption was 31 percent lower under the drip system. Fertilizer input cost was also reduced by 18 percent due to improved nutrient uptake efficiency. Total system fabrication cost for the 0.5-hectare area was approximately 95,000 Naira. Keywords: drip irrigation, fertigation, tomato cultivation, precision agriculture, Kaduna State