Effect of different amendments on some physical and chemical properties of a saline-sodic soil

Soil salinity and sodicity are two aspects of land degradation، especially in arid and semi-arid regions. This study focused on the role of different amendments on physical and chemical properties of a saline sodic soil، including EC، ESP، organic carbon، bulk density، saturated percent، field capacity and available water content. The experiments were conducted as factorial based on completely randomized design using six soil amendments، including control (C)، cattle manure (M)، pistachio residue (P)، gypsum (G)، M+G and P+G، moreover، two water treatments (with and without sulfuric acid) each at three replicates. The experiments were carried out under laboratory condition using soil column. Four intermittent leaching steps were applied with one month intervals and one pore volume. Results showed that at different treatments، final EC and ESP values compared to those of the initial soil decreased 66. 2- 84. 9% and 73. 6-90. 6%، respectively. Since the soil was calcareous، the final EC and ESP of soil compared to the initial soil decreased 80 and 84. 2%، respectively because of leaching. In presence and absence of sulfuric acid، the highest efficiency in reduction of EC was found for gypsum and pistachio residue. In addition، pistachio residue and cattle manure exhibited higher and less efficiencies in reduction of ESP، respectively. The finally، ESP of the treated soils was reduced to less than 11%، for all of the treatments. Furthermore، the application of organic matters led to improvement of soil physical properties. The results indicated that sulfuric acid had no significant influence on soil bulk density. Control and gypsum treatments showed the least amounts of available water. It was also found that the combined application of organic matters with gypsum compared to their exclusive application had more significant impact on available water. The findings of this research reveal the importance of pistachio residue in ameliorating saline sodic soil under leaching condition.