Dynamics of Soil Moisture and Salt Content After Infiltration of Saline Ice Meltwater in Saline-Sodic Soil Columns

Abstract

Saline ice meltwater can be used for irrigation and leaching of salts in salt-affected soil regions. A laboratory experiment was conducted using soil columns to investigate the redistribution of soil moisture, salt and sodium adsorption ratio (SAR) in saline-sodic soil under the infiltration of saline ice meltwater. Soils were treated using saline water of three irrigation volumes (1 600, 2 400 and 3 200 mL) at four salinity levels. These four salinity levels included salt free (0 g L−1), low salinity level (1.4 g L−1), moderate salinity level (2.7 g L−1) and high salinity level (4.1 g L−1). The prepared saline water was frozen into ice, and then the ice was put on the surface of soil columns. After 96 h, the infiltration rate and soil moisture content of saline ice treatments were greater than those of salt-free ice treatments, increasing with the increase of ice salinity. Infiltration of saline ice meltwater increased soil moisture content in the upper layers for all treatments. Both salt contents and SAR values in the upper soil layers decreased in all saline ice treatments and were lower than those in salt-free ice treatment. However, this trend was reversed in the deeper (below 20cm) soil layers. The highest desalting rate and lowest SAR were observed in high-salinity treatment under three irrigation volumes in the 0–15 cm soil layer, especially under irrigation volume of 2 400 mL. These results indicate that saline ice (0–20cm) meltwater irrigation is beneficial to saline-sodic soil reclamation, and the best improvement effect would be achieved when using high-salinity ice under optimal irrigation volume.