Nutritional Characteristics and Fertilization Technology of Rape

Brassica napus is a cruciferous oil crop. It is also the oil crop with the largest planting area and wide adaptability in China. The whole growth period can be divided into seedling stage, flood season, flowering stage, pod-forming stage and maturity stage. Rape is one of the crops that require more fertilizer, especially for nitrogen and potassium, and is more sensitive to boron. Adequate nitrogen fertilizer can not only ensure the normal development of rapeseed, but also increase the effective flower bud differentiation period, and lay a foundation for increasing pod number, grain number and grain weight; timely supply of phosphate fertilizer can enhance the resistance of rapeseed and promote early maturity and high yield. Increase the oil content; increase the application of potassium fertilizer can reduce the occurrence of Sclerotinia sclerotiorum, promote the formation of a large number of stems and branches, enhance the plant's resistance to stress; boron fertilizer can promote flowering and fruiting, pods and grains, and full of seeds. According to the research, for every 100 kg of rapeseed, it needs to absorb 9-11 kg of nitrogen, 3-3.9 kg of phosphorus, 8.5-12.8 kg of potassium, and the ratio of nitrogen, phosphorus and potassium is 2:1:2. The demand for nutrients in different growth stages is different. The nitrogen uptake at seedling stage accounts for 22% of nitrogen absorption in the whole period, the peak period of nitrogen absorption is 55% in the period of nitrogen absorption, and 23% in maturity; the rapeseed is not allowed in the whole growth and development process. Phosphorus deficiency, the most sensitive to phosphorus in seedling stage, high absorption and utilization rate, the flowering period is the peak period of phosphorus absorption and utilization, accounting for about 50% of the total absorption. At the seedling stage and the flowering stage, the proportion of potassium absorption is relatively high, accounting for about 70% of the total absorption. The amount of nitrogen, phosphorus and potassium absorbed by rapeseed is related to the growth and development rate, the growth and development are accelerated, the amount of absorption is correspondingly increased, the growth and development are slowed down, and the absorption is correspondingly reduced. Therefore, in the rapeseed production process, timely and sufficient supply of nitrogen fertilizer, balanced application of phosphorus, potassium fertilizer, appropriate application of boron fertilizer, has an important role in the high quality and high yield of rapeseed.

Fertilization technology

Applying the base fertilizer: The rapeseed plant is tall and requires a lot of fertilizer. The application of the base fertilizer should be emphasized, the base fertilizer is insufficient, and the seedlings are thin, which in turn affects the growth of the plant and even the economic yield of rape. The base fertilizer is mainly organic fertilizer, supplemented by chemical fertilizer, which lays a foundation for the need for fertilizer in rape. Generally, 2000 kg of organic fertilizer per mu, 45% of general-purpose compound fertilizer 25-30 kg or 36% of compound fertilizer (15-10-11) 30-40 kg, and boron fertilizer 0.5-1 kg. Application method: Combine the organic fertilizer, compound fertilizer and boron fertilizer in combination with ploughing and turning the soil, and avoid applying too shallow fertilizer to avoid defermenting in the middle and late rapeseed.
Early application of seedling fertilizer: early application, diligent application of seedling fertilizer, timely supply of nutrients required for rapeseed seedlings, use the short-term high temperature before winter to promote the growth of rapeseed, to achieve strong wintering, laying the foundation for high yield and stable yield of rapeseed. The seedling fertilization can be divided into two parts in the early stage of seedling and the late stage of seedling. The pre-emergence fertilizer is applied at the time of seedling or 5 true leaves. Generally, 5-6 kg of urea is applied per acre. In the soil lacking phosphorus and potassium, if the base fertilizer is not applied with phosphorus and potassium fertilizer, the phosphorus and potassium fertilizer should be supplemented; Miaoqing and climate depending on. Generally, 8-10 kg of high-nitrogen compound fertilizer is applied per mu. Spring-strength varieties or warmer winter seasons should be applied early, winter temperatures are low or the three-crop rape areas can be applied late.
Steady application of manure: rapeseed is the vegetative growth and reproductive growth and advancement, the plant quickly convulsions, long branches, increased leaf area, large differentiation of flower buds, is the most demanding period of fertilizer, but also a key period for increasing branches and increasing pods. Therefore, it is necessary to stabilize the application of manure according to the application situation and growth of the base fertilizer and the seedling fertilizer. The base and seedlings are sufficient, the plant grows robustly, and the fertilizer can be applied less or not; if the base and the seedlings are insufficient, the tendency to take off the fertilizer should be applied early. Generally, 15-20 kg of high-nitrogen compound fertilizer is applied per mu. Fertilization time is generally in the middle of the pumping period, and the height is 15-30 cm. However, the weaker ones can be fertilized at the beginning of the convulsion to avoid premature aging; the strong ones can be applied at the late 30-50 cm in the late twitching period, so as to avoid the flowering period and the stagnation.
Skillful application of flower fertilizer: After rapeseed twitching, flowering and pod formation, seed number and grain weight are closely related to nutrient conditions after flowering. For the strong growth, the amount of fertilization in the flood season may not be applied or applied less; the early maturing varieties are not applied, or the application is less in the initial flowering period; the flowering season can be applied on the foliar surface, spraying 0.1-0.2% during the flowering and pod-forming period. Urea or 0.2% potassium dihydrogen phosphate. In addition, 0.2% borax aqueous solution can be sprayed once in the late stage of seedling and twitching period to prevent the phenomenon of “flowers and not real” and increase the yield.

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