1. In the absence of nitrogen, the leaves are yellowish, weak in growth, and the plants are short. In general, dry and defertilized fertilizers are prone to nitrogen deficiency and red leaves. The remedial measures are: 7.5 kg of urea or 10?20 kg of ammonium bicarbonate or 500?750 kg of manure water per acre, and pour water.
2. In the absence of phosphorus, the plants grew slowly and dwarfed, the leaves became smaller, the leaves thickened, and the leaves were dark green or grayish green, lacking luster, purple petiole, and purplish red spots or plaques on the edges of the veins. The remedial measures are: 25 to 30 kilograms of superphosphate per acre or 2-3 times of continuous spraying of potassium dihydrogen phosphate.
3. Potassium deficiency starts from the old leaves and develops toward the center of the heart. It initially shows yellow spots. The leaf edges of the leaf tip gradually appear as "focal edges" and pale spots, and the leaves become thicker, harder, brittle, and the tissues of the leaves are presented. Obvious "burn-like", followed by wilting, remedial measures are applied per acre 7.5 ~ 10 kg of potassium chloride or 70 ~ 100 kg of ash.
4. In the absence of boron, the roots of the plants stopped growing. There were no root hairs and lateral roots. Some roots had small nodules, and the root bark turned brown. The leaves showed purple or blue-purple patches, leaf margins were rewinded, and rhizomes were enlarged. Boron deficiency during flowering can lead to "flowering and not realizing." The remedial measure is to apply 500-1000 g of borax and nitrogen fertilizer per acre to the water, or use borax 100 g to water 50 kg to select the foliar spray in sunny afternoon.
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