Key Technical Points and Management Methods for Tobacco Leaf Cultivation Explained

Tobacco is a thermophilic crop, and the optimum temperature for growth and development is 25—28°C. It needs water in the early growth stage, the most in the middle stage, and less in the late stage. During the seedbed stage, soil moisture should be maintained at about 70% of field capacity; watering should be stopped 10—15 days before transplanting for hardening off the seedlings. The suitable daily light duration for tobacco is 8—10 hours. Red soil is best, followed by red loess, sandy soil and loam. Tobacco should not be planted in areas with strong winds and hail.

1. Temperature: Tobacco is a thermophilic crop. The aboveground part can grow within the range of 8—38°C, and the optimum temperature for growth and development is 25—28°C. At minus 2—3°C, the tobacco plant will die. The underground part can grow between 7—43°C, but the most suitable temperature is 31°C. The optimum temperature for seed germination is 24—29°C, the minimum temperature is 7.5—10°C, and the maximum temperature is 35°C. When the temperature is below 7.5°C, the seed germination process stops; above 30°C, the germination process is slow; above 35°C, the already germinating seeds gradually lose vitality. The transplanting period for tobacco should generally be after the late frost, when the temperature is not lower than 10°C. The ideal average daily temperature during the leaf maturation period is about 24°C; lasting 30 days, it can produce high-quality tobacco leaves.

2. Water: Generally, water is needed in the early growth stage, the most in the middle stage, and less in the late stage. During the seedbed stage, soil moisture should be maintained at about 70% of field capacity; watering should be stopped 10—15 days before transplanting for hardening off the seedlings. From transplanting to the seedling recovery stage, leaf transpiration is small, and the average daily water consumption is 3.5—6.4 mm. From seedling recovery to the rosette stage, the average daily water consumption is 6.6—7.9 mm, and soil moisture should be maintained at 60% of field capacity; below 40%, growth is hindered, and above 80%, root growth is poor, which is unfavorable for later development. From the rosette stage to the budding stage, the average daily water consumption is 7.1—8.5 mm, and soil moisture should be maintained at 80% of field capacity. If water is lacking during this period, growth is hindered; if drought persists, premature flowering or premature curing may occur. From the budding stage to the maturity stage, the average daily water consumption is 5.5—6.1 mm, and soil moisture should be maintained at 60% of field capacity. During this period, water should be slightly less, which can improve tobacco leaf quality; if soil moisture is excessive, it easily causes delayed maturity and a decline in quality.

3. Sunlight: Tobacco always needs sufficient light, but most varieties do not have strict requirements for day length. Flue-cured tobacco requires abundant but not very intense sunlight during the growth period, and the suitable daily light duration is 8—10 hours. Especially during the maturity period, abundant sunlight is a necessary condition for producing high-quality tobacco leaves. Light rich in shortwave components and mild cloudy days are conducive to improving tobacco leaf quality.

4. Soil: Although tobacco can grow on many types of soil, it has relatively strict soil requirements for growing high-quality tobacco. Red soil is best, followed by red loess, sandy soil and loam, while meadow loess soil (black soil) is the worst.

5. Weather phenomena: Strong winds and hail are more harmful to tobacco leaves than to any other crop, and whether in the seedbed or the field period, they may bring serious losses. Therefore, tobacco cannot be planted in areas where strong winds and hail frequently occur during the tobacco growth period.