淮河流域农田生态系统碳通量变化特征

利用涡度相关技术对安徽寿县冬小麦／水稻农田碳通量进行连续观测，结果显示：日变化呈典型的u型曲线，峰值均出现在11：00左右；CO2的月均日变化差异显著，6、10月以正值为主，农田生态系统表现为碳源，4、8月对CO2的吸收最为强烈；春、夏季CO2通量的日变化也呈现出典型的u型曲线，但是秋、冬季的碳通量日较差较小。COz通量各季的日总量表现为春季〉夏季〉冬季〉秋季，四季均为碳汇，春夏两季的碳汇能力明显强于秋冬季。

The Characteristics of the Carbon Flux Variation in the Huaihe River Farmland Ecosystem

In this paper, using the eddy covariance technique to make a continuous observation on the carbon flux of wheat and rice in Shouxian, Anhui province.The result show that the daily variation presents a typical U- shaped curve,and the peak appears at 11：00am around.The monthly average daily variation of CO2 is significant- ly different.The CO2 flux is upright in June and October, and the farmland ecosystem performance as the carbon source,the absorption of CO2 is the strongest in April and August. The C02 flux＇ diurnal variation of the spring and summer also presents the typical U-shaped curve, but the diurnal range of carbon flux is smaller in autumn and winter. Daily amount of CO2 flux in each season presents as follow： spring 〉summer 〉winter 〉fall.The four season are all carbon sinks ,and the carbon sink capacity of spring and summer is stronger than the fall and win- ter.