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| Titel |
Variability of nitrogen exchange between the atmosphere and a semi-natural grassland in Hungary |
| VerfasserIn |
A. Machon, B. Grosz, L. Horvath, T. Weidinger, K. Pintér, Z. Nagy, E. Führer |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250071275
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| Zusammenfassung |
| The changes in different climate parameters evidently affect not only N-deposition but also
N-exchange and N-gas emissions through the processes of soil and plant metabolism.
Exchange dynamics of nitrogen compounds over Hungarian grassland (central Hungary,
Kiskunság National Park, Bugacpuszta) ecosystems were analyzed based on field
measurements and modeling approach. Measurements of i) nitrogen fluxes, ii) standard
meteorological parameters and iii) surface energy budget components have been started
above a semi-natural grassland ecosystem in 2002. Seasonal and long-term nitrogen exchange
(both emission and deposition) is under climatic control. Inter annual variations of N budget
components and meteorological parameters are investigated. In the years of 2006 and 2007,
the amount of the deposited N markedly decreased (by 27% and 15%, respectively)
compared to the average of the earlier (2002–2004) years. The main source of the
deposited N is NH3. The ratio of dry to wet deposition varies between 1.5 and
2.3. In the dry year of 2007, emissions of N2O were four times lower compared
to the average (90 mg N m-2yr-1) of the earlier years caused by the changes in
weather conditions including lower precipitation and 1°C higher annual average
temperature. With increasing soil temperature, NO flux grows faster than N2O up to 20°C
until the role of other factors will determine the magnitude of metabolism. The
relatively high soil N2O flux could come from the thawing period in early spring which
could resulting in high emission peaks for a few days period. It seems that soil
temperature usually generates short term variability of trace gas exchange, whereas the
magnitude of the biogenic emission is dominantly controlled by soil wetness, pH,
and other site specific factors. The net N flux – excluding grazing, manure, farm
management, etc. – ranged between 9.5 and 13 kg N ha-1yr-1 in period 2002–2010. |
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