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Media type:
E-Article
Title:
Soil carbon and belowground carbon balance of a short‐rotation coppice: assessments from three different approaches
Contributor:
Berhongaray, Gonzalo;
Verlinden, Melanie S.;
Broeckx, Laura S.;
Janssens, Ivan A.;
Ceulemans, Reinhart
Published:
Wiley, 2017
Published in:
GCB Bioenergy, 9 (2017) 2, Seite 299-313
Language:
English
DOI:
10.1111/gcbb.12369
ISSN:
1757-1693;
1757-1707
Origination:
Footnote:
Description:
<jats:title>Abstract</jats:title><jats:p>Uncertainty in soil carbon (C) fluxes across different land‐use transitions is an issue that needs to be addressed for the further deployment of perennial bioenergy crops. A large‐scale short‐rotation coppice (<jats:styled-content style="fixed-case">SRC</jats:styled-content>) site with poplar (<jats:italic>Populus</jats:italic>) and willow (<jats:italic>Salix</jats:italic>) was established to examine the land‐use transitions of arable and pasture to bioenergy. Soil C pools, output fluxes of soil <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>, <jats:styled-content style="fixed-case">CH</jats:styled-content><jats:sub>4</jats:sub>, dissolved organic carbon (<jats:styled-content style="fixed-case">DOC</jats:styled-content>) and volatile organic compounds, as well as input fluxes from litter fall and from roots, were measured over a 4‐year period, along with environmental parameters. Three approaches were used to estimate changes in the soil C. The largest C pool in the soil was the soil organic carbon (<jats:styled-content style="fixed-case">SOC</jats:styled-content>) pool and increased after four years of <jats:styled-content style="fixed-case">SRC</jats:styled-content> from 10.9 to 13.9 kg C m<jats:sup>−2</jats:sup>. The belowground woody biomass (coarse roots) represented the second largest C pool, followed by the fine roots (Fr). The annual leaf fall represented the largest C input to the soil, followed by weeds and Fr. After the first harvest, we observed a very large C input into the soil from high Fr mortality. The weed inputs decreased as trees grew older and bigger. Soil respiration averaged 568.9 g C m<jats:sup>−2</jats:sup> yr<jats:sup>−1</jats:sup>. Leaching of <jats:styled-content style="fixed-case">DOC</jats:styled-content> increased over the three years from 7.9 to 14.5 g C m<jats:sup>−2</jats:sup>. The pool‐based approach indicated an increase of 3360 g C m<jats:sup>−2</jats:sup> in the <jats:styled-content style="fixed-case">SOC</jats:styled-content> pool over the 4‐year period, which was high when compared with the −27 g C m<jats:sup>−2</jats:sup> estimated by the flux‐based approach and the −956 g C m<jats:sup>−2</jats:sup> of the combined eddy‐covariance + biometric approach. High uncertainties were associated to the pool‐based approach. Our results suggest using the C flux approach for the assessment of the short‐/medium‐term <jats:styled-content style="fixed-case">SOC</jats:styled-content> balance at our site, while <jats:styled-content style="fixed-case">SOC</jats:styled-content> pool changes can only be used for long‐term C balance assessments.</jats:p>