Study On Preparation And Application Effect Of Microecological Preparations For Tobacco

Tobacco soil-borne diseases are a type of diseases caused by pathogens which can infect tobacco roots and stems.At present,they are mainly controlled by spraying chemical pesticides.Although some effects have been achieved,they have brought about a series of problems such as excessive pesticide residues and environmental pollution.In order to reduce the application of chemical pesticides and maintain the sustainable development of the modern tobacco industry.This study used the principle of secondary fermentation to produce microecological preparations by fermenting the beneficial microorganisms,fresh sheep dung and weathered coal in a certain proportion.Different dose of fertilizer was applied for field experiment in Shicun,Gaoxiang,Yiyang County,Luoyang City.It explored the effects of microecological preparations on the microbial quantity,enzyme activity of soil around the roots and agronomic traits of tobacco at different growth stages.Moreover,Illumina Miseq sequencing technology was utilized to analyze the relationship between microecological preparations and the diversity,community structure and function of microorganism in soil around tobacco roots.The main results obtained are as follows.The preparation process of the microecological preparations included three steps.First,it needed the fresh sheep dung with about 30%moisture content and 1‰fermentation microbial inoculum during the first fermentation.The fermentation cycle was 18 d with stacking every 3 d.And then the obtained decomposed sheep dung was mixed with weathered coal(3:2)to make a ground mass with water content of about30%.Second,indoor solid culture was prepared by mixing 5%of the biological stock solution into the ground mass.The fermentation cycles of bacteria,fungi,and actinomycetes were 3～5 d,5～7 d,and 7～9 d,respectively.And the expanded production was achieved by mixing 15%of solid culture with the ground mass.The fermentation period was 6 d,and the times of stacking was once 3 d.Finally,the micro-ecological bacterial agent was prepared by mixing 15%of the solid culture and the ground mass,and the secondary fermentation cycle was 6 d with stacking every 2 d.The p H value(6.83～7.61),chloride ion content(0.45%～0.60%)of the three types of solid culture all accorded with the national standard.The viable count in the solid culture of the bacteria(6.28×108 CFU/g)met the national standard.The beneficial bacteria were easier to colonize on the fermentation base than the beneficial fungi(1.10×107 CFU/g)and actinomycetes(6.00×106 CFU/g).The microecological preparation product had no odor and effect on tobacco seedling growth.Within 30%of the water content,the measured indicators met the national standard of bio-organic fertilizers.The application of 200Kg,300Kg and 400Kg of microecological preparations for per 667m~2of tobacco field can increase the number of microbial colonies in soil around tobacco roots,improve soil enzyme activity and agronomic characters during the rosette stage.As compared to control group,the number of bacteria was increased by 123.47%,338.78%and 257.14%,respectively;the number of fungi was increased by 116.54%,793.98%and 664.66%,respectively;the number of actinomycete was increased by 62.88%,222.72%and 66.66%,respectively;the activity of urease was improved by 27.27%,9.09%and 22.73%,respectively;the activity of phosphatase was improved by 159.12%,381.39%and 552.92%,respectively;the activity of catalase was improved by 159.12%,381.39%and 552.92%,respectively;the tobacco height was increased 6.75%,15.61%and 16.93%,respectively;the stem girth was increased 1.47%,2.65%and 6.49%,respectively;the number of leaves was increased by 1.38%,8.30%and 4.32%,respectively;the area of leaves was increased by 4.62%,9.46%and 3.97%,respectively.Microecological preparations could increase the species of genus in prokaryotes in soil arround tobacco roots during the rosette stage and the long-term,and significantly increase the contents of Bacillus and streptomyces in the long-term,but reduce the species of genus in eukaryotic in the three growth stages of tobacco.Microecological preparations had little effect on the prokaryotic community structure in soil around tobacco roots,but could change the composition of the microbial community function in the three growth stages.Based on the principle of secondary fermentation of microorganisms,a microecological preparations containing beneficial microorganism flora was developed and trial-produced in this study.Field tests were conducted to determine the effects of the preparations on the agronomic characteristics of tobacco plants and soil microorganisms and enzyme activities in the roots of tobacco plants.The effects of the preparations on microbial diversity,community structure and function were also explored at the micro level.And this lays certain theoretical and practical basis for the popularization and application in Luoyang tobacco production.