Factors Affecting Soil Organic Carbon Content between Natural and Reclaimed Sites in Rudong Coast, Jiangsu Province, China

The physical and chemical properties of coastal soils in China have changed due to the development of reclaimed stretches of coastline, which has a significant impact on the dynamics of organic carbon (OC) in the soils. We evaluated changes in the physical and chemical properties of soils in both a natural area and a reclaimed area along the coast of Rudong County, China, as well as the effects that these changes had on the OC content of the soils. A partial least squares regression (PLSR) model was used to determine which factors are most important for driving changes in soil OC at four sites from each area. According to dominant vegetation types, there were significant differences in soil physical and chemical properties and OC content between the reclaimed area and natural coastal area. The mean grain size and pH increased gradually with depth, and values were highest in reclaimed areas. Mean total N (TN), P, and S, salinity, water content, and soil OC were highest in natural areas and decreased with depth. The PLSR model determined that TN, silt content, and sand content were the most important factors affecting soil OC in the reclaimed area, whereas TN, clay content, and water content were important factors affecting soil OC dynamics in the natural coastal areas. This study provides important reference data for correctly assessing the role and status of coastal areas in the global carbon cycle.