| 我国长江中下游平原典型稻田含碳温室气体通量变化特性 |
| 摘要点击 1917 全文点击 601 投稿时间：2021-07-12 修订日期：2021-09-16 |
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| 中文关键词 稻田 长江中下游平原 涡度相关 CO2和CH4通量 环境因子 |
| 英文关键词 paddy field middle-lower Yangtze Plain eddy covariance CO2 and CH4 flux environmental factors |
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| 中文摘要 |
| 近年来关于碳排放研究的内容越来越受到重视，我国提出了在2030年实现碳达峰的战略目标，因此对我国温室气体排放监测的研究显得非常重要.基于涡度相关法对我国长江中下游区域典型稻田生长季的CO2和CH4通量进行监测分析，结果发现整个观测阶段稻田CO2通量呈"U"型曲线，整体表现为汇，分蘖期开始出现负值，抽穗期降到最低，通量平均值为-3.33 μmol·（m2·s）-1.CH4通量与CO2通量趋势大致相反，先增加后减少，在分蘖期和拔节期迅猛上升，孕穗期从峰值降到低谷，通量平均值为0.11 μmol·（m2·s）-1，通量最大值为0.40 μmol·（m2·s）-1，出现在拔节期末端孕穗期初.CO2通量从07：00开始下降，在13：00左右达到最低约-16.01 μmol·（m2·s）-1，白天通量值为负，晚上通量值为正.CH4通量为晚上低白天高，06：00开始增加，14：00左右达到峰值约0.16 μmol·（m2·s）-1，夜间通量较平稳.整个观测阶段，空气温度与CH4通量呈指数相关，饱和水汽压差与CH4通量呈线性相关，且拔节期最为显著，但两因子与CO2通量的响应关系相对较弱.不同尺度分析表明，日变化尺度上的CO2和CH4通量与两因子的响应关系要好于季节尺度，白天的响应关系要好于晚上.CH4通量在日变化尺度上随着CO2通量的增加而显著降低，但在季节尺度上两者相关性不明显.人为施肥过程减缓了稻田CH4排放. |
| 英文摘要 |
| In recent years, carbon emission research has been receiving increasing attention. China has put forward the strategic goal of achieving a carbon emission peak by 2030. Hence this research is very important for the measurement of greenhouse gas emissions in China. CO2 and CH4 fluxes from a paddy field in the middle-lower Yangtze Plain in China were analyzed based on the eddy covariance technique. The CO2 flux showed an "U" curve during the observation period, with an average flux of -3.33 μmol·(m2·s)-1, which was a sink. Negative values appeared at the tillering stage, and the minimum was shown at the heading period. The CH4 flux trend was roughly opposite to the that of the CO2 flux, which first increased and then decreased. It raised rapidly during the tillering and jointing stages and then dropped rapidly from the peak to the trough during the booting stage, and only a slight increase was found in the blooming stage. The maximum flux[0.40 μmol·(m2·s)-1] appeared at the beginning of the booting stage and the end of the jointing stage, and the average flux was 0.11 μmol·(m2·s)-1. The CO2 flux was positive at night and negative during the day. It decreased from 07:00 and reached a minimum around 13:00 at -16.01 μmol·(m2·s)-1. The CH4 flux was low at night and high during the daytime. It increased at 06:00 and reached a peak around 14:00, at approximately 0.16 μmol·(m2·s)-1. An exponential correlation was found between air temperature and CH4 flux. The vapor pressure deficit showed a linear correlation with CH4 flux. The response of environmental factors on CO2 fluxes and CH4 fluxes on a diurnal scale was greater than that on a seasonal scale, and the daytime response was greater than that at night. CH4 flux decreased significantly with the increase in CO2 flux on the diurnal scale, but the correlation was not obvious on the seasonal scale. The increased CH4 flux slowed down after fertilizing. |
