Abstract:

Soil nitrous oxide (N₂O) and dinitrogen (N₂) emissions from denitrification are crucial to the nitrogen (N) cycle. However, the temperature sensitivities (Q₁₀) of gaseous N losses in forest soils are poorly understood, with implications for prediction of N cycle responses to warming. Here, we quantify temperature sensitivities of denitrification-derived potential N₂O and N₂ production. Using soils from 18 forest sites in China along a 4,000？km north–south transect we find that N₂O and N₂ production rates increased with temperature, with large variations across soils. In contrast, the Q₁₀ values for N₂O (2.1？±？0.5) and N₂ (2.6？±？0.6) were similar across soils. N₂ was more sensitive to temperature than N₂O, suggesting that warming could promote complete denitrification. Moreover, the Q₁₀ for denitrification (2.3？±？0.5) was comparable to Q₁₀ for aquatic sediments. This finding of universal temperature sensitivity of gaseous N losses from denitrification will facilitate modelling N losses in response to warming globally.