Effects of nitrogen deposition and litter layer management on soil CO(2), N(2)O, and CH(4) emissions in a subtropical pine forestland

Forestland soils play vital role in regulating global soil greenhouse gas (GHG) budgets, but the interactive effect of the litter layer management and simulated nitrogen (N) deposition on these GHG flux has not been elucidated clearly in subtropical forestland. A field trial was conducted to study these effects by using litter removal method under 0 and 40 kg N ha(−1) yr(−1) addition in a subtropical forestland in Yingtan, Jiangxi Province, China. Soil CO(2) emission was increased by N addition (18–24%) but decreased by litter removal (24–32%). Litter removal significantly (P < 0.05) decreased cumulative N(2)O emission by 21% in treatments without N addition but only by 10% in treatments with 40 kg N ha(−1) yr(−1) addition. Moreover, litter-induced N(2)O emission under elevated N deposition (0.094 kg N(2)O-N ha(−1)) was almost the same as without N addition (0.088 kg N(2)O-N ha(−1)). Diffusion of atmospheric CH(4) into soil was facilitated by litter removal, which increased CH(4) uptake by 55%. Given that the increasing trend of atmospheric N deposition in future, which would reduce litterfall in subtropical N-rich forest, the effect of surface litter layer change on soil GHG emissions should be considered in assessing forest GHG budgets and future climate scenario modeling.