Improve the cultivation environment and produce high quality lettuce

Lettuce can be divided into two types: leaf type and stem type, and the consumption of stem type lettuce is mainly in the market. The stem type is divided into spring lettuce, autumn lettuce and overwintering lettuce. In order to achieve high yield and high quality, these lettuce need to improve the cultivation environment in many aspects.

First of all, we should choose the soil with deep texture. It is necessary to choose loose and fertile sandy loam or clayey loam. When the nutrients are sufficient, the fleshy underground stem can expand and enlarge. Lettuce is sensitive to soil pH (pH). The most suitable pH value for growth is 6.8. if the pH value is higher than 7 or lower than 5, the growth and development of lettuce will be inhibited.

Secondly, temperature and moisture should be well regulated. Lettuce can also germinate at low temperature, but the optimum temperature for germination is 15 ℃ ~ 18 ℃, and the optimum temperature for growth and development is 15 ℃ ~ 20 ℃. Before flowering, when the temperature exceeds 28 ℃, lettuce will bolt quickly, the succulent young stem will grow, and the quality will decline. However, in the flowering and podding stage, the seed maturity was better when the temperature was 23 ℃ ~ 30 ℃.

In production, when sowing seedlings and field management, it is necessary to adjust the temperature according to the season. The yield of lettuce is reflected by the size of fleshy stem, the proportion of stout and fat lettuce is high, high yield and high quality have the foundation, but strong lettuce must have enough water to develop and expand normally. If the drought persists, there will be more crude cellulose in the fleshy stem, rough epidermis and bitter meat. Therefore, lettuce should be planted in the field to ensure wet management, so that the product is tender and delicious, and the taste is pure.

Third, scientific fertilization should be applied to improve the quality of tender stems. Lettuce for stems belongs to root vegetables. The appearance of normally growing lettuce should be: the leaves are thick and flat, the leaves are densely arranged, and the growth tip is below the highest point of rosette leaves. In order to promote the robust growth of tender stem, the following points should be grasped in fertilizer application: first, balanced fertilization should be formulated. Because root vegetables have a large demand for potassium fertilizer, the application ratio of nitrogen, phosphorus and potassium is generally 1 ∶ 0.5 ∶ 1.8. during the expansion period of fleshy stem, the amount of potash fertilizer should be increased appropriately. Second, it is necessary to prevent "bolting" when the tender stem enters the vigorous growth period, such as excessive watering when the fertility is insufficient, the tender stem may only grow and slender (waterlogging), high temperature and drought, rough stem bark, showing tender stem slender (dry run). In this regard, during this period, it is necessary to attack fertiliser and water, prevent waterlogging, drought, and de-fertilizing; third, it is necessary to apply sufficient basic fertilizer and topdressing by stages. The base fertilizer should be mainly organic fertilizer, with high content of inorganic compound fertilizer, 3000kg / mu of rotten farm fertilizer, or 150kg / mu of high-quality commercial organic fertilizer, and 40kg / mu of sulfur-based compound fertilizer with high potassium content. As for the times of topdressing, autumn lettuce and overwintering lettuce should be topdressing 2-3 times and 3-4 times respectively. The early growth period is mainly based on thin clear water dung, cultivate strong seedlings, topdressing can not be excessive, to prevent prosperous growth, overwintering lettuce in the tender stem expansion period, urea per mu can be recovered 25 kilograms.

Yu Hongzhang, Agriculture Bureau of Xiaogan City, Hubei Province