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| Titel |
Responses of soil respiration to elevated carbon dioxide and nitrogen addition in young subtropical forest ecosystems in China |
| VerfasserIn |
Q. Deng, G. Zhou, J. Liu, S. Liu, H. Duan, D. Zhang |
| 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. 1 ; Nr. 7, no. 1 (2010-01-25), S.315-328 |
| Datensatznummer |
250004382
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| Publikation (Nr.) |
 copernicus.org/bg-7-315-2010.pdf |
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| Zusammenfassung |
| Global climate change in the real world always exhibits simultaneous changes
in multiple factors. Prediction of ecosystem responses to multi-factor
global changes in a future world strongly relies on our understanding of
their interactions. However, it is still unclear how nitrogen (N) deposition
and elevated atmospheric carbon dioxide concentration [CO2] would
interactively influence forest floor soil respiration in subtropical China.
We assessed the main and interactive effects of elevated [CO2] and N
addition on soil respiration by growing tree seedlings in ten large open-top
chambers under CO2 (ambient CO2 and 700 μmol mol−1) and
nitrogen (ambient and 100 kg N ha−1 yr−1) treatments. Soil
respiration, soil temperature and soil moisture were measured for 30 months,
as well as above-ground biomass, root biomass and soil organic matter (SOM).
Results showed that soil respiration displayed strong seasonal patterns with
higher values observed in the wet season (April–September) and lower values
in the dry season (October–March) in all treatments. Significant exponential
relationships between soil respiration rates and soil temperatures, as well
as significant linear relationships between soil respiration rates and soil
moistures (below 15%) were found. Both CO2 and N treatments
significantly affected soil respiration, and there was significant
interaction between elevated [CO2] and N addition (p<0.001, p=0.003,
and p=0.006, respectively). We also observed that the stimulatory effect of
individual elevated [CO2] (about 29% increased) was maintained
throughout the experimental period. The positive effect of N addition was
found only in 2006 (8.17% increased), and then had been weakened over
time. Their combined effect on soil respiration (about 50% increased) was
greater than the impact of either one alone. Mean value of annual soil
respiration was 5.32 ± 0.08, 4.54 ± 0.10, 3.56 ± 0.03 and 3.53 ± 0.03 kg CO2 m−2 yr−1
in the chambers exposed to elevated
[CO2] and high N deposition (CN), elevated [CO2] and ambient
N deposition (CC), ambient [CO2] and high N deposition (NN), and
ambient [CO2] and ambient N deposition (CK as a control), respectively.
Greater above-ground biomass and root biomass was obtained in the CN, CC and
NN treatments, and higher soil organic matter was observed only in the CN
treatment. In conclusion, the combined effect of elevated [CO2] and N
addition on soil respiration was apparent interaction. They should be
evaluated in combination in subtropical forest ecosystems in China where the
atmospheric CO2 and N deposition have been increasing simultaneously
and remarkably. |
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