【摘要】 产甲烷菌是土壤中与甲烷产生和碳素循环有关的微生物菌群,大气CO2浓度升高可能对它们的数量产生影响。利用江都市小记镇的稻-麦轮作FACE平台,采用最大可能(MPN)法,在2004年水稻生长季研究了不同施肥情况(施常规氮量和低氮量)、不同秸秆还田情况(秸秆全还田、秸秆半还田、秸秆不还田)下,土壤中的产甲烷菌数量在大气CO2浓度升高条件下随时间的变化情况。结果表明,大气CO2浓度升高在秸秆全还田情况下对产甲烷菌数有明显的促进作用,在其他2种秸秆还田情况下,FACE与对照差异不显著。常氮处理仅在水稻生长初期促进产甲烷菌数,而在其他生长季不同氮肥处理之间无明显差异。总之,常氮处理产甲烷菌数量FACE比对照平均高104%～116%,低氮处理平均高101%～126%,进一步证实大气CO2浓度升高会促进稻田CH4的排放。更多还原

【Abstract】 Rice fields are one of the most important methane(CH4)sources.Methanogens is an important class of environmental microorganism.It plays a pivotal role in the global carbon cycle.A free-air CO2 enrichment(FACE)experiment was conducted in rice-wheat rotation crop system at Jiangdu of Jiangsu province,China,the influence of elevated atmospheric CO2 concentrations on metnanogens microbial populations were evaluated by using the most probable number(MPN)method under enriched CO2 conditions during the 2004 rice-growing seasons in a rice paddy.The Two different N fertilization levels(usual N and low N)and three conditions of rice straw(HR,AR and NR)were designed in the FACE experiment.The results showed that elevated atmospheric CO2 concentrations significantly increased methanogens number in the condition of HR(P<0.05),but no difference in the other rice straw conditions between FACE and the control was found.The usual N increased methanogens number only at the early stage of rice growth,and there was no significant difference in methanogens number between UN and LN at other stages.Totally,the methanogens number of FACE was higher than that of the control by 104%~116% and 101%~126% averagely at usual N and low N application,respectively,showing that elevated CO2 concentration could stimulate the number of methanogens.更多还原