Abstract:

To reduce the stem ratio and improve the industrial value of tobacco leaves, taking ‘Yunyan 105’ as the experimental material, the orthogonal test design was used to study the effects of four factors, including pure nitrogen amount, plant spacing, topping time and number of leaves remained, on the stem ratio of tobacco leaves, and to analyze the relationship between soil nutrients and stem ratio. The results showed that the optimal scheme to reduce the stem ratio of tobacco leaves was 82.5 kg/hm² of pure nitrogen application, 55 cm of plant spacing, topping at bud emergence and 22 leaves remained. The primary and secondary order of the influencing factors was topping time> plant spacing > pure nitrogen application amount > number of leaves remained, and the weight of topping time, which was the primary factor, was 0.6219. Soil pH and total soil phosphorus content were significantly correlated with tobacco stem ratio, and the regression equation was Y=-130.839+18.486X₄+22.112X₁ (X₄ was total phosphorus content, and X₁ was pH value). The optimal scheme of cultivation factors can effectively reduce the stem ratio of ‘Yunyan 105’, and soil total phosphorus content and pH value have significant effects on the stem ratio of ‘Yunyan 105’.

Key words: tobacco leaves, ‘Yunyan 105’, stem ratio, cultivation factors, orthogonal test, soil nutrient