Effects of simulated nitrogen deposition on microbial community and greenhouse gases emission of Pinus massoniana soil

To understand the driving mechanism of nitrogen deposition on greenhouse gases-emission from forest soil, we studied soil physical and chemical properties, microbial community structure and greenhouse gas-emission of potted soil of two-years old Pinus massoniana, fertilized with nitrogen. The results showed that simulated nitrogen deposition treatment significantly increased soil available nitrogen and seedling root nitrogen level. Soil microbial carbon (SMBC) decreased by 78% compared with that of the control. In contrast, soil microbial nitrogen (SMBN) increased by 2.6 times from that of control. Simulated nitrogen deposition treatment significantly reduced the level of soil total microbials. Nitrogen application had a significant effect on the soil emission rates of N2O and CO2: the N2O emission rate increased with higher level of nitrogen application, the CO2 emission rate also increased in the short term but decreased at the later stage due to the significant decrease of soil microbials. Correlation anal