Modeling global annual N2O and NO emissions from fertilized fields

Information from 846 N 2 O emission measurements in agricultural fields and 99 measurements for NO emissions was used to describe the influence of various factors regulating emissions from mineral soils in models for calculating global N 2 O and NO emissions. Only those factors having a significant influence on N 2 O and NO emissions were included in the models. For N 2 O these were (1) environmental factors (climate, soil organic C content, soil texture, drainage and soil pH); (2) management‐related factors (N application rate per fertilizer type, type of crop, with major differences between grass, legumes and other annual crops); and (3) factors related to the measurements (length of measurement period and frequency of measurements). The most important controls on NO emission include the N application rate per fertilizer type, soil organic‐C content and soil drainage. Calculated global annual N 2 O‐N and NO‐N emissions from fertilized agricultural fields amount to 2.8 and 1.6 Mtonne, respectively. The global mean fertilizer‐induced emissions for N 2 O and NO amount to 0.9% and 0.7%, respectively, of the N applied. These overall results account for the spatial variability of the main N 2 O and NO emission controls on the landscape scale.