A practical model for reclamation of saline and sodic soils

Proper management of saline and sodic soils is essential for optimal conservation of soil and water resources. Accumulation of soluble salts within the root zone is one of the major problems in arid and semi-arid regions. To overcome this problem، leaching of accumulated salts from such soils is necessary. The most important task in leaching practices is assessment of water quantity required for leaching of saline and saline-sodic soils. Therefore، reliable estimation of the required leaching water quantity is vital for reducing soil salinity to a desirable level. The objectives of this study were to introduce an empirical model to account for reclamation water and to compare the obtained results with some available models. Consequently، a large scale field experiment was conducted in jofeir region at south part of west Khuzestan plains، covering an area of 21285 ha with S3A2 salinity-sodicity classes. The intermittent pounding experiment was conducted with six double ring infiltrometers in a circular array. All experiments were accomplished by applying 100 cm of water in four-25 cm intervals. The leaching water was supplied from Karun rive. Four mathematical models were applied to the collected experimental data to derive a suitable empirical model. The results indicated that the proposed power model with maximum correlation coefficient of 0. 83 and minimum standard error of 0. 44 can provide reasonable estimates for leaching process compares to the previously proposed models. The results indicated that the empirical relations given by Rajabzadeh (2009)، Hoffman (1980) and Laffelar and Sharma (1977) can not resemble the field conditions. However، the empirical relationships introduced by Pazira and Kawachi (1981) and Revee (1957) overestimate the depth of reclamation water. The empirical models of Pazira and Keshavarz (1989)، Asadi et al.، (2013) and Dieleman (1963) underestimated the depth of required reclamation water compares to the newly proposed model.