Search

Fresh water sources are becoming scarce. Crop irrigation uses more than 70% of the world’s water, and thus, improving irrigation efficiency and saving water is key to sustaining the food demands of a fast-growing world population. Manually controlling irrigation often leads to over dosing and excess nutrients drain from the soil. Soil sensor activated irrigation is an important step in improving water use efficiency. By using sensors, irrigation water can be controlled more precisely to prevent excessive drainage and fertilizer leaching or even under dosing leading to yield reduction. Over the past decades, soil moisture sensor technology has been improved a lot, and meanwhile a large variety of TDR and FDR sensors with good performance are available. Water content may vary within an irrigated field. Since sensors only measure locally and existing sensors are relatively expensive, use of more sensors per field can become costly. The AquaTag is a prototype low-cost, wireless, near-field, passive, capacitance resonance type soil moisture sensor which can be read-out using a hand-held reading device. To help small-scale and low-tech farmers in saving water, we evaluated a simple irrigation support system making use of this sensor. The support system advises upon soil water activation levels and dosing taking crop stage and soil hydraulics into account, as well as the average water content of an irrigated plot obtained with the sensors. Its potential for useability was demonstrated in nine Turkish commercial farms with soil-grown vegetables. Farmers using the sensors were able to raise their irrigation water productivity on average with 22.9% as compared to farmers not using the sensors. The prototype performed well, but it should be further developed toward a sensor that can measure at rooting depth up to 30-60 cm.