稻田CH4和N2O排放关系及其微生物学机理和一些影响因子

用静态箱法原位观测和分析了我国北方稻田3～12月CH₄和N₂O的排放及其关系,并研究了这一关系发生的微生物学机理.同时,监测了土壤湿度、pH、水分及Eh的变化.结果表明,稻田CH₄和N₂O排放之间存在着互为消长的关系(R²=0.0494).土壤湿度、pH及Eh变化范围分别在0～24℃、6.87～7.02和415～300mv之间,水分从非淹水期的38～72%FC至5～10cm浅水淹灌.土壤Eh对CH₄和N₂O的释放起重要的调控作用.在整个观测期内,与CH₄和N₂O释放密切相关的6种菌群(发酵细菌、产氢产乙酸细菌、产甲烷细菌、甲烷氧化菌、硝化细菌、反硝化细菌)各有其数量消长及酶活性变化规律,稻田CH₄和N₂O排放之间互为消长的关系受这些相关微生物数量及酶活性变化的共同调控.

Relationship bwtween CH4 and N2O emissions from rice field and its microbiological mechanism and impacting factors

The CH₄ and N₂O emissions from rice field in northern China were measured in situ by chamber technique from March to December 1995～1996,and their relationship was discussed.Soil temperature,pH,moisture and Eh in the rice field were also determined.The results showed that there was a significant teade off between CH₄ and N₂O emissions(R²=-0.494).During the period of monitoring,soil temperature,pHand Eh varied between 0 and 24℃,6.87 and 7.02,adn 415 and 300mv,respectively.Soil moisture was 38～72% FC during the non-flooding period.Among these impacting factors,soil Eh was very important functionally on CH₄ and N₂Oemissions.Six related bacteria groups in this rice field,fermenters,H₂ producing acetogens,methanogens,methanotrophs,nitrifiers and denitrifiers,were obsered,All of them had their own dynamic patterns in their numbers and enzyme activities during the period of observation.The trade off between CH₄ and N₂O emissions from rice field could be controlled by the dynamics of the numbers and enzyme activities of these related microorgamisms.