Effect Of Vermicompost On Tobacco Planting Soil And Root Characteristics And Leaves Quality Of Flue-Cured Tobacco

Flue-cured tobacco is an important cash crop in China,which plays an important role in improving national tax revenue as well as helping in poverty alleviation.In recent years,the quality of flue-cured tobacco leaves is not up to the mark for tobacco companies.Qualitity of tobacco is mainly affected by imbalance in nutrient supply to plants which is mainly associated with excessive use of fertilizer that cause soil acidification,soil compaction and decrease in biological activity.Therefore,balanced fertilizer,such as use of application of biological organic fertilizer,has become one of the effective ways to improve the quality of tobacco leaves.Vermicompost,as an excellent biological organic fertilizer with excellent physical and chemical properties,high microbial activity and similar plant hormone effect,has a significant effect on promoting the growth of flue-cured tobacco and improving the quality of tobacco leaves.However,there are few studies on how vermicompost can improve the quality of tobacco leaves.Therefore,the effects of vermicompost on soil physical,chemical and biological characteristics,root growth and physiological characteristics of flue-cured tobacco were studied by pot experiment.The treatments were CK(0%vermicompost),T1(5%vermicompost),T2(10%vermicompost).T3(20%vermicompost),T 4(50%vermicompost),T5(100%vermicompost);At the same time,the effects of earthworm dung on the quality of flue-cured tobacco leaves were further studied by field experiment.The treatments were CK(no vermicompost),T1(1800 kg·hm~-22 vermicompost),T2(2400 kg·hm~-22 vermicompost),respectively.T3(3000 kg·hm~-22 vermicompost),T 4(3600 kg·hm~-22 vermicompost),in order to provide theoretical basis and technical measures for rational application of organic fertilizer for flue-cured tobacco,the main research results are as follows:1.Vermicompost increased cation exchange capacity,organic matter content and available nitrogen content in tobacco planting soil.The contents of microbial biomass carbon and microbial biomass nitrogen in soil and the content of ballomycin related proteins in soil were increased.The content of soil cation exchange,organic matter,microbial biomass carbon and microbial biomass nitrogen,and Glomalin-related soil protein(GRSP)were the highest in T5(100%vermicompost)treatment.2.Principal components 1 and 2 were extracted from the soil indexes determined in this study by principal component analysis(PCA).The order of contribution of each index to principal components was microbial biomass nitrogen content and microbial biomass carbon content in turn.Organic matter content,T-GRSP content,EE-GRSP content,cation exchange capacity,available nitrogen content.3.Compared with the control,the root length,fresh weight and volume of flue-cured tobacco plants treated with vermicompost increased,and with the increase of the proportion of vermicompost,the root length,fresh weight and volume of tobacco plants increased gradually.With the increase of the proportion of vermicompost in soil,the nicotine accumulation in flue-cured tobacco roots increased at first and then decreased,and the change trend of flue-cured tobacco root activity was consistent,but the soluble sugar content in flue-cured tobacco roots increased gradually and then tended to be stable.Under the treatment of T3(20%vermicompost),the nicotine accumulation and root activity of flue-cured tobacco roots reached the highest.4.The application of vermicompost in tobacco field could improve the chemical coordination and sensory quality of flue-cured tobacco leaves,among which T2(2400kg·hm~-22 vermicompost)and T3(3000kg·hm~-22 vermicompost)had the highest score of chemical composition coordination.The sensory quality score of flue-cured tobacco leaves treated with T3(3000kg·hm~-22 vermicompost)was the highest.Through the comprehensive analysis of the effect of earthworm dung on the quality of flue-cured tobacco leaves,3000kg·hm~-22 earthworm dung treatment(T3)can significantly improve the coordination of chemical components of tobacco leaves,improve sensory quality,and is the best treatment.In this study,it was found that vermicompost could improve the physical,chemical and biological characteristics of soil,promote the growth of flue-cured tobacco roots and synthesizing auxin.The application of vermicompost in tobacco field could improve the coordination of chemical composition and sensory quality of flue-cured tobacco leaves,and significantly increase the total amount of aroma substances in tobacco leaves(except neophytadiene).At the same time,the mechanism of improving the coordination of chemical composition and sensory quality of tobacco leaves by vermicompost was preliminarily explored,which provided certain theoretical basis and technical support for improving soil quality and industrial availability of tobacco leaves in southern Shaanxi tobacco area.