Conclusions
Our field experiments show that the alpine steppe was a net source of N2O. Our results also demonstrate that N addition intensified N2O emission, while altered precipitation and its interaction with N addition did not affect N2O emission. Changes in N2O flux were attributable to the synergy between soil abiotic parameters and functional microorganisms. Most importantly, however, altered precipitation attenuated the response of N2O flux to N addition, thereby mitigating N2O emissions. This study provides necessary insight to predict the future responses of N2O emissions to long-term N deposition and precipitation alterations in alpine grasslands.