Model based analysis of lateral and vertical soil carbon fluxes induced by soil redistribution processes in a small agricultural catchment |
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| Authors: | Verena Dlugoß Peter Fiener Kristof Van Oost Karl Schneider |
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| Institution: | 1. Department of Geography, University of Cologne, , Cologne, Germany;2. Indo‐German Centre for Sustainability, Indian Institute of Technology Madras, , Chennai, India;3. Earth and Life Institute, Georges Lema?tre Centre for Earth and Climate Research (TECLIM), Université catholique de Louvain, , Louvain‐la‐Neuve, Belgium |
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| Abstract: | Soil redistribution on arable land significantly affects lateral and vertical soil carbon (C) fluxes (caused by C formation and mineralization) and soil organic carbon (SOC) stocks. Whether this serves as a (C) sink or source to the atmosphere is a controversial issue. In this study, the SPEROS‐C model was modified to analyse erosion induced lateral and vertical soil C fluxes and their effects upon SOC stocks in a small agricultural catchment (4·2 ha). The model was applied for the period between 1950 and 2007 covering 30 years of conventional tillage (1950–1979) followed by 28 years of conservation tillage (1980–2007). In general, modelled and measured SOC stocks are in good agreement for three observed soil layers. The overall balance (1950–2007) of erosion induced lateral and vertical C fluxes results in a C loss of ?4·4 g C m–2 a–1 at our test site. Land management has a significant impact on the erosion induced C fluxes, leading to a predominance of lateral C export under conventional and of vertical C exchange between soil and atmosphere under conservation agriculture. Overall, the application of the soil conservation practices, with enhanced C inputs by cover crops and decreased erosion, significantly reduced the modelled erosion induced C loss of the test site. Increasing C inputs alone, without a reduction of erosion rates, did not result in a reduction of erosion induced C losses. Moreover, our results show that the potential erosion induced C loss is very sensitive to the representation of erosion rates (long‐term steady state versus event driven). A first estimate suggests that C losses are very sensitive to magnitude and frequency of erosion events. If long‐term averages are dominated by large magnitude events modelled erosion induced C losses in the catchment were significantly reduced. Copyright © 2011 John Wiley & Sons, Ltd. |
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| Keywords: | soil erosion soil carbon modeling soil conservation |
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