Worrall, F. and Burt, T.P. and Howden, N.J.K. (2016) 'The fluvial flux of particulate organic matter from the UK : the emission factor of soil erosion.', Earth surface processes and landforms., 41 (1). pp. 61-71.
Soil erosion has been identified as a potential global carbon sink since eroded organic matter is replaced at source and eroded material is readily buried. However, this argument has relied on poor estimates of the total fate of in-transit particulates and could erroneously imply soil erosion could be encouraged to generate carbon stores. These previous estimates have not considered that organic matter can also be released to the atmosphere as a range of greenhouse gases, not only carbon dioxide (CO2), but also the more powerful greenhouse gases methane (CH4) and nitrous oxide (N2O). As soil carbon lost by erosion is only replaced by uptake of CO2, this could represent a considerable imbalance in greenhouse gas warming potential, even if it is not significant in terms of overall carbon flux. This work therefore considers the flux of particulate organic matter through UK rivers with respect to both carbon fluxes and greenhouse gas emissions. The results show that, although emissions to the atmosphere are dominated by CO2, there are also considerable fluxes of CH4 and N2O. The results suggest that soil erosion is a net source of greenhouse gases with median emission factors of 5.5, 4.4 and 0.3 tonnes CO2eq/yr for one tonne of fluvial carbon, gross carbon erosion and gross soil erosion, respectively. This study concludes that gross soil erosion would therefore only be a net sink of both carbon and greenhouse gases if all the following criteria are met: the gross soil erosion rate were very low (<91 tonnes/km2/yr); the eroded carbon were completely replaced by new soil organic matter; and if less than half of the gross erosion made it into the stream network. By establishing the emission factor for soil erosion, it becomes possible to properly account for the benefits of good soil management in minimizing losses of greenhouse gases to the atmosphere as a by-product of soil erosion.
|Full text:||(AM) Accepted Manuscript|
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|Publisher Web site:||http://dx.doi.org/10.1002/esp.3795|
|Publisher statement:||This is the accepted version of the following article: Worrall, F., Burt, T. P., and Howden, N. J. K. (2016) The fluvial flux of particulate organic matter from the UK: the emission factor of soil erosion. Earth Surface Processes and Landforms, 41(1): 61-71, which has been published in final form at http://dx.doi.org/10.1002/esp.3795. This article may be used for non-commercial purposes in accordance With Wiley Terms and Conditions for self-archiving.|
|Date accepted:||27 July 2015|
|Date deposited:||03 May 2016|
|Date of first online publication:||07 October 2015|
|Date first made open access:||07 October 2016|
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