Influence of O2availability on NO and N2O release by nitrification and denitrification in soils

作者：Annette Bollmann, Ralf Conrad · 发表于：Global Change Biology · 年份：1998 · DOI：10.1046/j.1365-2486.1998.00161.x · 被引用次数：394 · 研究领域：Soil Carbon and Nitrogen Dynamics、Soil and Water Nutrient Dynamics、Plant nutrient uptake and metabolism

Abstract The availability of O2is believed to be one of the main factors regulating nitrification and denitrification and the release of NO and N2O. The availability of O2in soil is controlled by the O2partial pressure in the gas phase and by the moisture content in the soil. Therefore, we investigated the influence of O2partial pressures and soil moisture contents on the NO and N2O release in a sandy and a loamy silt and differentiated between nitrification and denitrification by selective inhibition of nitrification with 10 Pa acetylene. At 60% whc (maximum water holding capacity) NO and N2O release by denitrification increased with decreasing O2partial pressure and reached a maximum under anoxic conditions. Under anoxic conditions NO and N2O were only released by denitrification. NO and N2O release by nitrification also increased with decreasing O2partial pressure, but reached a maximum at 0.1–0.5% O2and then decreased again. Nitrification was the main source of NO and N2O at O2partial pressures higher than 0.1–0.5% O2. At lower O2partial pressures denitrification was the main source of NO and N2O. With decreasing O2partial pressure N2O release increased more than NO release, indicating that the N2O release was more sensitive against O2than the NO release. At ambient O2partial pressure (20.5% O2) NO and N2O release by denitrification increased with increasing soil moisture content. The maximum NO and N2O release was observed at soil moisture contents of 65–80% whc and 100%...