水稻田土壤甲烷氧化活性及其环境影响因子的研究

报道环境因子土壤含水量、温度和pH对发育于河流沉积物母质的水稻田土黄松泥田土氧化外源甲烷活性影响的研究结果。表明土壤中存在有氧和无氧两个甲烷氧化系统。有氧甲烷氧化系统 (AMOS)最适条件下的氧化甲烷最大活性比无氧甲烷氧化系统(AAMOS)最适条件下的氧化甲烷最大活性高 1至 2倍。在土壤通气良好的条件下 ,AMOS占主导地位 ,在无氧或极微氧的土壤中 ,AAMOS起主要作用。影响活性的主要因子是土壤的分子氧含量、甲烷含量、水含量、温度和pH值。分子氧对AAMOS氧化甲烷的活性具有一定抑制作用 ,土壤中甲烷量和含水量对AAMOS氧化甲烷活性的影响比对AMOS氧化甲烷活性的影响更为强烈。土壤氧化甲烷的活性对温度较为敏感 ,其最适氧化甲烷的温度范围在 2 5～ 35℃之间。当土壤在 5 0℃培养的时间超过 6h后 ,土壤氧化外源甲烷的活性全部丧失 ,且不能在2 8℃下得到恢复。pH是另一个影响土壤氧化甲烷的重要环境因子。其最适pH范围在 6～ 7之间 ,pH低于 3或pH高于 9时 ,几乎完全丧失氧化外源甲烷的活性。

EFFECT OF ENVIRONMENTAL FACTORS ON METHANE-OXIDIZING ACTIVI TY IN PADDY SOIL

Effect of environmental factors on oxidation activity of added methane in Huangsong paddy soil developed from fluvo aquic matrix was studied.The results indicated that there existed two methane oxidizing systems found in soil,an aerobic methane oxidizing system (AMOS),and an anaerobic methane oxidizing system(AAMOS).The maximal activity of methane oxidation of AMOS was higher than that of AAMOS.Under aerobic condition,the methane oxidizing activity of AMOS was affected mainly by the contents of oxygen,water,methane and pH,temperature in soil.The methane oxidizing activity of AAMOS,however,was mainly affected by the contents of oxygen,methane,water and also by pH,temperature in soil under anaerobic condition.Oxygen inhibited the activity of methane oxidation of methane oxidizing bacteria of AAMOS.The optimum temperature for methane oxidizing activity lied from 25 to 35.After incubation at 50 for over 6 hours the tested paddy soil was unable to restore the oxidation activity of added methane when incubated again at 28,indicating that oxidation activity of added methane was completed lost.The optimum pH ranged from 6 to 7 for methane oxidizing activity.