Effects Of Flue-cured Tobacco Rotating With C.violaceum And Intercropping With S.ningpoensis

Tobacco,C hinese herbal medicine Scrophularia ningpoensis and C huanminshen violaceum all have continuous cropping obstacles.There exists tobacco-herbal intercropping or rotation pattern in southwest china.But there have been relatively few studies on ecological mechanism of intercropping tobacco with chinese herbal medicine S.ningpoensis and C.violaceum.In order to study the ecological mechanism that exists in the process of intercropping or rotation tobacco with C hinese herbal medicine,this study regarded flue-cured tobacco,chinese herbal medicine Scrophularia ningpoensis and C huanminshen violaceum as the research object,exploring the influence of S.ningpoensis and C.violaceum leaf-stem litter water aqueous extracts on tobacco germination characteristics,and allelopathic effects of three plants leaf-stem litter water aqueous extracts on the physiological and biochemical effects of tobacco seedling.What's more,this study probes the filed experiment flue-cured tobacco rotating with C.violaceum and intercropping with S.ningpoensis.Soil moisture content,infiltration property,physical and chemical properties,yield and output value were used to evaluate the effects of flue-cured tobacco rotating with C.violaceum and intercropping with S.ningpoensis.The main results are as follows:1)The LEC(leaf-stem litter water aqueous extracts of C.violaceum,LEC)exerted positive promotion effects on tobacco germination characteristics under all concentrations.So,C.violaceum may be an alternative rotation or intercropping plant for tobacco.The LES(leaf-stem litter water aqueous extracts of S.ningpoensis,LES)had double concentration effect on tobacco germination characteristics,the content of chlorophyll a,chlorophyll b,carotenoid.The highest concentration(0.10 mg/L)showed inhibitory,while the lowest concentration(0.01~0.05 mg/L)showed stimulating effects.According to the S.ningpoensis yield of 1500 kg estimates,even if the S.ningpoensis stems and leaves completely back to t he field,the soil contention only reach to 1%(0.01 mg/L),S.ningpoensis-tobacco intercropping or rotation pattern in the field experiment may also be beneficial to tobacco;2)The aqueous extract of Scrophularia ningpoensis(LESH)showed double concentration effect,the highest concentration(0.10 mg/L)showed inhibitory effects,while the lowest concentration(0.01 mg/L showed stimulating effects.The aqueous extracts of C.violaceum(LEC)showed positive promotion effects.And under the aqueous extracts of S.ningpoensis(LES)and C.violaceum(LEC),SOD,POD,C AT activity were increased with increasing concentration of the extracts.And the indexes,soluble protein,the initial fluorescence(F0),the maximum enhancedfluorescence(Fm),variable fluorescence(Fv),PS? potential vitality(Fv/F0),PS? maximum photochemical efficiency(Fv/Fm)also showed better adaptability;3)In the field experiment of C.violaceum and tobacco rotation pattern,the tobacco growth state of three kinds of roation pattern(C.violaceum-tobacco,pea-tobacco and broad bean-tobacco)was better than that of winter leisure-tobacco pattern.There were no significant differences between the tobacco-bean rotation pattern(pea-tobacco and broad bean-tobacco)and tobacco-herbal rotation pattern(C.violaceum-tobacco).From the economic benefit index,the annual benefit of three roation patterns are higer,especially C.violaceum-tobacco,reaching to 10065.6 yuan/mu,2.1,2.4,4.0 times respectively than pea-tobacco,broad bean-tobacco,winter leisure-tobacco pattern.Therefore,flue-cured tobacco rotating with C.violaceum pattern is worthy of promotion.In the light of cropping pattern and the growth period of soil nutrient changes,the rotation pattern should be balanced application of nitrogen fertilizer and phosphate fertilizer in two seasons,avoiding excessive nitrogen fertilizer in tobacco season and it is better application phosphate fertilize in the winter;Under the conditions of potassium fertilizer in the tobacco season,winter should avoid re-application potassium;4)In the field experiment of S.ningpoensis and tobacco intercropping pattern,the narrow-line tobacco-S.ningpoensis intercropping was significantly lower than that of the monoculture tobacco and wide rows tobacco-S.ningpoensis intercropping due to the adverse effects of shading.Monoculture tobacco and wide rows tobacco-S.ningpoensis intercropping pattern had the biggest annual output value per unit area and the annualized benefit,followed by the monoculture S.ningpoensis pattern.The annualized output value and the annualized benefit of narrow-line intercropping are only 72.5% and 74.4% of monoculture tobacco pattern.However,compared with the continuous cropping tobacco(the previous crop tobacco,the output value of 3623 yuan / mu,the benefits of 2523 yuan / mu),the annualized output of another four pattern,monoculture tobacco(for the previous crop corn),wide rows tobacco-S.ningpoensis intercropping,monoculture S.ningpoensis,narrow line intercropping,were 36.2%,17.3%,2.7% and-1.2% higher than continuous cropping tobacco respectively.while the annualized benefits were 52.0%,39.7%,33.6% and 13.1% higer than continuous cropping tobacco respectively.Next year,if the monoculture tobacco and monoculture S.ningpoensis pattern change to rotation pattern,annual output and benefits are 19.5% and 42.8% higher than those of continuous cropping tobacco respectively,Therefore,it can be used " intercropping during the year,rotation next year" to avoid continuous cropping obstacle.In the light of intercropping mode and the change of soil nutrient during the growing period of tobacco,the nitrogen,phosphorus and potassium fertilizers were balanced in monoculture tobacco pattern,so the fertilization was reasonable.Planting S.ningpoensis should be an early application to nitrogen and phosphorus fertilizer and re-application potassium.5)The four kinds of planting patterns(tobacco rotating with C.violaceum,tobacco intercropping with S.ningpoensis,monoculture tobacco,monoculture S.ningpoensis)had significant effects on soil natural water content,non-capillary porosity and total porosity.The natural water content and capillary porosity of the soil can be significantly improved by monoculture S.ningpoensis.The soil non-capillary porosity can significantly improved by tobacco rotating with C.violaceum.The three kinds of planting patterns(tobacco rotating with C.violaceum,tobacco intercropping with S.ningpoensis,monoculture S.ningpoensis)can increase the soil infiltration water and soil infiltration rate in different degrees.The soil total amount of permeated water in different cropping patterns can be fitted with a univariate quadratic equation.The infiltration process of different planting patterns is well fitted by Kostiakov model.6)According to the germination,seedling growth and field test results of tobacco rotating with C.violaceum,tobacco intercropping with S.ningpoensis,had no adverse effect on the physiological and biochemical indexes of flue-cured tobacco,and it improved the physical and chemical properties of the soil.S.ningpoensis and C.violaceum can be an alternative crops for tobacco intercropping and ro tation pattern.And intercropping and rotation pattern may help ease the flue-cured tobacco and C hinese herbal medicine continuous cropping obstacles.