| A field experiment was carried out to study the relationship between methane emission and the community structure and abundance of methanogens under a double rice cropping system in Southern China. Several relevant parameters were measured including methane emission determined by closed static chamber technique, community structure of methanogens by PCR denaturing gradient gel electrophoresis（PCR-DGGE） and the population of methanogens by fluorescence in situ hybridization（FISH）. The results showed that the amounts of methane emission were 9.28 g·m-2 and 7.78 g·m-2 at early and late rice growing stage, respectively. The community structure and abundance of methanogens changed greatly with rice growing period for both early and late rice, but the main methanogens species existed in paddy field sostenuto. The diversity and abundance of methanogens in vigorous rice growing stage（20 days after rice transplanting） were higher than other stages. The peak abundance of methanogens were 1.14×107 In·g-1 dry soil and 6.72×106 In·g-1 dry soil for early and late rice growing season, respectively; which was significantly higher than other growing stages in the same growing season. The diversity and abundance of methanogens of early rice was higher than that of late rice, consistent with the methane emission pattern. The methane emission was significantly correlated with the abundance of methanogens, however, there was no significant correlation with the diversity of methanogens. In conclusion, reducing the abundance of methanogens will be an effective way to reduce the methane emission in paddy field. |
