Evaluating the impact of soil redistribution on the in situ mineralization of soil organic carbon
Article first published online: 25 AUG 2010
Copyright © 2010 John Wiley & Sons, Ltd.
Earth Surface Processes and Landforms
Volume 36, Issue 4, pages 427–438, April 2011
How to Cite
Van Hemelryck, H., Govers, G., Van Oost, K. and Merckx, R. (2011), Evaluating the impact of soil redistribution on the in situ mineralization of soil organic carbon. Earth Surf. Process. Landforms, 36: 427–438. doi: 10.1002/esp.2055
- Issue published online: 10 MAR 2011
- Article first published online: 25 AUG 2010
- Manuscript Accepted: 17 MAY 2010
- Manuscript Revised: 17 APR 2010
- Manuscript Received: 20 MAY 2009
- soil erosion;
- soil organic carbon (SOC);
- field and incubation study;
- carbon sequestration
Soil erosion, transport and deposition by water drastically affect the distribution of soil organic carbon (SOC) within a landscape. Moreover, soil redistribution may have a large impact on the exchange of carbon (C) between the pedosphere and the atmosphere. One of the large information gaps within this research domain, concerns the fate of SOC after erosion by water. According to different (mainly laboratory) studies, soil redistribution leads to aggregate breakdown, thereby exposing the contained SOC to mineralization.
Our study aims to quantify the extent to which such increased mineralization occurs in a real field situation. Carbon dioxide (CO2)-efflux was measured in the field after an important erosion event for a continuous period of 112 days. The specific situation on the field ensured that almost none of eroded SOC was exported from the field. Measurements of CO2-efflux were done in areas with sediment deposition, as well as in comparable areas without sedimentation. Comparison of these measurements allowed the net effect of soil deposition on CO2-efflux to be assessed. Field data were complemented by measurements on incubated, undisturbed soil core samples, in order to disentangle the contribution of environmental factors (moisture, temperature) from any erosional effect on CO2-efflux.
Results of these measurements on the field showed that CO2-efflux was regulated by a complex interplay of different factors (mostly soil porosity, soil moisture and soil temperature).
In combination with the incubation measurements, it could be concluded that the processes of erosion and transport indeed led to an increased mineralization of SOC, as a result of aggregate breakdown and exposure of previously encapsulated SOC. This effect was, however, much smaller than observed in previous laboratory studies. Moreover, it was only important in the first weeks, immediately after the erosion event. The calculated net erosional effect on CO2-efflux represented a mere 1·6% of total SOC, originally present in the soil. Copyright © 2010 John Wiley & Sons, Ltd.