CO 2 , CH 4 and N 2 O fluxes in an alpine meadow on the Tibetan Plateau as affected by N-addition and grazing exclusion

摘要: Limited understanding of the effects enhanced nitrogen (N) addition and grazing exclusion (E) on greenhouse gases fluxes (GHGs: CO2, CH4, N2O) in grasslands constrains our ability to respond challenges future climate change. In this study, we conducted a field experiment using static closed opaque chamber investigate response GHG N (69 kg N ha−1 year−1 applied 3 splits) an alpine meadow Tibetan Plateau during growing seasons from 2011 2013. Our results showed that winter significantly raised soil temperature (ST), while had no effect moisture (SM), fertilizer (F) ST or SM. Aboveground biomass (AB) root (RB) were not affected by E 2011-2013 (p > 0.05), but F AB RB (p < 0.05). Compared with grazing, only substantially reduced seasonal mean CO2 emissions (by about 20.1%) experimental period. did directly affect CH4 uptake, whereas uptake 6.5%, changed average absorption N2O into emission source. flux is major contributor equivalent area. indicate exclosure livestock might be promising measure reduce emissions, increase under