 |
| Titel |
Nitrous oxide production in boreal soils with variable organic matter content at low temperature – snow manipulation experiment |
| VerfasserIn |
M. Maljanen, P. Virkajärvi, J. Hytönen, M. Öquist, T. Sparrman, P. J. Martikainen |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1726-4170
|
| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 6, no. 11 ; Nr. 6, no. 11 (2009-11-05), S.2461-2473 |
| Datensatznummer |
250004085
|
| Publikation (Nr.) |
 copernicus.org/bg-6-2461-2009.pdf |
|
|
|
|
|
| Zusammenfassung |
| Agricultural soils are the most important sources for the greenhouse gas
nitrous oxide (N2O), which is produced and emitted from soils also at
low temperatures. The processes behind emissions at low temperatures are
still poorly known. Snow is a good insulator and it keeps soil temperature
rather constant. To simulate the effects of a reduction in snow depth on
N2O emission in warming climate, snow pack was removed from experimental plots on three
different agricultural soils (sand, mull, peat). Removal of snow lowered
soil temperature and increased the extent and duration of soil frost in sand
and mull soils. This led to enhanced N2O emissions during freezing and
thawing events. The cumulative emissions during the first year when snow was
removed over the whole winter were 0.25, 0.66 and 3.0 g N2O-N m−2 yr−1 in control plots of sand, mull and peat soils,
respectively. In the treatment plots, without snow cover, the respective cumulative
emissions were 0.37, 1.3 and 3.3 g N2O-N m−2 yr−1. Shorter snow
manipulation during the second year did not increase the annual emissions.
Only 20% of the N2O emission occurred during the growing season.
Thus, these results highlight the importance of the winter season for this
exchange and that the year-round measurements of annual N2O emissions from
boreal soils are integral for estimating their N2O source strength.
N2O accumulated in the frozen soil during winter and the soil N2O
concentration correlated with the depth of frost but not with the winter
N2O emission rates per se. Also laboratory incubations of soil samples showed
high production rates of N2O at temperatures below 0°C,
especially in the sand and peat soils. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|