Effects Of Nitrogen Fertilizer Dosage On Yield And Quality Of Cigar Tobacco

Cigar is an important component of the modern tobacco industry chain.At present,the development of cigar in China has many problems,such as high dependence of tobacco leaf raw materials on foreign countries,insufficient supply of high-end products,and difficulty in integrating into the international market.In particular,the low quality level of cigar leaf raw materials（cigar wrapper and filler）produced restricts the development of the cigar industry.Nitrogen is one of the three essential fertilizers for tobacco growth.Applying nitrogen can significantly improve the photosynthetic efficiency of tobacco leaves and promote the growth of tobacco plants;It is beneficial to improve the physical characteristics of leaves,coordinate chemical components,and enhance the taste sensation.The production of cigar tobacco in China is still in its infancy,and it is important to determine the appropriate nitrogen fertilizer rates for the wrapper and filler to increase tobacco yield and improve tobacco quality.Using the wrapper variety Chuxue 26（CX-26）and filler variety Chuxue 14（CX-14）as materials,field trial were conducted to study the effects of different nitrogen rates on the growth,yield,value,nutrient uptakes,and quality of CX-26 and CX-14,with a view to providing a theoretical basis for the scientific application of nitrogen fertilizer to cigar tobacco.The main research results are as follows:（1）Moderate application of nitrogen fertilizer can significantly improve the yield,value,nitrogen uptake,and appearance quality of CX-26 tobacco.Compared with the treatment without nitrogen application（N₀）,the yield of tobacco leaves increased by384.4 kg/hm²to 865.2 kg/hm²,with an increase of 22.2%to 50.0%;The value increased by 60300 yuan/hm²to 153200 yuan/hm²,with a growth rate of 61.1%to 155.8%.The yield and value both have a linear platform relationship with nitrogen application,with platform yield and value of 2512.7 kg/hm²and 251800 yuan/hm²,respectively.As the amount of nitrogen fertilizer increased,the aboveground nitrogen accumulation gradually increased.Compared with the N₀treatment,the nitrogen accumulation increased by 36.6kg/hm²to 70.2 kg/hm²,with an increase of 77.7%to 148.3%.The results of leaf physical characteristics showed that compared with the N₀treatment,the peak single leaf weight and tensile strength of each nitrogen application treatment increased by 32.3%～69.1%and 2.0%～24.2%,respectively;The specific leaf weight and stem content decreased by6.6%～11.2%and 11.5%～22.8%,respectively.The yield and yield of wrapper increased by 160.8 kg/hm²to 528.7 kg/hm²and 6.8%to 20.0%,respectively.（2）Moderate application of nitrogen fertilizer can significantly increase the yield,value,and nitrogen accumulation of CX-14,and improve its chemical composition.Compared with the N₀treatment,the tobacco yield of each nitrogen application treatment increased by 299.4 kg/hm²to 554.5 kg/hm²,with an increase of 16.7%to 30.9%;The value increased by 27400 yuan/hm²to 46900 yuan/hm²,with a growth rate of 43.2%to73.9%.The yield and value both exhibit a quadratic curve function relationship with nitrogen application,with the highest yield and output value reaching 2276.6 kg/hm²and110400 yuan/hm²,respectively.As the amount of nitrogen fertilizer increased,the aboveground nitrogen accumulation gradually increased.Compared with the N₀treatment,the nitrogen accumulation increased by 20.3 kg/hm²to 45.9 kg/hm²,with an increase of43.5%to 98.2%.The results of leaf chemical composition showed that compared with the N₀treatment,the nicotine content,potassium chloride ratio,and nitrogen alkali ratio of each nitrogen application treatment increased by 10.4%to 20.4%,27.0%to 159.6%,and3.6%to 16.1%,respectively,while the chlorine content and sugar alkali ratio decreased by 14.1%to 51.6%and 32.4%to 69.6%,respectively.In summary,nitrogen application significantly affects the yield,nutrient uptake,and quality of cigar tobacco leaves CX-26 and CX-14.Based on indicators such as value,wrapper rate,peak tensile force,and stem content,the suitable nitrogen fertilizer dosage for wrapper variety CX-26 under experimental conditions was determined to be 165kg/hm²～180 kg/hm²;Based on indicators such as value,nicotine content,sugar alkali ratio,and potassium chloride ratio,the suitable nitrogen fertilizer dosage for filler variety CX-14 is 210 kg/hm²～230 kg/hm².