设施种植模式对土壤细菌多样性及群落结构的影响

Effect of facility management regimes on soil bacterial diversity and community structure

  • 摘要: 为了研究有机和常规设施种植模式及轮作对土壤细菌多样性和群落结构的影响,本研究采用Illumina平台Hiseq 2500高通量测序技术,于2016年6月(作物处于收获期)对北京市顺义区不同设施种植模式(分别为有机设施种植模式和常规设施种植模式下的叶菜连作、茄果连作和叶茄轮作)下土壤细菌进行16SrRNA测序。测序质控后共获得17 278个操作分类单元(operational taxonomic units,OTUs),共计318 851条有效序列。比较不同种植模式和轮作下土壤细菌多样性、细菌群落结构组成、相对丰度及土壤理化性质与细菌群落多样性关系的差异性。结果表明:土壤微生物群落结构在有机和常规设施种植模式下差异明显,有机设施种植土壤细菌多样性高于常规设施种植;有机设施种植下轮作与连作土壤细菌群落结构表现出明显差异,而常规设施种植下,两者没有明显差异;有机种植模式下,轮作土壤细菌群落多样性高于连作土壤;设施种植土壤细菌群落主要属于鞘氨醇单胞菌属(Sphingomonas,5.05%)和芽孢杆菌属(Bacillus,4.84%),相对丰度大于0.5%的共有14个属。有机设施种植土壤含有较多促进植物生长、有机质分解的细菌,常规设施种植土壤中降解化学杀虫剂、防治土壤病害、促进硝化过程的细菌较多。RDA分析结果显示土壤细菌群落主要受全磷、速效磷、有机质的影响。TumebacillusCandidatus SolibacterAcidothermus都是分解有机质、利用碳源的细菌属,与土壤有机质含量呈正相关关系。由此可见,设施条件下,有机和常规种植土壤微生物群落结构的差异性主要源于肥料使用、有害生物防治措施和管理方式的不同。有机设施种植模式下,轮作更有利于发挥其改良土壤营养循环和防治土壤病虫害的作用。上述结果为在微生物水平上研究设施条件下不同种植模式的土壤生态质量差异提供了参考。

     

    Abstract: Organic agriculture is a sustainable alternative to conventional agriculture. However, little is known about the effect of both organic and conventional agriculture on the environment and on the soil microbial community. The hypothesis was that bacterial community structure is defined by different agronomic practices. The objective of this study was to show how cropping systems, organic and conventional facility management regimes affect bacterial community structure and diversity. The study was also intended to increase knowledge on the prediction of soil sustainability under specific agronomic practices. The Illumina platform Hiseq 2500 high-throughput sequencing technique was used to sequence facility soil bacteria 16S rRNA from 6 treatments (OS:organic management of Solanaceous vegetable continuous cropping; OL:organic management of leafy vegetable continuous cropping; OSL:organic management of leafy-Solanaceous vegetables rotation; CS:conventional management of Solanaceous vegetable continuous cropping; CL:conventional management of leafy vegetable continuous cropping; and CSL:conventional management leafy-Solanaceous vegetables rotation) in Shunyi District of Beijing in June 2016. A total of 17 278 operational taxonomic units (OTUs) and 318 851 effective sequences were detected in the sequence control condition. Compared with soil bacterial community composition, diversity, relative abundance and interaction between soil factors and bacteria in different treatments, the results showed great differences between organic and conventional soil samples in bacterial community composition, and with a higher diversity in organic management. Obvious differences were observed between crop rotation and continuous cropping for bacterial community composition under organic management, while there was no significant difference between crop rotation and continuous cropping for bacterial community composition under conventional management. Soil bacterial diversity for rotation treatments was higher under organic management. It was found that there were mainly 14 genera of bacterial community, including Sphingomonas (5.05%) and Bacillus (4.84%). The abundance of the 14 genera changed significantly between organic and conventional management. There were insecticides degrading bacteria (Sphingomonas, Pseudomonas and Agromyces), disease controlling bacteria (Blastococcus and Lysobacter) and nitrification promoting bacteria (Candidatus Entotheonella and Microvirga) in conventional system. There were plant growth promoting bacteria (Bacillus) and organism degrading bacteria (Arthrobacter, Bhargavaea, Bryobacter, Candidatus Solibacter, Acidothermus and Tumebacillus) in organic system. Redundancy analysis also showed that soil bacterial community was affected mainly by soil total phosphorus, available phosphorus, and soil organic matter. Organic matter-decomposing bacteria Tumebacillus, Candidatus Solibacter and Acidothermus were positive associated with soil organic matter content. Therefore, the difference between organic and conventional soil samples for bacterial community originated from different fertilizer use methods, insecticide use methods and management patterns. Crop rotation promoted soil nutrient cycle and disease control under organic management. The results suggested that ecological adaptation mechanisms of different functional micro-organisms had significant differences in facility vegetable soils under different facility management regimes. The study provided the basis for further studies on exploring and explaining the characteristics and adaptation mechanisms of micro-organisms in facility soils under different facility management regimes.

     

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