Abstract: In order to study the effects of different seed dressing(rhizobium) dosages on the growth of two alfalfa and rhizosphere soil microbial diversity in Qinghai Lake area,the methods of field observation and high-throughput sequencing were used to analyze the growth status and rhizosphere soil microbial community diversity of the two alfalfa (‘Beilin 201’ and ‘Beilin 202’). The results showed that the plant height of two alfalfa increased significantly after the seed dressing,and the best concentration was 50%. The seed dressing treatment increased the bacterial microbial species diversity of the two alfalfa rhizosphere soils,but reduced the abundance. The dominant bacterial groups at the soil bacterial phyla level of the two alfalfa were Proteobacteria,Actinobacteria,Firmicutes,and Bacteroidetes. Seed dressing and bacterial fertilizer treatment increased the relative abundance of Proteobacteria and Actinobacteria. Use of non-metric multidimensional scaling method (NMDS) analysis showed that there were certain differences in the soil microbial community structure of the two alfalfa soils after seed dressing,and the difference was not significant. This result would provide a scientific basis for the sustainable development of grass husbandry by microbial fertilizer.

Key words: Seed dressing, Alfalfa, High-throughput sequencing, Bacterial diversity

摘要： 为研究根瘤菌(rhizobium)拌种对两种苜蓿(Medicago sativa Linn)生长及根际土壤微生物多样性的影响，本研究采用田间观测和高通量测序的方法，分别对不同拌种剂量处理的两种苜蓿(‘北林201’和‘北林202’)生长状况和根际土壤微生物群落多样性进行分析。结果表明：拌种处理后，两种苜蓿的株高明显增加，且在拌种浓度为50%时效果最佳；拌种处理影响了两种苜蓿土壤细菌多样性和群落组成，其中，拌种处理增加了两种苜蓿根际土壤细菌微生物物种多样性，却减少了丰富度；两种苜蓿的土壤细菌门水平上优势菌群为变形菌门(Proteobacteria)、放线菌门(Actinobacteria)、厚壁菌门(Firmicutes)、拟杆菌门(Bacteroidetes)，拌种处理增加了变形菌门(Proteobacteria)和放线菌门(Actinobacteria)的相对丰度；使用非度量多维尺度法分析表明，拌种处理后两种苜蓿土壤微生物群落结构存在一定的差异，差异不显著。该结果可为微生物拌种对草牧业的可持续发展提供科学依据。

关键词: 拌种, 紫花苜蓿, 高通量测序, 细菌多样性