高寒草甸不同植被土壤微生物数量及微生物生物量的特征

用稀释平板法和氯仿熏蒸法研究了藏嵩草草甸、小嵩草草甸、矮嵩草草甸、禾草草甸、杂类草草甸及金露梅灌丛土壤的微生物数量、生物量及有机质的变化特征.结果表明:0～40 cm土层细菌和放线菌数量、微生物生物量碳和土壤有机质含量均以藏嵩草草甸最高,其微生物生物量及土壤有机质显著高于其它5种植被;真菌数量以金露梅灌丛最高;由表层到深层,随着土壤深度的增加以上各项指标均呈下降趋势.通径分析表明:土壤各生物环境因子之间存在着不同程度的相关性;土壤微生物数量、生物量及土壤有机质含量均与土壤水分含量存在显著的相关关系,说明土壤水分是调节高寒草甸生态系统土壤微生物代谢及物质转化的关键因子.

Quantitative characters of soil microbes and microbial biomass under different vegetations in alpine meadow

By using dilute plate counting and chloroform fumigation methods, this paper studied the quantitative characters of soil microbes, microbial biomass, and organic matter under the vegetations Kobresia tibetica , K. pygmaea , K. humulis , grass, forb, and Potentilla fruticosa shrub in alpine meadow ecosystem. The results showed that in 0-40 cm soil layer, the numbers of bacteria and actinomyces and the contents of microbial biomass C and organic matter were the highest in K. tibetica meadow, while the fungal number was the highest in P. fruticosa shrub meadow. The microbial biomass C and organic matter contents in K. tibetica meadow were obviously higher than those in the other five meadows. Path analysis indicated that there were varied degrees correlations among different bio-environmental factors, and the numbers of soil microbes as well as the contents of soil microbial biomass C and organic matter had significant correlations with soil moisture content, indicating that soil moisture could soil microbes and the transformation of substances in be a key factor regulating the metabolism of alpine meadow ecosystem.