In order to strengthen the field management of vegetables in summer, improve the yield and quality safety level of vegetables, and ensure sufficient supply of vegetables, the Crop Management Department of the Ministry of Agriculture and Rural Affairs organized 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 Technology System to study and put forward technical guidance opinions on summer vegetable production.

1. Intensive seedling management technology in summer

(I) Seedling environment management. Always pay attention to the changes in the environment of the seedling base. When exposed to strong light, use the sunshade net in time, and keep a distance of 10-30cm between the sunshade net and the greenhouse film to form an air duct. When the temperature in the facility is too high, open the vents and spray cooling agents at the same time. When it rains, close the vents in time and open them after the rain. Under extremely high temperatures, turn on forced cooling systems such as wet curtain fans and mist. Bottom irrigation and fertilization technologies such as tidal irrigation or floating irrigation can be used to improve water and fertilizer utilization.

(II) Seedling development regulation. Use comprehensive measures to regulate the environment and enhance the stress tolerance of seedlings. During the hypocotyl elongation stage when seedlings are prone to leggy growth, ventilation should be enhanced, substrate humidity should be reduced, mechanical stirring and spraying of growth inhibitors should be adopted to prevent leggy growth of seedlings. Inoculation substrates containing plant growth-promoting bacteria or biological fertilizers should be used to improve the microecology of the seedling rhizosphere and enhance the seedlings' ability to resist diseases and drought. Fertilizers containing trace elements should be used, and irrigation and fertilization technology with nutrient gradient increment should be implemented.

(III) Disease and insect control during the seedling stage. The ventilation openings of the seedling raising facilities should be fully covered with 50-mesh or 60-mesh insect-proof nets, and sticky insect boards and sex attractants should be hung in the seedling raising facilities, and protective fungicides should be sprayed to prevent the occurrence of seedling diseases and insect pests. Quarantine should be implemented before commercial seedlings are transported.

II. Key technologies for summer production of greenhouse vegetables

(I) Field management

1. Environmental management. Ventilation and cooling. When the temperature is high, open all ventilation openings of the facility to reduce temperature and humidity. Shading and cooling: Cover the outside of the facility with a sunshade net or spray sunshade paint. Fruit and vegetable vegetables are generally shaded and cooled from 10 am to 4 pm on sunny days, and the sunshade net is opened on rainy days and in the morning and evening; leafy vegetables can be shaded all day, and the sunshade net is opened 3-5 days before listing to increase light and improve the nutritional quality and commerciality of vegetables. In areas with strong light, multifunctional matting films such as diffuse reflection film or high reflectivity film can be selected. Spray cooling: If there is a spray device, the spray facility can be turned on before 11 am to cool down and turned off around 3 pm. Shelter from rain and prevent insects. In areas with high temperatures and heavy rain in summer, it is recommended to use the "two nets and one film" covering mode of top film + sunshade net + surrounding insect-proof nets.

2. Plant management. Pay attention to the balance between seedlings and fruits for fruit and vegetable vegetables, prune, tie vines and remove yellow and diseased leaves in time, remove the top core and side buds in time, maintain a suitable leaf area index, increase ventilation and light transmittance, and ensure balanced growth of plants. Remove deformed fruits at any time to reduce unnecessary nutrient consumption, extend the harvest time, increase the later yield, and improve the commercial quality. Plant growth regulators should be used reasonably to protect flowers and fruits during the high temperature period.

3. Water and fertilizer management. Apply drip irrigation, sprinkler irrigation, water and fertilizer integration and other water-saving and fertilizer-saving technologies, and manage fertilization in accordance with the principles of "controlling nitrogen and increasing potassium" and "thin fertilizer and frequent application", and apply medium and trace element fertilizers in a timely manner. The best time for watering in summer is early in the morning, and it is best to use well water or low-temperature river water for irrigation. For vegetables with relatively weak root or plant growth and high fruit load, foliar topdressing can be implemented to promote plant nutritional growth.

4. Prevention and control of diseases and pests. Adhere to "prevention first, comprehensive prevention and control", do a good job in disease and pest monitoring, and implement green prevention and control scientifically. Agricultural prevention and control, combined with crop rotation, clean vegetable gardens, and reasonable crop rotation. Combined with agricultural operations, timely weeding, removing old and diseased leaves (branches, plants, fruits), and reducing the base number of diseases and insects. Biological control, protect and utilize natural enemies, use biological agents such as Bacillus thuringiensis and avermectin, botanical insecticides, insect growth regulators and specific pesticides for control. Physical control, use insect-proof net covering, color plates, color films to repel, trapping and other technologies. Chemical control, choose the best time for control and use symptomatic drugs, use high-efficiency, low-toxic, low-residue pesticides, scientifically and rationally mix and rotate pesticides, and strictly implement the safe interval period for pesticide use.

(II) Management during the fallow period

1. Do a good job in facility disinfection. Apply high-temperature greenhouse technology. If soil-borne diseases are serious, calcium cyanamide or Weibaimu can be used in combination with high-temperature greenhouse to disinfect the soil. Vegetable straw can be returned to the field in situ, and the straw can be directly crushed and mixed with the soil using stubble machines, or 400-600 kg of field crop dry straw can be returned to the field per mu in the facility.

2. Plant fallow crops. Depending on the length of fallow time, crops such as corn, wheat, beans, and heat-resistant amaranth can be planted and straw can be returned to the field to improve the soil ecological environment, reduce diseases, and promote the growth and development of the next crop of vegetables.

III. Key technologies for summer production of open-field vegetables

(I) Plant management. Melons, solanaceous fruits, and bean vegetables should be framed as early as possible, and field operations such as pruning, pruning, and topping should be carried out in time to increase ventilation and light transmission and promote plant growth. Clean the vegetable garden in time, strengthen the vegetable frame, remove dead branches and diseased fruits, and cultivate the roots in time to enhance the ability to resist lodging. In areas with high light intensity, a certain number of leaves can be retained on the upper part of the fruit to avoid direct exposure to the fruit. Harvest in time when the harvest standard is reached.

(II) Water and fertilizer management. For fruiting vegetables such as tomatoes and cucumbers, moderate water control, shallow tillage, and seedling squatting should be carried out during the initial flowering period to promote fruit setting. When the fruit formation period begins, follow the principle of small amounts and multiple times, and apply fertilizer and water reasonably. Melons, solanaceous fruits, and legumes should be fertilized with nitrogen, phosphorus, and potassium fertilizers. During the critical period of yield formation, foliar topdressing can be carried out according to the growth of the plants. A mixed solution of 0.3%-0.5% potassium dihydrogen phosphate and 0.3% urea can be sprayed on the leaves of vegetables, sprayed once every 7-10 days, and sprayed 2-3 times in a row. For the cruciferous cabbage, cauliflower, Chinese cabbage, etc., it is necessary to control first and then promote, and to fertilize and irrigate reasonably. Water-saving technologies such as sprinkler irrigation, alternate irrigation between furrows, and furrow irrigation on the film can be used. Nitrogen fertilizer is mainly used for topdressing, and thin fertilizer is applied frequently.

(III) Prevention and control of diseases, insects, and weeds. In hot and humid weather, broad-spectrum fungicides such as carbendazim or methyl thiophanate can be sprayed 1-2 times. Green control technologies such as insecticidal lamps, black light lamps, pheromone trapping, and interference disorientation can be used for cruciferous vegetables. Weeds in and around the vegetable field should be removed in time. Timely prevention and control of diseases, advocating the alternating use of 2-3 kinds of pesticides, strictly implementing the safe interval period for the use of pesticides, and vegetables that are harvested multiple times should be harvested first and then sprayed to ensure the safety of vegetables.

IV. Key technologies for the production of short-term fast-growing leafy vegetables

Try to choose plots with high and dry terrain, fertile soil, convenient watering, and good drainage. Give priority to varieties that are resistant to high temperatures, drought, and waterlogging. Use intensive seedling technology to cultivate strong seedlings, connect crops in time, shorten the growth time of vegetables in the field, and improve land planting efficiency. Use high-bed cultivation to improve field ventilation and light transmission conditions and reduce field waterlogging. After sowing or transplanting, use light covering materials such as black sunshade nets with a shading rate of about 60%, thin non-woven fabrics, etc. for floating covering to reduce temperature and moisture, promote uniform emergence or slow seedlings, and remove the covering materials in time after emergence or slow seedlings. Cover with 40-mesh insect-proof nets throughout the growth period to reduce insect pests.

V. Key technologies for the production of alpine vegetables

(I) Variety selection. Medium and high altitude areas between 800 and 1,400 meters are suitable for growing warm-loving vegetables such as tomatoes, peppers and green beans. High altitude areas above 1,200 meters are suitable for growing cool-loving and cold-resistant vegetables such as radishes, Chinese cabbage and kale. Cruciferous vegetables should be selected as late-bolting varieties. In high mountain and high altitude areas, the temperature difference between day and night is large, the air humidity changes rapidly, the ultraviolet light is strong, and the product transportation distance is long. It is advisable to select varieties with strong disease resistance and stress resistance, good commercial properties, and storage and transportation resistance.

(II) Environmental management. Alpine tomatoes, peppers and other fruits and vegetables should adopt rain shelter cultivation technology, use simple steel frame greenhouses, cover the top with film, and surround with insect-proof nets to achieve rain shelter and insect prevention. Supporting construction of water collection pools and plastic rainwater collection pits, etc., adopt sub-film drip irrigation technology to achieve precise fertilization. Adjust acid and calcium, and increase the application of functional organic fertilizers containing beneficial bacteria to improve soil fertility.

(III) Disease and pest control. To prevent and control the root knot disease of cruciferous vegetables, rotation with non-cruciferous vegetables should be adopted, soil disinfection should be implemented, organic fertilizer should be added, acidification and calcium supplementation should be carried out to improve disease resistance, diseased plants should be removed in time when they are found, quicklime should be spread in time on diseased holes, and diseased plants should be burned in a centralized manner to reduce repeated infection of pathogens. For plots infested by underground pests, lime nitrogen or quicklime should be used for disinfection more than 20 days before sowing, and the surface of the ridge should be covered with film to keep it moist for 10 days before drying. After the vegetables are harvested, the diseased and insect-infested leaves and weeds should be cleaned up in time, and concentrated in the field for composting to reduce the source of insects. Insecticide lamps and yellow board trapping techniques should be used to reduce the damage caused by adult insects and the amount of egg laying.

In addition, alpine vegetable bases should implement ecological protection and ecological cultivation measures, build biological ridges and cooperate with slope digging to reduce slope runoff and control soil and water loss.