通过对江河源区不同建植年限多年生人工草地植物群落的调查，分析了其土壤理化性状和土壤微生物数量的变化.结果表明：随着人工草地建植年限的增加，植物群落的数量特征多呈高-低-高、杂类草生物量低-高-底、莎草生物量增加的趋势；土壤养分变化为高-低-高、容重为低-高-底、pH呈下降趋势；土壤中多数微生物的数量及微生物生物量碳含量的变化为高-低-高，纤维素分解菌数量逐渐升高，而反硝化菌数量逐年下降，溶磷菌数量呈低-高-低的动态变化.土壤微生物数量与土壤理化性状存在明显的相关关系，各生理类群明显受不同土壤理化因素的直接控制和间接调节.说明人工草地的建植及其正向恢复演替改善了土壤的理化性状，使土壤环境有利于有益微生物菌群的定居繁殖，有害微生物菌群的增殖受到抑制.
An investigation was made on the plant communities of artificial grasslands established for different years in headwater region of Yangtze River and Y
ellow River, and the related soil physical and chemical properties and soil microbial physiological groups were analyzed. With the increase of establishment years, most of plant communities on the grasslands showed a “V” type change trend in their quantities, i.e., high-low-high, but the forbs biomass had a “Λ” type change trend and the sedge biomass increased gradually. Soil nutrients presented a “V” type but soil bulk density presented a “Λ” type change trend, while soil pH presented a decreasing trend. Most of soil microbial physiological groups and microbial biomass carbon showed a “V” type change trend, phosphorusdissolving bacteria showed a “Λ” type change trend, denitrifying bacteria decreased gradually, while cellulosedecomposing bacteria showed an increasing trend. The numbers of soil microbes had a close relationship with tested soil factors, and the soil microbial physiological groups were directly or indirectly affected by the soil factors. All the results indicated that the establishment of artificial grassland and the positive succession of vegetation could effectively improve soil physical and chemical properties, which benefit for the beneficial microbes to settle down and propagation, while proliferation of the nonbeneficial microbes was inhibited.