| The planting soil physical and chemical properties and rhizosphere microorganism community structure could affect soil fertility and the formation of the quality of tobacco leaves after baking.So far,it is an urgent problem to be solved in flue-cured tobacco production that improving planting soil physical and chemical properties,promoting the beneficial microbial flora,and increasing the yield and quality of tobacco leaves after baking.The Yunyan 87 was selected as testing material,pot experiment and field experiment were conducted,and the soil sample collection time of field experiment at 30,60,and 90 days after transplanting,the soil sample collection time of pot experiment at 20,40,60,and 80days after transplanting,and the detrended correspondence analysis,redundancy analysis and partial least square path model and other statistics methods were used in this research,to investigate the effects of biochar on planting tobacco soil physical and chemical properties,rhizosphere microbial and the quality of flue-cured tobacco production.Results are as follows:1.The effects of biochar on soil physical and chemical properties were studied in this research.Result showed that soil bulk density and the ratio of solid phase were negatively related to the biochar application amounts(0~4500kg/hm~2),while the ratio of liquid phase and moisture content of soil present the change of"down up down"with the increase of the biochar application amounts(0~4500kg/hm~2);Continuous application of biochar could reduced soil bulk density and the ratio of solid phase,and increased soil porosity,while the effects on the soil moisture content and the ratio of liquid phase decreased with the extension of continuous cropping time.The content of soil available nutrients and organic carbon were significantly increased after applying biochar at 90 days after transplanting,as well as improve soil pH value,and the soil fertility was increased first and then decreased with the raised biochar application amounts.Continuous application of biochar could also increased the content of soil available nutrients and soil organic carbon,ease the tendency of soil to acidify and fertility decline due to prolonged continuous cropping,but its impact will be decreased year by year.2.The effects of biochar on rhizosphere microorganism were studied in this research.Result showed that the influence of biochar on rhizosphere microbial community increased with the extension of the growth period of flue-cured tobacco,and the maximum affect at 90days after transplanting,the rhizosphere microbial diversity(S and Chao value)increased under the biochar application of 3000~3750 kg/hm~2,and the microbial community relative abundance had the greatest difference between the biochar treatments and control at this time,e.g.inhibition of Actinobacteria and promotion of Planctomycetes and so on;Continuous application of biochar could affected rhizosphere microbial community structure(increasing microbial diversity,e.g.the index of Shannon,S and pielou;influencing the abundance of microbial community,e.g.Bacteroidetes,Nocardioides and so on),and the effects was increasing with the raise of year,which was more obviously in 90 days after transplanting.3.The effects of biochar on the quality of flue-cured tobacco production were studied in this research.Result showed that biochar application could significantly decreased the disease morbidity(decreased by 7.41%~8.33%)and disease-infected indexes(decreased by3.93%~4.40%)of black shank of flue-cured tobacco,and promoted the growth of flue-cured tobacco and development of root system in the earlier growing stage,coordinate the chemical compositions in tobacco leaves,and significantly affected the economic traits of flue-cured tobacco,and the economic traits of flue-cured tobacco were increased first and then decreased with the raised biochar application amounts(0~4500kg/hm~2).It was helps to alleviate the condition of black shank of flue-cured tobacco(in the three years,the disease morbidity decreased by 8.33%,3.81%,and 2.78%,respectively;the disease-infected indexes decreased by 4.40%,1.90%,and 1.39%,respectively),and promote dry matter accumulation of flue-cured tobacco,which was mainly conducive to the growth of underground parts of flue-cured tobacco that continuous application of biochar.At the same time,continuous application of biochar could also coordinate the chemical compositions in tobacco leaves,and improve the grade of tobacco leaves after baking and economic benefits.However,it also decreased with the extension of continuous cropping time that the promotion of continuous application of biochar on the quality of flue-cured tobacco production.4.The interaction of soil physical and chemical properties,rhizosphere microorganism and the quality of flue-cured tobacco production were studied in this research.Result showed that the changes of soil physical and chemical properties were closely related to rhizosphere microbial community structure after applying biochar.The interaction of rhizosphere microbial community and soil physical and chemical properties improve soil fertility after applying biochar,as well as can promote beneficial microbial(Firmicutes,Flavobacterium and so on)to enhance the anti-black shank of flue-cured tobacco,affecting the quality of flue-cured tobacco production(Acidobacteria,Gp3 and so on).The rhizosphere microbial community was mainly affected by soil organic carbon in the year after biochar application,and the rhizosphere microbial community was affected by soil pH,organic carbon and available phosphorus after continuous application of biochar,90 days after flue-cured tobacco transplanting who are the period that had maximum affected on soil physical and chemical properties and rhizosphere microbial community.5.The effects of introduction of high efficient microbial flora(the rhizosphere microbial of the treatment of application amounts of biochar at 3750 kg/hm~2 in 90 days after transplanting of the located experiment in 2017)on soil nutrient,organic carbon fractions,rhizophere microorganism and the growth of flue-cured tobacco were studied in this research by pot experiment.Result showed that the inoculation of high efficient microbial flora was beneficial to increase the contents of soil alkaline hydrolysis nitrogen and available phosphorus,the content of soil organic carbon and active organic carbon,the content of soil water-soluble organic carbon and its efficiency ratio,and carbon pool management index,and regulated the content of soil light fraction organic carbon,heavy fraction organic carbon(LFOC,HFOC)and their distribution ratio.The inoculation of high efficient microbial flora has little effect on rhizosphere microbial diversity,but could affect the relative abundance of rhizosphere microbial community,e.g.Proteobacteria,Sphingomonas and so on,which have a great influence at 80 days after transplanting,the content of soil organic carbon and light fraction organic carbon(LFOC)were closely related to rhizosphere microbial community.In summary,90 days after flue-cured tobacco transplanting who are the period that had maximum affected on soil physical and chemical properties and rhizosphere microbial community,and the beneficial effects of applying biocar on the quality of flue-cured tobacco production may be caused by the combination of soil physical and chemical properties and rhizosphere microbial community.It was closely related to the rhizosphere microbial community that the activation of soil carbon pool and fertility increased after inoculation of high efficient microbial flora,which jointly influenced and promoted the growth and development of flue-cured tobacco. |
PDF Full Text Request