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| Titel |
Sources of nitrous oxide emitted from European forest soils |
| VerfasserIn |
P. Ambus, S. Zechmeister-Boltenstern, K. Butterbach-Bahl |
| 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 ; 3, no. 2 ; Nr. 3, no. 2 (2006-03-20), S.135-145 |
| Datensatznummer |
250000884
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| Publikation (Nr.) |
 copernicus.org/bg-3-135-2006.pdf |
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| Zusammenfassung |
| Forest ecosystems may provide strong sources of nitrous oxide (N2O),
which is important for atmospheric chemical and radiative properties.
Nonetheless, our understanding of controls on forest N2O emissions is
insufficient to narrow current flux estimates, which still are associated
with great uncertainties. In this study, we have investigated the
quantitative and qualitative relationships between N-cycling and N2O
production in European forests in order to evaluate the importance of
nitrification and denitrification for N2O production. Soil samples were
collected in 11 different sites characterized by variable climatic regimes
and forest types. Soil N-cycling and associated production of N2O was
assessed following application of 15N-labeled nitrogen. The N2O
emission varied significantly among the different forest soils, and was
inversely correlated to the soil C:N ratio. The N2O emissions were
significantly higher from the deciduous soils (13 ng N2O-N cm-3 d-1)
than from the coniferous soils (4 ng N2O-N cm-3 d-1).
Nitrate (NO3-) was the dominant substrate for N2O
with an average contribution of 62% and exceeding 50% at least once
for all sites. The average contribution of ammonium (NH4+) to
N2O averaged 34%. The N2O emissions were correlated with gross
nitrification activities, and as for N2O, gross nitrification was also
higher in deciduous soils (3.4 µg N cm-3 d-1) than in
coniferous soils (1.1 µg N cm-3 d-1). The ratio between
N2O production and gross nitrification averaged 0.67% (deciduous)
and 0.44% (coniferous). Our study suggests that changes in forest
composition in response to land use activities and global change may have
implications for regional budgets of greenhouse gases. From the study it
also became clear that N2O emissions were driven by the nitrification
activity, although the N2O was produced per se mainly from denitrification.
Increased nitrification in response to accelerated N inputs predicted for
forest ecosystems in Europe may thus lead to increased greenhouse gas
emissions from forest ecosystems. |
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