The main reason for the cracking of tomatoes in greenhouses was the low temperature below 10°C during the flower primordium differentiation period, which resulted in fruit failure due to incomplete development of ovary wall cells. After the two true leaves of tomato in the seedling stage, the flower primordium on the ear begins to differentiate one after another. The optimum temperature for the flower primordium differentiation is 18°C-20°C, and the night temperature is 11°C-15°C. The minimum temperature at the seedling stage after the leaf stage cannot be lower than 10°C for a long time. In addition, a large number of nitrogenous fertilizers are applied during the growth period, and the deficiency of phosphorus and potassium fertilizers or excessive application of diammonium phosphate may affect the absorption of calcium and boron, or excessive nitrogen and phosphorus, and the shortage of potassium fertilizer and high temperatures exceeding 30°C for a long period of time are also important causes of tomato cracking. .
To this end, tomato seedlings are required to be cultivated in greenhouses. The temperature should be controlled at 18°C-20°C during the day, 11°C-15°C at night, and about 70 days of seedling age. However, it can be controlled at around 15°C during the rainy days. Tomato fertilization should be dominated by farmyard fertilizers, supplemented by chemical fertilizers. Fertilizer application should be controlled in every 100 meters long shed apply urea 5-7 kilograms, superphosphate 60-70 kilograms, potassium sulfate 30-35 kilograms, after the application of deep-dip twice, so that the soil is fully mixed, full-layer fertilization. Top dressing is mainly potassium dihydrogen phosphate. If the plants do not grow well, apply 3-5 kg ​​of urea per 100 m long shed in the early stage of growth.
In addition, spraying more than twice Merrill Lynch calcium during the young fruit period has a significant effect on the prevention and treatment of umbilical rot and fruit cracking. See the dry watering before flowering, and the fruit expansion period after flowering, we must keep the ground moist, can be conducive to high yield without cracking fruit. After the cracking fruit was found, it should be removed in time, and then a further 1-2 spikes should be reserved for remedy. To achieve these above, we can effectively achieve the purpose of controlling cracked tomatoes.
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