Application of physical model to simulate of permanent and intermittent leaching of saline and sodic soils

Salt-affected soils have gained a major global-regional-national-ecosystem-farm level concern (Hossain, 2018). One of the important options in leaching is to precisely determine the volume of water required due to the problem of water scarcity (Karandish, 2016; Babazadeh et al., 2017). The aim of this study was to evaluate the amount of leaching water in two continuous and intermittent methods to compare these two methods with each other and with pre-leaching soil characteristics on three series of saline soils of Mighan plain in Markazi province with different texture. Leaching operations were performed using the methods described in 50 cm in 5 alterations. Electrical conductivity and soil sodium absorption ratio after leaching were measured and compared with these two parameters before leaching. Also, in order to determine the most appropriate leaching method, Dunnett multiple comparison test was performed in three areas and five soil depths. The results of this study showed that, on average to the desired depth, leaching improved soil salinity and sodicity so that soil salinity was reduced from 20.12 ds/m to 7.80 ds/m in continuous leaching method and to 5.63 ds/m in intermittent method and exchangeable sodium percentage was declined from 40.35 to 37.11 in continuous leaching method and to 29.18 in intermittent method. The lack of decrease in exchangeable sodium percentage due to the decline in soluble salts and relative abundance of sodium ion in soil solution after leaching which confirms the study of soluble cations in the soil. It is resulted that, intermitted leaching method has better leaching efficiency in all three areas and can be recommended for leaching the soils of the study area.