ABSTRACT

What effects the stand age has on the soil microbial structure and composition remains unclear. The topsoil (0–20 cm) of 3- (YF), 12- (MAF), and 38-year-old (MF) Chinese fir plantations were selected as research objects. We found that the phospholipid fatty acid (PLFA) concentration and OTUs of bacteria and fungi exhibited an uptrend as the stand age increased. Among dominant bacterial and fungal phyla, the relative abundance of Actinobacteria in YF was significantly higher than that in MF and MAF and the relative abundance of Basidiomycota in MF was significantly higher than that in MAF and YF. Interestingly, the relative abundance of three predominant fungal phyla Ascomycota, Basidiomycota, and Zygomycota in MAF were lower than those in MF and YF. The significant difference in the relative abundance of some bacterial phyla (e.g., Ignavibacteriae, Latescibacteria, Nitrospirae, and Tectomicrobia) was also found with stand age, and organic matter, pH, available P, available N, and available K were the main factors for the variances in the biomass and structure of soil microbial communities. These findings showed that considering the shift in the structure and composition of microbial communities might improve our understanding of soil fertility maintenance and sustainable management of these plantations.

摘要

林分龄对土壤微生物结构和组成的影响尚不清楚。选择了3-（YF），12-（MAF）和38岁（MF）的杉木人工林的表土（0– 20 cm）。我们发现，随着树龄的增加，细菌和真菌的磷脂脂肪酸（PLFA）浓度和OTU呈上升趋势。在优势菌和真菌门系中，YF中放线菌的相对丰度明显高于MF和MAF，而MF中担子菌的相对丰度则明显高于MAF和YF。有趣的是，MAF中三种主要的真菌门孢子囊菌，担子菌菌纲和合子菌的相对丰度低于MF和YF。一些细菌门的相对丰度（例如，Ignavibacteriae，还发现了高分枝杆菌，硝化细菌和大肠微生物（Tectomicrobia）随年龄的增长，有机物，pH，有效磷，有效氮和有效钾是影响土壤微生物群落生物量和结构变化的主要因素。这些发现表明，考虑到微生物群落结构和组成的变化，可能会增进我们对土壤肥力维持和这些人工林可持续管理的理解。