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| Titel |
Response of carbon dioxide emissions to sheep grazing and N application in an alpine grassland – Part 2: Effect of N application |
| VerfasserIn |
Y. M. Gong, A. Mohammat, X. J. Liu, K. H. Li, P. Christie, F. Fang, W. Song, Y. H. Chang, W. X. Han, X. T. Lü, Y. Y. Liu, Y. K. Hu |
| 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 ; 11, no. 7 ; Nr. 11, no. 7 (2014-04-03), S.1751-1757 |
| Datensatznummer |
250117339
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| Publikation (Nr.) |
 copernicus.org/bg-11-1751-2014.pdf |
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| Zusammenfassung |
| Widespread nitrogen (N) enrichment resulting from anthropogenic activities
has led to great changes in carbon exchange between the terrestrial biosphere
and the atmosphere. Grassland is one of the most sensitive ecosystems to N
deposition. However, the effect of N deposition on ecosystem respiration
(Re) in grasslands has been conducted mainly in temperate
grasslands, which are limited largely by water availability, with few studies
focused on alpine grasslands that are primarily constrained by low
temperatures. Failure to assess the magnitude of the response in
Re outside the growing season (NGS) in previous studies also
limits our understanding of carbon exchange under N deposition conditions. To
address these knowledge gaps we used a combination of static closed chambers
and gas chromatography in an alpine grassland from 2010 to 2011 to test the
effects of N application on ecosystem respiration (Re) both
inside and outside the growing season. There was no significant change in
CO2 emissions under N application. Re outside the growing
season was at least equivalent to 9.4% of the CO2 fluxes during the
growing season (GS). Annual Re was calculated to be
279.0–403.9 g CO2 m−2 yr−1 in Bayinbuluk alpine
grasslands. In addition, our results indicate that soil temperature was the
dominant abiotic factor regulating variation in Re in the cold and arid
environment. Our results suggest that short-term N additions exert no
significant effect on CO2 emissions in alpine grassland. |
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