Management scheme influence and nitrogen addition effects on soil CO₂, CH₄, and N₂O fluxes in a Moso bamboo plantation

It is still not clear whether the effects of N deposition on soil greenhouse gas (GHG) emissions are influenced by plantation management schemes. A field experiment was conducted to investigate the effects of conventional management (CM) versus intensive management (IM), in combination with simulated N deposition levels of control (ambient N deposition), 30 kg N·ha^-1·year^-1 (N30, ambient + 30 kg N·ha^-1·year^-1), 60 kg N·ha^-1·year^-1 (N60, ambient + 60 kg N·ha^-1·year^-1), or 90 kg N·ha^-1·year^-1 (N90, ambient + 90 kg N·ha^-1·year^-1) on soil CO₂, CH₄, and N₂O fluxes. For this, 24 plots were set up in a Moso bamboo (Phyllostachys edulis) plantation from January 2013 to December 2015. Gas samples were collected monthly from January 2015 to December 2015.

Compared with CM, IM significantly increased soil CO₂ emissions and their temperature sensitivity (Q₁₀) but had no significant effects on soil CH₄ uptake or N₂O emissions. In the CM plots, N30 and N60 significantly increased soil CO₂ emissions, while N60 and N90 significantly increased soil N₂O emissions. In the IM plots, N30 and N60 significantly increased soil CO₂ and N₂O emissions, while N60 and N90 significantly decreased soil CH₄ uptake. Overall, in both CM and IM plots, N30 and N60 significantly increased global warming potentials, whereas N90 did not significantly affect global warming potential. However, N addition significantly decreased the Q₁₀ value of soil CO₂ emissions under IM but not under CM. Soil microbial biomass carbon was significantly and positively correlated with soil CO₂ and N₂O emissions but significantly and negatively correlated with soil CH₄ uptake.

Our results indicate that management scheme effects should be considered when assessing the effect of atmospheric N deposition on GHG emissions in bamboo plantations.