Abstract: In order to obtain the materials of composite functional microbial PGPR strains, and then understand the advantages of rice-rape system from the perspective of functional microorganisms, using the arable soil of rice-rice and rice-rape system as the screening sources, the cultivable bacteria, nitrogen fixing bacteria (NFB), phosphate solubilizing bacteria (PSB) and auxin bacteria (AB) were isolated and screened by traditional selective medium culture method. In the incubator culture experiment, the early biological growth promoting effect of some selected compound growth promoting strains on rape and cucumber seedlings was verified. The results showed that 35 strains of NFB strains and 3 PSB strains could be isolated from top soil in rice-rice rotation system, 38 NFB strains and 35 PSB strains could be isolated from top soil in ricerape rotation system, and 6 strains of compound type (NFB+PSB+AB) PGPR were isolated from top soil in two rotation systems, which could promote the growth of plant height of rape and cucumber seedlings by 25.45%-111.96% and 4.45%-18.22%, respectively. In addition, DD-69 and DY-111 had significant growth promoting effects on the cucumber root length, DY-6 and DD-79 had significant growth promoting effects on the fresh quality of cucumber, respectively. |