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Titel |
Stand age and tree species affect N2O and CH4 exchange from afforested soils |
VerfasserIn |
J. R. Christiansen, P. Gundersen |
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. 9 ; Nr. 8, no. 9 (2011-09-09), S.2535-2546 |
Datensatznummer |
250006118
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Publikation (Nr.) |
copernicus.org/bg-8-2535-2011.pdf |
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Zusammenfassung |
Afforestation of former agricultural land is a means to mitigate
anthropogenic greenhouse gas emissions. The objectives of this study were (1)
to assess the effect of oak (Quercus robur) and Norway spruce (Picea abies [L.] Karst.) stands of different
stand ages (13–17 and 40 years after afforestation, respectively) on
N2O and CH4 exchange from the soil under these species and (2)
identify the environmental factors responsible for the differences in gas
exchange between tree species of different ages. N2O and CH4
fluxes (mean ± SE) were measured for two years at an afforested site. No
species difference was documented for N2O emission (oak: 4.2 ± 0.7 μg
N2O-N m−2 h−1, spruce: 4.0 ± 1 μg N2O-N
m−2 h−1) but the youngest stands (1.9 ± 0.3 μg N2O-N
m−2 h−1) emitted significantly less N2O than older stands
(6.3 ± 1.2 μg N2O-N m−2 h−1). CH4 exchange did
not differ significantly between tree species (oak: −8.9 ± 0.9, spruce:
−7.7 ± 1) or stand age (young: −7.3 ± 0.9 μg CH4-C m−2 h−1,
old: −9.4 ± 1 μg CH4-C m−2 h−1) but
interacted significantly; CH4 oxidation in the soil increased with
stand age in oak and decreased with age for soils under Norway spruce. We
conclude that the exchange of N2O and CH4 from the forest soil
undergoes a quick and significant transition in the first four decades after
planting in both oak and Norway spruce. These changes are related to (1)
increased soil N availability over time as a result of less demand for N by
trees in turn facilitating higher N2O production in older stands and (2)
decreasing bulk density and increased gas diffusivity in the top soil over
time facilitating better exchange of N2O and CH4 with the
atmosphere. |
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