Temporal Variation of SOC Enrichment from Interrill Erosion over Prolonged Rainfall Simulations

Agriculture

Yaxian Hu¹  Wolfgang Fister¹ 

[1] Physical Geography and Environmental Change Research Group, Department of Environmental Sciences, University of Basel, Klingelbergstrasse 27, Basel 4056, Switzerland; E-Mails:

关键词: interrill erosion;    SOC enrichment ratio;    temporal variation;    crust formation;    prolonged rainfall duration;   

DOI  :  10.3390/agriculture3040726

来源: mdpi

【 摘 要 】

Sediment generated by interrill erosion is commonly assumed to be enriched in soil organic carbon (SOC) compared to the source soil. However, the reported SOC enrichment ratios (ER_SOC) vary widely. It is also noteworthy that most studies reported that the ER_SOC is greater than unity, while conservation of mass dictates that the ER_SOC of sediment must be balanced over time by a decline of SOC in the source area material. Although the effects of crusting on SOC erosion have been recognized, a systematic study on complete crust formation and interrill SOC erosion has not been conducted so far. The aim of this study was to analyze the effect of prolonged crust formation and its variability on the ER_SOC of sediment. Two silty loams were simultaneously exposed to a rainfall simulation for 6 h. The ER_SOC in sediment from both soils increased at first, peaked around the point when steady-state runoff was achieved and declined afterwards. The results show that crusting plays a crucial role in the ER_SOC development over time and, in particular, that the conservation of mass applies to the ER_SOC of sediment as a consequence of crusting. A “constant” ER_SOC of sediment is therefore possibly biased, leading to an overestimation of SOC erosion. The results illustrate that the potential off-site effects of selective interrill erosion require considering the crusting effects on sediment properties in the specific context of the interaction between soil management, rainfall and erosion.

【 授权许可】

CC BY   
© 2013 by the authors; licensee MDPI, Basel, Switzerland.