According to the forecast of the meteorological department, the first winter of this year will be warm, and the second winter will be close to the normal season. The temperature in most parts of the country will be close to the same period of the normal year or higher, and the precipitation in the southern region will be more than usual. In order to effectively prevent and respond to winter disastrous weather and promote stable production and supply of vegetables, the planting Management Department of the Ministry of Agriculture and Rural Affairs, together with the National Agricultural Technology Extension Service Center, the Vegetable expert Guidance group of the Ministry of Agriculture and Rural Affairs, and the national bulk vegetable industry technical system, studied and proposed technical guidance opinions on winter vegetable disaster prevention and reduction.
1 Technical measures to prevent and deal with continuous low temperature weather
(1) Choose stress-resistant varieties. Facilities Vegetable production areas to choose low-temperature and low-light resistance, fruit bearing ability, disease resistance of eggplant and melon bean vegetable varieties. Leaf vegetables, root vegetables and happy fruit vegetables with strong low temperature and low light resistance are preferred in the open field vegetable producing areas in South China.
(2) Strengthen thermal insulation and heat storage. Before the arrival of low temperature weather in winter, you can add two screens in the facility, small arch shed and other multi-layer coverage, pay attention to the distance between the agricultural film and vegetables to maintain more than 10 cm, to prevent the leaves from touching the agricultural film and cold damage. Can be scattered between the vegetable rows of rice husk ash, grass and wood ash, clay ash, wheat bran, etc., or covered with straw, straw, etc., on the bed and vegetables to reduce the harm of low temperature. Conditions allow the heating of hot lines, electric heating wires, air heating lines, furnaces, hot blast furnaces, etc.
(3) Increase light as much as possible. Fill light is installed in the facility and fill light for 4 hours a day. Facilities without artificial light as early as possible to cover the thermal insulation covering to ensure light time. The greenhouse can hang reflective film on the north wall to improve the northern light, and timely ventilation when the temperature is appropriate, reduce the water on the surface of the shed film, and increase the light in the greenhouse.
(4) Strengthen production management. Low temperature weather, as little watering and fertilizer as possible. If the vegetable is wilting without water, it should be selected to carry out drip irrigation under the film or pour small water under the film on sunny days, and topdressing with water. Suitable concentration of growth regulators such as brassinolide can be sprayed on the leaf surface for cold induction resistance, and 0.3% compound fertilizer and 0.2% calcium chloride can be added.
(5) Reasonable moisture control and disease prevention. Northern greenhouses or greenhouses should be ventilated in time to reduce air humidity, and ventilation should be carried out at noon on sunny days. The low temperature in winter in southern China is often accompanied by high humidity. After the cold wave, the rise of temperature and humidity may aggravate the occurrence of diseases such as gray mold, quenching and sclerotium in leaf vegetables. It is necessary to spray broad-spectrum fungicides in time to remove diseased leaves, old leaves and yellow leaves to prevent the spread of diseases.
2 Technical measures to prevent and respond to snow and ice disasters
(1) Maintain and reinforce facilities. Timely maintenance of reinforcement facilities, compaction, inspection and repair of broken and cracked membrane. Old facilities or facilities with large span and deformed skeleton should be supported by columns to prevent the collapse of the shed when it snows. As soon as possible, the equipment and circuits such as heating, lighting, snow removal are comprehensively overhauled to ensure the safe and normal operation of the equipment. Before the advent of strong cooling in the northern region, the lighting surface of the greenhouse can be covered with thermal insulation, and the cold curtain can be added inside. Before the snow and ice disaster strikes, covering materials such as plastic film, non-woven fabric or sunshade net can be directly covered on vegetable plants, and the covering can be removed in time after the weather turns good, but it is not appropriate to remove the covering immediately on the day when the snow and ice weather ends, so as to avoid extreme low temperature damage to vegetable plants caused by ice and snow melting.
(2) Reasonable fertilization of mulch. Before the snow and ice disaster, the leaf surface can be sprayed with 0.3% potassium dihydrogen phosphate +0.3% calcium nitrate +1% glucose mixture or 0.5% calcium chloride +1% glucose (also can be 0.01% brassicolide 2,000 to 3,000 times the liquid or 1% white granulated sugar) mixed solution to enhance plant resistance and promote the recovery of growth. The method of "backmulch" was used to spread proper amount of farm manure in border furrow or between plants. Soil and farm manure were cultivated next to vegetable roots during cultivation, which could not only increase ground temperature, but also provide nutrients for vegetables and enhance the low temperature tolerance of plants.
(3) Clear trenches and snow in time. Clear snow on top of and around facilities in a timely manner during snow and ice periods. When the snow on the roof of the shed cannot be removed and there is a risk of shed collapse, the film should be broken in time to protect the shed. After snow and ice disaster, vegetables in the open field are prone to retting root due to excessive soil moisture, and the surface of leaves is also vulnerable to freezing damage. It is necessary to dredge and clean ditches as soon as possible, speed up drainage, and reduce the groundwater level and soil and rhizosphere humidity of vegetable fields. In low-lying and poorly drained fields, ditches should be deepened and ditches dug to promote drainage.
(4) Timely expose the light. When the weather clears up, the insulation cover should be opened in three stages, that is, from small to large to completely uncovered, to prevent vegetables from acute leaf wilting due to sudden light, causing damage. If vegetables are found wilting, spray water or 1% alginate solution.
(5) Strengthen disease prevention and control. During snow and ice disasters, facilities should strictly control indoor air humidity and moderate ventilation to reduce humidity. It is advisable to choose smoke and powder to prevent low temperature and high humidity diseases. After the disaster, vegetable plants have weak resistance and are prone to diseases, especially leafy vegetables, which are prone to soft rot, down mildew, etc. It is necessary to remove dead plants, sick plants and frozen plants in the field in time, and spray low-toxicity and low-residue broad-spectrum fungicides such as carbendazim and chlorotenil once to strengthen disease prevention.
(6) Do a good job of picking up and sowing. Before the disaster, seize the ripe vegetables, growing points or heart leaves frozen and discolored vegetables to reduce losses. Severely frozen vegetable fields should be turned over when the weather is fine, and the fast-growing vegetables such as cabbage, spring vegetables, lettuce, mustard greens, spinach and chrysanthemum chrysanthemum should be planted after the temperature warms up.
Winter vegetable prevention and response to low temperature rain and snow weather technical guidance
2023 11/22