Using the open-path eddy covariance system to Huaihe River basin farmland for turbulence characteristics on a four-year continuous monitoring, For the study of major crops of wheat and rice to analysis and processing the CO2 flux data. The results show that: the farmland diurnal variation of CO2 flux changed significantly with the seasons, the magnitude of changes in spring and summer was significantly greater than the autumn and winter; The diurnal variation of CO2 flux from paddy fields showed a single peak in Huaihe River Basin from 2007-2010, it obviously a carbon converged on daytime; The daily maximum total absorption in 2007, can up to 16.12 mg-m"2-s'', the minimum in 2009, is 11.16 mgm'2s''; In the jointing stage of rice, vertical wind speed(W), latent heat flux(LE), sensible heat flux(//), Photosynthetic active radiation(PAR), net radiation(Rn)and CO2 flux have a significant negative correlation; Through principal component analysis by indicators, the new composite indicator F--0.36ZX1 + 0.42ZX2 +0.42 ZX3 +0.42 ZX4 +0.39 ZX5 +0.42 ZX6+0.13 ZX7, and the time in 13:00 is the calculated maximum carbon sinks, 24:00 is the largest carbon source.%采用开路涡度相关系统对淮河流域农田湍流特征进行了4年连续监测,以该地区主要农作物小麦和水稻为例,对CO2通量数据进行分析处理.研究结果表明:农田CO2通量的日变化随季节变化明显,春、夏变化幅度明显大于秋、冬.2007-2010年淮河流域夏季农田CO2通量日变化规律均呈单峰型,白天为明显的碳汇；其日最大累计吸收量出现在2007年,可达16.1mg.m-2·s-1,最小值出现在2009年,为11.1 mg·m-2·s-1.在水稻拔节期垂直风速(W)、潜热通量(LE)、显热通量(H)、光合有效辐射( PAR)、净辐射(Rn)与CO2通量均呈负相关,通过对各项指标进行主成分分析,得到了新的综合指标F=-0.36ZX1+0.42ZX2+0.42ZX3+0.42ZX4+0.39ZX5+0.42ZX6+0.13ZX7,并经过计算得出中午1点是最大的碳汇,凌晨12点是最大的碳源.
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