Sowing period The lettuce field in the Yangtze River Valley is overwintering. It is mainly spring lettuce. It is generally planted in the first year of fall from September to October. When 40 to 50 days, the plant will plant 5-6 leaves and planted in the winter. It can be safely wintered in the winter, and it is full after the spring return. Time to grow leaves, harvesting from April to May can get high yield. Cultivate strong seedlings lettuce Lettuce will be transplanted. Seedbed selection of fertilizers to maintain water, loose loose fertile loam, the first application of compost manure urine turned into base fertilizer. Seeding amount per seedling 100-150 grams, can be planted two acres. After sowing, the cover is covered with a layer of fine soil and moistened with grass tablets. After 7-8 days of bud emergence, the grass pieces are removed and the top dressing is applied 2-3 times. Each piece of ground water is 50-100 kg of feces or 0.5-1 kg of urea. Cotyledon flat and 1-2 leaves each time when the seedlings were transplanted once a week before transplanting, with 0.5-1 kg of urea per minute, and the water was sprayed one day before the emergence to avoid rooting. Large and small seedlings are planted separately to facilitate field management. Summer lettuce shade net cover cultivation First, choose good seeds, germination at low temperature, and cultivate strong seedlings. Choose high-product varieties with strong heat resistance, unresponsive to sunlight, and difficult to twitch, such as Tetsuoshan Cuiyu and Qishan Cuisheng. Seedlings are sown in late June, and the nursery beds are selected where the terrain is high and the soil is fertile. Soak germination before sowing to facilitate seedling emergence. The method is to soak the seeds with fresh water for 24 hours, remove and wash them and place them in a refrigerator with gauze, and treat them at −3° C. to −5° C. for 24 hours. Place the seeds that form the ice cubes in a cool place indoors. It gradually melts and can be sowed after 80% of the seeds are exposed in 3-5 days. It is also possible to suspend the soaked seeds in the well to germinate at a distance of 30 cm above the water surface. After seed germination, add a small amount of fine sand to sow the seeds and sow 2-3 grams per square meter. After sowing, it was covered with shallow, nutritious soil, and the surface was covered with shade nets to make up for the bottom water. The small arches above the surface covered the shade nets and the agricultural film. After the emergence, the surface shade nets were removed and fine soil and seedlings were sprinkled; the shading nets on the scaffolds were covered at 8 o'clock in the morning on sunny days and uncovered at 5 o'clock in the afternoon; cloudy days were not covered, and shade nets and agricultural film were timely covered under heavy rain. After two true leaves, the coverage time was gradually reduced. The seedlings were careful to prevent underground pests and snails. Seedlings age 22-25 days transplanting. Second, rational dense planting, shade moisturizing. In the middle and late July, after 4-5 true leaf leaves of lettuce seedlings are planted, they are selected for transplanting in the evening or on cloudy days. The general spacing is 33 cm and the spacing is 30 cm. Pay attention to the size of the seedlings transplanting, after the planting water foot live water, cover the shade nets on the scaffold to promote the slow seedlings. Third, Shizujifei, timely fertilizer. From the time of planting and harvesting of lettuce to more than one month, if there is a lack of fertilizer, the plants will grow poorly, prone to premature convulsions, and yield and quality will decline, so the base fertilizer should be sufficient. Generally, the Mushi is used to compost 2500-3000 kilograms of human or animal manure, 1,000 kilograms of decomposed chicken manure, and 25-30 kilograms of 45% NPK fertilizer. Lettuce wake up and live after planting 1-2 times diluted manure, promote seedling growth. After the rosette period, when the fleshy stems begin to swell, combined with watering, 15-20 kg of urea are applied per mu. Fourth, timely control, disease prevention and pest control. Lettuce seedlings 3-4 true leaves, sprayed 350 mg/kg chlormequat or 75 mg/kg paclobutrazol solution, can prevent seedling louse high; lettuce after rosette period, according to growth again spray 1-2 times 150 mg/kg paclobutrazol Solution or 350 mg/kg of chlormequat solution inhibits premature twitching and thickens the fleshy stem. The main diseases that endanger the growth of summer lettuce are downy mildew and virus diseases. It can be controlled with 500% metalaxyl manganese zinc and 500% fluid with 3.95% virus and 500 times fluid; when it is found to be harmful to aphids, 10% imidacloprid 1500 times can be used. , Spray control. Fifth, appropriate harvesting. When the leaves of the lettuce leaves are at the same level as the tips of the tallest leaves, they can be harvested and marketed. General yield of 1800-2000 kilograms per mu, income of 3,000 yuan. Cultivation Leaf lettuce lettuce After planting, it is necessary to increase the supply of nitrogen and phosphate fertilizers and at the same time, control the moisture so as to prevent the external leaves from being leggy. The total growth period of lettuce is top dressing 3 times. About 15 days after the first easing of seedlings, 15 kg of ammonium sulfate or 12 kg of urea per 667 square meters was used to promote seedling growth and growth. The second time in the early ball stage; the third time in the middle of the ball, the ball is fully expanded, with 15 kg of ammonium sulfate or 12 kg of urea per 667 square meters, and 0.3% of potassium dihydrogen phosphate is used for the leaves. Surface fertilizer application is beneficial to increase production. When spraying fertilizer, it is selected after 3 pm. Do not add fertilizer or water to late lettuce to avoid causing rot or cracking. Stem lettuce Lettuce has strict requirements on fertilizers and water. Improper management can lead to leggy and premature twitching and can not form fatty stalks. Spring lettuce. The sowing date was after September in the first year, and it stopped growing for a period of time before the winter. After the application of quick-release nitrogen fertilizer, 7.5 kg of urea or 10 kg of ammonium sulfate was used per 667 square meters to promote the increase of leaf number and the expansion of leaf area. Control the watering and seedlings after the deep cultivator and form the developed root system and rosette leaves. Prior to freezing, cover the plants with horse dung or manure. After returning to the green the following year, the leaf area rapidly rose to be rosette-like, and a fast-acting nitrogen fertilizer should be applied topped with 10-15 kg of ammonium sulfate per 667 square meters or 10 kg of urea. Topdressing was performed in conjunction with watering. After watering, the stem will grow faster and the fertilizer will increase. Generally, 15 kg of ammonium sulfate or 10 kg of urea can be applied per 667 square meters, and 10 kg of potassium dihydrogen phosphate can be applied. The fertilization can also be carried out in small quantities, since the stem is slightly dry on the ground during the period of the fertilization, so the fertilization can be applied less frequently and frequently to prevent the stem from cracking. During the expansion period of the stem, 500-1000 mg/L of Qingxin can be used for foliar spraying, which can inhibit convulsions. Autumn Lettuce Corn Starch ,Corn Starch Heb,Bulk Corn Starch,Cornstarch Healthy Shanghai J.Shine Co.,Ltd , https://www.jshinechem.com