Impact of quality of irrigation water on soil aggregate stability using high-energy moisture characteristic.

Abstract

An experiment was conducted in farmer's field of Beit She'an region of Israel to assess the impact of quality of irrigation water on soil aggregate stability using high energy moisture characteristic (HEMC) method. In this method, accurately controlled wetting of the aggregates (i.e., the driving force for slaking) was the only force exerted on the aggregates. The experiment was laid out in a randomized block design where Jordan river water, spring water, treated effluent water and salty spring water were used as drip irrigation in a calcareous silty clay soil. Samples from an adjacent uncultivated area were used as a reference. Aggregates of 0.5 to 1.0 mm were placed in a funnel equipped with a fritted disk, and wetted either fast (100 mm h−1) or slow (2 mm h−1) rate, using a peristaltic pump. Thereafter, the aggregates were subjected to a stepwise increase in matric potential up to 5.0 J kg−1, to obtain a moisture retention curve, which served as the base for calculations of stability parameters. Aggregate stability was positively correlated with organic carbon (r = 0.532) and negatively correlated with ESP (r = −0.574) and SAR (r = −0.507) of soil. The stability ratio was highest for uncultivated soils followed by soils irrigated with treated effluent water, spring water, salty spring water and lowest for Jordan river water. Highest stability ratio for uncultivated soils was due to low ESP and higher organic carbon in this soil. Saline Jordan river water increased the ESP of soil and decreased the aggregate stability.