Objective The aim was to investigate the soil ecological stoichiometric characteristics and their driving factors in typical mining-metallurgical watersheds of the Middle-Lower Yangtze River, in order to provide a theoretical basis for elucidating nutrient cycling mechanisms and guiding the rational utilization of land resources in mining-affected watersheds.

Method Based on soil sampling data collected from the Daye Lake Basin in 2023, geostatistical methods coupled with the Geodetector model were employed to quantitatively analyze the spatial distribution patterns and driving mechanisms of soil ecological stoichiometry.

Result In the 0 - 30 cm topsoil layer, the mean contents of soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) were 11.25, 0.99, and 0.72 g kg⁻¹, respectively. The corresponding mean ratios of C∶N, C∶P and N∶P were 10.84, 21.41, and 1.89, which were substantially lower than those of the national averages. Driven by the dual effects of high-phosphorus parent materials and excessive anthropogenic phosphorus inputs, the basin exhibited a distinct ecological status of "phosphorus surplus and relative nitrogen limitation". Spatially, SOC and TN demonstrated a highly synergistic distribution pattern predominantly controlled by topography and vegetation, forming a ring-like spatial structure (higher in the south and periphery, and lower in the north and center). Conversely, TP was primarily driven by anthropogenic activities, displaying strong spatial heterogeneity with a decreasing gradient from southeast to northwest. Interaction detection analysis revealed that the interactions of soil water content (SWC) with mean annual temperature (MAT) and clay content (q = 0.50 - 0.69) synergistically dominated the accumulation of SOC and TN by regulating mineralization rates and physical protection mechanisms. Total potassium (TK) emerged as the critical control factor for the spatial distribution of TP (q = 0.49, P < 0.001). Furthermore, the interaction between pH and cadmium (Cd) exhibited exceptionally high explanatory power for the spatial variations of C∶N, C∶P, and N∶P ratios, reaching 0.73, 0.84, and 0.76, respectively.

Conclusion The spatial patterns of soil stoichiometric characteristics in typical mining-metallurgical watersheds of the Middle-Lower Yangtze River are co-driven by natural factors and human activities. The region presents an overarching ecological pattern of phosphorus enrichment and nitrogen limitation, highlighting a distinct "pollution-nutrient" coupling effect unique to mining-impacted areas.