Soil salinity patterns reveal changes in the water cycle of inland river basins in arid zones

Abstract. Soil salinization caused by unreasonable water resource utilization severely impacts agricultural development and ecological construction in arid inland river basins. Therefore, clarifying the water cycle mechanism of salinization in arid inland river basins is crucial for watershed ecological environment management and rational water resource utilization. Based on remote sensing and observational data, this study quantitatively analyzed soil salinization changes in the Shiyang River basin of Northwest China's arid region from 2002 to 2022 and explored the impacts of water conservancy projects and agricultural irrigation on soil salinization. The results indicated that (1) the salinization area of the Shiyang River basin remains stable overall, but the degree of salinization is further intensifying; (2) the northern hills and oasis–desert transition zone of the Shiyang River are regions with severe salinization problems, while the central corridor plain and southern Qilian Mountain regions have lower risks of salinization; (3) regional salinization problems are particularly prominent, caused by groundwater evaporation near reservoirs, agricultural irrigation evaporation, and downstream ecological water input evaporation. Human activities have become the decisive factor in changing the salinization pattern of inland river basins, and rational utilization and management of water resources hold tremendous potential in mitigating soil salinization.