I. Breeding cold-resistant varieties, correctly grasping the sowing date In the selection of cold-resistant varieties, and correctly grasping the sowing period, it is necessary to stop irrigation and topdressing nitrogen fertilizers as early as possible after autumn, and add phosphorus and potassium fertilizers to strengthen loose soil and weeds. , ventilation, light and other management, so that the seedlings can be fully lignified before the winter to enhance cold resistance. Broadleaf saplings dormant later can be controlled by cutting tips to control growth and promote lignification. Second, to prevent seedlings from frost and cold wind hazards 1. Covered in the soil before freezing, the seedlings covered with straw, wheat straw and other cold. For a few rare tree species that are not tolerant to cold, cover soil can be used to prevent cold, and the thickness of seedlings is not exposed. Remove mulch after soil thawing in spring of the following year. 2. Set up the windbreak-proof soil before freezing and use the wind-barrier on the windward surface of the seedbed to prevent the cold. The average wind barrier is 2 meters high and the distance between the obstacles is 10 to 15 times the height of the obstacle. Removed after the spring frost of the following year was terminated. Wind barriers are not only able to block the cold wind, reduce the wind speed, so that the seedlings can reduce the cold damage, but also can increase the snow, help soil conservation, prevent spring drought. 3. The greenhouse warm shed should be slightly higher than the seedlings, south lower north high, the north must face the ground is not airy, with the straw curtain over night, in case of cold currents can cover all day. The greenhouse can reduce the radiation heat radiation from the surface and seedlings at night, alleviate the sudden increase in temperature at sunrise, and block the cold wind. 4. During the night when the fume smoke is frosty, in the upper hand of the seedbed, 3 to 4 fumes heaps are distributed per acre. When the temperature drops and there is frost, the fumes can be ignited. Try to make the fire small smoke, keep the thick smoke, lasting more than 1 hour, if you keep the smoke screen after sunrise 1-2 hours, the effect is better. Smoke smoke can increase surface temperature and effectively prevent frost. 5. Irrigate the soil with frozen water before freezing to prevent drawing and reduce frost damage. Watering at night in the early spring can increase surface temperature and prevent night frost. 6. Anti-cold counterfeit values ​​The cold-resistant seedlings that need to be transplanted in the spring of the following year will be dug before entering the winter, and they will enter the ditch after grading and be planted to prevent cold. In cold regions, seedlings can also be buried in soil to prevent water loss from pumping.
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