不同施肥措施对桉树人工林土壤细菌群落结构及多样性的短期影响

Short-term Effects of Different Eucalyptus Plantation Fertilization Treatments on Soil Bacterial Community Structure and Diversity

为探索桉树人工林土壤细菌群落对不同施肥措施的响应特征,本研究利用Illumina高通量测序技术,分析不同施肥处理下桉树人工林土壤细菌的群落结构、多样性及与土壤环境因子之间的关系。结果表明:(1)高施肥量处理虽然对土壤全氮、磷、钾含量未产生显著影响,但显著增加了土壤速效氮、有效磷、速效钾含量;随着施肥量的增加,pH呈现升高趋势但差异不显著。(2)桉树人工林土壤细菌门水平优势群落主要为绿弯菌门Chloroflexi、变形菌门Proteobacteria、放线菌门Actinobacteria和酸杆菌门Acidobacteria,不同施肥处理间土壤细菌群落多样性及丰富度均产生显著差异,施肥处理显著增加了土壤细菌丰富度而降低了其细菌多样性指数。(3)施肥处理显著改变桉树人工林土壤优势细菌门类的相对丰度,如绿弯菌门Chloroflexi以及放线菌门Actinobacteria的群落相对丰度。(4)冗余分析表明,全氮TN、全磷TP、pH与细菌群落结构相关性较强,是影响细菌群落结构的主要环境因子。放线菌门Actinobacteria对环境因子变化的响应极其敏感,与有效磷AP、有机质OM、全磷TP、全氮TN、全钾TK、pH、有效钾AK、有效氮AN均呈显著的负相关。

In order to investigate the responses of soil bacterial communities to different fertilization measures in Eucalyptus plantations,Illumina high-throughput sequencing was performed in this study.The soil bacterial community structure,diversity and their relationships with various impact factors were analyzed under different fertilization measures.The results showed the following:(1)The contents of available nitrogen,available phosphorus and available potassium in the soil were significantly increased by high rates of fertilizer application;with increasing fertilizer application,pH tended to increase but differences were not significant.(2)The dominant bacteria,at the phylum level,in soils of Eucalyptus plantations were Chloroflexi,Proteobacteria,Actinobacteria and Acidobacteria.The diversity and richness of soil bacterial communities differed significantly among different fertilization treatments,with higher rates of fertilizer being associated with significant increases in soil bacterial richness but decreases in soil bacterial diversity.(3)The relative abundance of dominant bacterial groups,such as Chloroflexi and Actinobacteria communities,in Eucalyptus plantation soils differed significantly among different fertilization treatments.(4)Redundancy analysis showed that total nitrogen,total phosphorus and pH had a strong correlation with bacterial community structure,and these were the main environmental factors associated with bacterial community structure.Actinobacteria were found to be extremely sensitive to changes in environmental factors,and their abundance was negatively correlated with available phosphorus,organic matter,total phosphorus,total nitrogen,total potassium,pH,available potassium,and available nitrogen.