Using desalinization models for scheduling crop rotation of saline-sodic soils: a case study in Ramhormoz region, Iran

Soil salinity is one of the important challenges for sustainable agriculture in arid and semi-arid regions. Accumulation of soluble salts within the soil profile adversely affects some physical and chemical properties of soils including osmotic pressure, permeability and hydraulic conductivity. As a consequence, growth and development of plant is seriously reduced or fully ceased. The objective of this study was to assess using desalinization models for scheduling crop rotation of reclamation saline-sodic soils. Consequently, a large area of 45,000 ha with S4A3 (extreme salinity and sodicity) salinity/sodicity class was selected to obtain the required data ,in Khuzestan, Iran. This experiment was conducted with two treatments each with three 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, 10 Ton gypsum (78% purity rate) was applied prior to salt leaching together with leaching water. 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 soil analyses were performed for the collected data. The results indicated that the logarithmic model can estimate the capital leaching requirement much better than other models. Based on the obtained model, the amount of net water needed to reduce initial soil salinity was calculated and finally crop rotation in two options was presented for reclamation of saline-sodic soils. The first option with preliminary leaching and cultivation of barley in continues leaching was assigned as the first priority. The second option with preliminary leaching and alfalfa cultivation and continues leaching was assigned as the next priority. The obtained results further indicated that the inclusion of scheduling crop rotation to the leaching practice, in addition to enhance effective leaching of soluble salts from the soil profile, causes considerable water saving.