NPK Ntrient Regulation Of Flue-cured Tobacco In Luzhou Tobacco-growing Regions

According to such problems as excessive fertilizer,unbalanced nutrient ratio and low utilization rate of fertilizer,two field experiments were carried out in Luzhou,Sichuan province from 2017 to 2019.In situ incubation experiment and different NPK ratio experiment were designed to study the agronomic characters,nutrient absorption and distribution of tobacco,fertilizer use efficiency and fertilizer functions and the characteristics of soil total nitrogen and organic dynamics.The results were as follows:1.The growth and agronomic characters of flue-cured tobacco were promoted with application of nitrogen,phosphorus and potassium fertilizer.The agronomic traits were promoted significally in the early growth stage with the application of nitrogen.The difference of agronomic traits between different nitrogen fertilizer treatments decreases with the growth stage,and the increase of planting years can prolong the influence of nitrogen fertilizer on the agronomic traits of flue-cured tobacco.With the increasing of nitrogen application rates,the growth,dry matter accumulation and nutrient accumulation of tobacco plants were firstly increasing and then decreasing and all indexes above reached a maximum at 90 kg/hm~2 of nitrogen application rate.Nitrogen accumulation ability of tobacco plant was strongest45 to 75 days after transplanting.The time of maximum nutrient accumulation rate was the earliest in potassium,the second in nitrogen,and the last in phosphorus.2.Compared with optimal fertilization treatment,no phosphorus application had significant effect on flue-cured tobacco agronomic traits,while no nitrogen application and no potassium application had little effect on flue-cured tobacco agronomic traits.The effects degree of nutrient NPK on dry matter accumulation were followed as P>N>K,dry matter distribution were followed as N>K>P,nitrogen content were followed as N>P>K,phosphorus content were followed as P>N>K,potassium content were followed as P>N>K.3.The results of in situ incubation experiment showed that,the application of organic fertilizers of vinasse organic fertilizer and oil cake organic fertilizer can not significantly improved soil nitrogen and organic matter content.The field trials shoed that the application of organic fertilizers of Vinasse and oil cake organic fertilizer can improved the agronomic triats,improved the absorption and distribution of nutrient of fule-cured tobacco,and improved the yield and output value of fule-cured tobacco.Compared with two organic fertilizer treatments,the effect of the organic fertilizer of Vinasse treatment on the yield and the proportion of superior and middle cured-leaf is greater than the oil cake organic fertilizer treatment.4.Treat IV has the highest nitrogen utilization efficiency,yield and output value of flue-cured tobacco,which can alleviate the adverse effects on high temperatureclimate condition.With increasing nitrogen application rate the nitrogen utilization efficiency,agronomic efficiency and the yield and output value of flue-cured tobacco was increased first and then decreased,and the partial factor productivity as decreased.The nutrient absorption as increased hile the nutrient physiological efficiency as decreased ith the increasing application rate of nitrogen.According to fertilizer effect function,the recommended fertilizer amount is N=69.5～70.5 kg/hm~2 on experimental field condition.According to nutrient restitution theory,the annual nutrient carrying capacity on experimental field condition is N=84.3～128.3kg/hm~2,P=6.3～9.2 kg/hm~2,K=143.4～172.1 kg/hm~2.Considering the climate,farmers’fertilizing precision and soil fertility status of the experimental field fertility status,the recommended low limits of nitrogen,phosphorus and potassium fertilizer nutrients in Luzhou tobacco-growing area are 82.5kg/hm~2,75kg/hm~2 and 195kg/hm~2.