Effects of Water Quality on Trend of Desodification of Heavy Soils by Continuous Leaching

Huge amount of drainage water is disposing from operating irrigation and drainage networks in Khuzestan، SW Iran، that needs to manage and/or reuse. One of the low risk methods of reusing drainage water is to use it for land reclamation. To investigate the effects of water quality on desodification of clay soils of this area، leaching experiments were done in 1. 5×1. 5 meter Plots in “Salman Farsi” sugarcane agro industry، South Khuzestan. Leaching with three different water qualities; 2. 61 dS/m (fresh water from Karun River)، 6. 0 and 9. 0 dS/m (mixture of agro industry drainage water and Karun River water) in three treatments; T1، T2 and T3 respectively، and six replications based on complete randomized blocks design were experimented. Rate of desodification were decreased with increasing leaching water salinity. Using drainwater with salinity of 6. 0 dS/m led to increasing dissolved Ca++ and Mg++ in soil after leaching. The SAR of 0-30 cm soil layer that was 84 (meq/lit) 1/2، after application of treatments T1، T2 and T3 decreased to 9، 10 and 18 (meq/lit) 1/2 respectively. So the sodicity problem was solved with leaching by drainage water with salinity of 6. 0 dS/m، and there is no need to use fresh water. The soil pH was not in the basic range neither before nor after leaching.