Nitrous Oxide Emission Rates over 10 Years in an Alpine Meadow on the Tibetan Plateau

The alpine grassland ecosystem covering about 85% of the Tibetan plateau is fragile and sensitive to natural and anthropogenic disturbances. However, it is unclear how nitrous oxide (N2O) has varied over the last 10 years. In order to accurately estimate the regional N2O emissions budget, the N2O levels, environmental factors, and biomass were investigated on a yearly, monthly, and seasonal basis from 2000 to 2014 in an alpine meadow. The results showed that there was an overall declining trend in emissions over 10 years, during which the two maximum emission rates were 64.8 +/- 11.1 and 41.8 +/- 18.2 mu g m(-2) h(-1) (in 2001 and 2006). The average N2O emissions rate was about 38.4 +/- 3.3 mu g m(-2) h(-1). Pearson correlation demonstrated that soil and air temperature exerted a crucial influence on N2O, followed by precipitation and aboveground biomass, but the effect of soil moisture at a depth of 10 cm was negative. Multiple linear regressions showed a good relationship between N2O and all environmental factors. Future scenarios of wetter and warmer weather would noticeably increase alpine meadow N2O emissions on the Tibetan Plateau.