How to do a good job in seedling management of western claw

(1) Temperature management A. It takes a high temperature to accelerate the emergence of melon buds from sowing to seedling emergence, so the seedbed should be tightly covered, and there should be enough light during the day to raise the bed temperature, and it should be heated at night and covered with straw curtains for insulation. B the fastest growth period of hypocotyl of melon seedlings is when the seedlings grow to 65,438+0 leaves. Therefore, the ventilation of seedbed should be strengthened and the temperature should be lowered appropriately to control the excessive growth of melon seedlings. 20 to 25 degrees during the day and 15 to 18 degrees at night. If the bed temperature is too high at this time, hypocotyls will grow in vain, which is easy to form tall seedlings and weak in growth potential. C. 1 After the leaves are unfolded, the growth of hypocotyl of melon seedlings basically stops at this stage, and the temperature can be appropriately increased to accelerate the growth of new leaves of melon seedlings. 25 ~ 28 degrees during the day and 18 ~ 20 degrees at night to accelerate the growth of melon seedlings. D. About 65,438+0 weeks before field planting, the seedbed can be ventilated or aired to gradually reduce bed shrinkage, promote seedling aging, and improve adaptability and transplanting rate.

(2) The light transmittance of the light management plastic film seedbed is about 70%. If the coverage is tight, the air humidity will reach saturation and the light transmittance will be lower. Therefore, we should try our best to be light in management. If a new film or a non-dripping film is used, the surface of the film should be kept clean, and the water droplets on the film should be removed by ventilation in time to increase the exposure; Within the allowable range of bed temperature, the cover should be uncovered early and covered late to extend the illumination time; The film can be uncovered on a warm sunny day; Try to be ventilated and transparent in continuous rainy days.

(3) Humidity management A. The seedbed should be kept at a suitable humidity until the melon buds are unearthed. Too much humidity is not conducive to seedling emergence. It is required to pour bottom water when sowing, and the soil is wet. Don't spray water after covering the soil, cover it with plastic film to keep it moist. B. Water should be strictly controlled from emergence to 1 leaf stage. Because the seedbed is fully watered before sowing, the seedbed is mainly kept warm after sowing, and the water evaporation is not great. Watering will reduce the bed temperature and increase the humidity, which will easily cause the seedlings to grow white and induce diseases. If the seedbed is short of water, the bed surface is dry and cracked, and the seedlings are wilting, water can be sprayed appropriately, a small amount of water can be sprayed many times, and the bed surface can be kept wet in the morning and dry at noon. C. 1 After the leaves are unfolded, the growth of hypocotyl of melon seedlings basically stops at this stage, and the number and amount of watering can be appropriately increased to keep the bed surface moist, improve the humidity of the seedbed and accelerate the growth of new leaves of melon seedlings. When the weather is fine, you can also cooperate with topdressing and water the seedbed. D. Before planting, the amount of water should be appropriately reduced, the growth of seedlings should be controlled, and containers such as paper bowls should be prevented from breaking. It can be watered 1 day/time before planting and seedling raising.

(4) Fertilization management Watermelon seedling stage is short, so it is not necessary to fertilize many times. There is usually no need for topdressing. If symptoms of fertilizer deficiency are found, urea (0.3%) and potassium dihydrogen phosphate (0.2%) can be combined to prevent diseases as topdressing outside the roots. After topdressing the leaves, cover them with plastic film and pay attention to ventilation and cooling, or sprinkle topdressing on the bed surface to prevent seedlings from burning.

(5) Ventilation management Ventilation is the main means to adjust the temperature and humidity of seedbed. Generally, more than 80% of the seedlings begin to ventilate when they are unearthed. Generally speaking, ventilation starts after 9: 00 a.m. when the temperature of the seedbed rises, and ends after 4: 00 p.m. when the temperature of the seedbed drops ... when ventilation, the tuyere should be opened with the wind. The size of the vent and the length of ventilation time should be determined according to the change of external climatic conditions. It is forbidden to suddenly ventilate a lot or end ventilation to prevent seedlings from flashing or baking. The position of tuyere should also be changed frequently, so as not to cause the seedling growth of tuyere.

(6) Control of Diseases, Insects and Pests The main disease at seedling stage is damping-off, and the pests include aphids, breeding flies and crickets. Preventive measures should be taken to control the temperature and humidity of the seedbed and spray chemicals regularly. Generally, after emergence, 600-800 times of thiophanate methyl or 600-800 times of disinfectant Wang 2-3 times are sprayed. After watering the seedbed and before sowing, spraying 800 times of self-insect liquid 1 time can effectively control the harm of seedbed flies and moles. After the seedbed is ventilated, spraying dimethoate 800 times and imidacloprid 10 times can control aphids. Spraying 1000 times of covering energy EC on the seedbed of weeds in the second to third leaf stage can prevent weeds, especially monocotyledonous weeds.