Unimodal response of N2O flux to changing rainfall amount and frequency in a wet meadow in the Tibetan Plateau

The rainfall amount and the frequency of extreme events have been predicted to increase in Qinghai-Tibetan Plateau during growing season. These changes will likely affect ecosystem processes, including those that control nitrogen (N) cycling storage; however, direction remains unclear. In this study, we experimentally altered precipitation season (May through October) at an alpine wetland Plateau. treatments included ambient rain (CK) plus 25 mm extra water for each irrigation event but with different frequency, i.e., weekly (DF1), biweekly (DF2), every three weeks (DF3) four (DF4). During season, N2O flux showed a large seasonal variation. Compared treatment natural events, promoted emission flux. As increased, aboveground biomass increased significantly from 85.82 g·m−2 245.79 g·m−2, accumulated emissions first then decreased; observed peak DF2 frequency. We also found significant linear relationships between soil flux, nitrate nitrogen, microbial content. Furthermore, among factors, higher (DF1) reduced relative abundance original dominant species (Alphaproteobacteria) studied soil. Our results indicate wetlands are highly sensitive variability high frequencies could reduce emission. Future patterns weaken contribution rate global warming.