The effects of different levels of irrigation water salinity and leaching on the amount and distribution pattern of soil salinity and ions in an arid region

Abstract

Soil salinity is a major environmental factor limiting the productivity of agricultural lands. To determine the effects of irrigation water salinity and leaching on soil salinity and ion concentrations, a field experiment was conducted on a siltyclay soil (a typical soil of the Rudasht region, Isfahan province, Iran). The experiment consisted of three irrigation water salinity levels (2, 8, and 12 dS/m) with/without leaching levels of 4, 19, and 32% under two irrigation water management scenarios. Using factorial design, four replications for each treatment were used. The results showed that as the irrigation water salinity increased, the EC (Electrical Conductivity), CO3 (Carbon Trioxide), Cl− (Chlorine), SO4 (Sulphate), Ca (Calcium), Mg (Magnesium) and Na (Sodium) concentrations in the soil decreased significantly. The minimum and maximum values of soil salinity were 4.2 and 9.4 dS/m, respectively. Irrigation management decreased salinity and soil ions and leaching decreased the amount of Cl−, SO4 and Na in soil but only the effect of irrigation management was significant in decreasing CO3, Cl− and Na values. Irrigation management was more effective than leaching in decreasing ions. As the irrigation water salinity increased, soil moisture content increased and leaching reduced soil salinity. In treatments which were irrigated with 2 dS/m water, soil salinity increased with depth. In treatments which were irrigated by 8 dS/m water, soil salinity increased to the depth of 30 cm, decreased to the depth of 60 cm and then remained constant. In treatments which were WIT Transactions on Ecology and The Environment, Vol 185, www.witpress.com, ISSN 1743-3541 (on-line) © 2014 WIT Press doi:10.2495/SI140041 Sustainable Irrigation and Drainage V 33