Abstract: Two-year field experiment were carried out to study the effects of different nitrogen application, planting density, different altitudes on the yield and quality of flue-cured tobacco leaves in Lichuan tobacco area of Enshi. The results showed that the optimum amount of nitrogen application was 97.5 kg/hm² on 1 000~1 100 m altitude, and the cultivation density was 15 150~16 650 plants/hm². On 1 100~1 200 m altitude, the cultivation density was 15 150 plants/hm² with 97.5 kg/hm² nitrogen application, but the cultivation density was 16 650 plants/hm² with 112.5 kg/hm² nitrogen application. The optimum amount of nitrogen application was 97.5 kg/hm² on 1 200~1 300 m altitude, and the cultivation density was 16 650 plants/hm². The effect of nitrogen fertilizer on the yield and quality of flue-cured tobacco was the greatest, followed by density, and the interaction between them was smaller. The effect of altitude on the yield and quality of flue-cured tobacco was next to nitrogen application amount and cultivation density. In conclusion, under the condition of 1 000~1 300 m altitude in Lichuan tobacco area of Enshi, the suitable nitrogen application amount and cultivation density were 97.5 kg/hm² and 15 150~16 650 plants/hm², respectively.

Key words: leaf area, single leaf weight, partial ETA square, interaction effect