Infiltration of meltwater from frozen saline water located on the soil can result in reclamation of a coastal saline soil

Abstract

The saline soil was irrigated by the shallow groundwater of high salinity (12 g L−1) during the air temperature below −5 °C in winter, and the saline water was frozen into saline ice on the soil expeditiously. With air temperatures increasing in spring, the saline ice melted and infiltrated into soil gradually, and the saline soil may be improved by the infiltration of the meltwater. Based on this, a field experiment was conducted to evaluate changes in saline ice during melting, seasonal dynamics of soil temperature, water, salt and sodium adsorption ratios (SAR). After the meltwater infiltrated into soil in spring, the plastic mulching (FM) and non-mulching (FN) were designed, and the control treatment (CK) did not include irrigation or mulching. The results showed that the salinity of the saline ice was reduced upon melting, and the mulching of saline ice increased the soil temperature and reduced the frozen soil layers. After infiltration of meltwater, the soil salinity and SAR were both reduced significantly (p < 0.05), and the mulching of plastic film maintained the lower level of soil salinity and SAR. During the sowing season for cotton, the soil salinity and SAR were below 4 g kg−1 and 9, respectively, in FM. And higher than 65 % of emergence rates and greater than 3.4 t ha−1 seed cotton yields were obtained in this treatment, while for the FN and CK treatments, the soil salinities were both above 8 g kg−1, which leads to yields that were not obtained.