Effects of water erosion on the redistribution of soil organic carbon in the hilly red soil region of southern China

Water erosion processes can significantly affect the delivery and distribution patterns of soil organic carbon (SOC) within the landscape. While many studies focus on the erosion processes and runoff transport of SOC, little attention has been paid to the on-site redistribution and vertical transport of SOC. This study characterizes SOC erosion dynamics, including infiltration-associated movement, and discusses the effects of rainfall intensity and slope position on SOC transport within the hilly red soil region of southern China. The results show that SOC loss was likely due to sediment transport rather than runoff. The eroded SOC was not significantly enriched, which may be due to the soil properties and the type of rainfall event. The initial SOC concentration affected the enrichment ratio of eroded SOC in the sediment. On-site horizontal redistribution occurred regardless of rainfall intensity, whereas the SOC transport trends varied with rainfall intensity and slope positions. This demonstrates that soil preservation could reduce SOC loss, and thus influence the global carbon cycle. •Rainfall intensity and slope positions influence SOC delivery process.•Soil properties can affect the enrichment ratio of eroded SOC in sediment.•SOC can be horizontally redistributed along a slope and vertically transported.•SOC can be preserved in the lower slope positions and deeper soil layers.