Study On Biological Effect Of Controlling Cotton Virticillium Wilt With Antagonistic Bacillus And Bio-organic Fertilizer

The temperature controlling, water content controlling, pots and plots experiments were carried out to study on biological effect of controlling cotton virticillium wilt with applied antagonistic bacillus and bio-organic fertilizer. Biomass of cotton, enzyme activities of soil catalase, alkaline phosphatase, sucrase, protease, urease and polyphenol oxidase, and soil microorganism diversity were measured.(1) Result of temperature controlling experiment showed that the optimum temperature for verticillium dahiae kleb(V.D) growth was 25℃.The V.D could grow slowly in 15℃, but be inhibited growth in 35℃. The antagonism bacterium numbers were increased with the temperature increase. The antagonism bacterium had strongly antagonistic effects on the V.D in three temperature treatments.(2) Results of the water content controlling experiment showed that the antagonistic effect of bacterium on inhibiting V.D decreased with the increase of the water content in soil. Main reason was that the V.D were suitable to live in high humidity environment.(3) Results of the pots experiment showed that using two antagonism bacterium(T3, T4) could improve cotton growth, biomass of cotton were higher than V.D control treatment. The treatments of antagonism bacterium mixed with the organic fertilizer(T5,T6,T7,T8)improved cotton to absorb N, P, K, the absorptions of nutrition were 4.73,4.95,4.14 times compared with V.D. Treatment T3,T4 could improve the activities of alkaline phosphatase, urease, sucrase, and polyphenol oxidase under the same fertilizer level in the prophase, and the activity of sucrase was significantly improved in the anaphase. The activities of alkaline phosphatase, protease and urease significantly increased, after using the mixture of antagonism bacterium, organic fertilizer and bio-organic fertilizer. While different influences on soil enzyme activity of antagonism bacterium had different effects on different periods of duration. The microorganism biomass carbon and biomass nitrogen of CK were lower than other treatments, and the T2's were notably increased. Promotion to microorganism biomass carbon and biomass nitrogen of T3, T4 were notable in the prophase while the T5, T6, T7, T8s' were notable in the anaphase. The analysis of fungal and bacterium diversity using the PCR-DGGE showed that the Shannon-wiener index, uniformity, and Simpson index of other treatments were all increased compared with CK. The population richness of T2, T3, T4 were higher than others. The fungal Shannon-Wiener index of T3, T5, T6, T7, T8 were higher compared with CK. But the uniformity and Simpson of all treatments nearly had no changes.(4) Results of the plots experiment showed that the activities of alkaline phosphatase, sucrase, protease, urease and polyphenol oxidase could be increase during the bud stage, flower season and boll stage after using the bio-organic fertilizer and organic fertilizer. The activities of soil catalase also increased in the bud stage and flower season. The resistances to V.D of all treatments from higher to lower were S37, bio-organic fertilizer, S44, S228, organic fertilizer. The effects of cotton productions from higher to lower were bio-organic fertilizer, S44, organic fertilizer, S37, S228. The unit productions were increased 163.34 g,143.56 g.101.33 g,90.34 g,81.49 g compared with CK.