氮水添加对中国北方草原土壤细菌多样性和群落结构的影响  

Effects of nitrogen and water addition on soil bacterial diversity and community structure in temperate grasslands in northern China

作　　者：杨山[1,2] 李小彬[2] 王汝振 蔡江平[2] 徐柱文[2] 张玉革[1] 李慧[2] 姜勇[2] 

机构地区：[1]沈阳大学环境学院,沈阳110044 [2]中国科学院沈阳应用生态研究所森林与土壤生态国家重点实验室,沈阳110016

出　　处：《应用生态学报》2015年第3期739-746,共8页Chinese Journal of Applied Ecology

基　　金：中国科学院战略性先导科技专项(XDB15010000);国家自然科学基金项目(41371251)

摘　　要：研究了我国北方典型温带草原土壤细菌多样性和群落结构对氮水添加及环境因素的响应.结果表明:在常规降水条件下,土壤微生物生物量碳(MBC)和微生物生物量氮(MBN)均随氮(N)梯度增加而逐渐降低;在增加降水条件下,MBC和MBN也随N梯度增加而降低,但降水增加削弱了N的抑制效应.在常规降水条件下,土壤细菌丰富度、Shannon多样性和均匀度等α-多样性指数随N梯度没有明显变化;增加降水条件下,各N梯度处理的土壤细菌α-多样性指数都显著高于常规降水条件下相应的N处理梯度.相关分析显示,土壤含水量、硝态氮(NO3--N)和铵态氮(NH4+-N)与土壤细菌均匀度指数呈显著负相关关系;MBC和MBN与Shannon丰富度指数和均匀度指数呈显著正相关关系.土壤细菌群落非度量多维标度排序(NMDS)显示,在常规降水和增加降水处理下,土壤细菌群落结构均随N梯度增加发生明显改变.冗余分析(RDA)表明,MBC、MBN、p H和NH4+-N是影响土壤细菌群落结构的重要环境因子.In this study,we measured the responses of soil bacterial diversity and community structure to nitrogen（ N） and water addition in the typical temperate grassland in northern China. Results showed that N addition significantly reduced microbial biomass carbon（ MBC） and microbial biomass nitrogen（ MBN） under regular precipitation treatment. Similar declined trends of MBC and MBN caused by N addition were also found under increased precipitation condition. Nevertheless,water addition alleviated the inhibition by N addition. N addition exerted no significant effects on bacterial α-diversity indices,including richness,Shannon diversity and evenness index under regular precipitation condition. Precipitation increment tended to increase bacterial α-diversity,and the diversity indices of each N gradient under regular precipitation were much lower than that of the corresponding N addition rate under increased precipitation. Correlation analysis showed that soil moisture,nitrate（ NO3--N） and ammonium（ NH4＋-N） were significantly negatively correlated with bacterial evenness index,and MBC and MBN had a significant positive correlation with bacterial richness and evenness. Non-metric multidimensional scaling（ NMDS） ordination illustrated that the bacterial communities were significantly separated by N addition rates,under both water ambient and water addition treatments. Redundancy analysis（ RDA） revealed that soil MBC,MBN,p H and NH4＋-N were the key environmental factors for shaping bacterial communities.

关 键 词：温带草原 细菌多样性 细菌群落结构 氮沉降 降水 

分 类 号：S812.2[农业科学—草业科学]