The effects of four Picea asperata plantations with different ages (50-, 38-, 27- and 20-year-old), in subalpine of western Sichuan, on the characteristics of soil microbial diversity and microbial community structure were studied by the method of phospholipid fatty acid (PLFA) profiles. The results showed that, with the increase of age, the contents of soil organic carbon and total nitrogen gradually improved, while Shannon's diversity index and Pielou's evenness index of soil microorganisms increased at first and then decreased. The amounts of microbial total PLFAs, bacterial PLFAs, fungal PLFAs, actinobacterial PLFAs, and arbuscular mycorrhizal fungal (AMF) PLFAs in soils consistently increased with increasing age. The principal component analysis (PCA) indicated that the soil microbial communities in different plantations were structurally distinct from each other. The first principal component (PC1) and the second principal component (PC2) together accounted for 66.8% of total variation of the soil microbial community structure. The redundancy analysis (RDA) of soil microbial community structure and environmental factors showed that soil organic carbon, total nitrogen, total potassium, and fine root mass were the key determinants influencing the microbial community structure. Our study suggested that, with the extension of artificialafforestation time, the soil fertility and microbial biomass were enhanced, and the restoration processes of forest ecosystem were stable.
以川西亚高山云杉人工林林地土壤为对象,采用磷脂脂肪酸(PLFA)法研究了4种不同林龄(50、38、27和20年)的人工林土壤微生物多样性和群落结构特征.结果表明: 随着林龄的增加,土壤有机碳和全氮含量逐步增加;土壤微生物Shannon多样性和Pielou均匀度指数则呈现先增后减的趋势.土壤微生物总PLFAs量、细菌PLFAs量、真菌PLFAs量、放线菌PLFAs量以及丛枝菌根真菌PLFAs量均表现为随林龄的增加而增加.主成分分析(PCA)表明,不同林龄人工林的土壤微生物群落结构之间存在显著差异,其中,第1主成分(PC1)和第2主成分(PC2)共同解释了土壤微生物群落结构总变异的66.8%.冗余分析(RDA)表明,对土壤微生物群落结构产生显著影响的环境因子分别为土壤有机碳、全氮、全钾以及细根生物量.随着人工造林时间的延长,土壤肥力和微生物生物量增加,森林生态系统的恢复进程稳定.
Keywords: Picea asperata plantation; forest restoration; phospholipid fatty acid; soil microbial community.