How to cultivate strong seedlings of rapeseed

The standard of strong rape seedlings is 6 leaves, 20 cm high, 6 cm thick rhizome and many fibrous roots. In the technology of cultivating strong seedlings of rape, we should mainly focus on the following points: select the nursery bed to choose fields or vegetable gardens with fertile and loose soil as seedbeds. In rice producing areas, we can make full use of the bed for raising rice seedlings in dry condition, so that one bed can be used for more than one purpose. The bed soil was cultivated on the cultivation bed according to the fertility of the seedling bed. Generally, 2000-2500 kg of rotten human feces and urine, 15 kg of calcium superphosphate, 15 kg of ammonium bicarbonate and 15 kg of rape special fertilizer should be applied per mu. Timely early sowing according to the transplanting period and climatic conditions of rape, the seedling age is about 35 days, so as to determine the suitable sowing time. The general sowing time is around September 15. Control seeding rate per mu of rape seedbed sowing rate should be 0.5-0.6 kg, adhere to sparse sowing and uniform sowing, compaction after sowing. In case of drought, straw can be used to cover and moisturize to promote seedling emergence. Do a good job in chemical control of rape seedlings by spraying paclobutrazol at 2-3 leaf stage to control the growth of aboveground parts and promote the growth of underground parts. Generally, 50 grams of paclobutrazol wettable powder is applied per mu, and 40-50 kg of water is evenly sprayed. Scientific fertilization seedling bed topdressing fertilizer is best to choose dilute water manure. If rape seedlings grow slowly after 3-4 leaf stage, and the leaf color turns red, it should be fertilized in time. 1500-2000 kg of dilute water manure should be applied per mu. If the basal fertilizer is sufficient and the seedling growth is exuberant, it is not suitable to top fertilizer and refine the seedlings from 4-5 leaves in order to prevent vigorous growth and the formation of tall seedlings.