Spatial distribution characteristics of soil water-salt gradients in the ecological buffer zone of arid zone lakes and their influencing factors

Abstract

Soil salinization exerts a severe impact on environmental degradation that threatens the structure and ecological functions of lake wetland. To study the characteristics of soil water-salt in the typical plant communities in the ecological buffer zone of the arid lake wetland, three zones were selected lakeshore as the starting point in Stone House, Bird Island, and Duck Bay management stations of Lake Ebinur wetland, August 2016 and 2017. These zones, including the waterward radiation zone, the water level variation zone, and the landward radiation zone, to investigate the variation patterns of soil water-salt in different zones and soil depths (0–5, 5–10, 10–20, 20–40, 40–60 cm). The results showed that: the soil pH in different plant communities in zones were all alkaline with weak varianbility. Soil moisture and total salt content were moderately variable. According to the Xinjiang saline-alkali classification standards, soils in the three zones were classified as non-salinized soil to mildly salinized soil, heavily salinized soil to saline soil, and non-salinized soil to heavily salinized soil, respectively; soil pH and moisture content in different plant communities of the zones tended to increase along with soil deepens and salt content decreased. The differences in soil pH and moisture between different soil profiles in the same zone were not so significant, but the differences in total salt content were bigger. The soil moisture and total salt content among different zones within the same soil profile remained prominent. The relationship between soil pH, moisture content, and total salt content in waterward radiation zone and water level variation zone was complex, showing an unclear pattern. In the landward radiation zone, soil pH and total salt content were negatively correlated with moisture, while soil pH was positively correlated with total salt content. The study demonstrated that the changes in soil water-salt in Lake Ebinur Wetlands were mainly influenced by structural factors (microtopography, soil characteristics, vegetation, parent material, hydrology), followed by random factors (irrigation, soil improvement, cultivation practices, and human activities).