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| Titel |
Direct contribution of nitrogen deposition to nitrous oxide emissions in a temperate beech and spruce forest – a 15N tracer study |
| VerfasserIn |
N. Eickenscheidt, R. Brumme, E. Veldkamp |
| 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. 3 ; Nr. 8, no. 3 (2011-03-08), S.621-635 |
| Datensatznummer |
250005566
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| Publikation (Nr.) |
 copernicus.org/bg-8-621-2011.pdf |
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| Zusammenfassung |
| The impact of atmospheric nitrogen (N) deposition on nitrous oxide
(N2O) emissions in forest ecosystems is still unclear. Our study
assessed the direct contribution of N deposition to N2O emissions in
temperate forests exposed to chronic high N depositions using a 15N
labelling technique. In a Norway spruce stand (Picea abies) and in a beech stand
(Fagus sylvatica) at the Solling, Germany, we used a low concentrated 15N-labelled
ammonium-nitrate solution to simulate N deposition. Nitrous oxide fluxes and
15N isotope abundances in N2O were measured using the closed
chamber method combined with 15N isotope analyses. Emissions of N2O were higher in the beech stand
(2.6 ± 0.6 kg N ha−1 yr−1) than in the spruce stand (0.3 ± 0.1 kg N ha−1 yr−1). We observed a direct effect of N input on 15N-N2O
emissions, which lasted for less than three weeks and was mainly caused by
denitrification. No further increase in 15N enrichment of N2O
occurred during a one-year experiment, which was probably due to
immobilisation of deposited N. The annual emission factor for N2O from
deposited N was 0.1% for the spruce stand and 0.6% for the beech
stand. Standard methods used in the literature applied to the same stands
grossly overestimated emission factors with values of up to 25%. Only 6–13% of
the total N2O emissions were derived from direct N depositions. Whether
the remaining emissions resulted from accumulated anthropogenic N depositions
or native soil N, could not be distinguished with the applied methods. The
15N tracer technique is a useful tool, which may improve estimates of
the current contribution of N deposition to N2O emissions. |
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