The successive infiltration of various saline waters accelerates the infiltration processes and enhances the salt leaching in a coastal saline soil

The local saline water resource has been widely used for soil water and salt managements in saline-alkali area. The soil desalinization is strongly affected by the infiltration mode, and the melting saline ice infiltration can obtain soil salt leaching effectively. In this work, four melting sections (S1, S2, S3, and S4) were divided artificially according to the changes in meltwater from 5 (W5), 10 (W10), and 15 g L-1 (W15) ice. Various saline water samples of the above four sections with different salinities and volumes were prepared and infiltrated successively into soil columns that were packed with the coastal saline soils. The infiltration parameters, distribution patterns of soil moisture, salt, and sodium adsorption ratio (SAR), and soil desalinization in different sections were investigated and analyzed. Results showed that the infiltration of higher salinity water in the initial section increased the infiltration rates of slightly saline and fresh water in the last section. A greater infiltration rate, cumulative infiltration, and infiltration depth were ranked as W5 < W10 < W15. Moreover, the faster infiltration process obtained higher soil water contents throughout the S1, S1 + S2, and S1 + S2 + S3 sections, and more water was ultimately distributed in the deeper soil layer (S1 + S2 + S3 + S4 section). Both the soil salt and SAR increased initially (Section S1) and then decreased in the following sections; >80% of the total leached salt loads occurred in the S2 section for all treatments. Lower levels of soil salt contents and SAR developed within the later infiltration sections. Ultimately, the 30 cm desalinization layer was obtained among all treatments, and the treatments corresponding to the saline ice with higher salinity acquired lower salt contents and SAR values. These results indicate that the successive infiltration of water with various salinity levels, characterized by meltwater from saline ice, accelerated the infiltration process, and resulted in an obvious soil desalinization effect on the coastal saline soil.