Modeling leaching requirement for desalinization of saline soils

Reclamation of saline soils is an important practice from soil and water resources conservation point of view. In saline soils, crop production is adversely affected by soluble salts within the root zone as well as by shallow saline water table. The first step for reclamation of such soils is reducing the soil salinity to optimum level by capital leaching. Reclamation of saline soils depends on quantity and quality of applied water, as well as soil drainage conditions. The objective of this study was to develop a model to estimate water requirement for reclamation of saline soils based on some obtainable soil physical characteristics. Consequently, a large area of 3,216 ha with S4A3 salinity/sodicity class in Khuzestan, Iran, was selected to obtain the required data. This experiment was conducted with two treatments and two replicates. In the first treatment, the experiment was conducted by applying just 100 cm water depth in four-25 cm intervals. In the second treatment, 5,000 kg/ha Sulfuric Acid was applied prior to salt leaching together with leaching water. The intermittent ponding method was conducted with double rings in a circular array. Soil samples were taken from 0-25, 25-50, 50-75, 75-100, 100-125 and 125-150 cm soil depths before, during and after each leaching water application interval. The required physical and chemical analyses were performed on the collected data. Several mathematical models were applied to the obtained data to verify their performances. The results indicated that the logarithmic model can estimate the capital leaching requirement much than other models. This empirical model with minimum weighted mean of capital leaching water (38 cm) represents the best performance from water saving point of view compares to other models.