| In order to improve tobacco soil environment, reduce tobacco plant pests and diseases and enhance the yield and quality of tobacco, the crop rotation in flue-cured tobacco and perilla, sesame, castor, fennel, the intercropping in flue-cured tobacco and soybean, crowndaisy chrysanthemum were used to dynamic investigation of KRK26varieties of black shank and root control of black rot. This research may be as scientific reference and lay a foundation for the construction of the modern tobacco agriculture. Its main findings are as follows:1. It was found that the crop rotation and intercropping almost have no influence on tobacco growing period through investigation records. However, no matter the crop rotation or intercropping could raise tobacco plant height, stem girth, leaf area, and promote its growth than continuous cropping. For example, tobacco plants which growing in the continuous cropping field were worse than the crop rotation and intercropping, whose average plant height was40%higher than continuous cropping. The date of stem girth has similar regularity too.2. Rotation has certain inhibitory action on tobacco black shank disease rate and the occurrence of disease index, perilla rotation which the fist two flue-cured tobacco black shank disease rate and disease index survey data were lower than the contrast, however, the third survey was significantly higher than that of the control, which was not obvious to black rot inhibition, with sesame seed, castor, anise crop rotation, black shank disease incidence and disease index were decreased compared with the contrast, fall in the range of0.1%-73.2%,and the effect on tobacco black root rot disease is the same as black shank。Rotation of different crops on tobacco virus disease, etch disease, tobacco budworm, Spodoptera litura and other pests have different effects, but part of the crop rotation also increased pest occurance rate, such as processing of Spodoptera litura, what the first findings of perilla rotation and the third surveys of fennel rotation, is higher than that of the control, sesame rotation compared with the control treatment can make the probability of occurrence of elevated tobacco aphid.3. The intercropping in flue-cured tobacco and soybean, crowndaisy chrysanthemum were conducive reduce black shank disease severity, significantly reduced root black rot incidence and disease index on KRK26and significantly difference compared with CK. In three investigates, soybean intercropping incidence of viral disease was better than CK, crowndaisy chrysanthemum intercropping in contrast. Intercropping might be sicker in sooty mold, especially soybean, increase the tobacco etch virus incidence probability or postpone time incidence at the end of growth period. Tobacco budworm incidence probability was higher in Soybean intercropping, while lower in crowndaisy chrysanthemum compared with CK. Both of them could reduce Spodoptera litura incidence to KRK26, and crowndaisy chrysanthemum was better. However, the incidence of tobacco aphid was extremely worse in intercropping, that might related with its source of infection that intercropping plant carried.4. In the aspect of KRK26production and output value,4crop rotation treatments yield, output value and proportion of superior tobacco were all higher than CK. The increase in production in the range of17.7%to34.4%(output value18.8%-51.8%; proportion of superior tobacco13.7%-22.3%); The three indexes in intercropping treatment also improved varying degrees:yield was30.4%and1.46%, output value was39.8%and23.5%, proportion of superior tobacco20.4%and11.4%. Both crop rotation and intercropping could significantly increase the income of farmers, obtain better economic. For example, castor rotation system than the control treatment income of24,141Yuan/hm2, added465.41%; Soybean intercropping system than the control treatment income of22670Yuan/hm2, added314.12%(crowndaisy chrysanthemum20958Yuan/hm2,290.40%).5. Rotation processing had greater impact on tobacco intrinsic chemical content, such as increase the nicotine, K and total nitrogen content, reduce the total sugar and reducing sugars, decrease the absorption of chlorine, improve the combustion property of tobacco leaf and security. For instance, the crop rotation in flue-cured tobacco and perilla could effectively improve the absorption of potassium, reduce the chlorine content and help to improve the quality of tobacco leaves; crop rotation in flue-cured tobacco and sesame could enhance nicotine content, decrease reducing sugars compared with CK. The upper leaves increased total sugar content, total nitrogen content decreased, while middle and lower leaves were contrast. Then improve tobacco leaves intrinsic quality. Intercropping could increase total nitrogen and nicotine content, reduce the content of total sugar and reducing sugars, and enhance K content, cut down the content of chlorine simultaneously. Of course, it also improved tobacco leaves intrinsic quality. |
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