黄河下游滩地杨树人工林土壤微生物分析

Soil Microbes of Poplar Plantations on Lowland of Yellow River Downstream

对山东省济南市长清区黄河下游滩地杨树人工林林地土壤微生物数量及分布特征进行了分析,结果表明:滩地杨树人工林土壤微生物主要分布在0～20cm的土层,20～50cm土层的微生物较少;各林地土壤微生物数量明显高于新淤地微生物数量;细菌是滩地杨树人工林林地土壤微生物的主要组成成分,在上、下层土壤中所占比例分别为81.7%～99.1%和75.1%～98.8%;土壤微生物数量随林龄的增长呈现高—低—高的变化趋势,但至林木主伐前,固氮菌和纤维素分解菌数量有所降低;不同管理模式影响微生物的数量,集约经营管理的林分土壤微生物数量较多;滩地杨树人工林土壤微生物数量与土壤颗粒组成密切相关。

An experiment was conducted to study the amounts and distributional features of soil microbes （fungi, actinomyce, bacteria, azotobacter, celluloytic bacteria） in poplar plantations on the lowland of Yellow River downstream, Changqing Prefecture of Ji＇ nan City, Shandong Province. Results indicate that soil microbes mainly distribute in 0 - 20 cm soil layer, but less in 20 - 50 cm. The microbial number in the plantations is obviously higher than that in the newly-formed sihland. Bacteria are dominant species among those soil microbes, accounting for 81.7% - 99.1% in topsoil and 75.1% - 98.8% in subsoil. Distribution of soil microbes shows a high-low-high pattern with forest age increasing, but the amounts of azotobacter and celluloytic bacteria tend to reduce before clear-cutting. The amounts of microbes under different management modes are various, and those in poplar plantation increase under intensive management. Microbe amount is closely correlated with soil grain-size composition.