Guan'gai paishui xuebao (Jan 2023)
An Injected Fertigation Device
Abstract
【Background and objective】 Fertigation has the advantage of delivering water and fertilizers simultaneously into the root zones to maximize their uptake by crops. It has seen a rapid application in China. Typical fertilization devices consist of a pressure tank, a Venturi fertilizer applicator, a proportional fertilizer pump and a fertilizer injection pump, but most of them can only use soluble fertilizers. The purpose of this paper is to present the prototype of an injected fertigation device that uses solid fertilizers. 【Method】 We redesigned the structure and fertilization part of fertigation device, and then analyzed and tested its operation parameters, including their influence on uniformity of fertilizer application. We compared its performance with that of the conventional pressure tank. 【Result】 The injected fertigation device works well. Its fertilizer injection flow rate is 300 L/h and the fertilizer-feeding flow rate is proportional to the speed of the stepper motor. Increasing mixing speed of the device improves the uniformity of the fertilizer concentration; the optimal mixing speed is 400 rpm. Reducing fertilizer-feeding flow rate improves uniformity of the fertilizer concentration, and increasing the water flow rate can also enhance the uniformity of the fertilizer liquid concentration. When the water flow rate is 1.5 m3/h, 1.0 m3/h and 0.5 m3/h, the fertilization concentration deviation after applying 10 kg of compound fertilizer is 51.67%, 55.07% and 52.75%, respectively, and their associated fertilization concentration deviation is 50% smaller than that of the pressure tank ovverall. The stability and uniformity of the outlet fertilizer concentration in the device is much higher than those using the conventional pressure tank. 【Conclusion】 The injected fertigation device can dispose of solid fertilizer into the irrigation pipe where it dissolves. Compared with similar fertigation devices that use soluble fertilizers, the new device has the advantage of high fertilization uniformity and fast disposing of fertilizers.
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