关键词: 坝上草原, 东沟, DCCA排序, 排序轴分类, 梯度分析, 人为干扰

Abstract: By using dilute plate counting method, the characteristics of microbial flora in 0-20 cm and 20-40 cm soil layers of alpine artificial grasslands established for 4, 8, 15, and 20 years in Bayanbulak were studied, with related ecological affecting factors analyzed. The amount of soil bacteria was the highest in 4-year old grassland and the lowest in 20-year old grassland, and was 2.19 and 1.58 times higher in 8-year old and 15-year old grasslands than in natural grassland, respectively. The amount of soil fungi was in order of 4year old grassland>20-year old grassland>15-year old grassland > 8-year old grassland > natural grassland; and the amount of soil actinomyces was the highest in natural grassland, followed by in 8-, 20-, 4-, and 15-year old grasslands. The three soil microbial groups reached the maximum in August and the minimum in September. The total amount of soil microbes and the amount of soil bacteria had significant positive correlations with vegetation coverage, and the amount of soil fungi was significantly positively correlated with soil moisture content and soil conductivity. Soil pH had the greatest effects on the amount of soil actinomyces, and the main ecological factors affecting the total amount of soil microbes were vegetation coverage and the time of grassland establishment.

Key words: Bashang region, Donggou, DCCA, OAC, Gradient analysis, Human disturbance