Interactions And Applications Of Antagonistic Microorganisms In Tobacco Field

In order to investigate the interaction between antagonistic microorganisms and their effects on tobacco agronomic traits and rhizosphere microorganisms,16 species of antagonistic microorganisms(mainly included 6 species of Trichoderma,4 species of bacteria and 7 species of actinomycetes),which were screened and proved that have strong inhibition effects on common soilborne pathogenic fungus from tobacco growing soil of Luoyang,were used as the research object of this experiment on the basis of previous studies.In this test,we measured the interactions between these antagonistic microorganisms with a method called improved confrontation culture.Firstly,we use the method of improved confrontation culture to determined the interaction relationship between these antagonistic microorganisms and choose the Affiliative antagonistic strains.Next,the complex bacteria of antagonistic strains are combined with the organic auxiliary materials to prepare the microecological preparation through the second fermentation.Finally,we set different treatments in Luoning County tobacco field for studying the effects of microecological preparation on agronomic traits and rhizosphere microorganism during different growth stages of tobacco.The mainly results obtained are as follows.(1)The determination results of the mutual inhibition rate between antagonistic strains showed that most antagonistic microbe have inhibitory effect on each other,and the interaction relationship is mainly reflected on competing for space and nutrients,influencing the growth of aerial mycelium and substrate mycelium by producing antibiotic substance and so on.Through this experiment,3 strains of antagonistic fungi,bacteria and actinomycetes were screened out.(2)The inhibition rates of Trichoderma T1,T2 and T3 were all below 50%,which manifest as nutrition competition and could coordinately grow;when confront culture with antagonistic actinomycetes S2,S4,S7 and bacteria B1,B2,B3,the inhibitory effects were smaller.The interactions between antagonistic bacteria B1,B2 and B3 are represented as basic affinity and could coordinately grow;when confront culture with antagonistic actinomycetes S2,S4,S7,antagonistic actinomycetes were able to grow normally and had a strong inhibitory effect on antagonistic bacteria.The inhibitory effects between antagonistic actinomycetes S2,S4 and S7 were smaller and could coordinately grow.(3)The primary product of microecological preparation(compound bioorganic fertilizer)through second fermentation have excellent physical properties,and microscopic detection proved that antagonistic microorganisms can be successfully colonized.(4)The determination of tobacco field economical character showed that the application of organic fertilizer and microecological preparation could increase the plant height and stem girth,enlarge the leaf number and leaf area effectively.(5)Adding organic fertilizer and microecological preparation can increase the quantity of culturable microorganism on tobacco rhizosphere soil at harvest time.When compared with control group,the number of fungi were increased by 379.12%and 78.06% respectively;the number of bacteria were increased by 16.45% and 5.21%respectively;the number of actinomycetes were increased by 9.37% and 5.14%respectively.The results showed that the increasing extent of the fungi number in rhizosphere soil by using the microecological preparation was significantly lower than that of using organic fertilizer.(6)With the application of organic fertilizer,the species richness and community diversity of rhizosphere microorganism on tobacco field were the highest,followed by the application of microecological preparation,the lowest is the control group.The results showed that the soil samples of two treatments have the Higher similarity,and the relative contents of the Streptomyces and Bacillus in this two soil samples were higher than those in the control group.Through the combination of laboratory screening and field investigation,the interaction relationship between different antagonistic microorganisms was cleared and definited,and the primary products of compound microecological preparation were developed.At the same time,we also discusse the impact of this product on agronomic traits and rhizosphere microorganism during different growth stages of tobacco.These results provide a theoretical and practical basis for the further use of multiple antagonistic microorganisms to prevent and control the soilborne fungal diseases of tobacco.