Dynamics of meltwater quality and quantity during saline ice melting and its effects on the infiltration and desalinization of coastal saline soils

Abstract

Laboratory experiments were conducted to investigate the changes in the quality and quantity of meltwater during saline ice melting and the redistribution of water, salt, and sodium adsorption ratio (SAR) in coastal saline soils following the infiltration of saline ice meltwater. Three salinity levels (5, 10 and 15gL−1) and three SAR (mmolL−1)0.5 levels (5, 10 and 30) of saline ice were tested, with salt-free ice as the control treatment. The results showed that during saline ice melting, the initial meltwater contained extremely high concentration of salts with high SAR, and about 60% of low salinity (<4gL−1) and low SAR (<9) water were produced from melting saline ice. The infiltration rate of saline ice meltwater to saline soils was greater than that of salt-free ice meltwater, and was increased with the increase of ice salinity and decrease of ice SAR. After infiltration, soil water content of the upper soil layers under saline ice treatments was lower than that of the salt-free ice treatment, and was increased with the increase of ice SAR. This trend was reversed in the deeper soil layers. Both salt contents and SAR values in the upper soil layers were reduced in all salt treatments, and were lower than those of salt-free ice treatment. The highest desalting rate and lowest SAR were observed in the SAR 5 saline ice treatment, but there was no significant difference among saline ices within the same SAR treatments. These results indicate that saline ice can be desalinized efficiently with melting, and saline soils can be improved through infiltration with melting saline ice water.