In the process of lettuce cultivation, if not properly managed, the fleshy stem is easy to crack in the later stage of expansion. The fleshy stem is longitudinally dehisced, reaching the center of the stem, and the dehisced part is yellowish-brown, perishable, and the product quality is reduced, which seriously affects its economic benefits. Measures to prevent split stems are as follows:
1. Choose the right variety. Depending on the local conditions and climatic conditions, the appropriate varieties are selected. For plots with poor drainage and irrigation conditions, in the season of large temperature changes, green leaf lettuce with low water content and strong resistance to cracking stems should be selected as much as possible.
2. Strengthen fertilizer and water management. In the succulent stem expansion stage, sufficient water and fertilizer supply is required to meet the nutrients required for succulent stem expansion. During this period, the requirements for water and fertilizer management are very strict, generally the ground is slightly dry to water, watering should be even, the amount of water should be moderate, so that "small water is watered frequently, thin fertilizer is applied frequently, and fertilizer is brought with water", and the flood irrigation is strictly prevented, and then the large water and fertilizer are "vigorously supplemented" after the severe drought, so as not to crack the stem. When fertilizing with water, the fertilizer is dissolved first and then applied to the field with water. In the process of growth, lettuce should be fertilized with water at least 2~3 times, and when urea is applied, 5~8 kg per mu is generally used; When applying biogas slurry fertilizer, 300~500 kg per mu is generally used. At the same time, pay attention to the timely shallow loosening of soil and breaking the compaction.
3. Control the temperature. For lettuce planted in the shed, the temperature in the shed can be adjusted by adjusting the ventilation measures, and the lettuce fleshy stem formation period should be ventilated and cooled in time when the temperature rises to about 24 °C in the morning. In the afternoon, when the temperature in the shed drops to about 18 °C, the film should be covered in time. Try to control the temperature in the shed within the range of 18 °C ~ 22 °C during the day and 12 °C ~ 15 °C at night.
4. Increase boron fertilizer. Apply 200~250 grams of boron per mu to the boron-deficient soil, lettuce can be combined with foliar top dressing at the stage of the lettuce, use 50 grams of solubor or 20 grams of polyboron per mu to 30~45 kg of water, spray 1~2 times, and the interval between each time is 5~7 days.
5. Harvest at the right time. When the top of the main stem of lettuce is the same as the tip of the highest leaf, it is the appropriate time for harvesting, and the fleshy stem has been fully expanded, the quality is brittle and tender, and the stem crack is not easy to occur.
The preventive measures for cracked stems of lettuce in greenhouses are introduced here, and I hope it will be helpful to everyone. If you want to buy high-quality and high-yield lettuce seeds, you can download the seed bank App, and the country's excellent lettuce varieties are available for everyone to choose.
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