Effect Of Adding Organic Materials On Soil Characteristics,growth And Quality Of Tobacco In Wuxi County

In flue-cured tobacco production,in order to pursue high yield,tobacco growers applied a large amount of chemical fertilizer,but did not pay attention to the application of organic fertilizer,resulting in soil nutrient imbalance,microbial biomass reduction,soil enzyme activity and carbon nitrogen ratio imbalance,which seriously restricted the sustainable development of tobacco production in China.Adding organic materials is an effective measure to improve soil,increase tobacco yield and improve the quality of cured tobacco.Therefore,this experiment took Yunyan 87 as the research object and carried out field experiments for two consecutive years in 2020 and 2021 to study the effects of organic materials on soil characteristics,growth and quality of flue-cured tobacco in Wuxi County.Four treatments were set in the experiment : pure chemical fertilizer(CF),pure chemical fertilizer + mushroom residue organic fertilizer(CMO),pure chemical fertilizer +high carbon base fertilizer(CHB),pure chemical fertilizer + biological organic fertilizer(CBO),the results are as follows :(1)The soil p H increased with the addition of organic materials,and the contents of soil available potassium,available phosphorus,organic matter and humic acid increased.Organic materials could increase the Hufu ratio and the degree of soil humification.Among them,the addition of high-carbon base fertilizer had the most obvious improvement on soil available nutrients.(2)The addition of organic materials could increase the total organic carbon content in tobacco-growing soil,but there was no significant difference compared with the control.Moreover,the content of active carbon components in soil organic carbon and the carbon efficiency of each active carbon component in soil were significantly increased.The carbon efficiency and soil carbon pool management index were increased by 13.00 %–65.71 % and 5.99 %–30.80 %,respectively.(3)Soil organic carbon functional groups mainly include phenolic alcohols,aromatic hydrocarbons,olefins,and secondary amides.There was no significant difference in the relative peak area of organic carbon functional groups in each treatment.Soil total organic carbon(TOC)was negatively correlated with the relative peak area of functional groups at 1634 cm-1,and positively correlated with the relative peak area of functional groups at 694 cm-1 and 468 cm-1.Soil microbial biomass carbon(MBC)was negatively correlated with the relative peak area of functional groups at 779 cm-1and 694 cm-1,and positively correlated with the relative peak area of functional groups at 468 cm-1.Soil EOC was negatively correlated with the relative peak areas of functional groups at 694 cm-1and 468 cm-1,and positively correlated with the relative peak areas of functional groups at 1634 cm-1.Soil DOC was negatively correlated with the relative peak areas of functional groups at 1634 cm-1and 468 cm-1,and positively correlated with the relative peak areas of functional groups at 779 cm-1and 694 cm-1.(4)Adding organic materials significantly increased the content of mechanical stability and water-stable aggregates of soil > 2mm,and reduced the contribution rate of organic carbon and total nitrogen in soil aggregates of 2mm.The addition of mushroom residue organic fertilizer had the best effect on the stability of soil aggregates and the contribution rate of organic carbon and total nitrogen.(5)The activities of sucrase and urease in tobacco-planting soil 60 days after transplanting were significantly increased by adding organic materials.Soil invertase activity and urease activity increased by 8.21%-22.10% and 8.99%-21.23%,respectively.Proteobacteria,Acidobacteriota,Actinobacteriota,Chloroflexi,Firmicutes and Bacteroidota are the main bacterial phyla in the soil of each treatment.Ascomycota,Mortierellomycota,Chytridiomycota,Basidiomycota,Zoopagomycota,Glomeromycota and Olpidiomycota were the main fungal phyla in the soil of each treatment.The relative abundance of Proteobacteria decreased,and the growth and reproduction of Acidobacteriota and Chloroflexi were promoted after the addition of bio-organic fertilizer and high-carbon-based fertilizer,indicating that the addition of bio-organic fertilizer and high-carbon-based fertilizer may change the bacterial community structure in soil during carbon sequestration,thereby affecting soil carbon sequestration.(6)The addition of organic materials increased the average color change rate(AWCD)of soil,indicating that the addition of organic materials could improve the comprehensive utilization ability of carbon sources of soil microorganisms.At the same time,the addition of organic materials increased the utilization rate of carbohydrates,amino acids and polymers by microorganisms,and the addition of high-carbon base fertilizer increased the microbial functional diversity index,making the soil microbial community more uniform and the utilization ability of various carbon sources more balanced.(7)Adding organic materials can significantly increase the maximum leaf area,dry matter accumulation and root volume during the growth period of flue-cured tobacco,and increase the plant height,stem circumference and effective leaf number60 d and 90 d after transplanting,and improve the yield and output value of flue-cured tobacco.In addition,the addition of organic materials significantly increased the content of total sugar and reducing sugar in flue-cured tobacco leaves from different parts,making the chemical composition of flue-cured tobacco more coordinated and improving the quality of tobacco leaves.Overall,adding organic materials can significantly improve soil physical and chemical properties,soil carbon pool,soil microbial community structure and functional diversity,improve the stability of soil aggregates,promote the growth and development of flue-cured tobacco,and improve the quality and economic traits of cured tobacco leaves.The addition of mushroom residue organic fertilizer had the most obvious effect on soil aggregates,and high carbon-based fertilizer could better improve the structure and functional diversity of soil microbial communities.Combined with the growth and development of flue-cured tobacco and flue-cured tobacco quality and economic traits,adding high carbon base fertilizer showed the best performance.