Salinity fractionation of saline-sodic soils reclaimed by CaCl2-amended brackish ice

Abstract The amelioration of saline-sodic soil and the rational utilization of irrigation water resources are important environmental problems worldwide, particularly in the arid and semi-arid regions. In order to study the water-salt dynamics and reclamation effects of CaCl2-amended brackish ice on saline-sodic soils, we conducted a laboratory experiment to study the salinity fractionation of brackish ice and the amelioration effects in different saline-sodic soils (ESP 20, 40, and 70) under four salinity levels (1, 1.6, 2.2, and 2.8 g/L) of brackish ice. Based on the analysis of soil pH, electrical conductivity (EC), sodium adsorption ratio (SAR), alkalinity, infiltration depth, and ionome, the results showed that the pH, SAR, and alkalinity of ESP 20 soil with a higher salinity (2.2 g/L, Na/Ca ≤ 1.14) of brackish ice could be improved. However, for high ESP soils (ESP 40 and 70), there was no significant difference among brackish ice treatments of 1, 1.6, 2.2, and 2.8 g/L, the 0–12 cm soil layer could be desalted, but more salts accumulated at the lower layer of the soil profile. We further determined an optimal brackish ice concentration to improve different ESP soils: 2.2 g/L brackish ice for ESP 20 soil, 1.6 g/L for ESP 40 soil, and 1 g/L for ESP 70 soil. CaCl2-amended brackish ice can be used to ameliorate saline-sodic soil, this study provides invaluable supporting information on saline-sodic soil reclamation by optimizing brackish ice salinity and sodicity.