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采用化学分析、微生物平皿培养及放线菌形态鉴定法,研究了黄土高原安塞试区5种乔灌木根区0～20cm及20～40cm土层17个土样的土壤性质及微生物的数量与组成。结果表明:①黄土高原丘陵沟壑区坡地人工林与无林裸地土壤中仍然生存着数量较多的细菌、放线菌及真菌,其中各类群的数量排序为:细菌>放线菌>真菌;②不同树种根区土壤中细菌、放线菌及真菌数量不同,土壤微生物的数量按灌木林>乔木林排序;③在黄土高原丘陵沟壑区坡地人工林及无林裸地土壤的放线菌组成中,链霉菌属（Streptomyces）占绝对优势,其次为小单孢菌（Micromonospora）和诺卡氏菌（Nocardia）。灌木林根区放线菌数量与种类均多于乔木;④黄土高原“沙棘人工林-微生物-土壤”生态系统微生物数量大,种类较多,生物活性强,对土壤物质转化及肥力提高有明显作用,在恢复黄土高原植被时应作为先锋树种。
The soil properties and the number of microbes in 17 soil samples of 0 ~ 20cm and 20 ~ 40cm soil layers in 5 kinds of shrub and shrub roots in the Ansai test area of the Loess Plateau were studied by chemical analysis, microbial plate culture and actinomycetes morphology identification. composition. The results showed that: (1) The number of bacteria, actinomycetes and fungi still remained in the sloping plantations and no-leaved soils in the hilly and gully regions of the Loess Plateau. The order of the number of the groups was bacteria> actinomycetes> fungi ; ② The amount of bacteria, actinomycetes and fungi in the root zone soil varied with different species, and the number of soil microorganisms was sorted according to shrub> arbor forest; ③ Actinomycetes in sloping land and bare land in the hilly and gully regions of the Loess Plateau Compositions, Streptomyces (Streptomyces) accounted for the absolute advantage, followed by Micromonospora (Micromonospora) and Nocardia (Nocardia). The number and species of actinomycetes in the shrubland zone were more than those in the arborous forest. The number of microorganisms in the “Hippophae rhamnoides plantation-microbial-soil” ecosystem in the Loess Plateau was large, with many species and strong biological activity, which significantly improved soil material conversion and fertility Role, in the restoration of vegetation on the Loess Plateau should be used as a pioneer tree species.