Investigation of Effect of Dry Drainage on the Transport and Distribution of Cations Using a Physical Model

In recent years, decreasing water resources stimulated researchers to consider dry drainage in dry area due to less cost and water requirement. Understanding mechanism and the amount of different salts transportation from the irrigated area to the non-irrigated area is necessary to evaluate the performance of this system and the pre-implementation of purification and recovery projects of the salt collected from the non-planted surface area. In this study, the effect of dry drainage on the transportation of important cations and salinity changes (EC) in a loamy soil were investigated using a physical model under barley cultivation in 2017. The physical model was made of galvanize and had useful length, width and height of 2, 0.5 and 1 meter respectively. On the basis of the results, changes in sodium and calcium concentration profiles were similar and they were different from changes in potassium and magnesium concentration profiles. Sodium, potassium and calcium ions were accumulated in the upper soil layer, but magnesium was accumulated in the lower soil layer of the non-planted area. At the end of experiment, sodium, calcium, potassium, magnesium concentrations and SAR at the soil surface of non-irrigated area were 210, 410, 125, 115 and 126 percent of their initial values respectively. At the end of experiment, the soil surface salinity of the planted and non-planted areas was increased up to 145 and 270% of their initial values, respectively.