关键词: 烤烟, 密度, 留叶数, 减量施氮, 经济性状, 物理指标, 化学成分

Abstract: A field experiment was conducted to study the effects planting density, leaf number and reducing nitrogen on flue-cured tobacco economic characters, physical characteristics and chemical composition. The results showed that applying nitrogen fertilizer at 60 kg/hm2 under high density and low leaf number could increase the output value (013%) by a small margin, but significantly improve the proportion of superior tobacco (11.62%) and the average price (2.38 yuan/kg). In medium density and medium leaf number applying 75 kg/hm2 nitrogen fertilizer could significantly increase the leaf length, leaf width, leaf open degree, and single leaf weight, while there was no significant change in stem ratio. Under high density and low leaf number, applying 60 kg/hm2 nitrogen fertilizer could make no remarkable differences between leaf length, width and open degree and low density and high leave number, but the stem ratio was significantly lower than that of low density and high leaf number. Therefore, the physical properties of both treatments were superior to that of low density and high leaf number treatment. Under these 3 production structures, reducing nitrogen fertilizer application by 15 kg/hm2 could significantly improve chemical components coordination. Under high density (19 500 plants/hm2）and low leaf number(15 piece/plant) applying 60 kg/hm2 nitrogen fertilizer could improve the comprehensive score by 4.59. Therefore, in high nitrogen soil, increasing planting density, reducing leaf number per plant coordinately with reducing nitrogen fertilizer could increase tobacco production value, fine tobacco ratio and average price, and also improve the coordination of tobacco chemical composition. These results have provided new idea for the optimization of flue-cured tobacco grade structure.

Key words: flue cured tobacco, density, leaf number, reducing nitrogen application, economic character, physical index, chemical components