Objective The profile characteristics, spatial distribution characteristics, and influencing factors of soil organic carbon (SOC) contents in Anhui Province were explored to provide an important basis for upgrading the soil quality of arable land, as well as for managing and improving the environment.

Method The 397 typical soil profiles in Anhui Province were divided into 0-15 cm, 15-30 cm, 30-60 cm, and 60-90 cm layers based on the fixed depth, and the influencing factors of SOC content were analyzed using spatial analysis, geostatistical methods, geodetectors, and structural equation modeling.

Result ① The mean SOC contents in four soil layers of typical profiles in Anhui Province were determined to be 15.56, 8.98, 5.66, and 4.19 g kg⁻¹, respectively. The spatial trend of increasing SOC from north to south was observed across all depth intervals. ② In the study area, the driving forces of two-factor interactions were found to be significantly stronger than those of single-factor interactions. The interaction types were dominated by two-factor enhancement and nonlinear enhancement. Among these, the strongest driving force on SOC (0.33) was identified for the interaction between MAP and Clay content in the 30 - 60 cm soil layer. ③ The strongest direct and total effects in the 0 - 15 cm soil layer were attributed to anthropogenic factors, with coefficients of 0.24 and 0.22 (P < 0.01), respectively. This was followed by NDVI, which exhibited direct and total effect coefficients of 0.20 and 0.22 (P < 0.01). In the 15 - 30 cm layer, the strongest direct effect was associated with climatic factors (coefficient = 0.22, P < 0.001), while the strongest total effect was maintained by anthropogenic factors (coefficient = 0.21, P < 0.001). Across the 0 - 30 cm profile, the direct effects of vegetation factors on SOC were consistently above 0.18. In the 30 - 90 cm layer, the strongest direct and total effects were held by soil properties.

Conclusion SOC content in Anhui Province was jointly determined by a combination of influencing factors. Anthropogenic activities, NDVI and climatic elements exerted the greatest influence on SOC in the surface layer (0 - 30 cm), and the magnitude of their effects progressively weakened with increasing soil depth. Consequently, topographic and edaphic properties become the dominant drivers of SOC content at greater depths.