Effects Of Different Material Treatments On Soil Environment And Tobacco Leaf Quality Of Continuous Cropping Tobacco Planting

Tobacco continuous cropping obstacle is an important factor restricting the improvement of tobacco leaf yield and quality in agricultural production.The application of exogenous materials can improve soil nutritional status and microhabitat,which is an effective measure to improve tobacco leaf yield and quality.Therefore,in order to explore the alleviation effect of chitosan oligosaccharide,vermicompost and high-carbon-based organic fertilizer addition on the continuous cropping obstacle of flue-cured tobacco,five treatments were set up in this study,CK: control;T1: application of chitosan oligosaccharide;T2: application of vermicompost;T3: application of high-carbon-based organic fertilizer;T4: application of chitosan oligosaccharide + vermicompost + high-carbon-based organic fertilizer.The effects of different material treatments on soil chemical nutrients,growth and development of flue-cured tobacco,quality and economic characters of flue-cured tobacco leaves were studied.The main conclusions of the paper are as follows:1.The effects of different material treatments on tobacco planting soil nutrients,microorganisms and enzyme activities were studied.T2,T3 and T4 treatments all effectively increased the content of tobacco planting soil organic matter,alkali-hydrolyzed nitrogen,available phosphorus and available potassium,and T4 relatively high processing.In terms of soil microbial and enzymatic activity indexes of tobacco planting,the number of bacteria,fungi and actinomycetes in tobacco planting soil under the combined application of different materials,namely T4 treatment,was relatively higher,and all were significantly higher than those of T1,T2 and T3 single application treatments.The application of different materials increased the soil enzyme activity of tobacco planting to different degrees,and there were significant differences compared with the control treatment.Moreover,under the combined application treatment,the activities of invertase,urease and phosphatase in the tobacco planting soil were significantly higher than those in the single application of soil improvement materials.2.The analysis of growth indexes of flue-cured tobacco under different material treatments showed that flue-cured tobacco had higher growth indexes under T4 treatment.Compared with the single application,the combined application of chitosan oligosaccharide,vermicompost and high-carbon-based organic fertilizer had a more significant effect on the growth and development of flue-cured tobacco under continuous cropping conditions.Volume and leaf dry weight were significantly higher than those in T1 and T2 treatments.The root dry weight and total dry weight of tobacco plants in T4 treatment were significantly higher than those in T1 treatment,with an increase of 7.99% and 8.36%,respectively.The combined application of chitosan oligosaccharide,vermicompost and high carbon-based organic fertilizer has a good effect on improving the chlorophyll content of flue-cured tobacco leaves,and tobacco leaves have higher photosynthesis efficiency.Specifically,the net photosynthetic rate,stomatal conductance and transpiration rate of tobacco leaves in T4 treatment were higher than those in T1,T2 and T3 treatments,while the intercellular CO2 concentration in leaves was relatively lower.3.The research on the intrinsic quality indicators of cured tobacco leaves under different treatments showed that the combined application of chitosan oligosaccharide,vermicompost and high-carbon-based organic fertilizer had more significant effects on improving the physical properties of cured tobacco leaves,and the T4 treatment had more significant effects on cured tobacco leaves.The leaf length,leaf width,single leaf weight,pulling force and filling values were relatively high,while the stalk content rate was low.The contents of reducing sugar,total sugar and potassium in tobacco leaves after application of different materials increased to different degrees,while the contents of nicotine,total nitrogen and chlorine decreased to different degrees.The coordination indexes of chemical components such as sugar-alkali ratio,nitrogen-alkali ratio and potassium-chloride ratio of cured tobacco leaves were relatively high under T4 treatment.Especially in the indicators of sugar-base ratio and potassium-chloride ratio,T4 treatment was significantly higher than T1 and T2 treatments,in which the increase of sugar-base ratio was 21.63% and 15.48%,and the increase of potassium-chloride ratio was 12.03% and 9.63%,respectively.On the total amount of neutral aroma substances in cured tobacco leaves,the T4 treatment showed a relatively high performance.Economic shape indicators such as yield,average price and output value of flue-cured tobacco leaves under T4 treatment were relatively high,especially in terms of output value,T4 treatment was significantly higher than T1,T2 and T3 treatments.In conclusion,the combined application of chitosan oligosaccharide,vermicompost and high-carbon-based organic fertilizer can play a synergistic effect,improve the soil nutrients and micro-ecological environment of tobacco planting under continuous cropping conditions,and then promote the growth and development and dry matter accumulation of tobacco plants.Moreover,the combined application treatment improves the physical properties and chemical quality of the cured tobacco leaves,and increases the yield and economic benefits of the cured tobacco leaves.