Abstract:
To optimize tobacco leaf structure and to determine appropriate nitrogen fertilization rate and number of residual leaves for flue-cured tobacco planted in high altitude areas, field experiments were conducted on cv. Yunyan 87 to study the effects on grade proportion, stalk position proportion, yield and quality of flue-cured tobacco in Yanyuan County (altitude of 2 350 m above sea level), Sichuan Province. The results showed that under the treatment of nitrogen fertilization at 90.0 kg/ha and residual 16 leaves per plant, the proportion of middle leaves was the highest, those of high grade and mid-high grade leaves were higher. The average price of leaves was the highest, the yield of leaves was moderate, the output value was higher. The sensory quality of middle leaves were the best, with the upper leaves also achieving better sensory quality. The appearance quality and chemical composition harmony of flue-cured tobacco were also improved. Taking leaf grade, stalk position, economic traits, chemical composition, appearance and sensory quality of tobacco leaves into account, nitrogen fertilizing at 90.0 kg/ha and residual 16 leaves per plant were considered appropriate at the planting density of 20 800 plants/ha in soils with moderate fertility in Yanyuan.