Spatiotemporal Variation in Saline Soil Properties in the Seasonal Frozen Area of Northeast China: A Case Study in Western Jilin Province

Abstract

Due to the impact of climate change and human activities, the problem of soil salinization is increasingly prominent, posing a threat to the safety of the ecological environment and engineering construction. To understand the development tendency of soil salinization, this paper took the saline soil in Western Jilin province as the research object and carried out a long–term investigation into the basic properties of the soil at several monitoring stations. The results showed that the properties of saline soil in Western Jilin province changed regularly at the spatial and temporal scales. In the longitudinal profile, the water content, soluble salt content, and organic matter content in the soil vary greatly with the seasons at a depth range of 0–50 cm, while their changes below 50 cm are not significant. This is related to the influence depth of the external environment. Meanwhile, the content of sand is relatively stable in the depth direction, mostly between 5 and 15%, while the content of silt and clay fluctuates greatly, and there seems to be a mirror relationship between them. Along the N(W)–S(E) direction, the crystallization proportion of clay minerals gradually increases by about 28% because the relatively humid and hot climate is conducive to mineral crystallization. Over time, in the S(E) study area, the precipitation is relatively abundant, and the shallow soil is desalted due to leaching, resulting in high salt storage in the deep soil. However, in the N(W) study area, salt migrates upwards with water under the dominant effects of evaporation and freeze-thaw, leading to the accumulation of salt in shallow soil and a decrease in salt storage in deep soil. In addition, the saline soil in the study area has strong alkalinity, and the pH increases from 8.2 to 9.8 in the N(W)–S(E) direction. Overall, the soil salinization situation in Western Jilin is not optimistic.