A 3-year continuous record of nitrogen trace gas fluxes from untreated and limed soil of a N-saturated spruce and beech forest ecosystem in Germany: 2. NO and NO2fluxes

摘要: For 3 years we followed the complete annual cycles of N2O emission rates with 2-hour resolution in spruce and beech plantations Hoglwald Forest, Bavaria, Germany, order to gain detailed information about seasonal interannual variations emissions. In addition, microbiological process studies were performed for identification differences N turnover soil a site estimation contribution nitrification denitrification actual emission. Both pronounced extreme emissions identified. During long-term frost periods, while was frozen, during thawing, extremely high occurred, contributing up 73% total loss. The enormous releases period due microbial (tight coupling ammonification, nitrification, denitrification) small unfrozen water films frozen at concentrations easily degradable substrates derived from pool dead biomass produced period. Liming resulted significant increase as compared an untreated control site. exhibited 4–5 times higher than site, indicating that forest type itself is important modulator release soil. At all sites, contributed ∼70% flux, whereas markedly less (∼30%). There positive correlation between amount situ input by wet deposition magnitude 10% released form N2O, fraction 0.5%. positively correlated net rates. results demonstrate need measurements over several more precise estimates losses ecosystems. On basis our conclude importance temperate boreal forests global source strength may have been significantly underestimated past these contribute most likely ≫1.0 Tg N.