土壤细菌群落组成对有机与无机培肥措施的响应

为揭示旱作区农田土壤细菌群落对有机、无机培肥措施的响应机制,以农田生态系统为研究对象,采用高通量测序技术研究不同培肥措施下土壤细菌群落结构组成、多样性与土壤理化性状间的关系。结果表明:持续8 a的有机、无机培肥显著影响土壤基本理化性状指标,降低土壤碳氮比。所获得的细菌序列46 531条,分属于3 494个土壤细菌OTUs,共分为58门、67纲、143目、271科、639属、435种;但不同有机、无机培肥措施下土壤细菌群落丰富度指数、多样性指数无显著差异。变形菌门(Proteobacteria)相对丰度占35.91%～42.03%,是土壤细菌的优势菌门。化肥配施牛粪、化肥配施羊粪处理下土壤变形菌门(Proteobacteria)、绿湾菌门(Chloroflexi)等的相对丰度均与对照间有极显著或显著差异。细菌前10门的相对丰度在化肥配施黄腐酸钾、生物有机肥等低量外源有机碳处理下,两者间无显著差异。低量外源有机碳配施化肥处理下土壤细菌群落组成与对照处理间的相似度较大,而牛粪配施化肥与羊粪配施化肥处理间的土壤菌群结构相似度较高。土壤变形菌门(Proteobacteria)、酸杆菌门(Acidobacteria)、芽单胞菌门(Gemmatimonadetes)的相对丰度与土壤pH、土壤碱解氮质量分数呈负相关;第一、二排序轴能分别在累积变量78.67%、97.49%上揭示土壤细菌优势菌门的相对丰度、土壤细菌多样性、丰富度与土壤理化性状间的相互关系。土壤pH和碱解氮是影响酸杆菌门、放线菌门相对丰度高低的主要驱动因子。旱作区中长期有机和无机培肥措施下,外源有机碳输入数量及有机肥类型影响土壤细菌群落结构组成。

Response of Soil Bacteria Community Structure to Application of Inorganic and Organic Fertilizer

In order to reveal the response mechanism of soil bacterial communities to organic manure and inorganic fertilizer application in arid region,the farm land soil ecosystem was selected as the research object,and the soil bacterial community structure and diversity were analyzed by high-throughput sequencing technology after 8 a organic manure and inorganic fertilizer application.The relationship between soil bacteria communities diversity and structure was also discussed based on the phylum level and soil physical and chemical properties. The results showed that the soil physical and chemical characteristics were significantly affected by continuous organic and inorganic fertilization application,but the ratio of soil carbon and nitrogen decreased. 46 531 sequences of the bacterial V3-V4 region belonged to 3 494 OTUs,the total 3 494 soil bacteria operational taxonomic units(OTUs) were divided into 58 phylum,67 class,143 order,271 families,639 genus and 435 species. However,the soil bacterial community richness index and diversity index were not significant difference under the different organic and inorganic fertilization application. The relative abundance of Proteobacteria of all treatments accounted for 35.91%-42.03%,and it was a dominant phylum of bacteria. There was a significant or obviously significant difference for the relative abundance of Proteobacteria and Chloroflexi between the treatments of cow manure or sheep manure with chemical fertilizer,compared with the control. The top 10 bacteria with the higher relative abundance were not significant difference between the treatment of potassium fulvic acid and bio-organic fertilizer with chemical fertilizer based on the phylum level. The composition of soil bacterial communities were similar between the control and the treatments by organic fertilizer combined with the lower amounts of organic carbon and chemical fertilizer application,while there were a higher similarity between cow manure and sheep manure combined with chemical fertilizer. The relative abundances of Proteobacteria,Acidobacteria,and Gammatimonadetes were negatively correlated with soil pH and soil available nitrogen.Based on 78.67% and 97.49% of accumulated variables in principal component analysis(PCA) ordination of based on the phylum leve,the relationship between the relative abundance of the dominant bacteria,soil bacterial communities diversity and soil physicochemical properties could be explained separately . Soil pH and the available nitrogen were the main driving factors affecting the relative abundance of Acidobacteria and Actinobacteria.The composition and the structure of soil bacterial community were influenced by the varieties and the amounts of organic fertilizer with addition of exogenous organic matter in soil under the the medium and long-term organic and inorganic fertilization application.