Study on Prediction of the Final Soil Salinity for Soil Desalinization and the Amount of Reclamation Water Requirement for Salt Leaching of Saline and Sodic Soils Using Empirical Simulation Models (Case Study: Khuzestan Province, Iran)

The study area was located at central part of Khuzestan province, Iran. Soil survey and land classification of the area showed that from total surveyed area of about 41,855 hectares, an area of about 14,100 hectares (33.7%) were saline / saline - sodic soils, in different extents. Also about 36,430 hectares (87.0 % of the total area) was subjected to water logging and poor internal drainage conditions. To study the possibilities of Desalinization and Desodification, six different sites were selected in the most Saline – Sodic parts of the study area for which eight treatments (Six for leaching water applications and two with gypsum as soil amendment) by means of 1.0 meter depth of leaching water application in four 0.25 meter intervals. Soil samples were taken before, during and after each leaching water application interval. The collected soil and water samples were then analyzed in the laboratory. Based on the collected data from salt leaching experiments, the Desalinization and Desodification leaching curves were obtained. Different theoretical models were also tested by comparing the calculated and experimental Desalinization and Desodification data. Reasonable agreements between theoretical and typical experimental leaching curves were observed. Some empirical exponential relationships were then obtained, enabling users to insert leaching efficiency coefficient and volumetric soil water content and depths to predict both final soil salinity and sodicity along with required depth of leaching water application. Also, application of any amendment materials such as gypsum was not needed for the reclamation of these soils.