Guiding Opinions on Summer Vegetable Production Technology

In order to strengthen the field management of vegetables in summer, improve the per unit yield and quality safety level of vegetables, and ensure the adequate supply of vegetables, the Plantation Management Department of the Ministry of Agriculture and Rural Affairs organized the National Agricultural Technology Extension Service Center, the Vegetable Expert Steering Group of the Ministry of Agriculture and Rural Affairs, and the national bulk vegetable industry technology system to study and put forward technical guidance for vegetable production in summer.

1、 Summer management techniques for intensive seedling cultivation
（1） Management of seedling cultivation environment. Always pay attention to changes in the environment of the seedling breeding base. When exposed to strong sunlight, use a shading net in a timely manner, and maintain a distance of 10-30cm between the shading net and the greenhouse film, which is conducive to forming an air duct. When the temperature inside the facility is too high, open the ventilation opening and spray cooling agent at the same time. When it rains, close the ventilation opening in a timely manner, and then open it again after the rain. Under extreme high temperatures, turn on forced cooling systems such as wet curtain fans and mist eliminators. Bottom irrigation and fertilization techniques such as tidal irrigation or floating irrigation can be used to improve water and fertilizer utilization efficiency.

2、 Key Technologies for Summer Vegetable Production in Facilities
（1） Field management
1. Environmental management. Ventilation and cooling. When the temperature is high, open all ventilation openings of the facility to reduce low temperature and humidity. Shading and cooling, covering the outside of the facility with a shading net or spraying shading paint. Fruits and vegetables are generally shaded and cooled from 10am to 4pm on sunny days, and the shading net is opened on rainy days and in the morning and evening; Leaf vegetables can be managed under sun shading throughout the day. Open the shading net 3-5 days before listing to increase light, improve the nutritional quality and commercial value of the vegetables. In areas with strong sunlight, multifunctional extinction films such as diffuse reflection films or high reflectivity films can be selected. Spray cooling. If there is spray equipment, the spray equipment can be started before 11:00 am to cool down, and it can be closed around 3:00 pm. For areas with high temperatures and abundant rainfall in summer, it is recommended to adopt a “two net and one film” coverage mode of top film, shading net, and surrounding insect prevention net.

4、 Key Technologies for the Production of Short Term Fast Growing Leaf Vegetables
Try to choose plots with high and dry terrain, fertile soil, convenient watering, and good drainage. Priority should be given to varieties that are resistant to high temperatures, drought, and waterlogging. Utilize intensive seedling cultivation techniques to cultivate strong seedlings, timely connect stubbles, shorten the growth time of vegetables in the field, and improve land planting efficiency. Adopting high border cultivation to improve ventilation and light transmission conditions in the field and reduce water accumulation in the field. After sowing or transplanting, use lightweight covering materials such as black shading nets and thin non-woven fabrics with a shading rate of about 60% for floating coverage, cooling and moisturizing, promoting neat or slow emergence of seedlings, and promptly removing the covering materials after emergence or slow emergence. It can cover 40 mesh insect prevention nets throughout the entire reproductive period, reducing pest damage.