Enrichment of Eroded Soil Organic Carbon and its Influencing Factors on Hillslopes in the Mountainous Regions of Beijing, Northern China

Abstract

Study RegionThe soil-rock mountainous area of the semi-humid region of China.Study FocusThe aim of this research is to determine the delivery of soil organic carbon (SOC) and the enrichment ratio of soil organic carbon (ERSOC) resulting from soil erosion. We conducted experiments across eight plots with varying surface cover types (bare and natural), three different plot lengths (1, 2, and 5 m), and three rainfall intensities (70, 92, and 126 mm/h).New Hydrological Insights for the RegionThe findings indicate that (1) SOC mainly moved with the sediment in slope erosion. The particulate organic carbon (POC) dominated with a contribution of 95.90 ± 2.17 % during the delivery of SOC, while dissolved organic carbon (DOC) accounted for 4.10 ± 2.17 %. Conversely, in rivers, DOC transport is significant. (2) The effects of topographic factors on OC erosion (plot length and slope) are more insignificant than the conditions of rainfall intensity (35.63%) and litter (33.14%). (3) Natural plots have significantly higher ERSOC than bare plots, their ERSOC are 2.40 ± 0.29 and 1.99 ± 0.33, respectively. High rainfall intensity tended to low ERSOC, but it still shows enrichment with ERSOC greater than 1. This study obtains a better mechanistic understanding of OC erosion and its response to rainfall intensity, litter cover, and plot length under extreme storms.

Keywords: Plot erosion, Organic carbon loss by erosion, Enrichment ratio, Field-simulated rainfall