Exploring the spatial heterogeneity of soil organic carbon and the influence of coastal factors: A case study in the Yellow River Delta, China.

Abstract

Terrestrial ecosystems have vital impacts on soil carbon sequestration, but under disturbances from anthropogenic activities, the typical indicator combinations of SOC distribution in coastal areas remain unclear. On the basis of surface soil sampling and calculations of related eco-environmental indices in the Yellow River Delta (YRD), we performed geostatistical analysis combined with Spearman's correlation analysis, principal component analysis (PCA), and hierarchical clustering analysis (HCA) to explore the spatial heterogeneity of soil organic carbon (SOC) and influential spatiotemporal factors. Overall, the results revealed that in the seaward direction of the Yellow River, the SOC concentration decreased from west to east, with a low mean value of 5.57 g·kg^-1. We selected nine indicators that significantly influenced the SOC distribution among four types of coastal factors, namely, land cover, soil components, geographical conditions and anthropogenic activities. On the basis of these results, potential anthropogenic interventions that can increase SOC sequestration are presented: the coverage of saline-alkali-tolerant plant types should be increased, especially in bare areas on the east coast and in saline-alkali land, forests, and grassland, and soil fertility in agricultural areas should be maintained to improve the carbon sequestration capacity of surface vegetation. Herein, we present new insights for exploring the dynamic impacts of ecosystem factors on terrestrial soil carbon and present targeted sequestration strategies in areas with intense sea-land interactions.