Red Soil Microbial Diversity of Peanut Continuous Cropping and Effects of Microorganisms on Growth of Continuous Cropping Peanut
|School||Nanjing Agricultural College|
|Keywords||DGGE RFLP Peanut Continuous Cropping Bacillus Photosynthetic Bacteria Microbial diversity|
Peanuts are the main oil crops and economic crops in low-hillt red soil region of south China. Culture without rotation in the peanut yield, the output and the VCR are tending to decline in 2-5 years. Some researchs from different angles analysed the reasons of continuous cropping obstacles, showing unbalance of soil microbial population was the most important elementary of causing crop. Based on extracting the total community DNA by the direct lysis method, Bacterial universal primers were used to amplify 16S rDNA V3 region fragments and fungal universal primers were used to amplify 18S rDNA of fungus; DGGE method was applied to study microbial community structure in different samples. By the method of isolating pure Bacullus strains from soil samples, Bacterial universal primers were used to amplify 16S rDNA fragments; PCR products digested by restriction endonucleases Hha I and Xsp I, and their fingerprints analyzed for diversity of Bacullus species from soils.The result of DGGE about Bacterial showed that band numbers were abundant in all the soil samples, revealed that richness of bacteria in three soils was relatively high. Dominant species mainly distribution in Bacullus. While the result of DGGE about fungus showed that band numbers were few in all the soil samples, revealed that richness of bacteria in three soils was not high. Mould were detected widespread in peanut continuous cropping soils. Cluster Analysis showed that almost same soil type samples were in same Cluster.Bacillus subtilis have more reports in the studies of Bacillus, widely existing in soil, lakes, oceans and surface plants and animals. Not only because of their non-pathogenic and can secrete a variety of enzymes and antibiotics but also have a good foundation of Fermentation, so they have a very wide range of uses. The result showed that the total number of culturable Bacullus spp.were high, being 2.00×105～2.25×105cfu/g dry soil. The three gene libraries included 9 OUTs restriction endonuclease types. Diversity index of PCC 1 were higher than other two samples, which suggested Bacullus spp. were more abundant in PCC 1. There were three main restriction types accounting for 54%、12% and 14% of the total 16S rDNA clones, respectively. They were B. pumilus, B. subtilis and B. altitudinis.In order to alleviate peanuts continuous cropping obstacles, the application of microbial agents were used to the soils of peanut continuous cropping obstacles, observing the peanut fertility quality and yield of influence in different treatments. The results showed: the microorganism preparation could increase the crops the output to a certain extent, which is increased by 32.14% compared to the control. As a microorganisms regulator, Bacillus are new environmentally friendly bio-agents to anti-cropping, expected to become an economic and effective countermeasure to reduce or lift the barriers of peanut cropping in the future.