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Detailed Reference Information |
Yoo, K., Amundson, R., Heimsath, A.M. and Dietrich, W.E. (2005). Erosion of upland hillslope soil organic carbon: Coupling field measurements with a sediment transport model. Global Biogeochemical Cycles 19: doi: 10.1029/2004GB002271. issn: 0886-6236. |
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Little is known about the role of vegetated hillslope sediment transport in the soil C cycle and soil-atmosphere C exchange. We combined a hillslope sediment transport model with empirical soil C measurements to quantify the erosion and temporal storage of soil organic carbon (SOC) within two grasslands in central California. The sites have contrasting erosional mechanisms: biological perturbation (Tennessee Valley (TV)) versus clay-rich soil creep (Black Diamond (BD)). The average SOC erosion rates from convex slopes were 1.4--2.7 g C m-2 yr-1 at TV and 5--8 g C m-2 yr-1 at BD, values that are <10% of above ground net primary productivity (ANPP) at both sites. The eroded soil accumulates on depositional slopes. The long term SOC accumulation (or C sink) rates are ~1.9 g C m-2 yr-1 in the TV hollow and 1.7--2.8 g C m-2 yr-1 in the BD footslope. We found that the hillslope C sink is driven primarily by the burial of in situ plant production rather than preservation of eroded SOC, a finding that differs from existing hypotheses. At TV, the net sequestration of atmospheric C by long-term hollow evacuation and refilling depends on the fate of the C exported from the zero order watershed. This study suggests that erosion and deposition are coupled processes that create a previously unrecognized C sink in undisturbed upland watersheds, with a potential to substantially affect the global C balance presently, and over geological timescales. |
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Abstract |
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Keywords
Global Change, Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912), Hydrology, Erosion, Biogeosciences, Carbon cycling, Hydrology, Sedimentation, Biogeosciences, Soils/pedology, soil organic carbon, soil erosion and deposition, hillslope sediment transport |
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Publisher
American Geophysical Union 2000 Florida Avenue N.W. Washington, D.C. 20009-1277 USA 1-202-462-6900 1-202-328-0566 service@agu.org |
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