Response of CH4 and CO2 fluxes to simulated nitrogen deposition in a boreal forest in the Northeastern China

It is not clearly understand that the effects of changes in nitrogen (N) deposition on soil carbon (C) fluxes in boreal forests. Moreover, little is known about how the temporal pattern (daytime and nighttime) has impacted on soil carbon fluxes. To investigate these effects, 12 plots (20 m×20 m) were established in boreal forests in May 2012. Four NH4NO3 treatments (three replicates) were applied. The CH4 uptake and CO2 emission rates were measured daily and soil properties were simultaneously observed. The results showed that N deposition tended to restrain soil CH4 uptake but significantly promoted soil CO2 emission (except TH). There were significant difference in soil CO2 and CH4 fluxes between daytime and nighttime. In addition, N deposition had significantly impacted on soil properties. These results suggest that a longer study period is needed to verify effects of increasing N deposition on soil C fluxes and soil properties.