贝加尔针茅草原土壤微生物功能多样性对养分添加的响应

为揭示养分添加对草原土壤微生物群落功能多样性的影响,采用Biolog-Eco技术,研究了在无养分添加对照(CK)和7种不同氮磷钾养分添加方式(单养分添加:N、P、K,不同组合添加:PK、NK、NP、NPK)下贝加尔针茅草原土壤微生物群落功能多样性变化。结果表明:(1)不同养分添加条件下土壤微生物群落单孔平均颜色变化率(Average Well Color Development)AWCD值从高到低依次为NPPNPKNKNCKKPK。(2)含磷添加处理(PK除外,NP、P、NPK)和含氮添加处理(N、NK)的丰富度指数H均显著高于CK、K、PK,而均匀度指数E和优势度指数D在各处理间差异不显著。(3)主成分分析结果表明,CK、K、PK、NK处理土壤微生物群落碳源利用方式相似,而NP、P和N、NPK分别具有不同的碳源利用方式。据此可知,NP、P、NPK、N养分添加方式可以提高土壤微生物代谢活性、物种丰富度指数和微生物群落碳源利用能力,有利于土壤微生物群落功能多样性的提高。

Responses of Functional Diversity of Soil Microbial Communities to Nutrient Additions in Stipa Baicalensis Steppe in Inner Mongolia,China

To reveal the influence of nutrient additions on functional diversity of soil microbial communities in grassland, Biolog-Eco technique was used to study the changes in microbial functional diversity in Stipa Baicalensis steppe under seven different N, P and K fertilizer treatments including single and combined additions of nutrient N, P, and K.The AWCD values of the soil microbial communities followed the order:NP>P>NPK>NK>N>CK>K>PK. The richness index of microbial communities in soil was significantly higher in NP, P, NPK, NK, and N treatments than in K and PK treatments. However, evenness index(E) and dominance index(D) of the soil microbial communities were not different among the seven treatments. Principal component analysis showed that microbial carbon utilization was similar in CK, K, PK and NK treatments, but different in NP, P and N, NPK treatments. These results implied that NP, P, NPK, and N can increase the metabolic activity of microorganism, the diversities and the carbon utilization ability of soil microbial community, which improves the soil microbial functional diversity.