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Limited water resources have increased the necessity for optimal water consumption in the agricultural sector. One of the options to achieve this goal is to use modern irrigation methods. The use of these systems in soils prone to degradation through salinization and alkalinization requires soil quality monitoring over time. In the present study, the effect of sprinkler irrigation system on soil salts in fine-textured soils prone to salinity and alkalinity in Khuzestan province was investigated. The experimental farm was located in the Agricultural and Natural Resources Research and Education Center of Khuzestan Province. Summer corn was cultivated in 2016 and 2017.
The average yield of two years for the sprinkler irrigation system consisting of three irrigation intervals, And the surface irrigation system consisting of two furrow and basin methods showed that not only the yield of biomass and grain yield in the surface method is much higher than the sprinkler system, but also the water productivity of the surface system is higher than the sprinkler irrigation method. So that the ratio of dry biomass yield, grain yield, dry biomass water productivity, and grain water productivity in the surface method to sprinkler system was 1.7, 1.5, 1.5, and 1.3, respectively. The reason for this condition can be related to the high concentration of chlorine in irrigation water, which is poisonous for most plants. The heat and the intensity of the sun also added to it, causing severe burn marks on the leaves and weakness of the plant. In the surface irrigation system, in both years, the basin method was more productive than the furrow due to better salinity control in the basin irrigation method than the furrow irrigation method. Because the initial salinity of the soil is high and in the interval between irrigations, the accumulation of salts towards the furrow crown is high. It seems that in sprinkler irrigation, especially when the irrigation interval is shorter, the topsoil is more exposed to evaporation, although theoretically the leaching efficiency is higher in the sprinkler method, but there is a more opportunity of evaporation of the topsoil in sprinkler irrigation. Therefore, instead of moving deeper and joining the groundwater, the water flow moves upwards and is exposed to evaporation, leaving more salts. At a depth of 0 to 50 cm in the soil, the amount of salinity, sodium and sodium adsorption ratio at the end of cultivation compared to its initial value increased in both methods. In sprinkler irrigation method, this ratio was 1.2, 1.7 and 0.2, respectively, for surface irrigation method, 1.03, 1.4 and 1.7, respectively.
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