Nitrogen addition increased CO2 uptake more than non-CO2 greenhouse gases emissions in a Moso bamboo forest

Abstract

Atmospheric nitrogen (N) deposition affects the greenhouse gas (GHG) balance of ecosystems through the net atmospheric CO2 exchange and the emission of non-CO2 GHGs (CH4 and N2O). We quantified the effects of N deposition on biomass increment, soil organic carbon (SOC), and N2O and CH4 fluxes and, ultimately, the net GHG budget at ecosystem level of a Moso bamboo forest in China. Nitrogen addition significantly increased woody biomass increment and SOC decomposition, increased N2O emission, and reduced soil CH4 uptake. Despite higher N2O and CH4 fluxes, the ecosystem remained a net GHG sink of 26.8 to 29.4 megagrams of CO2 equivalent hectare−1 year−1 after 4 years of N addition against 22.7 hectare−1 year−1 without N addition. The total net carbon benefits induced by atmospheric N deposition at current rates of 30 kilograms of N hectare−1 year−1 over Moso bamboo forests across China were estimated to be of 23.8 teragrams of CO2 equivalent year−1