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

Pärn, Jaan; Verhoeven, Jos T A; Butterbach-Bahl, Klaus; Dise, Nancy B; Ullah, Sami; Aasa, Anto; Egorov, Sergey; Espenberg, Mikk et al. · Nat Commun · 2018

basic_science · Level V

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Abstract

Nitrous oxide (N<sub>2</sub>O) is a powerful greenhouse gas and the main driver of stratospheric ozone depletion. Since soils are the largest source of N<sub>2</sub>O, predicting soil response to changes in climate or land use is central to understanding and managing N<sub>2</sub>O. Here we find that N<sub>2</sub>O flux can be predicted by models incorporating soil nitrate concentration (NO<sub>3</sub><sup>-</sup>), water content and temperature using a global field survey of N<sub>2</sub>O emissions and potential driving factors across a wide range of organic soils. N<sub>2</sub>O emissions increase with NO<sub>3</sub><sup>-</sup> and follow a bell-shaped distribution with water content. Combining the two functions explains 72% of N<sub>2</sub>O emission from all organic soils. Above 5 mg NO<sub>3</sub><sup>-</sup>-N kg<sup>-1</sup>, either draining wet soils or irrigating well-drained soils increases N<sub>2</sub>O emission by orders of magnitude. As soil temperature together with NO<sub>3</sub><sup>-</sup> explains 69% of N<sub>2</sub>O emission, tropical wetlands should be a priority for N<sub>2</sub>O management.