Responses of greenhouse gas emission to simulated nitrogen deposition in Calamagrostis angustifolia wetlands of Sanjiang Plain, China.

A long-term simulated nitrogen deposition experiment was carried out in Ecological Locating Research Station of the Institute of Nature and Ecology of Heilongjiang Academy of Sciences, with three different treatments including low nitrogen treatment (40 kg N·hm·a), high nitrogen treatment (80 kg N·hm·a) and the control (0 kg N·hm·a). The greenhouse gas emission fluxes were measured using a static box-gas chromatography method, with environmental factors being simultaneously investigated to understand the responses of greenhouse gas emission to the nitrogen deposition in the Calamagrostis angustifolia wetland. The results showed that low and high nitrogen treatments significantly increased the greenhouse gas emission fluxes. The CO emission flux increased by 47.5% and 47.9%, the CH emission fluxes increased by 76.8% and 110.1%, and the NO emission fluxes increased by 42.4% and 10.6% in low nitrogen treatment and high nitrogen treatment, respectively. Low nitrogen input changed the seasonal dynamics of NO emission fluxes but had no significant effect on that of CO and CH emissions. High nitrogen treatment did not affect the seasonal dynamics of greenhouse gas emissions. Soil temperature significantly positively correlated with CO and CH emission fluxes. There was no correlation between soil temperature and NO emission flux because the factors affecting NO emission were complex.