Effects of reclaimed water irrigation on soil water repellency

Performing further research on soil water and solute distributions as well as the variations of soil water repellency under reclaimed water irrigation for different soils can offer some referential information on the causes of soil water repellency using reclaimed water and the possible factors influencing the soil water repellency. Sandy soil, Shajiang black soil, Lou soil and saline-alkaline soils were selected to do column infiltration experiments with reclaimed water. Soil samples along vertical profiles were taken to measure soil potential water repellency, soil water content, Cl- mass concentration, organic matter (OM) mass fraction and electrical conductivity (EC) under different irrigation quotas. The results showed that, after reclaimed water irrigation, Lou soil and saline-alkaline soil indicated repellency of 0-2 and 1-3 degrees, respectively; whereas both sand soil and Shajiang black soil displayed repellency of degree 0. Water repellency of all four types of soil on surface was stronger than the subsoils. Soil water repellency increased with the increase of reclaimed water irrigation quantity and irrigation time dramatically, and the larger the irrigation quota, the more notable the differences of soil water repellency. ?OM of the all four types of soil had positive correlations with soil difference of water droplet penetration time ?TR, while ?Cl- and ?EC presented negative correlation with soil difference of water droplet penetration time ?TR. Compared with the three other types of soil, sand soil is more suitable for irrigating with reclaimed water.