1. When the nitrogen-deficient rapeseed is deficient in nitrogen, the new leaves grow slowly, the leaves are few, the leaves are light, the chlorotic gradually turns purple, the lower leaves of the stems turn red, the severe leaves are scorched, and the reddish veins appear; the plants grow thin, the main stem Short, slender, loose plant type, few pods, early flowering and short flowering time, early flowering early. Control method: The nitrogen-deficient plot can be applied with compost or fully decomposed organic fertilizer. Apply coated urea, long-acting ammonium bicarbonate, and control slow release fertilizer. In case of emergency, 7-8kg of urea or 15-20kg of ammonium bicarbonate can be applied per 667m2. Watering should be done after topdressing in drought to prevent burning. In addition, foliar fertilizer can be applied, and the foliage can be sprayed with 40-50 kg of 1%-2% aqueous urea solution.
2. When the phosphorus is deficient in phosphorus, the leaves are dark blue-green to lavender, the leaves are small, the leaves are thick, and there are no petioles. There are purple-red spots or plaques on the edges of the veins, the number of leaves is small, the lower leaves turn yellow and fall off easily, and the leaves are severe. Necrosis, the old leaves withered early, the leaves become narrow, the plants are short, the stems become thinner, the branches are less, the plants are thin and tall and erect, the roots are small, the development is poor, the lateral roots are less, and the ripening period of rapeseed is delayed for 1-2 days. Control method: the application of phosphorus-deficient plots is mainly calcium-magnesium-phosphorus fertilizer or 20-30kg of calcium phosphate applied at 667m2, and timely irrigation after application. If necessary, foliar spray can promote Fengbao liquid fertilizer No. 1 400-500 times liquid or foliar spray Potassium dihydrogen phosphate was mixed with 50% water per 667 m2 of 200-250 g to 50 kg of water, and sprayed 2-3 times.
3. The potassium-deficient seedlings are scorpion-like, the leaves are dark green, the leaves are small, the leaf flesh is like hot water, the leaf margin is under the leaf, the leaf surface is uneven, crisp and easy to break. There is chlorosis between the edges of the leaves or between the veins, and at the beginning there are small spots, followed by plaque-like necrosis. The severe potassium-deficient leaves all die, but do not fall off. Potassium deficiency is first manifested in the leaves with strong metabolism, which is not easy to see on old leaves. The main stem of potassium deficiency grows slowly, and is small and easy to break down. The pods are short and the cuticles have brown spots. Control method: Potassium-deficient plots can be applied with silicate bacteria bio-potassium fertilizer or 5-10kg of potassium sulphate or potassium chloride or 100kg of ash per plant at 667m2. It is also possible to spray 50-kg of potassium dihydrogen phosphate to 50 kg of water to prepare a 0.4%-0.5% aqueous solution.
4, magnesium deficiency often leaves the leaves green, but the veins are still green, the old leaves of the base are yellow; flowering is often inhibited, the petals appear pale, and the plant size does not change significantly. Control method: When magnesium is deficient, foliar spray 0.1%-0.2% magnesium sulfate solution per 667m250kg, continuous 2-3 times.
5, calcium-deficient new leaves withered, old leaves withered yellow; leaf margin, leaf veins whitish, leaf edge down, apical leaf bud base bending or death. Control method: The calcium-deficient plot is first sprayed with 2% calcium perphosphate leaching solution per 667m2 of 50-75kg jin, and 25-30kg of superphosphate per 667m2.
6. The symptoms of sulfur deficiency are basically similar to the symptoms of nitrogen deficiency. The seedlings are narrow and yellow, the veins are green, and gradually spread throughout the whole leaves and stems and inflorescences during bolting and flowering; pale yellow flowers tend to turn white, and flowering continues. In the mature stage, there are flowers and flower buds in addition to mature and immature horns. The tip of the pod is dry and about half of the seeds are stunted. The plants are short and the stems are easily lignified or broken. Control method: when formulating fertilization technology in the case of sulfur deficiency or 10-20kg of potassium sulfate per 667m2 when severe sulfur deficiency occurs.
7. Boron-poor rapeseed is deficient in boron at the seedling stage, the roots turn brown, the new roots are less, the root neck is swollen, and some roots have small knob-like protrusions; the stems do not story long whites withered; the leaves are dark green, shrinking, showing purple Plaques or all leaves are purple-red, causing dead seedlings when severe. The buds are deficient in boron, the flower buds are withered and browned, the moss is thin and short, the top flower buds are green and withered, the flowers are dim, the petals shrink and dry and can not bloom and bear well, flowers appear unreal, and unfavorable to form normal pods, young fruit A large number of shedding, the individual deformed pods have fewer kernels and different sizes. Control method: In case of boron deficiency, the boron fertilizer should be applied to the disease. Apply 21% of high-efficiency instant boron fertilizer or 0.5-1kg of borax per 667m2. It should be re-applied to the severe boron-deficient area, generally mixed with nitrogen, phosphorus and potassium, or 667m2. It is necessary to spray borax 100-200g to 50-60kg of water for 2-3 times.
8. When zinc deficiency rapeseed is deficient in zinc, the veins are chlorotic, the leaves are slightly thickened, and the severe leaves are all white. Plants generally grow short
Control method: zinc-deficient plots can be applied with zinc sulfate, sprayed with 0.3kg-0.4% zinc sulfate solution per 667m2 3-4kg or foliar surface.
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