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| Fluxes of CO2, CH4 and N2O from seasonal freeze-thaw arable soils in Northeast China |
| Received:September 23, 2015 |
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| KeyWord:black soil;non-growing season;greenhouse gas;freeze-thaw cycle;snow cover;source and sink;net greenhouse effect |
| Author Name | Affiliation | E-mail | | CHEN Zhe | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | | | HAN Rui-yun | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | | | YANG Shi-qi | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | | | ZHANG Ai-ping | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | | | ZHANG Qing-wen | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | | | MI Zhao-rong | Farmland Irrigation Research Institute, Chinese Academy of Agricultural Sciences, Xinxiang 453002, China | | | WANG Yong-sheng | Beijing Research Center for Information Technology in Agricultural, Beijing 100097, China | | | YANG Zheng-li | Agricultural Clear Watershed Innovation Group, Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences/Key Laboratory of Agro-Environment, Ministry of Agriculture, Beijing 100081, China | yangzl426@126.com |
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| Abstract: |
| We monitored the dynamics of soil CO2, CH4 and N2O fluxes of two typical agricultural ecosystems(paddy/maize field) in Songnen Plain using static opaque chamber-gas chromatograph method. The greenhouse gases(GHG) emissions showed obvious seasonal pattern, which could be divided into four periods——freezing, snow cover, snow melting, and frost free. The freezing and snow melting periods were critical for greenhouse gases(GHG) emissions. During these two periods, CO2 emissions from paddy and maize fields accounted for 74.9% and 68.6% of the total cumulative CO2 emissions, respectively. The CH4 emissions from paddy field amounted to 95.7% of the total CH4 emissions. In the maize field, CH4 showed absorption during the experimental period. However, it had large releases during snow melting. Soil N2O emissions showed intensive explosive release during the short snow melting period. The peak of N2O flux from paddy and maize fields was respectively 40 times and 99 times higher than that before soil freezing. The cumulative emissions of N2O from two farmlands accounted for 73.9% and 80.4% of the total N2O emissions, respectively. During the snow covering period, CH4 and N2O were weakly absorbed. In addition, different land uses showed different patterns of GHG emissions. Paddy had higher potential GHG emissions than maize field did. Taken together, CO2, CH4 and N2O fluxes from paddy field were net emissions(source), and the total cumulative emission was higher than that of maize field. The average emission rates of CO2 and CH4 were significantly higher in paddy than in maize field. However, CH4 flux of maize field was net absorption(sink). The average GHG flux was significantly different between these two types of farmland. In conclusion, GHG emissions during soil freezing, thawing and snow melting periods should be taken into account when evaluating the GHG emissions in seasonal frozen regions. GHG emissions under different land uses are different. |
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