THE EFFECT OF EXCESSIVE SODIUM-CONTAINING IRRIGATION WATERS ON SOIL INFILTRATION RATE

Due to increasing demand for limited water resources, the pressure on irrigation water used in agricultural production is also increasing. One of the alternative solutions to meet the irrigation water needed in agricultural production is to use low-quality water resources. However, use of these waters can cause serious problems for the environment, especially for soil and plants, in the short, medium and long term. The sodium concentration of the irrigation water affects the structure of the soil, infiltration rate and hydraulic conductivity properties, as well as negatively affects the nutrient uptake of the plants. In this study, the effect of irrigation water with excess sodium content on the infiltration rate, which is one of the important parameters for the design and operation of irrigation systems and sustainable agricultural production, was researched. The infiltration rate was measured by the double-ring infiltrometer method. In this study, irrigation water with four different Electrical Conductivity (ECi = 0.6 [control], 5, 10 and 15 dS m-1) and Sodium Adsorption Ratio (SAR) (1, 20, 40 and 50) were used. Cumulative infiltration values varied between 360-446 mm, and a 9-19% reduction was determined as compared to the control treatments, depending on the increasing ECi and SAR ratios. The steady-state infiltration rate of the treatments varied between 24.5-36.5 mm h-1 and decreased by 24-34%. In response to increased EC and SAR in irrigation water, the infiltration rates and cumulative infiltration values of soils decreased.