Long-Term Irrigation with Treated Wastewater: Effects on Soil-Structure Stability Related Indices.

The sustainability of intensively managed agricultural systems is affected by various a factor amongst which is irrigation water quality. Due to increased demand for irrigation water, various qualities of treated wastewater (TWW) are being used for crop production. We evaluated the effects of long-term irrigation with TWW on selected soil-structure stability related indices (e.g., hydraulic characteristics, aggregate stability, slaking and swelling, etc.) in different production systems in Israel varying in tillage intensity, irrigation methods and soil texture. Compared to irrigation with  fresh water, TWW irrigation led to a deterioration in soil-structure stability by increasing soil salinity and sodicity, enhancing slaking and swelling, and decreasing hydraulic and aggregate stability characteristics. The effects were primarily controlled by soil clay content and to a lesser extent by tillage and irrigation method. When compared with different types  of saline sodic irrigation waters, irrigation with TWW contributed to an improvement in the various indices that characterize soil-structure stability. Under such conditions, use of TWW can be viewed as an asset especially in drought affected areas and areas where better quality of waters are not available.