According to the meteorological department**, strong cold air will arrive in our city from Saturday, and the minimum temperature will drop to minus 3 5 degrees Celsius, and this wave of cold air will last for a long time, which will adversely affect the growth of vegetable crops in the field. In order to effectively cope with the impact of strong cold air and ensure the safety and stability of vegetable production in the district, the District Agricultural Technology Extension Center has formulated the following technical guidance for the production of vegetables to cope with the cold wave
1. Strengthen heat preservation, cold and freeze protection
For old greenhouses, damaged film and other production facilities should be repaired, replaced and reinforced in a timely manner. Close the greenhouse in a timely manner, and adopt multiple covering cultivation technologies such as plastic film + small arch shed + non-woven fabric, which can effectively increase the temperature by 3 -5 , and has a good cold protection and thermal insulation effect. Temporary heating measures can be taken if conditions permit, and the temperature is controlled in the principle that the plants are not frozen, and pay attention to the smoke concentration in the shed, and ventilate in a timely manner. If necessary, open-field vegetables can be temporarily covered with white mulch, non-woven fabrics, shade nets, straw and other insulation.
2. Strengthen fertilizer and water management to improve plant stress resistance
Before the cold wave comes, timely supplement crop nutrition, strengthen plants, resist frost damage, and ensure rapid recovery after freezing. Proper spraying of foliar fertilizer or plant-derived growth regulator to supplement the medium and trace elements urgently needed by the plant can not only avoid nutritional deficiency, but also improve the cold resistance of vegetable plants and reduce the occurrence of rotten vegetables and frostbite. In winter, not only the temperature is low, but the ground temperature is also low, such as overwatering, which directly affects the activity and absorption function of the root system. Greenhouse facilities should be cultivated by drip irrigation under the film for watering. After the rain in the open field, it is necessary to clear the ditch and manage the moisture in time to reduce the stain and prevent waterlogging.
3. Do a good job in forecasting pests and diseases, and prevent and control pests and diseases in a timely manner
In winter, the ventilation frequency of greenhouse facilities is reduced, and the temperature and humidity in the shed are high, which is prone to a variety of pests and diseases such as whitefly, gray mold, and downy mildew. The forecasting of pests and diseases should be strengthened to reduce losses such as failure to harvest due to weather conditions and decline in commerciality. After the cold air, it is necessary to sow seeds, raise seedlings and transplant in time according to the arrangement of vegetable stubble and the growing season. When the low temperature lasts for too long, seedlings can be sown in factory seedling facilities, and planted when the soil in the field or greenhouse is dry and warm.
4. Emergency response to chilling injury
For the vegetable plants in the facility due to the damage of the roof mulching or slight frost damage, in addition to timely repairing the film, increasing the mulching, covering the non-woven fabric, thermal insulation and other methods of thermal insulation and warming, can take foliar spraying 20 -25 warm water, 02% potassium dihydrogen phosphate solution, amino acid foliar fertilizer and other measures to reduce plant damage. After the occurrence of frost damage, the shed can not be closed immediately to raise the temperature, and the temperature in the shed should rise slowly to avoid the necrosis of the frozen tissues of vegetables due to the rapid rise in temperature. At the same time, it is necessary to cut off the stems, leaves and fruits that are severely frosted in time. For the vegetables that have just been planted in early spring, if the seedlings are dead due to the lack of disasters, they should be replanted with fruits and vegetables or leafy vegetables in time according to the situation.