Controls over N₂O, NO_x and CO₂ fluxes in a calcareous mountain forest soil

B. Kitzler (1) , S. Zechmeister-Boltenstern (1) , C. Holtermann (2) , U. Skiba (3) , K. Butterbach-Bahl (4)

1 Federal Research and Training Centre for Forests
2 Sellenyg. 2?4/52
3 Institute of Terrestrial Ecology
4 IMK-IFU - Institut für Meteorologie und Klimaforschung - Atmosphärische Umweltforschung

We measured nitrogen oxides (N₂O and NO_x), dinitrogen (N₂) and carbon dioxide (CO₂) emissions from a spruce-fir-beech forest soil in the North Tyrolean limestone Alps in Austria. The site received 12.1 kg nitrogen via wet and dry deposition. Fluxes of nitric oxide (NO) were measured by an automatic dynamic chamber system on an hourly basis over a two year period. Daily N₂O emissions were obtained by a semi-automatic gas measuring system. In order to cover spatial variability biweekly manual measurements of N₂O and CO₂ emissions were carried out, additionally. For acquiring information on the effects of soil and meteorological conditions and of N-deposition on N-emissions we chose the autoregression procedure (time-series analysis) as our means of investigation. Hence, we could exclude the data's autocorrelation in the course of the time. We found that soil temperature, soil moisture and wet N-deposition followed by air temperature and precipitation were the most powerful influencing parameters effecting N-emissions. With these variables up to 89% of observed temporal variations of N-emissions could be explained. During the two-year investigation period between 2.5 and 3.5% of deposited N was reemitted in form of N₂O whereas only 0.2% were emitted as NO. At our mountain forest site the main end-product of microbial activity processes was N₂ and trace gases (N₂O and NO) were only of minor importance.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]; Interfaces continentales, environnement; Océan, Atmosphère; Sciences de la Terre

B. Kitzler, S. Zechmeister-Boltenstern, C. Holtermann, U. Skiba, K. Butterbach-Bahl. Controls over N₂O, NO_x and CO₂ fluxes in a calcareous mountain forest soil. Biogeosciences Discussions, 2005, 2 (5), pp.1423-1455. ⟨hal-00297816⟩