Recently, most of the central and eastern parts of my country have started the”quick freezing” mode, ushering in a cold wave. Sudden low temperature, strong wind and snow weather may cause serious damage to overwintering vegetable production. In order to reduce the impact of disasters, strengthen the management of vegetable production in the field to ensure stable vegetable production in various regions and sufficient market supply. The National Agricultural Technology Extension Service Center and the Ministry of Agriculture and Rural Affairs vegetable experts guide The group put forward the following technical guidance:
1. Measures to cope with cold wave in facility vegetables
(1) Pay attention to the weather. It is necessary to make full use of radio, television, mobile phone text messages, WeChat and other methods to keep abreast of weather changes, enhance safety awareness and risk prevention awareness, and make effective preparations for disasters such as low temperature, strong wind and snow as early as possible.
(2) Reinforcement facilities. Check the shed frame of the maintenance facility in time. For sheds with poor snow pressure resistance, columns should be added as soon as possible to enhance snow resistance, prevent the shed from collapsing, and ensure personal safety. Repair film loopholes in time and tighten the film pressing line to prevent ventilation, rain and snow. The rear roof of the soil-wall solar greenhouse should be covered with a film to prevent the wall from being damaged by the snow water.
(3) Prepare snow removal tools. Prepare snow removal, snow removal and snow removal tools in advance, such as manual snow removal shovel, snow removal machine, etc., in order to clear the snow in the shed in time to prevent the shed from collapsing due to the snow.
(4) Strengthen heat preservation. The outside of the shed is covered with materials such as heat preservation quilts and grass thatch, and a layer of plastic film is added to prevent the heat preservation material from absorbing water and reducing the heat preservation effect. In the shed, build simple middle sheds and small arch sheds to form multiple layers of coverage to reduce heat loss. Multi-layer grass thatch (curtain) is added around the shed, the back wall and the foot of the shed, which can effectively prevent wind and heat. Buffer films are set at the vents and the door of the greenhouse, or multi-layer covering is used for heat preservation. Prepare Yuba heat conversion bulbs, electric heaters, automatic heating fans, air heating wires, electric blast furnaces, emergency heating fuel blocks, oil-fired hot blast stoves, stoves and other auxiliary heating items for temporary heating when the cold wave strikes.
(5) Apply fertilizer appropriately. Before the cold wave and rain and snow, you can add organic fertilizer, such as pig, cow manure and compost and other thermal fertilizers; moderately increase magnesium, zinc, boron and other medium and trace element fertilizers; it is not suitable to apply quick-acting nitrogen fertilizer, and spray on the leaves 0.3%potassium dihydrogen phosphate solution 2-3 times to improve plant resistance.
(6) Low temperature exercise. Appropriate plant low temperature exercise management is carried out 1-2 days before cold wave and rain and snow. The maximum temperature and minimum temperature are reduced by 1℃-2℃ under the premise of ensuring the basic physiological needs of the crops. This helps vegetable crops adapt to the low temperature environment in advance and can reduce the temperature. Physiological obstacles such as falling flowers and fruits caused by sudden drops.
(7) Control watering. Watering is strictly prohibited during the low temperature period before the arrival of rain and snow to avoid lowering the ground temperature and aggravating cold and freezing damage. It is necessary to achieve”three pouring and three non-watering”, that is, watering on sunny days and no watering on cloudy days; watering in the morning and not watering in the afternoon; watering small water and not heavy water.
(eight) disease prevention. Before the arrival of cold wave and rain and snow, choose fine weather to spray the vegetables to prevent the occurrence of diseases. As the spraying of liquid medicine in rainy and snowy weather can easily lead to the increase of humidity and the occurrence of diseases, it is advisable to choose dust method and aerosol. Do not perform agricultural operations such as watering, spraying, pruning and forks on cloudy days to avoid the occurrence and prevalence of diseases due to increased humidity in the shed and vegetable wounds.
2. Measures to cope with the cold wave of open-field vegetables
(1) Thermal insulation and cold protection. Active soil cultivation:When low temperature, snowfall, freezing or cold currents arrive, cultivate arable soil beside vegetable roots to effectively loosen the soil, prevent frostbite of the root system, promote root growth, and ensure root vitality. Scientific irrigation:Two days before the cold wave and snowfall, choose sunny, windy and sunny weather for watering to increase the soil heat capacity, slow down the cooling rate, and alleviate the impact of low temperature. Strengthen coverage:before the cold wave or rain and snow, covering materials such as plastic film, non-woven fabric or sunshade nets can be used to directly cover and prevent the cold; after the cold wave, strengthen the cover and cover to delay the freezing and thawing process to prevent vegetable frostbite from losing its commercial properties .
(2) Dehumidification and stain reduction. In winter, the groundwater level is high, and it is easy to cause excessive soil moisture in case of rain and snow, resulting in the phenomenon of retting. At the same time, the surface of vegetables is susceptible to freezing damage, which can easily cause dead vegetables in open fields. Before and after the cold wave, the open field vegetables should be cleared in time to prevent water accumulation in the field.
(3) Strong plants. Before the arrival of the cold current, measures such as spraying chitin, alginic acid and other total nutrient foliar fertilizers and plant-derived growth regulators can be used to supplement the urgently needed medium and trace elements of the plants, which can avoid insufficient nutrient supply and Improve the cold resistance of vegetable plants and reduce the appearance of rotten vegetables and frostbite.
National Agricultural Technology Extension Service Center, Vegetable Expert Guidance Group of the Ministry of Agriculture and Rural Affairs