Abstract: In this paper,a total of 22 bacterial isolates capable of fixing nitrogen and/or solubilizing phosphorus were inoculated,and mixed incubated in 15 liquid media.The isolates were obtained from soil with selective media,and not purified.After grown for 48 hours,the mixed cultures were continuously inoculated to the same media,and then incubated under the same conditions.The procedures were repeated for 12 times,and 15 stable bacterial mixtures (SBM) were obtained.Each SBM was purified,which contained two or three bacterial species.Agar plate bacteriostasis test showed that 6 mixed cultures of the SBM exhibited significant inhibition effects to one or more plant pathogens of Verticillium dahliae,Rhizoctonia solani,and Pseudomonas syringae.It was found that C₇ and C₁₅ were the two SBM with most obvious antibiological effect.SMB C₁₅ had the ability of nitrogen fixation,and C₄,C₅,C₇,C₉,C₁₄ and C₁₅ showed the ability of phosphorus solubilization.These results suggested a possible approach to develop stable,synergistic,and multi-functional antibiological agents.

Key words: West of northeast China, Sandy desertification region, Vegetation, Classification