Studies On Regulated Technology Of Nitrogen For Flue-cured Tobacco In Qianxinan,Guizhou Province,China

Qianxinan Prefecture is one of the most important tobacco producing areas of high-quality tobacco production area in Guizhou Province,where tobacco leaves have more distinctive fragrance style.A series of field experiments were carried out.Frist,research analysised relationship between nitrogen mineralization in soil and nitrogen nutrition of flue-cured tobacco by experiments of field soil in-situ culture.Secondly,combined upper result,paper discussed nitrogen absorption and distribution in flue-cured tobacco plants by 15 N tracer method.Thirdly,in order to determine the optimal dosage of traditional fertilization and nitrogen in tobacco planting,researcher compared effects of different nitrogen treatment on yield and quality of flue-cured tobacco.Fourthly,comparing water soluble fertilizer and traditional fertilization in flue-cured tobacco production to study water soluble fertilizer with fertilizer application ratio and the effect on yield and quality of flue-cured tobacco.The main studies are as follows:Inorganic nitrogen content of free soil during the growth period showed a fluctuation trend.As inorganic nitrogen absorbed by flue-cured tobacco,planting tobacco soil inorganic nitrogen content during the growth period is lower than free soil after planting.Applying fertilizer can increase the inorganic nitrogen content in the soil in a short period of time.Mineralization accumulation increased along with time,and gradually come to a standstill from 90 days after transplanting.Marking the main source of nitrogen accumulation inside flue-cured tobacco plants clearly by15 N tracer technique.To judge nitrogen source effect on the flue-cured tobacco nitrogen accumulation by 15 N accumulation.All organs of the proportion of fertilizer nitrogen drops rapidly.During growth period,fertilizer nitrogen accumulation quantity of 20.95-46.81% of the total nitrogen accumulation and mature period was 20.95%.At the same time the proportion of fertilizer nitrogen to total nitrogen decrease with stalk position up.Furthermore,the proportion of fertilizer nitrogen of three stalk position and rootstock to total nitrogen decreased with the growing of plants significantly after topping.It showed the proportion of soil nitrogen to total nitrogen increased with the growing of plants significantly.The proportion of fertilizer nitrogen in different parts in the form of lower leaves > middle leaves > root > stem >upper leaf,and the proportion of soil nitrogen showed upper leaves> stem > root > middle leaves > lower leaves.Yield and economic character of flue-cured tobacco showed “increased at first and then decreased” with the increasing of nitrogen fertilizer rate in different fertility tobacco planting soil.The indexes occurred the maximum in the treatment of 90kg/ha.Therefore,we suggested the best nitrogen fertilizer rate for tobacco planting soil with medium low fertility is 90kg/ha,for medium high tobacco planting soil is about 67.5kg/ha according to flue-cured tobacco nutrient status of different fertility levels planting tobacco soil during tobacco planting.As water soluble fertilizer ratio of top dressing increased from 30% to 70%,flue-cured tobacco plant height,leaf area and largest accumulation of nutrient absorption,tobacco economic characters,leaves chemical composition evaluation scores were present at the beginning of the change tendency of “increased at first and then decreased”.When ratio reached 50%,flue-cured tobacco growing best,nutrient uptake most,tobacco economic traits optimal,and evaluation score of chemical composition about the upper leaves highest.In conclusion,the usability of upper leaves have improved significantly by application of water soluble fertilizer.