Studies on microbial population dynamics in rhizospheres of the continous cropping peanuts in red soil at different growth periods.

The microbial population dynamics in the rhizospheres of continous cropping peanuts was studied by the plate counting method and DGGE.The results showed that the numbers of bacteria,actinomycete and fungus significantly increased in peanut continuous cropping soil with long-term fertilization.The numbers of bacteria and actinomycete in M(pig manure) and BM(pig manure with effective microorganisms) were significantly higher than those in F(chemical fertilizer),but the numbers of fungus were less in M and BM than in F.PCR-DGGE analysis indicated that the microbial biodiversity decreased in continuous different fertilization treatments,the dominant species was Sphingomonas sp,and the number of R.solanacearum increased.The Shannon Index and the Richness of M and BM were higer than F,Compared with F,BM could improve the microbial community diversity in the rhizospheres of continous cropping peanuts.Soil microflora unbalance and increasing soil borne-desease pathogens were two main factors of the peanut continuous cropping obstacle in red soil.