Microbial Diversity In Sugarcane Field Treated With Different Rates Of Vinasse

In order to investigate the effects of vinasse application on the microbial diversity in soil and provide with references for rational application of vinasse in sugarcane field, the number of microbes at different growth stages and the DNA sequence of microbial Community in the soil treated with different rates of vinasse were studied with traditional isolating and culturing methods and PCR-DGGE Molecular marker technique. The changes and differences of the number of soil microbe and the genetic diversity were analyzed, and the factors that may influence the soil microbial community were discussed.The main results were summarized as follows:1. During sugarcane growth, the quantities of bacterium, fungi and actinomyces, and the total number of microbes in the soil treated with vinasse increased obviously as compared with the controls without vinasse application.2. The effectiveness of two soil DNA extraction methods was compared. The results showed that the direct method gave better DNA and was more efficient, and provided ideal template DNA for further molecular study. 3. The PCR method was optimized. Both traditional and touchdown strateges were experimented comparatively for PCR because the primer used in the present study has "GC clamp" structures. The result showed that better aim gene fragment could be amplified with the touchdown strategy, suggesting that this method is more suitable for the present study.4. Micobial richness in soil was in the order of 75t/ha vinasse >105t/ha vinasse > 45t/ha vinasse > CK2 > CK1 > 75t/ha vinasse + no planting treatments. The soil microbial similarity index was the highest (41%) in 45t/ha vinasse and 75t/ha vinasse treatments, and the lowest in 75t/ha vinasse + no planting and CK2 treatments, CK1 and 7t/ha vinasse (both 19%). UPGMA cluster analysis showed that microorganisms in the soils of 75t/ha vinasse and 45t/ha vinasse treatments were in the same cluster, and the genetic similarity reached 75 %.5. In general, application of vinasse is good for microorganisms in the soil of sugarcane field, which resulted in higher microbial richness and higher populations as compared with the controls without vinasse application, which is beneficial to amelioration of soil structure and improvement of soil fertility.