太湖流域农田稻季CH4通量特征及影响因子  

Characteristics and impact factors of methane flux in the paddy fields of Taihu Lake Basin

作　　者：鲍远航 徐昔保[2] 陈晔 BAO Yuanhang;XU Xibao;CHEN Ye(College of Geography,Nanjing Normal University,Nanjing 210023,China;Key Laboratory of Watershed Geography,Chinese Academy of Sciences,Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China;College of Marine Science and Engineering,Nanjing Normal University,Nanjing 210023,China)

机构地区：[1]南京师范大学地理科学学院,南京210023 [2]中国科学院南京地理与湖泊研究所,中科院流域地理学重点实验室,南京210008 [3]南京师范大学海洋科学与工程学院,南京210023

出　　处：《生态学报》2020年第21期7690-7698,共9页Acta Ecologica Sinica

基　　金：国家自然科学基金面上项目(41771571);中科院南京地理与湖泊研究所前沿探索与基础性研究(NIGLAS2016QY02);江苏省自然资源科技项目(KJXM2019007)。

摘　　要：开展太湖流域农田稻季CH4排放研究,深入了解稻田CH4排放规律,为稻田CH4减排、制定合理稻田管理措施提供科学依据。以太湖流域稻麦轮作农田为研究区域,运用涡度相关法观测其稻季CH4通量变化,分析其通量变化特征及影响因子。结果表明:太湖流域典型稻麦轮作区稻季为CH4的源,CH4排放总量为28.95 g/m^2,稻季CH4通量日变化表现为无规则型与单峰型两种模式;稻季CH4排放整体集中在水稻生长前期(81.61%)及中期(16.16%)、后期排放相对较弱(2.23%),返青期排放量较低(日均0.102μmol m^-2 s^-1),分蘖期较强(日均0.451μmol m^-2 s^-1),成熟期最低(日均0.006μmol m^-2 s^-1);模型所模拟的累计CH4排放通量比累计测量CH4通量低6.69%,较好地模拟了太湖流域稻田CH4的排放,土壤温度、土壤水分、土壤电导率、摩擦风速可确认为太湖流域农田稻季CH4排放的主要驱动因子。Methane emissions play a key role in global warming and climate change.The mechanism of methane emission in the paddy fields of the Taihu Lake Basin—a typical rice-wheat rotation region of China and also an area with one of the highest rates of land use change in the country—is still unclear,largely due to limited observation and the spatial heterogeneity of the environment.Eddy covariance,one of most popular approaches to observing methane flux,has many advantages,including long-term continuous observation,high frequency,and large monitoring range,without destruction of the original soil environment.We utilized the eddy covariance method to observe the methane flux in rice-wheat rotation paddy fields in the Taihu Lake Basin.The missing flux values were interpolated with the GA-BPNN model.The characteristics and influencing factors of methane flux were then analyzed,and a semi-empirical multiplicative model was built.The results showed that the rice-wheat rotation paddy fields were the main source of methane in the Taihu Lake Basin.During the observation period,the total amount of emitted methane was 28.95 g/m^2,and methane flux values varied in the range of 0—0.861μmol m^-2 s^-1.The diurnal variation in methane flux during the rice season appears under two modes:irregular and unimodal.In the irregular mode,methane flux was unstable throughout the day,and in the unimodal mode,the emissions during the day were significantly higher than that at night.The emission of methane in the rice season is concentrated in the early and middle stages of rice growth,relatively weak in the later stage,relatively low in the green stage(0.102μmol m^-2 s^-1 per day),strong in the tillering stage(0.451μmol m^-2 s^-1 per day),and lowest in the maturity stage(0.006μmol m^-2 s^-1 per day).The results of the analysis of various impact factors are as follows:The methane flux in the rice season increased exponential with air temperature and soil temperature at 10/20/40 cm depth(R^2=0.589,0.584,0.521,0.459,P<0.0001).Methane flux

关 键 词：太湖流域 稻麦轮作 CH4通量 涡度相关 

分 类 号：S181[农业科学—农业基础科学] S511