稻-鸭复合生态系统产甲烷细菌数量

Studies on amount of methanogens in the rice-duck agroecosystem

采用厌氧培养箱技术 ,用最大或然数计数法 (MPN法 )和滚管法同时测定稻 -鸭复合系统和常规稻作系统早稻不同生育期土壤中的产甲烷细菌数量。结果表明 :(1)两系统产甲烷菌数量具有明显的季节变化规律。水稻返青期前 ,两系统的产甲烷菌数量相差不大 ,随着水稻生育期的推进 ,两处理的产甲烷菌数量逐渐增加 ,均在分蘖盛期明显增高 ,孕穗期达到最高 ,乳熟期又显著减少 ,生长后期又有所回升。(2 )稻田围栏养鸭能减少稻田中的产甲烷菌数量 ,特别是减少了稻田甲烷排放高峰期的产甲烷菌数量。在水稻分蘖盛期和孕穗期 ,MPN计数法中 ,稻 -鸭复合生态系统低于常规稻作系统 2 0 .0 %～ 96 .9% ;滚管法计数中 ,前者比后者降低 33.3%～ 98.1% ,两系统的产甲烷菌数量之间的差异均达极显著水平。 (3)产甲烷细菌对甲醇、异丙醇、CO2 / H2 、乙酸钠有嗜好表现 ,对甲胺、甲酸、甲胺 +甲醇 +甲酸 +异丙醇 +乙酸钠 (混合基质 1)、甲酸 +甲醇 +异丙醇 +乙酸钠 (混合基质2 )、甲醇 +异丙醇 +乙酸钠 (混合基质 3)

The study was focused on the relationship between the intensify rice-duck planting and its effects on the amount of methane emission from the paddy field. During the study,the author took a careful study and appraisal of the basis of rice-duck complex planting and breeding pattern,and how it could evidently decrease the total amount of methane emission present on the paddy field.The study also covers the amount of methanagens present and the influence of the substrates on it in the rice-duck complex ecosystem. It is aimed at expounding the mechanism of rice-duck ecological planting and breeding pattern evidently decrease the total amount of methane emission in paddy field and its adjusting and controlling factors;And also offer the theoretical foundation and practice basis for setting up measure to mitigate methane emission.We examined the amount of methanogens in the rice-duck complex ecosystem and ordinary early paddy system with the aid of Anaerobic box with probable number and roll tube methods.The results obtained were as follows:(1) The amount of methanogens had obvious seasonal law of variation in paddy field, and it was relatively fewer at re-green stage of the paddy in the ecosystem. It increases step by step with extension of growth stage of paddy and it is therefore the greatest at booting stage of paddy but decreases significantly at the milk-ripe stage of paddy,and increases at the yellow-ripe stage of paddy.(2) Rice-paddy ecological planting and breeding pattern could greatly decrease the amount of methanogens in paddy field especially during the methane emission peak period but the amount of methanogens in rice-duck complex ecosystem was obviously less than that of ordinary of paddy system at active tillering and booting stage of the paddy;for instance,20%～96.9% less than that of the later for the MPN method; And for the roll tube method,less than 33.3%～98.1% of the later, and the differences between both ecosystems was significant by statistics.(3) We deduce from our findings that methanogens can use Methanol,Isopropanol, CO_2,H_2,Sodium Acetate for growth and methanogenesis but None Methylamine, Formate, and that of Mixed None Methylamine,Methanol,Isopropanol,Sodium Acetate, Mixture of Formate,Methanol, Isopropanol and Sodium Acetate.From the aforementioned results, we can see that the seasonal law of variation of the amount of methanogens in paddy field was consistent with methane emission from paddy field. It also confirmed that the amount of methanogens was one of the main factors affecting the amount of methane emission from paddy field. This research has suppressed the production of methanagens through breeding duck in paddy field and also achived the goal of mitigating methane emission from paddy field; More so, the research could also increase economic efficiency of the ecosystem.It is therefore significant for making counter measure on mitigating emission of greenhouse gas.