Nitrogen deficiency
1. Symptoms. When soybeans are deficient in nitrogen, the leaves turn green and grow slowly, and the leaves gradually turn yellow.
2. Remedial measures. Nitrogen fertilizer should be topdressed in a timely manner. Topdressing 5 to 7.5 kg of urea per acre or 1% to 2% of urea solution should be used for foliar spray. Every 7 days or so should be sprayed once and sprayed 2 or 3 times.
Phosphorus deficiency
1. Symptoms. Phosphorus deficiency nodule, slender stems, plant leaves dark green, thick leaves, uneven, long and narrow; phosphorus deficiency is severe, the veins yellow-brown, after the whole leaf was yellow.
2. Remedial measures. Timely application of phosphate fertilizer, per acre can be superphosphated 12.5 ~ 17.5 kilograms or with 2% to 4% of superphosphate aqueous solution foliar spray fertilizer, spraying once every seven days or so, spray a total of 2 or 3 times.
Potassium deficiency
1. Symptoms. The old leaves lacking potassium appear irregular yellow spots from the edges of the leaves and gradually expand. The leaves near the middle part of the leaves and other parts are still green, and the grains often shrink and deform.
2. Remedial measures. Each acre can be topdressed with potassium chloride 4 to 6 kg or 0.1% to 0.2% potassium dihydrogen phosphate aqueous foliar spraying, spraying once every seven days or so, spray a total of 2 or 3 times.
Mo
1. Symptoms. The pale yellow color of the leaves, poor growth, showed symptoms of nitrogen deficiency, severe necrotic veins, and deformed leaves.
2. Remedial measures. Fertilizer can be sprayed with 0.05% to 0.1% ammonium molybdate aqueous solution.
Iron deficiency
1. Symptoms. In the early stage, the upper leaves were yellow and somewhat curled. The veins remained green. When the iron was severely deficient, the newly grown leaves almost turned white, including the veins, and soon brown spots appeared near the leaf margin. The old leaves changed. Yellow and fall off.
2. Remedial measures. Can be used 0.4% ~ 0.6% of ferrous sulfate aqueous solution foliar spray fertilizer.
Boron deficiency
1. Symptoms. Boron-deficient soy has slow growth, young leaves turn pale green, leaves are deformed, internodes are shortened, stem apex meristems die, and cannot flower.
2. Remedial measures. 0.1%~0.2% borax aqueous solution can be used for foliar spray fertilizer.
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