Accurate estimation of N2O emission is one of the
primary objectives to project the warming potential. However, the global
patterns and main controlling factors of soil N2O
emission remain elusive. We compiled a dataset with 6016 field
observations from 219 articles and found that the averaged soil
N2O emission rate was 1111.8 ± 26.59 µg N
m-2 day-1. Soil N2O
emission rates were significantly influenced by climatic factors (i.e.
mean annual temperature), soil physical and chemical properties (e.g.
pH, nitrate, ammonium, and total nitrogen), and microbial traits
(microbial biomass nitrogen) at a global scale. The combined direct
effects of soil nitrate, ammonium, and total nitrogen (combined standard
coefficient = 0.45) accounted for the most variance of global soil
N2O emissions (total standard coefficient = 0.84). This
study highlights the critical roles of soil nitrogen substrates on
N2O emission, which will be helpful to optimize the
process-models on soil N2O emissions.