Abstract: This study analyzed the changes of nitrifying bacteria,denitrifying bacteria,nitrogen fixing bacteria and ammonifying bacteria in alpine meadow in the Sanjiangyuan affected by warming and nitrogen fertilization.. The results showed that the quantity distributions of soil microbial nitrogen physiology groups were presented as abiogenous azotobacter > denitrifying bacteria > ammoniated bacteria > nitrifying bacteria. The number of soil microbial nitrogen physiological groups in warming and adding nitrogen treatment was increased significantly in the soil levels of 0~15 cm and 15~30 cm. The number of four physiological groups of nitrate nitrogen addition was higher than that of ammonium nitrogen addition,and the number of nitrifying bacteria and abiogenous azotobacter was significantly different in different types of nitrogen addition,but the numbers of denitrifying bacteria and ammonifying bacteria were close;There was an interaction between warming and adding nitrogen,which could be affected by the quantitative distribution characteristics of soil microbial nitrogen physiological groups. Its specific performance is the role of promotion. The results provide data revealing the response of alpine meadow to global warming and nitrogen deposition.

Key words: Ammonium nitrogen, Nitrate nitrogen, Nitrifying bacteria, Denitrifying bacteria, Abiogenous azotobacter, Ammoniated bacteria

摘要： 为了揭示高寒草甸土壤微生物氮素生理群对增温和氮素添加的响应机制，本研究采用模拟增温和添加不同形态氮素的方法，研究了增温和氮素添加对三江源区高寒草甸土壤中硝化细菌﹑反硝化细菌﹑自生固氮菌﹑氨化细菌的影响。结果表明：各处理中土壤微生物氮素生理群的数量分布呈现自生固氮菌 > 反硝化细菌 > 氨化细菌 > 硝化细菌；增温和氮添加处理均显著增加0~15 cm和15~30 cm土壤氮素生理群数量，硝态氮处理下4种氮素生理群数量均高于铵态氮处理，且硝化细菌和自生固氮菌的数量在添加的不同氮素之间差异极显著（P<0.01），而反硝化细菌和氨化细菌的数量差异不显著；增温和添加氮素交互影响土壤微生物氮素生理群数量分布特征，具体表现为促进作用。本研究结果为揭示高寒草甸在全球气候变暖和氮沉降的背景下的响应规律提供数据支撑。

关键词: 铵态氮, 硝态氮, 硝化细菌, 反硝化细菌, 自生固氮菌, 氨化细菌