Quality of Irrigation Water and Soil Amendment Effects on Leaching a Saline-Sodic Soil

Abstract

Field and laboratory experiments were conducted to determine the effects of three qualities of irrigation water and their interaction with gypsum (CaSO4-2H2O) or sulfuric acid (H2SO4) on infiltration rates and time and water requirement to leach a calcareous saline-sodic soil. In both field and laboratory experiments city water (lowest salt) reduced infiltration rates, while use of well water (highest salt) resulted in higher infiltration rates. Sulfuric acid improved the infiltration rates significantly with all sources of irrigation water. Gypsum improved infiltration rates only with well water. Equations were developed to predict time and amount of water required to leach soil columns to a given salt content for the three water qualities, and kind and rate of amendment applied.

The poorest quality irrigation water required the least time and amount of water to leach the soil, until the EC of the leachate was equal that of the irrigation water. Both (H2SO4 and CaSO4-2H2O) reduced the time of leaching but required more water when compared with untreated columns.