Precociously cultivated tomato in plastic greenhouse in spring
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Tomato is a common vegetable in people's daily life. Tomatoes are extremely rich in nutrients, mainly containing vitamin C, lycopene, etc., and are popular with people. Tomato juice and tomato sauce processed with tomatoes are also popular. The tomato varieties suitable for cultivation in plastic greenhouses should have the following characteristics in addition to having matured early, high yield in the early stage, high yield, good quality, and commercial quality in line with market requirements. (1) Low temperature resistance. Under the condition of lower temperature, the flowering results can be normal, the fruit setting rate is high, the deformed fruit and the rate of cracking fruit is low. (2) Low light resistance. Under weak light conditions, they can grow and grow normally. The plants have the characteristics of small leaves, thick leaves, strong light and ability, compact plant type, strong growth potential but no long growth. (3) Strong disease resistance. It has strong resistance to leaf mold, gray mold and early and late blight. Such as: Zhengzhou City, selected for the study of gold powder early crown, pink champion, Zhengfen No. 4 (Yu Tomato No. 6), 853 (Yu Tomato No. 1), disease resistance 011 and Other fine tomato varieties, have the above characteristics. Due to the different varieties of ripeness and different ways of raising seedlings, the appropriate seedling age is also different. In general, early maturing cultivars should be shorter in age, 60 days to 70 days is appropriate; mid-late maturing cultivars may be longer, and 70 days to 80 days are appropriate. The seedling age is too short and the seedlings are too small. The fruiting period is delayed and does not reach the goal of precocious maturity. On the contrary, the seedling age is too long, the seedlings are susceptible to ageing, and the living rate is reduced. Even before the seedlings are planted in the seedbed, the seedlings have blossomed, resulting in planting. Falling flowers and falling fruit also fail to reach the goal of early maturation and high yield. Temperature and humidity management: The temperature in the greenhouse in early spring is relatively low. In the early stage of tomato growth, the management should focus on cold protection, heat preservation, and accelerated seedling growth. Generally, 3 days to 4 days after planting, ventilation is not conducted, so that the temperature of the greenhouse is maintained at about 30°C during the day, 15°C to 17°C at night, and about 18°C ​​to 20°C at the ground temperature. If the temperature in the shed is too high during the sunny days, add grass and hoe to cover the shade for a short time and open it again in the afternoon. Do not take measures to prevent the dehydration and wilting of the seedlings. Ventilation and cooling are started after easing the seedlings, and as the ambient temperature rises, the ventilation volume is gradually increased, and the ventilation time is prolonged. Generally, the daytime shelf temperature is controlled at 22°C-25°C, nighttime at 12°C-15°C, and the relative air humidity is controlled at 60%- 70%; ventilation from small to large, ventilation time from short to long, early ventilation can not pass through the end of the wind, should be released from the upper part of the greenhouse, the latter in the upper air temperature when the lower down, then ventilation from the bottom. In the middle and late stages of tomato, the outside temperature keeps rising. At this time, the focus of management should be to strengthen ventilation and reduce the temperature of the greenhouse. If the temperature of the greenhouse reaches 35°C, it should be ventilated overnight, or even the greenhouse film around the greenhouse can be completely opened. Take all measures to keep the greenhouse temperature at 25°C-27°C during the day, 15°C-18°C at night, and 20°C at night. -24°C, relative humidity of air is about 50%. If the temperature in the greenhouse is too high and the humidity is too high, it will cause physiological obstacles to the growth of tomatoes, and it will also cause various diseases. Especially after watering, it must be ventilated and ventilated to reduce the air humidity in the greenhouse. If the temperature in the greenhouse is too high or too low, if the air humidity is too high or if the management of fertilizers and water is improper, if the light is insufficient, and the cultivation is too dense, it will result in falling and fruiting. Therefore, greenhouse tomatoes must use growth regulators to preserve the fruit. The 2.4D spot flower is usually used at a concentration of 10ppm-20ppm. Take care not to get any tender leaves on the shoots to avoid curling, or to use a 30 ppm to 40 ppm drop. In addition, in the use of plant growth regulators to spend, spray spray, should be added 0.1% of Skoda wettable powder or Park Hydration WP, can receive better results. The environmental conditions of greenhouse cultivation are different from those of open fields, and the pests and diseases that harm tomato are also different. The main diseases are leaf mold, gray mold, early and late blight, virus disease and root nematodes. Control methods, in addition to the above-mentioned control of a suitable temperature and humidity, the critical period can be used to control chemicals. For leaf mold and gray mold, the plants can be sprayed with 50% of Skoda WP 1000 times, or 50% of the compound carbendazim suspension 500 times. For early and late blights, it can be sprayed with buprofezin, Rhizoctonia or Baiyinqing, once every 7-8 days. For virus diseases, in addition to doing a good job of seed disinfection as mentioned above, management should prevent infection. For whitefly and other insect pests, it can be sprayed with 1000 times solution of bufalin EC, or 1000 times of 50% dichlorvos EC, or 1000 times of 40% dimethoate EC, which has better control effect.