Pedosphere 27(2): 306--317, 2017
ISSN 1002-0160/CN 32-1315/P
©2017 Soil Science Society of China
Published by Elsevier B.V. and Science Press
| Simulated NH4+-N deposition inhibits CH4 uptake and promotes N2O emission in the meadow steppe of Inner Mongolia, China |
LIU Xingren1, ZHANG Qingwen1 , LI Shenggong2, ZHANG Leiming2,REN Jianqiang3 |
1Key Laboratory of Agricultural Environment, Ministry of Agriculture, Agricultural Clear Watershed % Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing 100081 (China)
2 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101 (China)
3 Institute of Agricultural Resources and Regional Planning, Chinese Academy of Agricultural Sciences, Beijing 100081 (China) |
| Corresponding Author:ellenzhqw@163.com. |
| ABSTRACT |
| Few studies are conducted to quantify the effects of enhanced N deposition on soil nitrous oxide (N2O) emission and methane (CH4) 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$_{4})_{2}$SO4) on soil N2O and CH4 fluxes.The seasonal and diurnal variations of soil N2O and CH4 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 (NH4+-N and NO3--N) concentration were simultaneously measured.Results showed that low level of (NH$_{4})_{2}$SO4 (10 kg N ha-1 year-1) did not significantly affect soil CH4 and N2O fluxes and other variables.High level of (NH$_{4})_{2}$SO4 (20 kg N ha-1 year-1) significantly increased soil NO3--N concentration by 24.1% to 35.6%, decreased soil CH4 uptake by an average of 20.1%, and significantly promoted soil N2O emission by an average of 98.2%. Soil N2O emission responded more strongly to the added N compared to CH4 uptake.However, soil CH4 fluxes were mainly driven by soil moisture, followed by soil NO3--N concentration. Soil N2O fluxes were mainly driven by soil temperature, followed by soil moisture.Soil inorganic N availability was a key integrator of soil CH4 uptake and N2O emission. These results suggest that the changes of availability of inorganic N induced by the increased N deposition in soil may affect the CH4 and N2O fluxes in the cold semi-arid meadow steppe over the short term. |
| Key Words: grassland ecosystems, greenhouse gases, N deposition rate, nitrification, denitrification, mineral N |
| Citation: Liu, X., Zhang, Q., Li, S., Zhang, L. and Ren, J. 2017. Simulated NH4+-N deposition inhibits CH4 uptake and promotes N2O emission in the meadow steppe of Inner Mongolia, China. Pedosphere. 27(2): 306-317. |
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