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| Titel |
Free atmospheric CO2 enrichment increased above ground biomass but did not affect symbiotic N2-fixation and soil carbon dynamics in a mixed deciduous stand in Wales |
| VerfasserIn |
M. R. Hoosbeek, M. Lukac, E. Velthorst, A. R. Smith, D. L. Godbold |
| 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 ; 8, no. 2 ; Nr. 8, no. 2 (2011-02-14), S.353-364 |
| Datensatznummer |
250005447
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| Publikation (Nr.) |
 copernicus.org/bg-8-353-2011.pdf |
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| Zusammenfassung |
| Through increases in net primary production (NPP), elevated CO2 is
hypothesized to increase the amount of plant litter entering the soil. The
fate of this extra carbon on the forest floor or in mineral soil is
currently not clear. Moreover, increased rates of NPP can be maintained only
if forests can escape nitrogen limitation. In a Free atmospheric CO2
Enrichment (FACE) experiment near Bangor, Wales, 4 ambient and 4 elevated
[CO2] plots were planted with patches of Betula pendula, Alnus glutinosa and Fagus sylvatica on a former arable
field. After 4 years, biomass averaged for the 3 species was 5497 (se 270)
g m−2 in ambient and 6450 (se 130) g m−2 in elevated [CO2]
plots, a significant increase of 17% (P = 0.018). During that time, only a
shallow L forest floor litter layer had formed due to intensive
bioturbation. Total soil C and N contents increased irrespective of
treatment and species as a result of afforestation. We could not detect an
additional C sink in the soil, nor were soil C stabilization processes
affected by elevated [CO2]. We observed a decrease of leaf N content in
Betula and Alnus under elevated [CO2], while the soil C/N ratio decreased
regardless of CO2 treatment. The ratio of N taken up from the soil and
by N2-fixation in Alnus was not affected by elevated [CO2]. We infer
that increased nitrogen use efficiency is the mechanism by which increased
NPP is sustained under elevated [CO2] at this site. |
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