Northern summer vegetable production technical guidance

In order to effectively prevent and respond to the summer disastrous weather, strengthen the management of vegetables in the field, and promote the 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 put forward technical guidance opinions on northern summer vegetable production.

1. Intensive seedling cultivation of vegetables

1. Strengthening preparedness against severe weather disasters

Pay close attention to the short and medium term weather forecast of the local meteorological department, timely shade and cool down, shelter from rain and prevent disease, and actively do all the work of autumn seedling breeding. First, carefully check the seedling facilities, timely strengthen the facilities, walls, pillars, shed film and other key points to prevent collapse. Second, carefully inspect the drainage system of the seedling field area, dredge the drainage ditch in advance, keep the whole network connected, and do a good job in the maintenance and preparation of drainage pumps and other equipment. Third, timely maintenance of power facilities and equipment to prevent leakage and power failure. Fourth, it is necessary to improve the facilities and equipment for shading and cooling, rain and disease prevention, and comprehensively improve the ability of the seedling base to cope with extreme weather.

(2) Strengthening environmental management for seedling breeding

When the strong light is exposed, the external sunshade facilities should be used in time, and the distance between the sunshade net and the shed film should be kept 10-30cm as far as possible to form an air duct. When the temperature in the shed is too high, the top and side vents of the shed should be opened to enhance the air circulation exchange and reduce the temperature. When the temperature is extremely high, the cooling system such as shade, wet curtain - fan and mist can be opened at the same time. Before a thunderstorm, close the tuyere in time to prevent rain from pouring into the shed, and ventilate and cool down after the rain. In the morning, evening and cloudy days, care should be taken not to cover the shading facilities to increase the light time of seedlings and promote photosynthesis. Tidal irrigation, floating irrigation and other bottom irrigation fertilization methods are recommended.

(3) Strengthening regulation of seedling development

According to the growth and development of seedlings, comprehensive measures are taken to prevent vegetable seedlings from growing. First, it is reasonable to regulate the growth environment of seedlings, increase the light time, and it is not appropriate to cover the shading facilities at night to reduce the temperature and increase the temperature difference between day and night. The second is to use ventilation to disturb seedlings and appropriately enhance the mechanical strength of stems and leaves; If necessary, turn on the fan in the morning and evening to force the exhaust air to disturb the seedlings. The third is to control the irrigation amount reasonably, so that the relative humidity of the matrix can be maintained at 55%-65% for a long time. The fourth is reasonable choice of fertilizer, increase the application of potassium fertilizer, control the application of nitrogen fertilizer. Fifth, the rational use of growth inhibitors should follow the principle of "three looks" and "three noes", that is, look at the development stage and growth of seedlings, look at the future weather trend, see the seedling time, "three noes" that is, do not apply high doses, should be light multiple times, do not choose products with too long effect period, and do not apply rhizosphere (irrigation).

2. Open field vegetable production

(1) Preventive measures against severe weather

Pay close attention to weather changes and implement corresponding preventive measures in a timely manner according to weather forecasts. High mountains and plateaus and areas prone to strong convection weather should focus on preventing sudden hail hazards. Brackets should be set up in advance in high incidence areas, and hailstorm nets should be installed in advance when there is hail warning. When the strong light area enters the high temperature and strong light season, the support should be set up to install the sunshade net; Rainfall concentration areas should be designed in advance of scientific and reasonable drainage system, ready pumping machinery, as far as possible to implement deep ditch and high ridge cultivation, after heavy rain in time to clean up the gutter debris, drainage as soon as possible, reduce flooding time.

(2) Management techniques of vegetables in the field

At present, the vegetables in the north are mainly cucumbers, tomatoes, eggplants, peppers, cowpeas, beans and other fruits and vegetables and kale, cauliflower and other cruciferous vegetables, focusing on the following management work.

1. Plant management. For vegetables that need to be planted as soon as possible, field operations such as pruning, pruning and core picking 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 rack, remove the residual branches and diseased fruit, and cultivate the soil and root in time to enhance the anti-toppling force; In areas with high light intensity, to prevent the occurrence of sunburn diseases such as tomatoes and peppers, a certain number of leaves can be retained through the upper part of the fruit to avoid direct sun exposure of the fruit; When the harvest standard is reached, it should be harvested in time to prevent the deterioration of the value of commodities in the event of rain and high temperature fading.

2. Water and fertilizer management. Tomatoes, cucumbers and other fruits and vegetables at the initial flowering stage, moderate water control, shallow cultivation, squat seedlings to promote fruit setting; Into the product formation period, follow the principle of small amount and multiple times, rational application of fertilizer and water, if conditions can be used drip irrigation facilities, integrated management of water and fertilizer, to promote the formation of production. Melons, jackets, legumes and vegetables should be combined with nitrogen, phosphorus, potassium fertilizer; In the critical period of yield formation, leaf spraying fertilizer can also be performed according to plant growth, which can be used to spray 0.3% -0.5% potassium dihydrogen phosphate and 0.3% urea mixed solution on the crop leaf surface, spray once every 7-10 days, and spray 2-3 times in order to improve yield, prevent premature aging of plants, and reduce the occurrence of deformed fruit. For cruciferous cabbage, cauliflower, Chinese cabbage, etc., it is necessary to first control and then promote, and rational topdressing irrigation can be adopted, such as drip irrigation, spray irrigation, alternate irrigation of ditches and irrigation on film. Leafy vegetables mainly use nitrogen fertilizer, thin fertilizer frequently applied. Summer high temperature watering should be chosen before 10 am and after 4 PM, especially leafy vegetables should not be watered at noon when the temperature is high. In case of high temperature and drought, water should be diverted in time to irrigate and keep the soil moist.

3. Control weeds and pests. When the weather is high temperature and high humidity, it can spray 1-2 times of carbendazim or methyl tolbuzine and other broad-spectrum fungicides to prevent diseases. Remove weeds in and around the vegetable field in time to prevent fertilizer competition with vegetables, reduce the host of diseases and insects, and reduce the occurrence of diseases. Cabbage, cabbage and cauliflower and other cruciferous vegetables are prone to rapeseed insects, diamond-moth harm, can be installed in the field insecticidal lights, black light and so on. Timely prevention and control of diseases, promote the alternate use of 2-3 kinds of chemicals, and strictly implement the safety interval of pesticide use.

3. Facilities for vegetable production

(1) Disaster prevention and facility reinforcement

Preventive measures against severe convective weather such as heavy rainfall and short-term gale should be implemented in a timely manner. First, improve drainage facilities, dredge drainage pipes, ensure smooth drainage in the event of heavy rain disasters, and prevent rainwater from pouring back into the shed. The second is to strengthen the facilities, press the film line to prevent strong winds from lifting the film. Third, the earth wall greenhouse should strengthen the wall protection, and use the shed film to protect it well to prevent the wall from collapsing due to rain erosion.

(2) Vegetable management in the field

1. Environmental management. (1) Ventilation and cooling. When the temperature is high in summer, the greenhouse, the roof vent, the waist vent are all opened, the vent is installed 40 mesh insect-proof net, day and night ventilation, reduce the temperature and humidity in the shed. (2) Shading and cooling. According to the requirements of light intensity and management cost of cultivated crops, black sunshade nets with different shading rates can be selected, vertical cooling paint or mud can be sprayed on the shed film for shading and cooling. The greenhouse film in the strong light area can also choose diffuse reflective film or high reflectivity film to increase the transmittance of scattered light and reduce the temperature in the shed. Fruits and vegetables generally shade and cool from 10 a.m. to 4 p.m. on sunny days, and open the shade net in rainy days and in the morning and evening to ensure the yield and quality; Leafy vegetables can be sunshade management throughout the day, but the sunshade net can be opened 3-5 days before the market to increase light, improve vegetable tenderness and vitamin C, soluble solids and other contents, and improve nutritional quality and commerciality.

2. Plant management. The focus of fruit and vegetable management is to balance the relationship between seedlings and fruits, timely rectification of branches, binding of vines, removal of yellow leaves and diseased leaves in the middle and lower part of the plant, so as to increase ventilation and light. Remove deformed fruit at any time, reduce unnecessary nutrient consumption, in order to extend the harvest time, increase the later production, and improve the marketability. The high temperature period, especially the high night temperature, will lead to low pollen amount and poor vitality of tomato and other fruits, so it is necessary to rationally use plant growth regulators to protect flowers and fruits.

3. Water and fertilizer management. According to the growth stage of vegetables, water and fertilizer management is reasonable, and the principle is small amount and multiple times. Summer watering time should be chosen in the early morning, avoid strong light, high temperature at noon, to prevent damage to plant roots and reduce water evaporation loss. It is best to use well water or low-temperature river water to reduce soil temperature while watering and promote root growth. According to the different types of vegetables, water saving and fertilizer saving technologies such as drip irrigation, sprinkler irrigation and water and fertilizer integration can be selected; In the stage of relatively weak root or plant growth and high fruit load, it can also be combined with foliar topdressing to promote plant nutrient growth. The types and principles of topdressing can be referred to the field management of open-field vegetables.

4. Comprehensive pest control. In summer, with high temperature and high humidity in the facilities, it is necessary to strengthen the control of vegetable diseases and pests, adhere to the comprehensive control measures of "biological control, physical control and scientific application of chemical control on the basis of agricultural control", and control the harm of vegetable diseases and insects within a certain range.

(3) Management of shed leisure period

The northern solar greenhouse generally has a 30-50 day leisure period from mid-July to the end of August, and the following management can be carried out according to the specific situation of the greenhouse:

(1) Return fruit and vegetable straw to the field in situ in combination with high temperature confinement shed or other soil disinfection technologies (such as lime nitrogen disinfection). Straw and soil can be directly broken and mixed by stubble removal machinery, reducing the labor cost of straw removal, solving the problem of vegetable straw waste treatment, and improving the soil available nutrient content, reducing the soil bulk density, and improving soil fertility.

(2) Planting filler crops. According to the length of leisure time in the shed, corn, wheat bean, heat-resistant amaranth, etc., can be planted to improve the soil ecological environment, reduce disease, and promote the growth of next crop vegetables.