Effects of Nitrogen Application Rate and Planting Density on Plant Type and Leaf Quality of Yunyan 87 Tobacco

Fang Zhaoyang; Qian Jiancai; Lu Jun; Wang Yuan; Zhao Ruihan; Wang Hang; Huang Wuxing

doi:10.14083/j.issn.1001-4942.2026.01.014

Abstract：In order to investigate the regulatory effects of nitrogen application rate and planting density and their interaction on plant type and tobacco quality of Yunyan 87,and clarify its reasonable plant type and appropriate nitrogen application rate and planting density in Lingbao tobacco area of Sanmenxia,a two-factor randomized block design was adopted to study the effects of nitrogen application rate and planting density on plant type,appearance quality,sensory quality,conventional chemical composition and coordination,and the post-roasted tobacco quality of Yunyan 87 was comprehensively evaluated.The results showed that the plant height,effective leaf number,and stem-leaf pinch angle,stem-leaf droop angle,leaf length,leaf width and leaf area of the middle and lower leaves of Yunmu 87 increased with the increase of nitrogen application rate,while the stem girth and leaf shape parameters of upper leaves firstly increased and then decreased.The plant height,stem girth,effective leaf number,and leaf shape parameters of upper,middle and lower leaves de-creased overall with the increase of planting density,but the leaf shape parameters of upper leaves increased with the increase of planting density under high nitrogen condition.With the increase of nitrogen application rate and the decrease of planting density,the total score of appearance quality and sensory quality of the roast-ed tobacco leaves increased first and then decreased,the nicotine content and total nitrogen content increased,the potassium-chlorine ratio and nitrogen-alkali ratio increased,and the content of reducing sugar,total sugar and chlorine decreased,and the sugar-alkali ratio decreased.But the total score of appearance quality under the condition of high nitrogen increased with the increase of planting density.In summary,the reasonable plant type of Yunyun 87 was longcylindrical,and the most suitable nitrogen application rate and planting density in Lingbao tobacco area of Sanmenxia were 82.50 kg/hm2 and 15 000 plants per hectare,respectively.