Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide(N_2O) emission and methane(CH_4) uptake in the meadow steppe of Inner Mongolia, China. A two-year field experiment was c...Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide(N_2O) emission and methane(CH_4) uptake in the meadow steppe of Inner Mongolia, China. A two-year field experiment was conducted to assess the effects of nitrogen(N) deposition rates(0, 10, and 20 kg N ha^(-1)year^(-1) as(NH_4)2SO_4) on soil N_2O and CH_4 fluxes. The seasonal and diurnal variations of soil N_2O and CH_4 fluxes were determined using the static chamber-gas chromatography method during the two growing seasons of 2008 and 2009. Soil temperature, moisture and mineral N(NH_4^+-N and NO-3-N) concentration were simultaneously measured. Results showed that low level of(NH_4)2SO_4(10 kg N ha-1year-1) did not significantly affect soil CH_4 and N_2O fluxes and other variables. High level of(NH_4)_2SO_4(20 kg N ha^(-1)year) significantly increased soil NO-3-N concentration by 24.1% to35.6%, decreased soil CH_4 uptake by an average of 20.1%, and significantly promoted soil N_2O emission by an average of 98.2%.Soil N_2O emission responded more strongly to the added N compared to CH_4 uptake. However, soil CH_4 fluxes were mainly driven by soil moisture, followed by soil NO-3-N concentration. Soil N_2O fluxes were mainly driven by soil temperature, followed by soil moisture. Soil inorganic N availability was a key integrator of soil CH_4 uptake and N_2O emission. These results suggest that the changes of availability of inorganic N induced by the increased N deposition in soil may affect the CH_4 and N_2O fluxes in the cold semi-arid meadow steppe over the short term.展开更多
基金supported by the National Natural Science Foundation of China (No. 31300375)the National Non-Profit Institute Research Grant of the Chinese Academy of Agricultural Sciences (No. BSRF201505)the Key Project of the National Scientific and Technical Support Program, China (No. 2013BAC03B03)
文摘Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide(N_2O) emission and methane(CH_4) uptake in the meadow steppe of Inner Mongolia, China. A two-year field experiment was conducted to assess the effects of nitrogen(N) deposition rates(0, 10, and 20 kg N ha^(-1)year^(-1) as(NH_4)2SO_4) on soil N_2O and CH_4 fluxes. The seasonal and diurnal variations of soil N_2O and CH_4 fluxes were determined using the static chamber-gas chromatography method during the two growing seasons of 2008 and 2009. Soil temperature, moisture and mineral N(NH_4^+-N and NO-3-N) concentration were simultaneously measured. Results showed that low level of(NH_4)2SO_4(10 kg N ha-1year-1) did not significantly affect soil CH_4 and N_2O fluxes and other variables. High level of(NH_4)_2SO_4(20 kg N ha^(-1)year) significantly increased soil NO-3-N concentration by 24.1% to35.6%, decreased soil CH_4 uptake by an average of 20.1%, and significantly promoted soil N_2O emission by an average of 98.2%.Soil N_2O emission responded more strongly to the added N compared to CH_4 uptake. However, soil CH_4 fluxes were mainly driven by soil moisture, followed by soil NO-3-N concentration. Soil N_2O fluxes were mainly driven by soil temperature, followed by soil moisture. Soil inorganic N availability was a key integrator of soil CH_4 uptake and N_2O emission. These results suggest that the changes of availability of inorganic N induced by the increased N deposition in soil may affect the CH_4 and N_2O fluxes in the cold semi-arid meadow steppe over the short term.
