關鍵字：肥液灌溉系統（Fertigation system）、液體肥料（Liquid fertilizer）PE穿孔灌溉軟管（PE perforated irrigation tube）、滴灌（Trickle irrigation）、洋香瓜隧道式栽培（PE sheet-tunnel cultivation of muskmelon）
Studies on the Fertigation System and the Application of Liquid Fertilizer for PE Sheet Tunnel
T. T. Lin & S. L. Hwang
Since the successful extension of PE sheet tunnel cultivation of muskmelon develop by Tainan DAIS, the existence of a plastic sheet mulched on the soil became the barrier of irrigation and fertilizer application, and always caused deficiency of water and nutrient in the middle to late growth stage. In order to overcome the difficulties of irrigation and fertilizer application after transplanting, a new “Fertigation” system to combine irrigation and liquid fertilizer placement together was designed.
The equipment of “Fertigation” system was divided into 3 parts: a control head, a main line and the lateral lines. Control head is consisted of a liquid fertilizer tank, a pressure gage, a flow meter and a flow control valve. Main line is a 2-inch PVC pipe in diameter. The lateral lines are some low pressure (less than 1 kg/cm) and perforated PE twin tubes which were installed under the mulched PE sheet. Only one water pump is needed to operate this system as the power source.
The liquid fertilizer and irrigation water could be mixed automatically when fertilizer application is desired. The concentration of liquid fertilizer can be adjusted by changing the difference of water pressure between the main pipe and the tank of liquid fertilizer.
Results of this experiment in the winter of 1985 showed that under the “Fertigation” system, both irrigation and fertilizer application can be operated easily, and resulted in 12 and 7 days earlier than control plots for fruit setting and harvesting, respectively. The yield of muskmelon was increased 40% more than the control plots. Top dressing of liquid fertilizer also showed a great benefit in supplying nutrients for the rooting system of muskmelon that covered by a PE sheet. The new system is durable, very easy to install and operate. The cost is very low in contrast with the traditional “trickle/drip irrigation” system, which is much expensive to install and not easy to maintain.