西南典型岩溶区土壤微生物数量研究

Soil Microorganisms in Typical Karst Region of Southwest China

分别选取桂林、重庆、贵州三地的林地、耕地等几种不同土地利用方式下20、40、60 cm深3个土层土壤样品,采用稀释平板法对土壤中细菌、放线菌、真菌三大微生物类群进行计数,结果显示:(1)与非岩溶区相比,岩溶区土壤细菌和放线菌数量明显高于非岩溶区,真菌数量反之,且岩溶区微生物总量大于非岩溶区。(2)岩溶区土壤中细菌数量占绝对优势,夏季所占比例最高达到94.7%,秋季达93.8%;放线菌最高夏季为33.1%,秋季为55.4%;真菌夏季最高达55.9%,秋季为4.4%。(3)微生物数量变化存在时间和空间差异性,但总体而言,夏季各微生物数量明显高于秋季,细菌数量变化趋势在不同地区存在一致性,真菌和放线菌则不明显。造成这种区别的因素包括土壤理化性质、微生物生理特性等。

Choosing the 20 cm,40 cm and 60 cm soil layer of different land use patterns such as woodland and farmland in Guilin,Chongqing and Guizhou,and using dilution plate method,the number of soil Bacteria,Actinomycetes,Fungi have been counted,the results show that：（1） Compared with non-karst areas,the Bacteria and Actinomycetes were significantly higher in karst areas,but the the number of Fungi is opposite,and the total amount of microbes in karst area is higher than that in non-karst area;（2） In the soil of karst areas,the number of Bacteria was superior.Its proportion reaches 94.7% in summer and 93.8% in autumn,followed by Actinomycetes,33.1% in summer and 55.4% in autumn,then the Fungi reaches 55.9% in summer and 4.4% in autumn;（3） The amount of microorganisms changes with the time and space.In summer the amount of microorganisms is significantly higher than that in autumn,and the amount of Bacteria exists the same trend in different regins but this trend is not significant in the Fungi and Actinomycetes.The factors causing such differences include soil physical and chemical properties,microbial physiological characteristics and other factors.