Winter rape is an overwintering crop. The variety is mainly cabbage. It is sown in autumn and harvested in summer. The whole growth period is more than 200 days. It has strong adaptability and great potential for increasing yield. Like spring rape, its growth and development can be divided into seedling stage, bud and stalk stage, flowering stage, pod setting stage and mature stage. At present, winter rape is in the seedling stage, and the following points should be paid attention to in management.

1. Thinning and setting seedlings

Requires morning seedlings, thin seedlings. The principle of thinning is to keep dense and thin, remove the weak and stay strong, adjust the spacing between plants to maintain uniformity. Generally divided into two thinnings, the first time is performed when the first true leaf appears after the Qi seedlings, and the leaves are not set up between the leaves; the second thinning is performed when the second true leaf appears. For fields with a large amount of seeding, the number of thinning can be appropriately increased. Thinning the weeds at the same time to ensure the healthy growth of the seedlings. The seedling can be fixed when the rape has grown to 3-5 true leaves. The density of the seedling should be controlled reasonably and the seedling should be fixed according to the characteristics of the rape variety. If the pest is serious, the seedling should be postponed appropriately; if the seedling is lacking, it should be replanted.

2. Early application of seedling fertilizer

Rape has two key growth periods, namely the seedling stage and the budding stage. Among them, the seedling stage is the critical period for rapeseed to grow mainly vegetatively. The dry matter accumulated in this stage accounts for about 10% of the dry matter weight of the whole growth period. The proportion of nitrogen, phosphorus, and potassium absorption in the total absorption is respectively 43.9%, 20.0% and 24.2%. Therefore, the seedling stage is the peak of nutrient absorption and the key period for top dressing. Topdressing in the seedling stage should be carried out according to the principle of "early, fast and more". Direct seeding of rapeseed is generally applied at the time of seedlings or five true leaves. It is recommended to topdress 10-15kg/mu haofangzi NPK 24-6-16 to ensure early onset Strong seedlings to prepare for safe overwintering.

3. Irrigation and drainage

The growth of rape is not only afraid of drought but also avoids flooding, water management should be able to irrigate with drought and drain with waterlogging, and keep the border and surrounding ditch unobstructed to facilitate irrigation and drainage. When the drought is mild, watering can be combined with seedling fertilizer. When the drought is severe, furrow irrigation can be carried out. The frequency of irrigation should be determined according to the condition of the seedlings and the flexibility of the soil texture. If the water retention of sandy soil is poor, more irrigation can be appropriate; if the water retention of clay is good, less irrigation should be appropriate. During irrigation, avoid flooding with flooding and too long time to prevent the seedlings from being flooded, soil compaction, affecting root development and forming rigid seedlings. In areas where there is a lot of rain in autumn, attention should be paid to clearing ditch and draining water and lowering the groundwater level.

4, Pest control

In the process of rapeseed planting, once pests and diseases occur, if they are not controlled in time and effectively, they will spread rapidly, directly affecting the safety and economy of rapeseed planting. The main pests in the seedling stage of rape are cabbage caterpillars, aphids, and cabbage borers; the main diseases are sclerotium, virus, powdery mildew, and downy mildew, which should be controlled in time. Three days before transplanting seedlings and direct seedlings after sowing, it is best to spray thoroughly with the medicine once to eliminate the pests in the seedbed and before they occur.