未干扰黑土土壤微生物群落垂直分布特征

Vertical Distribution Characteristics of Soil Microbial Communities in Undisturbed Black Soil

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0~150 cm土层范围内土壤微生物群落的垂直分布特征。结果表明:(1)土壤微生物总数、细菌和真菌数量随土壤深度增加呈减少趋势,以0~10 cm土层数量最高,分别为4.10×106cfu g-1干土、4.05×106cfu g-1干土和5.04×104cfu g-1干土;而放线菌数量随土壤深度的增加表现为先减后增的趋势,最高值出现在30~50 cm土层,可达0.94×104cfu g-1干土。(2)在培养168 h时,土壤微生物碳源平均颜色变化率(AWCD)的变化范围为0.09~1.21,并表现出随土壤深度增加而逐渐减小的趋势。(3)土壤微生物群落功能多样性指数同样表现为随土壤深度增加而逐渐减小的趋势,且丰富度指数、Shannon-Weiner指数、Simpson指数和McIntosh指数的变化范围分别为0~27、0.46~3.17、0.33~0.95和0.09~8.19。(4)初步确定氨基酸类、羧酸类和多聚物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。

Soil samples were collected from the Populus davidiana natural secondary forest in Keshan farm, Heilongjiang province of northeastern China. The vertical distribution characteristics of soil microbial communities of soil depth(0 ~ 150 cm) in undisturbed typical black soil were studied by using the method of Biolog ECO-microplate culture and dilution-plate method. Results showed that the quantity of soil microorganism, bacteria and fungi decreased with soil depth increasing and achieved maximum value of 4.10×106cfu(Colony Forming Unit) g-1dry soil, 4.05 × 106cfu g-1dry soil and 5.04 × 104cfu g-1dry soil in top soil of 0 ~ 10 cm, respectively. The number of actinomycetes presented a unimodal curve relationship with the increase of soil depth and the maximum occurred in 30 ~ 50 cm soil depth with 0.94 × 104cfu g-1dry soil. The average well color development(AWCD) decreased gradually with soil depth increasing, varying from 0.09 to 1.21(168 h). The microbial functional diversity also decreased with soil depth increasing gradually. For soil in 0 ~ 150 cm depth, richness indexes ranged from 0 to 27, and Shannon-Weiner diversity indexes from 0.46 to 3.17, and Simpson diversity indexes from 0.33 to 0.95, and McIntosh indexes from 0.09 to 8.19. The carbon sources with higher utilization efficiency or utilization intensity by soil microbes were amino acids, carboxylic acids and polymers. These results will provide primitive characteristics of microbial communities for estimating degradation and restoration processes of black soil habitat scientifically.