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| Effects of simulated warming on carbon emissions from farmland soil and related mechanisms |
| Received:December 04, 2019 |
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| KeyWord:simulated warming;conventional tillage system;soil;CO2 flux;CH4 flux |
| Author Name | Affiliation | E-mail | | DU Kun | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Yucheng Shandong Agro-ecosystem National Observation and Research Station, Ministry of Science and Technology, Yucheng 251200, China
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China | | | LI Fa-dong | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Yucheng Shandong Agro-ecosystem National Observation and Research Station, Ministry of Science and Technology, Yucheng 251200, China
College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China | lifadong@igsnrr.ac.cn | | TU Chun | Key Laboratory of Karst Ecosystem and Rocky Desertification Control, Institute of Karst Geology, Chinese Academy of Geological Sciences, Guilin 541004, China | | | LI Zhao | Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China
Yucheng Shandong Agro-ecosystem National Observation and Research Station, Ministry of Science and Technology, Yucheng 251200, China | |
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| Abstract: |
| Cropland ecosystem is one of the most critical sources of carbon emissions. It is of great importance to study the changes in greenhouse gas emissions from farmland under global warming, and their mechanisms, to understand the global carbon cycle, and to lessen the acceleration of the global greenhouse effect. We carried out a simulated warming experiment at the Yucheng Shandong Agro-ecosystem National Observation and Research Station, Ministry of Science and Technology, located on the North China Plain. The experiment involved a conventional tillage and warming(CTW)treatment, and a conventional tillage with no-warming(CTN)control, or a typical local crop rotation of winter wheat(Triticum aestivum L.)and summer maize(Zea mays L.). The warming period was from October 2014 to December 2015, after which the heating equipment was shut down from the beginning of 2016 to September 2016 due to technical failure. The results showed that, from 2014 to 2015, soil temperature in the winter wheat period was increased significantly by 1.31℃(P<0.05), but heating had no distinct effect on soil temperature in the summer maize period(P>0.05). The mean soil water content had no significant response to warming during the two-year study period, and only the soil water content in the winter period was increased significantly by the warming. During the two-year study period, heating inhibited cumulative CO2 emissions in the winter wheat period by 20.35%, especially in March and May. In the winter wheat season from 2014 to 2016, the average annual cumulative CH4 absorption of CTW and CTN was 1 641.2 g·hm-2 and 2 185.7 g·hm-2, respectively. Warming inhibited CH4 absorption in the winter wheat season but had no significant effect on CH4 flux in the summer maize period. The soil microbial biomass carbon of CTW was decreased by 26.55% in the winter wheat season, but the response of microbial biomass nitrogen to warming was only obvious in special fertilization and irrigation months. The mean aboveground biomasses of CTW and CTN in winter wheat and summer maize were 12.19, 16.33, 16.41 and 21.18 mg·hm-2, respectively, indicating that warming had reduced the aboveground crop biomass. It was found that long-term warming significantly inhibited soil CO 2 emissions and CH4 absorption in the winter wheat season, but the responses of carbon emissions and absorption in the maize stage were not significant. Under warming conditions, soil water and heat conditions and aboveground biomass are still important factors in limiting the soil carbon flux. |
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