氮肥对土壤氧化甲烷的影响研究

Effect of nitrogen fertilizers on methane oxidation in soils by methanotrophs

阐述了N肥用量、品种对土壤氧化甲垸(CH_4)的影响以及高浓度CH_4对这一影响的反作用,土壤可通过固定一定量的外源N确保土壤具有相对稳定的氧化大气CH_4能力,N含量低的土壤适量施用N肥可刺激甲烷氧化菌繁殖和功能的发挥,促进大气CH_4氧化。但当外源N用量超出一定范围时甲烷氧化菌Type Ⅰ对环境变化十分敏感,会产生抑制作用并表现为长期和短期2种效应,铵态氮具有短期更具长期效应,其直接结果是引起土壤中甲炕氧化菌尤其是Type Ⅰ数量的减少和作用的减弱,该抑制作用是单向、不可逆的。由于甲烷氧化菌Type Ⅰ和Ⅱ可被高浓度CH_4激活,不易受N肥的长期影响,有些水田土壤施用N肥甚至促进甲烷氧化菌繁殖,即N的影响是双向且可逆的。

The paper reviews the effects of the applied amount and the type of nitrogen fertilizers on methane oxidation in soils by methanotrophs and the counteraction of high methane concentration on nitrogen suppression.Soils have a natural ability to fix the allowed extent of exogenous nitrogen through absorption and chelating and so on with soil colloids,etc.and ensure a constant rate of methane consumption from atmosphere.The activity and growth of methanotrophs can be stimulated by appropriate nitrogen addition into soils,but also suppressed by nitrogen more than the critical value fixed by soils.In general,methanotroph Type I is more sensitive to environmental disturbation than methanotroph Type Ⅱ.Atmospheric methane oxidation mainly affected by methanotroph Type Ⅰ and methanotroph Type Ⅱ in natural soils can be reduced by addition of nitrogen fertilizers into soils,which is a long-term suppression effect and is unreversible,and can not be restored by high methane ratio as such in paddy soils.