What should I do if the temperature in leek shed is high in July and August?

The temperature of leek covered shed is high in July and August, and the indoor humidity is high due to sealing. In order to prevent the room temperature from being too high or the humidity from being too high, ventilation should be adopted. Generally, natural ventilation is used to reduce indoor humidity by adjusting the size, time and location of ventilation openings. It is better to use mechanical forced ventilation when conditions permit. In addition, covering the greenhouse with plastic film can greatly reduce soil moisture evaporation and effectively reduce air humidity. Micro-irrigation technology is used to control irrigation quantity, save water and reduce humidity.

High-yield and high-efficiency cultivation techniques of leek

1 Select fine varieties.

Variety is the key to the success of planting, and the benefits are high and low. In recent years, Xipu leek varieties have been screened out through comparative experiments and demonstrations. This variety has a long cultivation history, stable characters, strong fragrance of leek, fresh and crisp quality, high yield, strong cold and heat resistance, and can grow in all seasons, which is suitable for shading and softening.

2 land selection and preparation

Leek requires high soil quality, so it should be planted in sandy loam with deep soil layer, high organic matter content, loose air permeability, strong water and fertilizer conservation ability and convenient irrigation and drainage conditions. Try not to pick up stubble or onion stubble. After planting leeks, the roots "jump" every year after years of no tillage. Leek yellow needs to be cultivated, so it needs deep ploughing before sowing. The ploughing depth of soil layer is generally 25 ~ 30 cm, even more than 40 cm. After deep ploughing, the soil was exposed to sunlight for 3 ~ 5 d, and the clods were broken. After careful soil preparation, furrow is opened to make a border. The plot is flat, with ditches around it, and the uneven plot does not need to be used as a drainage ditch.

3. Choose a suitable cultivation method.

In the case of seedling transplantation, seeds are prepared in the field at the rate of 7.5 kg/hm2, and the sowing time is from the end of March to the beginning of April, and the seedbed in the field is 750 m2/hm2. Soak the seeds in warm water below 40℃ 10 h before sowing, and then dress the seeds with 2% carbendazim dry and wet powder for later use. First, pour the prepared seedbed with bottom water, then sow, spray 800 times of 5% phoxim, cover with fine screen soil with thickness of 1 cm, cover with plastic film, and compact both sides with soil. When 80% of leek seedlings emerge, remove the plastic film in the clear evening. Water 1 time, urea 150 kg/hm2 twice 5-7 days after five leaves, and stop watering 5-7 days before transplanting. Leek seedlings can be transplanted when they grow to 15 ~ 20 cm. If it is propagated by individual plants, it is best to separate the old seedlings and plant them in autumn and winter, and the time is from the current year 10 to the next year 10. Before planting, apply 7.5~ 15.0 t/hm2 of decomposed farmyard manure or 2 250~3 750 kg/hm2 of organic compound fertilizer, and fully mix with soil. Planting specifications: row spacing 75 ~ 80 cm, planting ditch depth 25 ~ 30 cm, double row "pin" planting 5 cm, each hole 1 ~ 2 seedlings is appropriate, and foot root water can be sprayed.

4 Water and fertilizer management

After leek seedlings survive, combined with water supply, 10% human and animal feces and urine can be properly applied twice; 1 time before soil cultivation 1 time before heavy fertilizer application, 600 kg/hm2 chlorine-free organic compound fertilizer can be applied, and then 300 kg/hm2 organic compound fertilizer can be applied before soil cultivation and applied to both sides of leek seedlings. In order to improve the yield of Chinese chives, Pterocarya stenoptera powder with the concentration of 1 000 times can be sprayed as foliar fertilizer, and it can be sprayed three times during the whole growth period, that is, 1 time before green cutting, 1 time after green cutting and 15 days after yellow cutting [3]. Advocate water-saving irrigation. At present, sprinkler irrigation and drip irrigation with integrated water and fertilizer are mainly promoted in Guangxi. The installation cost of sprinkler irrigation is 6000 ~ 9000 yuan /hm2, and its service life is 6 ~ 8 years, which is 4500 ~ 6000 kg/hm2 higher than that of conventional irrigation. The advantages of sprinkler irrigation mode are low requirements for water quality and low input cost, which can achieve the effect of increasing production and income; The disadvantage is uneven irrigation, which is easy to cause soil hardening. The installation cost of water and fertilizer integrated drip irrigation is 37,500 yuan /hm2, and its service life is 6-8 years, which is 9.6- 12.0t/hm2 higher than that of conventional irrigation. Compared with sprinkler irrigation, the yield increased by 5100 ~ 6000 kg/hm2. The advantages of this irrigation method are water saving, fertilizer saving, medicine saving and labor saving; Disadvantages are high requirements for water quality and high one-time investment cost.

5 cultivate soil and cut green

Raising soil is one of the main measures to soften pseudostems. Before the first 1 harvest of Chinese chives, the soil should be fertilized twice a year, that is, 6 months after planting Chinese chives, and the time is from May to 165438+ 10 of the second year after planting Chinese chives. After the first 1 harvest of leek, the soil should be cultivated for the first 1 harvest twice a year. When cultivating the soil, stir up and fix the leek leaves with a thin bamboo pole first, and then cultivate the soil, taking care not to hurt the roots, stems and leaves. When the leek leaves grow well, cut off the leek leaves by more than 2 cm at Qihekou, which is called green shearing.

6 gaipeng

Cover the shed after cutting green. Once the leek has been planted for 1 year, you can start to cut green and cover the shed to harvest the leek yellow. The tile specification of leek shed is generally 270 cm (length) × 170 cm (width), and the material is 15 kg straw and thatch inside and 3 kg tarpaulin outside. Use wood as a bracket, spread a handful of straw and thatch on the bracket, arrange the grass tails neatly, and tie the bracket tightly with fine wire. Covering 450 leek sheds /hm ~ 2 on the leek ridge, it is triangular, with two sides 270 cm long, the bottom 40 cm wide and the height 85 cm. The thickness of leek shed should be opaque, and the coverage height should be high rather than low, otherwise it will affect the yield and quality of leek.

7. Prevention and control of diseases, insects and weeds

The common diseases of leek in Guangxi are gray mold, Fusarium wilt and rust. Gray mold mainly harms leaves, especially in low temperature and high humidity weather. In terms of prevention and control, the field should be cleaned, ventilated and dehumidified, and 25% carbendazim 1 000 times should be sprayed in time after the leek is cut and the new leaves germinate. Phytophthora infestans can harm roots, stems and leaves, especially pseudostems, and the damage is more serious when the humidity is high. During prevention and control, the lower old leaves should be removed in time to prevent water accumulation in the field. At the initial stage of the disease, 68.75% Yinfali can be sprayed with water for 900 ~ 1. 1.25ml/hm2, every 5 ~ 7 d 1 time, for 2 ~ 3 times continuously. Rust mainly harms leaves, which are covered with brown powder spots and rust powder, so the leaves are inedible. Warm and humid weather is conducive to the occurrence and prevalence of infection, and 15% triadimefon wettable powder 1 500 times solution should be sprayed in time at the initial stage of infection. The pests of leek are mainly leek maggots, thrips and aphids. The yellow board was used to trap and kill aphids, and 40% omethoate was sprayed with 800 ~ 1 000 times solution to control thrips. Leek maggots mainly gather underground to harm young stems, and in spring and autumn, they harm young stems of leeks, causing them to rot and their leaves to turn yellow and die. In contrast, 3000 ~ 3750 kg/hm2 plant ash was applied in furrow between rows of Chinese chives. Irrigation with 800 ~ 1 000 times of 80% trichlorfon crystal. The main weeds in leek field are barnyard grass, wild amaranth and dandelion. Herbicide can be dug up or sprayed manually, and 675 kg of water can be sprayed with 15% glyphosate 2.25 kg/hm2.

8 cut leeks in time

When the leek grows to more than 60 cm and the leek tip begins to wilt, it can be harvested. The harvest time depends on the season, from June 5438 to February of the following year, and it can be harvested about 30 days after the shed is built. From March to May, it can be harvested after 15 ~ 20 d; Harvesting in June-June, harvesting after 13 ~ 15 d covered with shed; 11-65438+February, generally harvested 20 ~ 25 days after shed cover. When harvesting, first uncover the leek shed, help the leek leaves to one side, and cut them evenly along the ground with a 7-shaped knife. It is best to harvest in the morning. In order to increase yield, improve quality, avoid premature aging and prolong life, it is better to harvest twice a year in/kloc-0. In autumn and winter, the purchase price of leek is higher, and the time is from 10 to February of the following year.