| First,We screened 146 strains of the fungus and bacteria from the soil of different regions,using 8 plant disease bacteria as the indicator strains to screening the antagonistic strains by plate confrontation method,and obtain 3 strains of significant inhibitory effect and broad spectrum.Three strains were identified and named as Bacillus subtilis LWJ-4,Bacillus licheniformis ZZY-7 and Trichoderma harzianum YNX-18.The optimal fermentation conditions of Bacillus subtilis LWJ-4 and Bacillus licheniformis ZZY-7 were determined by single factor and orthogonal experiment and pilot fermentation experiment:The cassava residue was used as substrate and 7.5%molasses were added as carbon source,With 10.0%corn steep liquor as nitrogen source,adjust the initial pH to 7.0,and fermented at 37?for about 24 hours by pile fermentation.The yeild of Bacillus subtilis LWJ-4 can reach 6.7×10~9cfu/g and the yeild of Bacillus licheniformis ZZY-7 can reach 8.0×10~9cfu/g.The optimum fermentation conditions of Trichoderma harzianum YNX-18 were as follows:the cassava residue was used as the substrate,7.5%corn flour was added as the carbon source,10.0%rice bran was used as the nitrogen source,the initial pH was adjusted to 6.5,and fermented at30?for about 144 hours.The final yield of Trichoderma harzianum YNX-18 was reach34.2×10~8 spore/g.Then we further to test the mixed fermentation of the three strains and determined that the Bacillus licheniformis ZZY-7 and the Trichoderma harzianum YNX-18 can fermentation in a step-by-step manner to the ideal yield level of mix fermentation.The process conditions of mixed fermentation was:Using Bacillus licheniformis ZZY-7fermented material as matrix,after adding corn flour,wheat bran and other nutrients inoculate the spore fluid of Trichoderma harzianum YNX-18 to mixed fermentation,the fermentation yield of Bacillus licheniformis ZZY-7 reach to 7.7×10~9cfu/g and the fermentation yield of Trichoderma harzianum YNX-18 reach to 31.3×10~8 spore/g.Finally,we selected the two experimental fields of Laiyang and Weifang to carry out the field experiment.The soil samples of different microbial agents were analysis by compared with the Shannon-Wiener diversity index by the DGGE method.The results showed that the application of microbial agents had a significant effect on the microbial diversity of soil in different plots,and this effect gradually weakened with the passage of time.Part of the probiotics containing bacteria can inhibit the fungi in the soil,greatly reducing the richness of fungi in the soil,such as microbial agents F3 makes the fungi richness and diversity index of experiment group J3 were reduced to 45%and54%of control group.The diversity index and abundance of the fungi were the lowest in the H2 experiment group,which was only 1.22 and 3.67.The application of compound probiotics can increase or maintain the diversity of microorganisms in the soil,which is reflected in the bacterial and fungal experimental groups of the two experimental fields(in the experimental group of Laiyang peanut,bacterial and fungal abundance of the compound agent F6,was 3.29 and 1.01 times of the control group;in the experimental group of weifang ginger,the enrichment of the experimental group adding compound agent F6 bacterial is 1.14 times of the control group).The diversity of microbes in the soil is also closely related to the external factors such as soil properties,environment,and climatic conditions.For example,the richness of microbes in the field of Laiyang peanut test(the total richness of bacteria and fungi is 13)was lower than Weifang ginger plots(The total richness of bacteria and fungi is 16.33).In summary,using the probiotics produced by solid fermentation can change the diversity of soil microbes and richness and improving the crop's living environment.In the production of agricultural can promote crop growth,prevent disease and reduce the use of chemical fertilizers and so on,have a wide range of applications. |
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