bei Google ScholarTitelangaben
Goldberg, Stefanie D. ; Knorr, Klaus-Holger ; Blodau, Christian ; Lischeid, Gunnar ; Gebauer, Gerhard:
Impact of altering the water table height of an acidic fen on N2O and NO fluxes and soil concentrations.
In: Global Change Biology.
Bd. 16
(2010)
Heft 1
.
- S. 220-233.
ISSN 1365-2486
DOI: https://doi.org/10.1111/j.1365-2486.2009.02015.x
Abstract
The impact of experimentally intensified summer drought and precipitation on N2O and NO turnover and fluxes was investigated in a minerotrophic fen over a 2-year period. On threetreatment plots, drought was induced for 6 and 10 weeks by means of roofs and drainageand decreased water table levels by 0.1–0.3m compared with three nonmanipulated control plots. When averaged over the three treatment plots, both N2O and NO emission showed only little response to the drought. On the single plot scale, however, a clear impact of the treatment on N2O and NO fluxes could be identified. On the plot with the weakest water table reduction hardly any response could be observed, while on the plot with the greatestdrainage effect, N2O and NO fluxes increased by 530% and 270%, respectively. Rewettingreduced NO emissions to background levels (0.05–0.15 µmol m-2h-1), but heavily enhancedN2O emission (18–36 µmol m-2h-1) for several days in the plots with largest water table reduction. These peaks contributed up to 40% to the cumulative N2O fluxes and were causedby rapid N2O production according to isotope abundance data. According to N2O concentrations and isotope abundance analysis N2O was mostly produced at depths between 0.3 and 0.5 m. During water table reduction net N2O production in 0.1m depth steadilyincreased in the most effectively dried plot from 2 up to 44 pmol cm-3 day-1. Rewetting immediately increased net N2O production in the topsoil of the drought plots, showing rates of 18–174 pmol cm-3 day-1. This study demonstrates that drought and rewetting can temporarilyincrease N2O emission to levels that have to date only been reported from nutrientrich and degraded fens that have been drained for agricultural purposes.