Desalination of saline fields by soil leaching in the Karkhehnur Watershed, Iran

Abstract Since large parts of agricultural fields are saline or subjected to salinity stress, practical and efficient methods may be used for recycling fields, worldwide. The effects of the type and amount of soil leaching on the quality of saline fields, in different parts of the world have yet to be investigated. The objectives were to investigate: (1) the optimum depth of water required to decrease soil salinity of saline fields to the levels, suitable for crop production in the Karkhehnur Watershed, Khuzestan province, Iran, and (2) the most suitable method of soil surface leaching. Four different regions were selected for the experiment, and a wide range of soil-related parameters as well as water properties was determined. Soil leaching was conducted by surface continuous irrigation (three regions), and surface alternative irrigation (one region). The depths of soil leaching were equal to 0–25, 25–50, 50–75, 75–100, 100–125, and 125–150 cm. The class of salinity was changed to S2 (EC = 24 dS/m) from an initial class of S4 (EC = 87 dS/m) using a water depth of 25–125 cm in different experimental regions. If soil is highly saline, continuous irrigation may be a more effective method, however, under less stressful conditions, alternative irrigation can also be recommendable.