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

Abstract

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-2·a-1), high nitrogen treatment (80 kg N·hm-2·a-1) and the control (0 kg N·hm-2·a-1). 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 CO2 emission flux increased by 47.5% and 47.9%, the CH4 emission fluxes increased by 76.8% and 110.1%, and the N2O 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 N2O emission fluxes but had no significant effect on that of CO2 and CH4 emissions. High nitrogen treatment did not affect the seasonal dynamics of greenhouse gas emissions. Soil temperature significantly positively correlated with CO2 and CH4 emission fluxes. There was no correlation between soil temperature and N2O emission flux because the factors affecting N2O emission were complex.