Effect of specific microbial fertilizer on the rhizosphere microbial flora of different continuous cropping obstacles soil

In order to explore the effect of application of special microbial fertilizer on the rhizosphere microflora in different continuous cropping obstacles soil,the soils with different degrees of continuous cropping obstacles were collected and amended with 2% special microbial fertilizer to be used in the pot experiment for peppers cultivation.The methods of dilution plate count and PCR-DGGE were employed to analysis the rhizosphere microflora.The results obtained were as follows.With the increase of continuous cropping year,the number of rhizospheric bacteria and actinomycetes were decreased while the number of rhizospheric fungi was increased;After fertilization of special microbial fertilizer,the number of microbes had changed obviously,bacterial number increased 78.6%,66.7%,54.5%,fungi number decreased 5.0%,12.5%,7.5%,and actinomycetes number increased 18.2%,9.1%,23.5% in 3 different kinds of continuous cropping soils(with low,medium and high degrees of continuous cropping obstacles),respectively;The PCR-DGGE fingerprinting showed that the richness and diversity index of rhizospheric microorganisms decreased with the increase of the continuous cropping year while the population number and structure of rhizospheric microorganisms could be improved and the diversity index could be increased after fertilization of special microbial fertilizer.It was suggested that the special microbial fertilizer could have a significant effect on improving the population density and population structure of microorganisms in rhizosphere soil,but the improved effect could be different due to the different degrees of continuous cropping obstacles.