Estimation of electrical conductivity of saline-sodic soils during leaching process using HYDRUS-1D

Soil degradation caused by salinization and sodification is one of major problem in arid and semi-arid regions. To overcome this problem, leaching of accumulated salts from such soils is necessary. In this research, HYDRUS-1D model was used to predict desalination process in saline-sodic soil located in north of Ahvaz. Therefore, Leaching experiments in both with (sulfuric acid) and without reclaiming material was performed in in 11 m2 plots. All experiments were accomplished by applying 100 cm of water in four-25 cm intervals. Desalinization leaching curves were measured. Also, soil texture, field capacity and permanent wilting point water contents, saturated hydraulic conductivity and solute distribution in soil profile were measured. Then, solute transport during leaching process was simulated using HYDRUS-1D by inverse method. The results of the study indicated that all the used amendments showed a pronounced difference in EC compared with control but the difference wasn't significant. Because of, the soils have enough calcium carbonate and gypsum which provide requirement calcium for reclamation. The model predicted solute transport in depths less than 100cm better than other. The simulated results indicated that amount of estimated EC in the first and second period of leaching fit to observed data better than other periods. Over all, the results of solute transport simulation during leaching experiments revealed that HYDRUS-1D provide reasonable description EC distribution in soil profile. So HYDRUS-1D model can be introduced as a suitable tool for prediction solute transport in soil under field condition.