灌溉对稻田甲烷排放的影响

Effect of irrigation on methane emission in the paddy soil:

稻田土壤Ｅｈ值＜－１５０ｍＶ时甲烷大量产生，甲烷排放速率随着温度的上升而加大，与稻田水层温度的相关系数ｒ＝０．９６１１＊＊，水稻整个大田生长期的甲烷平均排放通量为１８２．１８ｍｇ·ｍ－２·ｄ－１。通过控水晒田可迅速提高土壤Ｅｈ值，使土壤水溶解的甲烷量和排放量骤然下降，其下降幅度在９０％以上。稻田耕层土壤水溶解的甲烷量，随土层深度增加而逐渐上升，土层为５ｃｍ、１０ｃｍ和１５ｃｍ的溶解甲烷量，分别为０．４６、１．８３、２．２４和３．１３μｇ·ｍｌ－１。较低的Ｃ％和Ｎ％水稻土，其甲烷产生和释放的潜力较弱。

The rice soil with Eh<-150mV was found to release a large amount of methane with an average of 182 18mg·m - 2·d - 1 during the rice growing season.The rate of methane emission increased as temperature climbed up and significantly correlated to the water temperature in the rice field (r=0.9611 * *).Water control by drainage could rapidly increase the value of Eh,resulting in a sharp decrease of water soluble methane in the soil and>90% of its emission.The content of water soluble methane significantly correlated to thedepth of the soil,which was 0 46,1.83,2 24,and 3 13μg·ml - 1 in the depths of 5,10,and 15cm,respectively The rice soils with lower estimates of C% and N% had less potential for methane production and emission.