【摘要】 为研究优化施肥对柳枝稷土壤理化性质及细菌多样性结构和多样性的影响，以半干旱区种植3年的柳枝稷表层土壤为对象，采用高通量测序技术研究了不同施氮水平（0、60、120和240 kg·hm-2）对0～20cm土层土壤理化性质、细菌多样性及其结构的影响，以盐碱荒地作为对照（CK）。结果表明，总的来看，施氮可显著降低土壤pH值和全盐含量，同时施氮能够显著提高土壤养分含量，有效改善土壤环境，提高土壤理化性质。与CK相比，土壤pH值和全盐含量分别降低了3.32%～11.53%和43.27%～73.32%，土壤养分含量提高了14.05%～20.98%。5个处理的15份土壤样品共获得约7.4万条有效序列，基于≥97%的相似度水平下，通过聚类分析对可操作分类单元（OTU）进行归类，CK、N0、N60、N120和N240平均分别有8696、9210、9403、8450和8239个OTU类型，Chao1指数、ACE指数和Shannon指数分别在6623.06～7627.90、7457.14～8412.28和6.40～6.67之间；在5个处理的土壤样品中，门和属分类水平上细菌种群组成较为一致，优势菌门主要为变形菌门（Proteobacteria）、放线菌门（Actinobacteria）、酸杆菌门（Acidobacteria）、拟杆菌门（Bacteroidetes）和浮霉菌门（Planctomyoetes），相对丰度共占75.74%～91.30%；优势菌属主要为鞘氨醇单胞菌属（Sphingomonas）、Gp6、芽单胞菌属（Gemmatimonas）、Ohtaekwangia、节细菌属（Arthrobacter）、Subdivision3 genera incertae sedis、假单胞菌属（Pseudomonas）、Sphingobium、Geminicoccus和Aridibacter，相对丰度共占55.72%～62.98%；层级聚类及相关分析发现，增施氮肥对细菌多样性结构有一定影响，其中土壤全盐、有效磷、速效钾、有机质、全氮、全磷和碱解氮含量是影响假单胞菌属和Aridibacter细菌多样性的主要理化因子。综上所述，施肥处理显著提高了柳枝稷土壤养分含量，改变了土壤理化性质，但没有改变土壤细菌多样性。更多还原

【Abstract】 For researching the effect of optimized fertilizer on soil chemical properties of switchgrass fields and the influence on the bacterial diversity structure and diversity,different types of surface soil planted with three-year switchgrass in saline wasteland and switchgrass fields in half arid areas were studied using high-throughput sequencing technologies,different nitrogen application rates(0,60,120 and 240 kg·hm^-2)were adopted and the saline wasteland was used as CK.The results showed that,in general,nitrogen application significantly reduced soil pH and total salt content,and increased soil nutrient content and soil chemical property.Compared with saline wasteland（CK）,soil pH and total salt content decreased by 3.32% ～ 11.53% and 43.27% ～ 73.32%,respectively,and soil nutrient content increased by 14.05% ～ 20.98%in switchgrass fields.74000 valid sequences were obtained from the five treatments with 15 soil samples,based on the similarity level of 97% or more,through clustering analysis of operational classification unit（OTU）categorization,CK,N0,N60,N120 and N240 had an average of 8696,9210,9403,8450 and 8239 OTU types,respectively,Chao1index,ACE index,and Shannon index were 6623.06 ～ 7627.90,7457.14 ～ 8412.28 and 6.40 ～ 6.67,respectively.Among the soil samples of five treatments,bacterial populations were relatively consistent at the classification level of phylum and genus,and dominant phylums were mainly Proteobacteria,Actinobacteria,Acidobacteria,Bacteroidetes and Bactertomyoetes,with relative abundance accounting for 75.74% ～ 91.30%.The dominant genera were Sphingomonas,Gp6,Gemmatimonas,Ohtaekwangia,Arthrobacter,Subdivision3 Genera Incertae Sedis,Pseudomonas,Sphingobium,Geminicoccus and Aridibacter,with relative abundance of 55.72% ～ 62.98%.The hierarchy clustering and correlation analysis showed that the application of nitrogen fertilizer had a certain effect on the bacterial diversity structure,in which the total salt,available phosphorus,available potassium,organic matter,total nitrogen,total phosphorus and alkalihydrolyzed nitrogen content were the main physical and chemical factors that affect the bacterial communities of Pseudomonas and Aridibacter.In conclusion,fertilization significantly increased soil nutrient content and changed soil physical and chemical properties,but did not change soil bacterial diversity in switchgrass field.更多还原