Abstract: A laboratory incubation test was conducted to study the effects of different nitrogen inputs (N0: 0 mg·g^-1; N1: 0.1 mg·g^-1; N2: 0.2 mg·g^-1; N3: 0.5 mg·g^-1) on the characteristics of N2O emission and organic carbon mineralization in a meadow marsh soil, and the variation patterns of soil microbial carbon and nitrogen. During the incubation period (23 d), the N₂O emission in treatments N0, N1, N2, and N3 was 91.12, 133.02, 147.75, and 303.45 μg·kg^-1, respectively, illustrating that nitrogen input promoted soil N₂O emission. Except at the late phase of incubation, the mineralization rate of soil organic carbon under nitrogen input lowered, suggesting that nitrogen input restrained the mineralization of soil organic carbon to some degree. Compared with treatment N0, the soil microbial biomass carbon in treatments N1, N2, and N3 was significantly lower (P<0.05), but no significant difference was observed among the latter three treatments. Soil microbial biomass nitrogen increased linearly with increasing nitrogen input, and there were significant differences among different nitrogen inputs (P<0.05). Our results suggested that supplying exogenous nitrogen affected the structure and composition of soil microbes, and the related mechanisms should be studied further.

Key words: Flora, Riparian zone, Community, Plant, Changbai Mountain