Characteristics and Risk Assessment of Soil Salinization in the Yellow River Delta Region, China

Analyzing the characteristics of soil salinization and conducting risk assessments are crucial for ensuring the sustainable development of agriculture and ecosystems. In order to analyze the characteristics of soil salinization and conduct a risk assessment in the Yellow River Delta region, 63 surface soil samples and 37 groundwater samples were collected from this area in August 2023. Based on the test results of the samples and using soil salt content as the criterion, the types, degrees, and risks of soil salinization in the Yellow River Delta region were analyzed separately. The results revealed a relatively high average soil salt content of 4.59 g/kg, with Na+ and Cl− as the dominant ions. The primary salinization types were chloride and sulfate-chloride, covering 46.69% and 51.54% of the area, respectively. Moderate salinization was the most widespread, accounting for 45.35% of the region. Severe salinization, extremely severe salinization classes were mainly found in the coastal lowlands of the north and east, constituting 19.73% and 16.25% of the area, respectively. Groundwater exhibited transitional freshwater-saltwater characteristics, indicating widespread seawater intrusion across the region, which significantly contributed to soil salinity. Proximity to the Bohai Sea was the most critical factor influencing salinization, with areas closer to the sea showing a higher risk. High-risk zones, primarily along the coastline, covered 32.67% of the total area. The research findings can serve as valuable references for local wetland management and protection, the scientific enhancement of saline soils, rational soil utilization, effective prevention and control of soil salinization, and the sustainable development of water and soil resources.