Analysis Of The Microflora Changes At Tobacco Rhizospheresoil In Different Areas

In order to study the relationship between tobacco bacterial wilt and the soil, rhizosphere soil were collected from different regions at Shaowu(Fujian) in tobacco growing period, soil microbes, related nutrients and other parameters were then measured. Results are shown as follows:1. The soil of the four pilot sites, which were taken from Shaowu(Fujian), was light loam and sandy loam. During the growth period, the p H of the soil had some improvement at a certain extent; however, the difference between different soil samples were not significant. The utilization of nutrients at mild loam were bigger than at loam, and the difference were significant. According to the results, at the light loam, the quantity of fixing phosphorus was less, but the capacity of supplying potassium was good, which was helpful in leaves’ yellowing and maturity, and finally improved the quality of tobacco.2. During the growth period, the light loam had a positive effect at expanding the area of tobacco leaf, increasing yield field, and improving the quality of inside and outside. Light loam preceded roam, when compared with the yield field of the tobacco, and the yield field at Xuxi was the highest.3. Tobacco soil samples from 4 test points were bacterial soil. Combined with different soil types, mild loam were larger loam when compared with the total number of micro-organisms and bacteria. Results of metagenomic sequencing showed that microbial population and abundance of light loam were higher than sandy loam, and the structure were more stable. During the occurrence period of tobacco wilt, microbial population and abundance of rhizosphere soil at healthy plants were greatly higher than at sick plants, which indicated that the complex microbial flora was beneficial to inhibit pathogenic microorganisms, and balance soil rhizosphere micro-ecology, and thus increase the resistance of tobacco plants. The survey of tobacco wilt occurrence at experimental points showed that light loam was higher than loam.4. Two kinds of bacteria(QJ-1 and QJ-2) were isolated from soil in the tobacco fields, which can inhibit the growth of tobacco wilt, and the inhibiting ability of QJ-2 was stronger, which the inhibition size ringed up to 10.0 ~ 11.5 mm. Field trials were then conducted, with organic fertilizer inoculated with the bacteria. The Result of two years(2013 and 2014) showed that, at the field inoculated with antagonistic bacteria, microbial population was higher, and the occurrence and disease index of tobacco wilt decreased 10.1% and 8.0%, respectively; thus achieved the purpose of inhibiting the tobacco wilt.