Spatial heterogeneity and interacting drivers of cadmium contamination in China's soils

Heavy metal contamination, especially cadmium (Cd), in agricultural soils poses a severe threat to food security and sustainable agriculture. This study explores the spatial heterogeneity of Cd concentrations in soils across China and identifies the key influencing factors. We analyzed a dataset of 669 soil samples collected between 2010 and 2021 using GeoDetector and GeoTree models to examine spatial variations and the interactions among natural and anthropogenic drivers. Our results reveal substantial regional heterogeneity in the factors affecting Cd levels. Anthropogenic activities dominate Cd accumulation in North and Southwest China, while lithology and climatic interactions govern contamination in the Northeast and Central-South. Key nonlinear interactions between fertilizers, pesticides, and industrial emissions exacerbate the risks of Cd contamination. We propose region-specific mitigation strategies integrating soil lithology, agricultural practices, and industrial policies in accordance with Sustainable Development Goals (SDGs). This study advances the mechanistic understanding of Cd dynamics in heterogeneous environments and provides actionable frameworks for global agricultural sustainability.