呼伦贝尔地区人工草地生长季土壤微生物数量变化研究

The Variability of Soil Microorganisms during the Growing Season of Artificial Grassland in Hulunbeier

通过分析呼伦贝尔地区人工草地及天然草地生长季土壤微生物（细菌、真菌、放线菌、固氮菌）的数量变化,比较人工草地与天然草地的差异性,揭示人工草地土壤微生物的变化规律.结果表明：土壤细菌数量在2012年生长季可能由于降水量的迅速减少而呈下降趋势;真菌、放线菌和固氮菌数量在生长季均呈上升趋势.人工草地土壤细菌数量在生长季基本高于天然草地,真菌数量基本为苜蓿（Medicagao sativa）人工草地＞天然草地＞无芒雀麦（Bromus inermis）人工草地,放线菌数量多为苜蓿人工草地＞天然草地＞无芒雀麦人工草地,固氮菌数量在生长季初期无芒雀麦人工草地稍高,生长季后期苜蓿人工草地和天然草地稍高.从整体上看,呼伦贝尔地区人工草地在生长季0～10 cm土壤微生物数量基本高于10～20 cm,部分月份表现出差异性.

The differences of soil microorganisms （bacterium, fungus, actinomyces azotobacter） between artificial grassland and natural grassland during growing season in Hulunbeier were studied to reveal the variation of soil microorganisms in artificial grassland. Results showed that the number of soil bacteria re duced in the growing season probably due to a rapid decrease of precipitation in 2012, whereas other soil microorganisms increased during growing season. The number of soil bacteria in artificial grassland was higher than that in natural grassland. The number of soil fungi and actinomycetes was ordered as follow： artificial grassland of alfalfa~〉 natural grassland~ artificial grassland of smooth bromegrass. The number of soil azotobacteria in the artificial grassland of smooth bromegrass was higher than others in the initial stage of growing season, but lower than others in later stage. On the whole, the number of soil microor- ganisms in the 0~10 cm soil layer of artificial grassland was higher than in 10~20 cm soil layer for most of the year in Hulunbeier.