Simulations Of Both Soil Water Content And Salinity Under Tape Drip Irrigation With Different Salinity Levels Of Water

The purpose of the present research is to evaluate HYDRUS-2D model so as to simulate soil water content and salinity under field conditions. Soil texture is a heterogeneous heavy soil. In this research, drip irrigation (tape) system was applied as a line source with water salinities of 1.279, 2.5, and 5 dSm(-1) in three volumes of irrigation water including 10, 15, and 20l. The observed soil moisture and Electrical conductivity of soil saturated extract (ECe) values were compared with the simulated values using normalized Root Mean Square Error (nRMSE) and Coefficient of Residual Mass (CRM). Ranges of water content nRMSE were between .91 and 2.07%, and those of CRM were between -.0080 and .0170. For salinity, ranges of CRM for beneath the tape were between -.049 and .097 and between -.065 and .081 for the horizontal distance. Ranges of nRMSE for beneath the tape and the horizontal distance were between 2.79 and 18.49% as well as 3.08 and 20%, respectively. The performance of the model was placed in excellent category to simulate the soil water content; in addition, it was placed in good to excellent classes to simulate soil salinity.