Dinitrogen emissions and the N2:N2O emission ratio of a Rendzic Leptosol as influenced by pH and forest thinning

Soil pH was the main controlling factor of the denitrification rates and N2/N2O emission ratios in forest and grassland soils along the Northeast China Transect (NECT)

“…Notwithstanding that the methods used in previous investigations could affect the absolute value of the N 2 / N 2 O ratio, the effects of soil pH on this ratio were confirmed here. Previous studies have suggested that the activity of nitrous oxide reductase, which is responsible for the reduction of N 2 O to N 2 in soils, can be repressed by low pH (Chapuis-Lardy et al 2007;Dannenmann et al 2008). Thus, denitrification yields relatively more N 2 O at lower soil pH, for a constant level of substrates (Š imek and Cooper 2002;Wolf and Brumme 2003;Dannenmann et al 2008;Zhang et al 2009).…”

“…Numerous studies manipulating soil pH or comparing soils of different natural pH values have shown that the ratio of N 2 /N 2 O in denitrification decreases with soil pH Wolf and Brumme 2003;Dannenmann et al 2008;Č uhel et al 2010). For example, Wolf and Russow (2000) reported a similar N 2 /N 2 O emission ratio of 3 for the black earth soil in the semi-arid climate in central Germany (neutral soil) in water-saturated conditions, using a 15 N tracer technique.…”

“…Kitzler et al (2006) obtained an N 2 /N 2 O emission ratio of 6, measured using the acetylene inhibition technique, for a shallow calcareous mountain forest soil (pH ¼ 6.4). Wolf and Brumme (2003) Dannenmann et al (2008) reported high N 2 /N 2 O emission ratios (ranging from 21 to 220) for intact soil cores taken from a mountainous beech forest ecosystem (pH > 6) and suggested that the low value for the N 2 /N 2 O emission ratio (e.g., in Kitzler et al 2006) may have been due to artefacts of the applied acetylene inhibition technique. Notwithstanding that the methods used in previous investigations could affect the absolute value of the N 2 / N 2 O ratio, the effects of soil pH on this ratio were confirmed here.…”

“…NO À 3 concentrations and organic matter are known to affect the ratio of N 2 /N 2 O during denitrification (Kralova 1991;Wolf and Brumme 2003;Manconi et al 2006;Chapuis-Lardy et al 2007;Dannenmann et al 2008;Miller et al 2008). Organic matter, especially available organic C, can increase the ratio of N 2 /N 2 O in denitrification (Weier et al 1993;Miller et al 2008).…”

Nitrogen balance of a boreal Scots pine forest

“…There is no field measurement data available on N 2 emissions of boreal ecosystems, whereas laboratory measurements indicate high N 2 emissions (10-120 kg N ha −1 yr −1 ) from temperate forest soils (Dannenmann et al, 2008;Butterbach-Bahl et al, 2002). Based on these results, we can expect that N 2 is also emitted from the soil at our measurement site; however, the rates remain unresolved.…”