Simulation of the effect of irrigation with Saline-sodic water on Soil infiltration Rate changes with Kostiakov and Philip's infiltration model

In order to evaluating effects of irrigation with saline-sodic water, we conducted three infiltration experiments in clay-loam soil in end-close furrow. We were using 5cm water depth every week, which had EC=12 ds/m and SAR=32. Experiments were done with volume-index method in end-close furrow in third, sixth and tenth irrigation. Therefore infiltration speed and cumulative infiltrations curves were fitted in different times with Kostiakov and Philip models. Results showed that great decrease in infiltration rate was happened since irrigation with saline-sodic water in experiment. Therefore infiltration rate decreased 40.6 and 68 percent from third irrigation to sixth and sixth to tenth irrigation, respectively. So using saline-sodic water can decreased infiltration rate up to 81 percent in 50 days. Evaluation of the simulation results of test data again Kostiakov &loese and Philip model data with RMSE and MBE parameters showed that these models could simulate soil infiltration rate changes good under the effect of irrigation with saline-sodic water. Also simulation accuracy was increased at the end of experience time than initial and mead time infiltration tests