Phytoremediation of Saline-Sodic Soils by Sesbania acuelata, Rubia tinctorum and Cynodon dactylon Compared to Chemical Methods

The reclamation of salt-affected soils which occur on 831×106 ha can be effective in increasing agricultural production. Cultivation of plant species which are resistant to salinity can improve the soil by increasing the solubility of calcite and releasing the calcium in soil solution. This study was conducted as a column experiment with a saline-sodic soil (SAR = 23. 8، EC= 12. 88 dS m-1، pH= 7. 7، CaCO3= 15. 15 %). Three plant treatments including Sesbania acuelata، Cyanodon dactylon and Rubia tinctorum، and three chemical treatments including gypsum in two levels (50% and 100% gypsum requirement) and sulfuric acid with a control were arranged. All treatments were replicated 3 times. The soil columns were similarly leached by 41 liters of tap water during 30 days in 8 stages. After leaching، SAR and EC in soil، the amounts of sodium in leachate and total amount of sodium in plants shoot were determined. Results showed that the SAR was decreased compared to control by the plant treatments and the chemical amendments by about 59% and 65%، respectively. Moreover، two plants of Cyanodon dactylon and Rubia tinctorum had maximum amount of leachate sodium، which shows an impressive role of these plants in dissolution and leaching of exchangeable or sediment sodium in comparison with the other treatments. According to salient performance of phytoremediation in improvement of physicochemical properties of soil compared to chemical amendments، phytoremediation can be recommended as a profitable low-cost and effective method for remediation of saline-sodic soils.