Nitrogen-rich organic soils under warm well-drained conditions are global nitrous oxide emission hotspots.

Nitrous oxide (N2 O) is a powerful greenhouse gas and the main driver of stratospheric ozone depletion. Since soils are the largest source of N2 O, predicting soil response to changes in climate or land use is central to understanding and managing N2 O. Here we find that N2 O flux can be predicted by models incorporating soil nitrate concentration (NO3 - ), water content and temperature using a global field survey of N2 O emissions and potential driving factors across a wide range of organic soils. N2 O emissions increase with NO3 - and follow a bell-shaped distribution with water content. Combining the two functions explains 72% of N2 O emission from all organic soils. Above 5 mg NO3 - -N kg-1 , either draining wet soils or irrigating well-drained soils increases N2 O emission by orders of magnitude. As soil temperature together with NO3 - explains 69% of N2 O emission, tropical wetlands should be a priority for N2 O management.