Technical and Hydraulic Evaluation of Subsurface Emitters and Subsurface Drip Irrigation System Efficiency under Sugarcane Cultivation

To ensure optimal operation of the drip irrigation system, it should be evaluated periodically. This research was conducted to evaluate the technical and hydraulic performance of subsurface drip irrigation system in sugar cane plantation in Sugar Cane Research and Training Institute of Khuzestan during growing seasons of 2016-2017 and 2017-2018. For this study, four laterals were selected in experimental field (the first, one third, two third and the last laterals) and four sections including the first, one third, two thirds, and the last were determined on each laterals. Then, the volume of effluent water was measured for three minutes at any measurement point and the system parameters were calculated. Results of the evaluation of the drippers in the laboratory showed that the manufacture's coefficient variations (Cv), coefficient of uniformity (Cu), and distribution uniformity (Eu), coefficients were 15%, 90%, and 84 percent and the values of the exponent x and the k coefficient in the discharge-pressure equation were, respectively, -0.043 and 2.41. Means of Cu, Eu, coefficient of flow variations (Vqs), and Uqs during two growing seasons were 89.2%, 87.8%, 10.3%, and 89.7 percent, respectively. Based on these results, system performance was generally good. Also, by measuring pressure at different points of the system in the middle of the second growing season, the ASAE assessment indicators including: Vqs, Uqs,Vhs, and Vpf were 9%, 91%, 25%, and 13 percent, respectively. Thus, in terms of the overall performance of the drippers and uniformity of distribution the studied irrigation system was considered to be relatively good to good.