Factors controlling regional differences in forest soil emission of nitrogen oxides (NO and N2O)

Kaltenburg-Lindau

2006

S. 651-661

Bandaufführung

9945S

135856

Soil emissions of NO and N2O were measured continuously at high frequency for more than one year at 15 European forest sites as part of the EU-funded project NOFRETETE. The locations represent different forest types (coniferous/deciduous) and different nitrogen loads. Geographically they range from Finland in the north to Italy in the south and from Hungary in the east to Scotland in the west. The highest NO emissions were observed from coniferous forests, whereas the lowest NO emissions were observed from deciduous forests. The NO emissions from coniferous forests were highly correlated with N-deposition. The site with the highest average annual emission (82ıÊg NO-Nm.2 h.1) was a spruce forest in South-Germany (HœNoglwald) receiving an annual N-deposition of 2.9 gm.2. NO emissions close to the detection limit were observed from a pine forest in Finland where the N-deposition was 0.2 gNm.2 a.1. No significant correlation between N2O emission and N-deposition was found. The highest average annual N2O emission (20ıÊgN2O-Nm.2 h.1) was found in an oak forest in the MœLatra mountains (Hungary) receiving an annual N-deposition of 1.6 gm.2. N2O emission was significantly negatively correlated with the C/N ratio. The difference in N-oxide emissions from soils