Harm of high temperature to vegetables in summer and countermeasures

     High temperature in summer has many adverse effects on the growth and development of vegetables, which is the basic reason for the autumn of vegetables. Therefore, it is particularly important for summer vegetable cultivation to do a good job in high-temperature defense work in vegetable production.

    First, the main hazard of high temperature on the growth and development of vegetables

    Plant water loss   When the temperature is above 30 °C, if there is no rain or less rain, it will cause soil drought and atmospheric drought. When the water absorbed by the roots of the vegetables can not meet the evaporation demand of the plants, the leaves of the vegetable plants will curl, fall off and the quality will change. Inferior, production decline, even withered, dry.

    Plant growth   High temperature is prone to appearing long seedlings, especially after the night temperature is too high, it is prone to appear long, affecting the flowering fruit and yield of the later vegetables.

    Affecting flower bud differentiation and gender differentiation    High temperature and long sunshine increased the male flowers of cucumber, and the female flowers differentiated late. When tomato and pepper flower buds differentiate, they have less flowering and dysplasia under high temperature conditions.

     Disease resistance loss    When the temperature or ground temperature is higher than the normal temperature range of vegetable plants, the disease resistance of some disease-resistant varieties will be lost and become susceptible varieties, which will aggravate the occurrence of diseases.

    Prone to physiological diseases    High temperature is often accompanied by strong light photography. When strong sunlight is used to illuminate the fruits of solanaceous fruits, melons and other vegetables for a long time, the sunny side of the fruit will be burnt by the sun, causing sunburn; high temperature and drought can make the solanes and beans The flowering result process of vegetables such as the class is adversely affected, causing the flowers to fall into the fruit; the drought and water shortage make it easy for the Chinese cabbage to dry heart disease, and the tomato to have umbilical rot. At high temperatures (over 35 °C), lycopene is difficult to form, so the fruits often appear yellow, red and white, which greatly reduces the value of the commodity.

    Inducing multiple pests and diseases    High temperature and drought can aggravate viral diseases, powdery mildew, and mites.

    Second, the main measures to deal with high temperature and heat damage

    Intercropping with high stalk crops    Make full use of the shading effect of high-stalk crops, and do a good job of matching the Xiyang and Xiyin crops. For example, between eggplant and pepper, corn and pepper, and ginger in the shade of mulberry, tea and orchard.

    Cover the cooling at the right time    In the summer and autumn breeding, it is best to take a shed to protect the sun. Planting leafy vegetables in summer and autumn, it is best to cover the sunshade net, sunscreen and pest control. Open sweet pepper, can cover the shade net, sunscreen disease prevention (virus disease). The sun protection net or the mud can be covered with sunscreen on the protective shed film. For the bare crop line, a layer of wheat straw, straw, broken straw, etc. can be laid to prevent the ground temperature from being too high. To prevent the water from being washed away, the soil can be pressed on it. For the fruits of vegetables exposed in the sun, weeds can be covered with weeds, old newspapers, etc., in case the sun burns the fruits.

    Use your own blade to block sunscreen    In the high temperature period of summer and autumn, the stems and leaves should be fully utilized for shading and fruit preservation. For picking the heart of the tomato, two leaves should be left on the top layer of fruit to shield the young eggplant from sunscreen; after the cabbage is ripe and the broccoli is finished, the outer leaves are removed and covered on the leaf ball. Sun protection, improve quality. Cultivation of vegetables in summer and autumn, generally should not be planted in close planting, play a mutual shade, which is conducive to growth.

    Reasonable watering   Watering is one of the most effective measures to alleviate hot weather. It can increase the number of watering and the amount of watering each time. When conditions permit, watering can be sprayed or sprayed on the leaves to prevent dehydration of the leaves. The time should be chosen in the morning or evening. It is not allowed to water when the temperature is high at noon. It should be watered with well water or low-temperature river water. It should be poured thoroughly to keep the soil moist. After the hot thunderstorm, drain it in time and water the cold water to prevent hot rain damage.

    Timely topdressing    According to the type and growth stage of vegetable crops, combined with watering, timely topdressing, but can not be followed by human excrement. Nitrogen, phosphorus and potassium should be combined with application. For example, nitrogen fertilizer is the main seedling stage, supplemented by phosphorus and potassium fertilizer. The result is phosphorus and potassium fertilizer, supplemented by nitrogen fertilizer. Seedling initial results and results of peak, should each dressing 1; leaf yellowing, when weak, foliar spraying 0.1% 0.2% potassium dihydrogen phosphate solution, Penshibao, Ainong, and promote the growth of vegetables, Prevent premature aging of the leaves. Especially after the hot thunderstorm, it is necessary to strengthen the cultivating loose soil and timely apply the quick-acting fertilizer.

    Symptomatic prevention and control of pests and diseases    It can be sprayed with a mixture of calcium chloride and naphthaleneacetic acid from the early flowering stage of tomato or the rosette period of Chinese cabbage to prevent umbilical rot or dry heart disease; plant growth regulation such as naphthaleneacetic acid, anti-fallin, 2, 4 - D To treat flowers of the solanaceous or legumes, to prevent falling flowers and fruits; to spray viruses A , phytopathology, fungi and other agents to prevent viral diseases; spray triadimefon, Wuyincin, Fuxing and other agents, prevention and treatment Powdery mildew; spray acaricide to prevent cockroaches. However, it should be noted that the sprayed vegetables should be listed after the safety interval, so as not to affect human health.

 

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