Soil nitrous oxide (N₂O) and dinitrogen (N₂) emissions from denitrification are crucial to the global nitrogen (N) cycle. However, the temperature sensitivities of gaseous N losses in forest soils are poorly understood, limiting our ability to predict N cycling responses to global warming. We quantified temperature sensitivities (Q10) of denitrification-derived potential N₂O and N2 production ex-situ for 18 forest soils across China. N₂O and N₂ production rates increased exponentially with temperature, showing large variation among soils. By contrast, the Q10 values for N₂O (2.1±0.5) and N₂ (2.6±0.6) were surprisingly similar across soils. N₂ was more sensitive to temperature than N₂O, suggesting warming could promote complete denitrification. The Q10 values for denitrification (2.3±0.5) were similar to those reported for aquatic sediments. Collectively, our results indicate a universal temperature sensitivity of gaseous N losses from denitrification, which will facilitate modelling N losses in response to warming on the global scale. 

We conducted laboratory incubation experiments with soils from 18 forest sites across China along a 4000 km south-north transect spanning a 33° latitudinal range. The soils were anaerobically incubated between 5 and 35°C for 12 h after amending them with Na¹⁵NO₃ (99.26 atom%). Next, the production of N₂O and N₂ as well as the consumption of nitrate (NO₃-) were measured. In addition, we also measured several chemical and biological soil variables of potential importance for denitrification, such as pH, C/N ratio, water extractable organic carbon (WEOC), and functional genes (nirK, nirS, nosZ) abundance associated with gaseous N production.