Affected by the cooling, precipitation and other environmental impacts, the cultivation of shed vegetables in autumn and winter seasons should take precautions to prevent “warm and wet discomfortâ€. The specific symptoms are: (1) root rot in seedling stage; (2) leaf physiological water-filled type; (3) microclimate discomfort; (4) improper ventilation management. Performance symptoms and preventive measures are as follows.
In the seedling stage, regardless of the seedling transplanting of seedlings or the seedlings of the live seedlings, the root shoots of the shoots appear yellow-green or milky white from the bottom to the top. The leaf margins begin to scorch and the growth is extremely slow. The reason is that the ground temperature is below 15°C for a few days in a row, watering is large or long-term and rainy, the temperature of the seedbed is low, and the seedlings are slow to grow for a long time. Preventive measures: Add organic fertilizer, acupuncture organic bio-fertilizer, appropriate amount of water (small irrigated seedlings or roots), foliar spray Nongdu happy humic acid foliar fertilizer plus hymexazol or strong seedlings 2116 plus evil Frost Spirit.
During the process of growth, the leaves of the leaves are filled with water. The edges of the leaves appear watery and hot, and the leaves appear polygonal or dot-like. The water-stained bubble spots look like downy mildew and bacterial angular spot. If the temperature of the greenhouse rises, the humidity will reduce the normal return of the leaves; if the duration is long, the spots and leaves will lose their green color, and they will gradually turn into brownish-brown dead spots. The cause of the disease is the high humidity in the air in the enclosed greenhouse, the inhibition of leaf transpiration, the absorption of moisture from the roots, and the inflow of water from the leaf cells into the cells. Preventive measures: Increase the temperature in the shed, properly ventilate and ventilate the leaves and spray antifreeze or melon fruit 2116. Strengthen the insulation measures, take early as soon as possible to cover the straw curtain, indoor temperature conditions.
Microclimate Discomfort During autumn and winter, due to the short illumination time, temperature and light in the shed can hardly meet the normal growth needs of fruits and vegetables. Especially for melons, the middle and lower stalks have a phenomenon of leggy, the upper stalk becomes thinner, the leaves become smaller, the tendrils are weaker, and the “lead†of the cucumber appears curved or the leaves are compact, and even the “flower tip†occurs, and the growth point is serious. The phenomenon of "baldness" appears. The reason is that after the establishment of the seedlings, the seedlings were not well watered and the rooting was controlled. After the initial flowering period, the temperature was not treated, especially if the fertilizers were watered prematurely, especially if there were excessive nitrogen fertilizers (or other available fertilizers). In case of overgrowth of nutrients, in the event of disaster weather, low temperature and low illumination, and a sharp drop in temperature, the ground temperature is low, the root system is inhibited, and the vegetative growth potential is weakened.Precautionary measures: preserving temperature, using large and small rows, and small rows Membrane, large line open deep ditch covering 3 ~ 4 cm wheatgrass, small ditch to take measures of micro-irrigation, can prevent sudden temperature drop, especially ground temperature, reduce the damage to the root system.In addition, the use of aerosol, sterilization and pest control effect is significant. Ignore.
Improper ventilation management Fruit and vegetables cultivated in autumn and winter, due to the influence of temperature (including ground temperature), neglected ventilation and humidity management. Many people confuse ventilation and cooling. This is a mistaken understanding. In fact, ventilation is ventilation (mainly carbon dioxide). As long as we grasp the ventilation time, the effect is very good. According to the author's observation, every morning at 9 o'clock the air is released for half an hour and covered at night. The next day, 3 to 4 o'clock, another 10 to 15 minutes of tuyere, which is very beneficial to the growth of fruits and vegetables. Symptoms caused by poor ventilation management: normal development of the middle and lower leaves, the middle leaflets rolled up on the edge, slightly wilting, severe slow growth, the upper leaves close together. This phenomenon is caused by the early release of air in the morning, a long time, fruit and vegetables have not been adapted to change the temperature, resulting in a larger reduction in the temperature of the greenhouse, in severe cases, the leaves can not be normal expansion, the other is the leaf blade edge near the vents scorch, Or there are unplanned necrotic spots on the foliage, which resemble phytotoxicity or some invasive disease. Others, such as the greenhouse temperature above 40 °C, the leaves of the melon leaves will also appear curled leaves, leaves dehydration wilting or even dry, above 38 °C when spraying pesticides or foliar fertilizer, there will be high-temperature burning leaves. Preventive measures: scientific fertilization, to take "a small number of times" approach to chase or quick-applied fertilizer points, careful careful grasp of the temperature within the shed, both insulation and anti-shedding temperature is too high, reduce the shed of harmful gases (such as ammonia) Too concentrated to add carbon dioxide gas.
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