Abstract:

To determine the appropriate magnesium (Mg) input in Fujian flue-cured tobacco production, a gradient Mg input experiment was conducted in a field experimental station. The soil Mg supply, the Mg accumulation of plant and the quality of flue-cured tobacco leaves were analyzed during the whole growing season. The experimental results showed that, the soil exchangeable Mg increased with the increase of Mg input. Soil Mg supply capacity had a linear correlation with Mg input at different growth stages. Mg content and accumulation of tobacco leaves at different plant positions also had a linear correlation with Mg input at the final harvest stage. Compared with those of no Mg input treatment, the average price, production value, proportion of upper class leaves and proportion of middle-upper class leaves increased by 6.39%-11.67%, 6.13%-14.63%, 18.43%-31.46% and 5.36%-8.96%, respectively. The total potassium (K) content of flue-cured tobacco leaves decreased with Mg application increase. The best sensory evaluation quality of flue-cured tobacco leaves was observed in the treatment with 19.5 kg/hm² Mg input (MgO), and that was followed by 39 kg/hm² Mg input. The treatment with 58.5 kg /hm² Mg input had the highest production value. The accumulation of biomass in tobacco plant and the yield of flue-cured tobacco leaves were not obviously affected by Mg input. Based on actual soil exchangeable Mg status, soil Mg supply, nutrients’ accumulation in tobacco plant and quality of flue-cured tobacco leaves in Fujian tobacco (Nicotiana tabacum ‘CB-1’) production, the range of recommended Mg input is from 19.5 to 39 kg/hm² (MgO), which could not only ensure the relative balance of soil Mg supply and Mg nutrient, but also meet the requirements of tobacco plants for Mg nutrition, and improve the quality of flue-cured tobacco leaves.

Key words: flue-cured tobacco, magnesium, growth, economic characters of tobacco leaves, quality of tobacco leaves