Effect of Water Quality and Managements on Soil Chemical Characteristics

One of the water resources available in arid and semi-arid regions is the saline groundwater and drainage water from upstream farmlands، which should be used in a proper manner. One of the methods of reducing salinity effects of such water resources could be soil leaching including proper irrigation management. In this respect، an experiment was conducted on wheat (Triticum aestivum l.) on a clay soil in the southeast of Isfahan city. The treatments included three irrigation water salinity levels of 1. 7، 9، and 12. 5 dS. m-1 (S1،S2 and S3، respectively) and two irrigation water managements: (GU)، irrigation with low saline water in early season (germination and establishment stage) and، thereafter، using the abovementioned saline water، and (GQ)، irrigation with the three saline water treatments during the whole season. Two leaching treatments including without leaching (LR0) and with leaching (LR1) were also studied. The experiment was laid in a completely randomized block design، arranged as split-split plots with four replications. Salinity of irrigation water increased soil profile salinity، especially in the surface soil layer. Application of low saline water during germination and establishment (GU) and leaching reduced the soil salt contents compared to GQ and LR0 treatment. But، salt accumulation hazard still existed due to high surface evaporation potential and heavy texture of the soil، which could threaten the soil salt balance sustainability. In general، the irrigation water salinity caused an increase in soil salinity، and application of leaching and low saline water at initial stages of crop growth reduced increasing trend of soil salinity. Proper irrigation management، i. e. using low salinity irrigation water at the germination and establishment period، was more effective than leaching application.