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Nitrous oxide emissions from grazed grasslands in China: Progresses and prospects |
Received:January 22, 2020 |
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KeyWord:static chamber-gas chromatography method;soil freeze-thaw cycle;nitrogen-limited ecosystem;permafrost;atmospheric dry deposition |
Author Name | Affiliation | E-mail | HUANG Jun-xiang | School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | | LIU Chun-yan | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | lcy@post.iap.ac.cn | YAO Zhi-sheng | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China | | ZHENG Xun-hua | State Key Laboratory of Atmospheric Boundary Layer Physics and Atmospheric Chemistry, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China | | NI Chang-jian | School of Atmospheric Sciences, Chengdu University of Information Technology, Chengdu 610225, China | |
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Abstract: |
Nitrous oxide(N2O)is a long-lived greenhouse gas with a high radiation efficiency. Grasslands are important natural sources of N2O. Grazing and climate change intensively influence N2O emissions from grasslands in China. Deficiencies on the measuring methods, the integrality of study, and the research of key processes, e.g. soil freeze-thaw cycles, cause huge uncertainties on the estimates of grassland N2O emissions and grassland nitrogen(N)feedback on climate change. In this study, we analyzed the possible influences of measuring methods, including the analysis method of N2O concentrations by gas chromatography and the sampling frequency, on the quantification of N2O emissions from grasslands; emphasized the importance of grazing-related sources, e.g. dung and urine patches on grasslands, livestock night barns, and forage croplands,on the budget of regional N2O emissions from grasslands; revealed the determinant of climate change influencing N2O emissions from grasslands, namely, the limitation of low N substrate availability on microbial N2O production in soils. The future research should focus on the evaluation of measurement errors induced by the observation methods, the importance of high-frequency measurements during the non-growing season on the quantification of annual total emissions, the triggering mechanisms of freeze-thaw-related N2O emissions, and the contribution of pulsed N2O emissions during the freeze-thaw period to the national emission inventory in grasslands, the responses of N2O emissions from alpine grasslands to changing climate change, and the impacts of increased dry N deposition and changing N components in the deposition on grassland N2O emissions. |
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