Lettuce has been cultivated in many places for four consecutive years. However, in the cultivation, the plants are often prone to early bolting with fewer leaves, fewer stems, more shoots, longer stems and longer sticks, which affects the yield and reduces the quality. After summarizing the production experience in recent years, the reasons for the high escaping rate of lettuce stems and their effective control measures mainly include the following 10 aspects. 1. Improper selection of varieties There are many varieties of lettuce, and its adaptability and degree of sensing of sunshine and temperature are not the same. Often early-maturing varieties have stronger resistance to low temperature and higher temperature resistance than mid- and late-maturing varieties, but they have high temperature and long daylight. More sensitive. Therefore, suitable varieties should be selected according to the cultivation season. For example, lettuce grown in spring and summer harvests and summer harvests are grown under high temperatures and long days. Therefore, mid- and late-maturing varieties that are resistant to high temperatures and unresponsive to long days of sunshine should be selected; Early-maturing varieties planted in early spring, the market is early, high yield, good efficiency, if late planting, due to the late growth temperature, long sunshine, high yield and low efficiency. 2. Sowing period is not suitable for spring lettuce cultivation. If the seedlings are sown early in the fall, the growth period is long before winter, the seedlings are too large, the flower buds are differentiated early, the wintering is easy to suffer from freezing injury and the jujube is also easy to pick up; if sowing is late, before winter Shorter growth period results in smaller seedlings, less accumulation of nutrients, and winterization, which is also prone to frost damage and late for market in the coming year. Late summer lettuce sowing or autumn sowing early sowing lettuce, high temperature during the growing season, long sunshine, prone to seedling growers. Therefore, lettuce cultivation should pay attention to mastering the sowing time, general spring lettuce sowing seedlings exposed in early October, nursery protection seedlings in early and late January, summer lettuce shoots in early April, autumn lettuce sowing in early August, winter lettuce sowing in late August should. 3. Immature seedling management poor planting rate, emergence too dense, seedlings are not timely and appear crowded seedlings; seedbed partial nitrogen fertilizer, too much watering and shading seedlings shading too heavy, removal is not timely, etc., can cause Miaotuchangchang. Therefore, seedling management should be aimed at controlling legacies and cultivating short-sturdy seedlings. Specific measures include: seedbed base fertilizer with organic fertilizer, can be applied with appropriate amount of compound fertilizer; appropriate dilute sowing, and time seedlings, control of watering, to see the bed see dry see wet is appropriate, shade seedlings should gradually after the whole seedlings The cover was uncovered until it was no longer shaded after 3 leaves; summer and autumn lettuce was sprayed with 1 or 2 shots of CMC for a concentration of 500 mg/kg, which can effectively prevent leggy. 4. Implantation is not timely and colonization is not timely, the seedlings often grow too fast, the hypocotyl elongation was in a state of leggy, and it is difficult to obtain the hypertrophic stems after planting. It is generally required to have 5 to 6 leaves of seedlings of the appropriate age for timely colonization. The seedling age for autumn sowing shall be about 40 days, the seedling age for spring sowing or summer sowing shall be about 25 days, and the seedling age for autumn sowing shall be 30 to 35 days. should. 5. Cultivation of dense planting density is too large, before the formation of rosette leaves have been ridged, resulting in plant crowded, lack of light, and have to pull high and win light. Under normal circumstances, the spring harvest lettuce can be moderately densely planted with early benefits, and 8,000 plants can be planted at 667 square meters. Summer harvest lettuce is suitable for sparse planting due to high temperature and long days, and 5,000 planted plants at 667 square meters are good; , 7000 plants planted at 667 square meters are of good quality and high yield. 6. Fertigation and rainfall after fertilization with less cultivated loose soil can cause soil compaction, high humidity, and poor ventilation. If the soil is not ploughed in time, it will affect the growth of the root system and the absorption of water and fertilizer, so that the leaves do not get enough water and fertilizer, but easy to grow into plants that are not robust and have thin stems. Therefore, timely cultivating after culturing the vegetative seedlings should be carried out in a timely manner so as to facilitate the seedlings, promote the development of the roots, and increase the number of rosette leaves. 7. Improper Watering If lettuce is not properly planted after cultivating, if too much water or rain is not removed in time, the soil moisture is too high. Under high temperature conditions, the growth of young shoots is weak, and it is easy to show “drought and droughtâ€. Therefore, the watering of lettuce cultivation should be appropriate. It is necessary to prevent "slugs" and prevent "drought floods." Before the formation of rosette leaves and ridging of the plants, proper watering should be controlled so that it is better to see the wet surface. After the ridges are closed, the water supply should be increased to keep the surface wet to meet the needs of rapid growth and expansion of the tender stems. 8. Insufficient fertility or partial application of nitrogen fertilizer base fertilizer or fertilizer is not timely, soil fertility is low, plant nutrient growth is controlled, will accelerate reproductive growth, but also prone to immature convulsions. However, the partial application of nitrogen fertilizer causes the leaves of the plants to be long and has less accumulated nutrients. Therefore, in addition to basal fertilizer to apply enough, 667 square meters of manure fertilizer 4,000 kg, 25 kg of compound fertilizer, so that organic fertilizer and compound fertilizer combined, it should also be timely application of slow Miao Fei, Tuan tree fertilizer, prompting bamboo shoot fertilizer, top dressing Each time 667 square meters with ammonium sulfate or urea 15 ~ 20 kg, or the first two times with 50% of 1,000 kg of diluted fecal water. 9. Climatic conditions are unsuitable for lettuce, late-breeding or summer-autumn cultivation. Due to high temperature and long days of sunshine, there are often few leaf differentiation, early flower bud differentiation, and rapid flower development. The management is slightly careless and can easily affect the quality and yield. . To this end, in addition to strengthening water and fertilizer management, regular spraying of chlormequat is an effective measure for the cultivation of lettuce control pods at high temperatures. Spraying chlormequat can delay the growth of lettuce, promote leaf growth, increase nutrient area, and thicken tender stems. Spraying is usually started at the rosette stage, 7 to 10 days, 2 to 3 times in total, with a concentration of 350 mg/kg. 10. Timely picking is not suitable for harvesting from the “flat mouth†leaves and outer leaves. If harvesting is too late, especially late spring bamboo shoots, summer bamboo shoots, and autumn bamboo shoots that grow during the high temperature season, buds are often formed before harvest and are not harvested in time. If it is delayed for harvesting and supply, Acer spirillum can effectively control the high stem twitching of the shoots, that is, timely picking up the top growth point or buds of the lettuce during the “flat mouth†period on a sunny day, and suppressing the top growth after the top-down plants. Increase the backflow of nutrients in stems, prevent hollow stems and promote shoot stem hypertrophy, which can be delayed for 5-7 days and increase production by 1 or 20%.
ZHOUSHAN SINOMEGA BIOTECH ENGINEERING CO.,LTD , https://www.sinomegabiotech.com