The effect of long-term irrigation with treated wastewater on some chemical properties of soil layers in (Kermanshah city Located in the west of Iran)

Abstract In different countries located in arid and semi-arid regions of the world, one of the most important problems in the agricultural sector is finding different alternative and reliable water sources for irrigation and wastewater is the only source of water that is increasing despite the decrease in the volume of other sources. Therefore, this study was performed to investigate the effects of long-term irrigation with municipal treated wastewater (TWW) of Kermanshah city on cover lands compared to well water (WW) as a control treatment on soil chemical properties in three layers with three replications in a two-year split plot trial design. The results showed that irrigation with TWW compared to WW caused an increase of 35.94, 32.35, 38.24, 20, 76, 1.68, 40, 40.77, 4.27 percent in the Cl-, HCO3-, CaCO3, TN, TP, K, OC, EC, pH in the 0–90 cm soil layer respectively. According to these results, the increasing of soil organic carbon, in addition to soil fertility, can stabilize and stop the mobility of heavy metals by creating organic bonds with heavy metals. Also, the results showed that due to sufficient access to treated wastewater; it is possible to do leaching, which reduces the risk of salinization of those lands. However, in some areas, increase of sodium percentage led the soil compaction and permeability reduce of lands due to the high clay content.