Effects Of Different Planting Patterns On Soil Physi-chemical Properties,yield And Quality Of Nicotiana Tabacum L.

In order to explore the effect and mechanism of Intercropping of flue-cured tobacco and different crops on the growth and development of flue-cured tobacco.In this study,with Nicotiana tabacum K326,Tuber pattern,Gingerand Pinelliatenatachosen as the test material,agronomic trait,chemical component,aroma substances,economic properties,soil physical and chemical properties as well as microbial diversity under intercropping of flue-cured tobaccoconditions were studied,aiming to provide a theoretical basis for solving the continuous cropping obstacles of flue-cured tobacco in the future.The main results are as follows.(1)Relay-intercropping of tobacco with tuber pattempromoted the growth of flue-cured tobacco.Compared to tobacco monoculture,relay-intercropping of tobacco with tuber pattern significantly increased the plant height,maximum leaf area and stem girth of flue-cured tobacco.All intercropping treatments significantly increased the ratio of sugar to alkali in the middle leaves of flue-cured tobacco,the total amount of neutral aroma substances and soil fertility,and reduced the nicotine content.The results showed that the agronomic traits,total aroma compounds and soil fertility of T3 were higher than those of other treatments,and T3 had the best effect on alleviating continuous cropping obstacles.(2)Compared with monocropping,flue-cured tobacco intercropping with ginger significantly increased the maximum leaf area,leaf orientation value,net photosynthetic rate,SPAD value in the late growth stage,the contents of total sugar,reducing sugar,potassium in the leaves of flue-cured tobacco and the contents of aroma substances such as neophytadiene and carotene degradation products,and it significantly reduced the occurrence of brown spot disease and chlorine content.Flue-cured tobacco intercropping with ginger also increased the contents of alkali hydrolyzable nitrogen,available potassium,organic matter,the number of OTUs in soil microbial community and the soil fertility and microbial diversity of rhizosphere soil and non rhizosphere soil.Flue-cured tobacco intercropping with ginger improved the comprehensive economic benefit by increasing the first-class tobacco proportion,average price and output value of superior tobacco.The results showed that the content of total sugar,potassium,soluble sugar and aroma substances in the upper and middle leaves of flue-cured tobacco were increased,chemical components such as chlorine content were decreased,and brown spot disease were prevented and controlled of ginger/flue-cured tobacco 1:2 intercropping mode has the best effect than those of other treatments.Ginger/flue-cured tobacco 1:3 intercropping mode has the best effect,in promoting net photosynthetic rate and leaf orientation value of flue-cured tobacco.And ginger/flue-cured tobacco 1:4 intercropping mode can promote the growth of flue-cured tobacco.The results showed that,ginger/flue-cured tobacco 1:3 intercropping mode has the most significant promotion of comprehensive benefit.(3)Compared with monocropping,flue-cured tobacco intercropping with pinellia ternata significantly increased plant height,maximum leaf area,stem leaf angle,leaf orientation and net photosynthetic rate,SPAD value in late growth stage,the contents of total sugar,reducing sugar and potassium in upper and middle leaves,the chemical composition of leaves of flue-cured tobacco Coordination;content of neophytadiene and carotene degradation products,and reduced the occurrence of brown spot disease and chlorine content.What’s more,the contents of alkali hydrolyzable nitrogen,available potassium,organic matter and OTUs of soil microbial community were increased,and the soil fertility and microbial diversity of tobacco rhizosphere soil and non rhizosphere soil were improved.Pinellia ternata/flue-cured tobacco 1:2 intercropping mode increased the content of total sugar,potassium and soluble sugar in upper and middle leaves,and decreased the content of chlorine and other chemical components,and had the best effect on controlling brown spot disease;intercropping of Pinellia ternata/flue-cured tobacco 1:4 intercropping mode increased the content of aroma substances,and promoted the net photosynthetic rate and leaf orientation of flue-cured tobacco;and intercropping of Pinellia ternata/flue-cured tobacco 1:4 intercropping mode had the best effect on promoting the growth of flue-cured tobacco.In a word,intercropping practice improved the yield and quality of flue-cured tobacco by the aspects of improving soil fertility,improving the agronomic traits,chemical components,aroma substances,etc.In addition,relay-intercropping of tobacco with tuber pattern-straw returned and 3:1 flue-cured tobacco intercropping with ginger were conducive to solve the obstacles of continuous cropping of flue-cured tobacco and improve the comprehensive level of flue-cured tobacco.Although flue-cured tobacco intercropping with pinellia ternata improved the quality of flue-cured tobacco from all aspects,the improvement of economic benefit was not obvious because of the high management cost of pinellia ternata.