Journal cover Journal topic
Biogeosciences An interactive open-access journal of the European Geosciences Union
Journal topic
Volume 7, issue 12
Biogeosciences, 7, 3971–3986, 2010
https://doi.org/10.5194/bg-7-3971-2010
© Author(s) 2010. This work is distributed under
the Creative Commons Attribution 3.0 License.
Biogeosciences, 7, 3971–3986, 2010
https://doi.org/10.5194/bg-7-3971-2010
© Author(s) 2010. This work is distributed under
the Creative Commons Attribution 3.0 License.

  07 Dec 2010

07 Dec 2010

The effect of soil redistribution on soil organic carbon: an experimental study

H. Van Hemelryck1,5, P. Fiener2, K. Van Oost3, G. Govers1, and R. Merckx4 H. Van Hemelryck et al.
  • 1Division of Geography, Department of Earth and Environmental Sciences, K. U. Leuven, Leuven, Belgium
  • 2Geographisches Institut der Universität zu Köln, Köln, Germany
  • 3Earth and Life Institute, Georges Lemaître Centre for Earth and Climate Research (TECLIM), Université catholique de Louvain, Louvain, Belgium
  • 4Laboratory of Soil and Water Management, Department of Earth and Environmental Sciences, K. U. Leuven, Leuven, Belgium
  • 5Aspirant, Fonds voor Wetenschappelijk Onderzoek, Vlaanderen, Belgium

Abstract. Soil erosion, transport and deposition by water drastically affect the distribution of soil organic carbon (SOC) within a landscape. Furthermore, soil redistribution is assumed to have a large impact on the exchange of carbon (C) between the pedosphere and the atmosphere. There is, however, significant scientific disagreement concerning the relative importance of the key-mechanisms at play. One of the major uncertainties concerns the fraction of SOC that is mineralized when soil is eroded by water, from the moment when detachment takes place until the moment when the SOC becomes protected by burial. In this study, the changes in C-exchange between soil and atmosphere as affected by soil redistribution processes were experimentally quantified. During a laboratory experiment, three types of erosional events were simulated, each of which was designed to produce a different amount of eroded soil material with a different degree of aggregation. During a 98-day period, CO2-efflux was measured in-situ and under field conditions on undisturbed soils with a layer of deposited soil material. Depending on the initial conditions of the soil and the intensity of the erosion process, a significant fraction of eroded SOC was mineralized after deposition. However, results also suggest that deposition produces a dense stratified layer of sediment that caps the soil surface, leading to a decrease in SOC decomposition in deeper soil layers. As a result, the net effect of erosion on SOC can be smaller, depending on the functioning of the whole soil system. In this study, soil redistribution processes contributed an additional emission of 2 to 12% of total C contained in eroded sediment.

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