未干扰黑土土壤微生物群落特征的季节变化

Seasonal Variations of Soil Microbial Communities of Undisturbed Typical Black Soil,Northeastern China

采用稀释平板法和Biolog—ECO微平板检测法，以山杨天然次生林土壤为对象，研究了典型黑土区未经开垦干扰黑土表层土壤（0～10cm）微生物群落的季节变化特征。结果表明：①土壤微生物数量表现为夏季最多，春季次之，秋季最少，且总菌数、细菌、真菌和放线菌数量的变化范围分别为（4．76～16．44）×10^6、（4．68～16．19）×10^6、（4．29～10．07）×10^4和（3．97～14．96）×10^4 cfu／g干土。②在培养168h时，土壤微生物碳源平均颜色变化率（AWCD）的变化范围为O．81～1．21，并表现为夏季最高，春季次之，秋季最低。③土壤微生物群落功能多样性指数则表现为夏季显著高于秋季和春季（P〈0．05），而春、秋两季间无显著性差异，且夏季丰富度指数、Shannon—Wiener指数、Simpson指数和McIntosh指数分别为27、3．18、0．95和8．19。④初步确定氨基酸类、多聚物类和羧酸类碳源是未经开垦干扰黑土土壤微生物利用率较高的碳源类型。研究结果为科学评价典型黑土区土壤生境质量退化与恢复过程中微生物特征的变化提供了本底值参考。

Seasonal variations of soil microbial communities in surface soil （0-10 cm） of undisturbed typical black soil （the Populus davidiana natural secondary forest in Keshan farm, Heilongjiang Province of northeastern China） was studied by using the method of dilution-plate method and Biolog ECO-microplate culture. Results showed that soil microbial population was the maximum in summer, fewer in spring, and the minimum in autumn. The quantity of soil microorganism, bacteria, fungi and actinomycetes was （4.76-l6.44）×10^6, （4.68-16.19）×10^6, （4.29-1O.07）×10^4 and （3.97-14.96）×10^4 cfu/g dry soil, respectively. The peak value of the average well color development （AWCD） was found in summer followed by spring and autumn in consequence, varying from 0.81 to 1.21 （168 h）. The microbial functional diversity was significantly higher in summer than in spring and autumn （P〈0.05） and showed no significant difference in spring and autumn. For summer, Richness index was 27, Shannon-Wiener index was 3.18, Simpson index was 0.95 and McIntosh index was 8.19. The carbon sources with higher utilization efficiency or utilization intensity by soil microbes were amino acids, polymers and carboxylic acids. Above all, this result would provide more important primitive characteristics of microbial features in the degradation and restoration process of the quality of the soil habitat scientifically.