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| Titel |
Quantifying and isolating stable soil organic carbon using long-term bare fallow experiments |
| VerfasserIn |
P. Barré, T. Eglin, B. T. Christensen, P. Ciais, S. Houot, T. Kätterer, F. Oort, P. Peylin, P. R. Poulton, V. Romanenkov, C. Chenu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 11 ; Nr. 7, no. 11 (2010-11-26), S.3839-3850 |
| Datensatznummer |
250005073
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| Publikation (Nr.) |
 copernicus.org/bg-7-3839-2010.pdf |
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| Zusammenfassung |
| The stability of soil organic matter (SOM) is a
major source of uncertainty in predicting atmospheric CO2 concentration
during the 21st century. Isolating the stable soil carbon (C) from other, more
labile, C fractions in soil is of prime importance for calibrating soil C
simulation models, and gaining insights into the mechanisms that lead to
soil C stability. Long-term experiments with continuous bare fallow
(vegetation-free) treatments in which the decay of soil C is monitored for
decades after all inputs of C have stopped, provide a unique opportunity to
assess the quantity of stable soil C. We analyzed data from six bare fallow
experiments of long-duration (>30 yrs), covering a range of soil types and
climate conditions, and sited at Askov (Denmark), Grignon and Versailles
(France), Kursk (Russia), Rothamsted (UK), and Ultuna (Sweden). A conceptual
three pool model dividing soil C into a labile pool (turnover time of a
several years), an intermediate pool (turnover time of a several decades)
and a stable pool (turnover time of a several centuries or more) fits well
with the long term C decline observed in the bare fallow soils. The estimate
of stable C ranged from 2.7 g C kg−1 at Rothamsted to 6.8 g C kg−1
at Grignon. The uncertainty associated with estimates of the stable pool was
large due to the short duration of the fallow treatments relative to the
turnover time of stable soil C. At Versailles, where there is least
uncertainty associated with the determination of a stable pool, the soil
contains predominantly stable C after 80 years of continuous bare fallow.
Such a site represents a unique research platform for characterization of
the nature of stable SOM and its vulnerability to global change. |
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