Effect of Slope on Soil Wetting Pattern under Surface Drip Irrigation and Simulation HYDRUS-2D Model

In this study,  effect of slope on soil wetting pattern under surface drip irrigation and simulation with HYDRUS-2D model evaluated. The physical model made of Plexiglas to size 83, 6 and 54 cm (length, width, height) filled with silty clay loam soil was used. To achieve the desired discharge, a small drip irrigation system created that includes a water tank with a fixed height (About 2 meters), a emitters regulated manually, and pipe transferring the water to emitters. Discharge was 4 L/hr and the slopes of selective were 0, 5, 15 and 25 percent. Irrigation time for each test was fixed and 2 hours. Readings of wet pattern was performed until 24 hours after irrigation and fixed wetting pattern. HYDRUS-2D model was Simulation selection model. To determine soil hydraulic parameters Rosetta model used. For The maximum wet depth and maximum wet width obtained RMSE value between 1.44-3.4% that shows the error is low. The results showed that HYDRUS-2D model have high ability to simulate the wetting pattern flat and slope lands.