大豆连作条件下施肥对东北黑土细菌群落的影响

发布时间：2018-11-15 07:37

【摘要】：【目的】表征大豆连作条件下不同施肥处理土壤细菌的群落结构特征和组成差异,并侧重分析接种根瘤菌处理的不同之处;与土壤化学性质进行关联分析,探讨引起黑土细菌菌群变化的主效环境因子,为进一步了解连作条件下东北耕地土壤中细菌群落结构的变化以及大豆的高效种植和氮肥减施提供理论支持。【方法】依托5年大豆连作定位试验,选取不施肥(CK)、磷钾肥(PK)、氮磷钾肥(NPK)、磷钾肥+接种根瘤菌(Bradyrhizobium japonicum 5821)处理(PK+5821)共4个处理的耕层土壤为研究对象,采用高通量测序(Illumina HiSeq)和real-time PCR技术,以16S rRNA基因V4区为分子标靶,解析不同施肥处理土壤细菌的菌群变化,并对细菌群落结构与环境因子进行相关性分析。【结果】与CK相比,施肥明显增加了大豆的产量和土壤养分的含量,但单施化肥降低了土壤的pH。接种B.japonicum 5821显著增加了土壤细菌的基因拷贝数,提高了土壤细菌的丰度。细菌门水平和纲水平的群落分析发现,变形菌门(Proteobacteria)、放线菌门(Actinobacteria)和酸杆菌门(Acidobacteria)为土壤中的3大优势菌群,占所有优势菌门的70%以上;施肥明显降低了土壤中放线菌门的相对丰度,这与细菌纲水平的分析一致。多样性分析发现,CK处理与3个施肥处理的丰富度和多样性指数不同,且主坐标分析(PCoA)显示,3个施肥处理的细菌群落结构在PC1轴上聚在一起,而与CK处理是分开的,表明施肥明显改变了土壤细菌的群落构成。冗余分析(RDA)显示,全氮(F=3.2,P=0.002)对土壤细菌群落结构的影响最大,解释了24%的群落变化,各因子的贡献率依次为全氮有效磷速效钾有机质p H;Spearman相关性分析也表明,5项土壤化学指标均与不同优势菌门存在密切的相关关系。【结论】施肥改变了大豆连作条件下土壤细菌的群落结构。全氮是影响土壤细菌群落结构变化的主效环境因子。接种根瘤菌明显提高了大豆产量,同时保持了良好土壤化学性状和土壤菌群结构,很大程度地减少了化学氮肥的施用,对大豆的高效种植和氮肥减施具有重要意义。
[Abstract]:[objective] to characterize the community structure and composition of soil bacteria under different fertilization treatments, and to analyze the differences of rhizobia inoculation. Correlation analysis with soil chemical properties was carried out to explore the main environmental factors that caused the change of bacterial flora in black soil. In order to further understand the change of bacterial community structure in cultivated soil of Northeast China under continuous cropping conditions, and to provide theoretical support for the efficient planting of soybean and nitrogen fertilizer reduction. [methods] based on the 5 year continuous cropping location experiment of soybean, no fertilization (CK), was selected. High-throughput sequencing (Illumina HiSeq) and real-time PCR techniques were used to study four treatments of topsoil treated with phosphorus and potassium fertilizer (competitive 5821) and nitrogen, phosphorus and potassium fertilizer (NPK),) inoculated with Rhizobium rhizobia (Bradyrhizobium japonicum 5821 (5821). Taking the V4 region of 16s rRNA gene as molecular target, the variation of bacteria community in soil under different fertilization treatments was analyzed, and the correlation between bacterial community structure and environmental factors was analyzed. [results] compared with CK, the relationship between bacterial community structure and environmental factors was analyzed. Fertilization significantly increased soybean yield and soil nutrient content, but only fertilizer application decreased soil pH.. Inoculation with B.japonicum 5821 significantly increased the gene copy number of soil bacteria and increased the abundance of soil bacteria. Community analysis of phylum level and class level showed that (Actinobacteria) of (Proteobacteria), and (Acidobacteria) of actinomycetes were three dominant bacteria in soil, accounting for more than 70% of all dominant phylum. Fertilization significantly reduced the relative abundance of actinomycetes in soil, which was consistent with the analysis of the level of bacteria. The diversity analysis showed that the richness and diversity index of CK treatment were different from those of three fertilization treatments, and the main coordinate analysis (PCoA) showed that the bacterial community structure of the three fertilization treatments gathered together on the PC1 axis, but separated from CK treatment. The results showed that fertilization significantly changed the community composition of soil bacteria. Redundancy analysis (RDA) showed that total nitrogen (FN 3.2) had the greatest effect on soil bacterial community structure, which explained 24% community change, and the contribution rate of each factor was in turn total nitrogen and available phosphorus available potassium organic matter (pH). Spearman correlation analysis also showed that five soil chemical indexes were closely related to different dominant bacteria. [conclusion] fertilization changed the community structure of soil bacteria under continuous cropping of soybean. Total nitrogen (TN) is a major environmental factor affecting the change of soil bacterial community structure. Inoculation with Rhizobium significantly increased soybean yield, maintained good soil chemical properties and soil microbial structure, reduced the application of chemical nitrogen fertilizer to a large extent, and played an important role in the efficient planting of soybean and the reduction of nitrogen fertilizer application.
【作者单位】：中国农业科学院农业资源与农业区划研究所/农业部微生物产品质量安全风险评估实验室(北京);吉林省农业科学院大豆研究所;
【基金】：国家“863”计划(2013AA102802-04) 国家现代农业产业技术体系(nycytx-004) 农业部生物有机肥创制重点实验室开放课题
【分类号】：S154.3;S565.1

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