Abstract: Wetland is a major source of nitrous oxide. Climate changes can influence N2O emission. To explore its emission′s characteristics of wetland ecosystem during the growth of Phragmites australis from 2018 to 2100, three RCP (Representative concentration pathway) scenarios in six models selected from IPCC (International Panel on Climate Change) were used by DNDC (Denitrification decomposition) model. The results showed that multipoint historical position experiments present a clear relationship between observed values and simulated ones, and correlation coefficient r is 0.723, while determination coefficient (R2) is 0.522 with RMS(Root mean square error) of 76.75 μg/m2 · d. No obvious and regular fluctuations are found in the condition of RCP2.6 and RCP4.5 scenarios, whose annual nitrous oxide emission range from 0.69-23.84 and 0.59-31.92 simulated by DNDC in the future. Compared to RCP 8.5 scenario, N2O emission increases significantly in both CanEMS2 and MIROC5 with year total emission from 0.49-38.82, respectively. N2O emission does not show a significant increasing or decreasing trend in the three sections divided in the period of 2008-2100. Under multi-modes and multi-scenarios, the N2O emission has no significant periodic changes but it is affected obviously by precipitation and temperature. The maximum N2O emission is likely to occur during the year with moderate temperature and abundant precipitation.

Key words: reed, wetland, nitrous oxide, DNDC (denitrification-decomposition) model, RCP