Study On The Component Of Flue-cured Tobacco Yield And Optimization Of The Supply Of Nitrogen Fertilizer

This paper mainly studied the effect of reducing nitrogen rate and population rate on the agronomic characters, physical and chemical characteristics, yield and the effect of remained leaf design and reducing nitrogen fertilization on the agronomic characters, physical and chemical properties, yield and soil nutrient content, the main results are as follows:1. When the group leaf number remained 20000/667m, the treatment of high density and low remaining leaf numbers had an abvious effect on shortening field growth period.With the nitrogen to reduce in the population structure,field growth period showed gradually shorten trend. At the 75th days after transplanting, the treatment of high density and low remaining leaf numbers could reduce the plant height,improve the lighting environment, make the leaf area coefficient more appropriate. When the nitrogen application rate fixed, chlorophyll relative content in lower leaf showed the treatment of high density and low remaining leaf numbers< middle density and middle remaining leaf numbers<low density and high remaining leaf numbers, and this trend showed the most obvious under low nitrogen conditions. On the condition of 20000/667m2 group leaf number and 60kg/hm2 nitrogen application rate,the treatment of high density and low remaining leaf numbers could effectively enhance the ratio of potassium to chlorine in the middle and lower leaves. Compared with the treatment of low density and high remaining leaf number, high density and low remaining leaf number combined with 60kg/hm2 lower nitrogen application rate could significantly decrease sugar-nicotine ratio and the difference of total sugar and reducing sugar, make the ratio of total nitrogen to nicotine more close to 1, significantly increased the ratio of potassium to chlorine in the lower leaf. On the condition of 75kg/hm2 nitrogen application rate,the treatment of middle density and middle remaining leaf numbers could significantly increase the leaf length, leaf width, leaf weight, open degree and significantly reduce the leaf thickness, leaf weight, but the stem ratio had no significant difference in the middle leaf. Compared with the treatment of low density and high remaining leaf number,high density and low remaining leaf numbers enhanced output value and significantly enhanced average price, the proportion of superior leaves.2.On the condition of the same planting density,leaf length,leaf width,leaf thickness,leaf weight in different parts of leaves increased with the increase of nitrogen application rate.60kg/hm2 nitrogen application rate was beneficial to enhance the effective utilization rate in the lower leaves and the opening degree in upper and leaves. When nitrogen application rate was fixed,with the increase of planting density,the total nitrogen and nicotine content showed the tendency of first decreasing and then increasing in the lower leaves and decreased in the middle and upper leaves; Total sugar and reducing sugar content had the tendency of significantly decreasing in middle and lower leaves; the starch content showed the tendency of first decreasing and then increasing in different parts of tobacco leaves;The potassium content showed a decreasing trend in lower and upper leaves;On the condition of 60kg/hm2 nitrogen application rate and middle planting density(16433 plant/hm2),the coordination of chemical composition in different parts of tobacco leaves was the best;The effect of planting density on the proportion of medium and superior leaves, average price, yield and output value were less than that of nitrogen application rate. Overall, when the planting density was 16433 plant/hm and the nitrogen application rate was 60kg/hm2, it could obtain the highest yield and economic benefit of tobacco.