Abstract: In order to screen soybean rhizobium with strong nitrogen fixation ability for vegetable soybean with different salt tolerance,ten Soybean Rhizobium strains （NGR234,HH103,B16,N18,USDA110,USDA122,CB1809,ACCC15067,AS1.826,and AS1.909）were selected and used in the study with vegetable soybean salt-tolerant varieties LvLingBaHao Symbiotic matching of salt-sensitive cultivar RiBenQing.The results showed that there was no significant difference in the overground biomass between LvLingBaHao-USDA122 combination and the inoculation of USDA110,the fresh weight of nodules had no significant difference with the inoculation of N18,USDA110 and AS1.826,and the total nitrogen content of plants had no significant difference with the inoculation of HH103,but they were significantly higher than other combinations.The number of nodules,the fresh weight of nodules,the activity of nodules dinitrogenase and the total nitrogen content in plants of RiBenQing-HH103 combination were significantly higher than those of other combinations,but there was no significant difference in the overground biomass between RiBenQing-HH103 combination and USDA110 inoculation.In order to accurately evaluate the nitrogen fixation ability of each strain and two vegetable soybean varieties,a comprehensive evaluation method was adopted in this study.The results showed that the symbiotic nitrogen fixation ability of each strain and LvLingBaHao from strong to weak was：USDA122>AS1.826>H103,USDA110>N18>AS1.909>ACCC15067,NGR234>B16,CB1809,the symbiotic nitrogen fixation ability with RiBenQing was HH103>USDA110>N18>USDA122,NGR234>AS1.909>B16>ACCC15067,AS1.8>CB1809.Those results showed that there were significant differences in nodule and nitrogen fixation ability among different Soybean Rhizobium strains.The salt-tolerant cultivar LvLingBaHao and USDA122 had stronger nodule and nitrogen fixation ability,while the salt-sensitive cultivar RiBenQing and HH103 had stronger nodule and nitrogen fixation ability. In addition,the comprehensive evaluation method introduced in this study can also provide a reference for the study of symbiotic matching between soybean and rhizobium.

Key words: Vegetable soybean, Soybean rhizobium, Nitrogen fixation