Method of investigation in rhizobacterial flora of crops and application case by using Biolog's identification system

Fifty strains of rhizobacteria were isolated from roots of crops in rotatio n and monocropping plots of soybeans and sweet potatos one month before har vest, and they were identified by using Biolog's identification system duri ng the period from 1994 to 1997. The strains of 38.3% of the rhizobacteria isolates were identified, and the others were on the process of classificat ion or unidentified. It was assumed that the relative high percentage in un identification was attributed to insufficient database related to environme ntal bacteria. If this database were thoroughly improved, however, this sys tem would be useful for dynamic analyses of rhizobacterial flora in terms o f genus or species level, since a large amount of strains of rhizobacteria of crops could be smoothly identified with this system. The effects of rota tion and monocropping systems on the rhizobacterial flora of crops were eva luated by a diversity index using this system. The diversification of the r hizobacterial nora was not improved in the monocropping plot of soybeans co mpared with rotation plots of soybeans and sweet potatos and the monocroppi ng plot of sweet potatos.