How do you know what kind of fertilizer soybeans lack?

How do you know what kind of fertilizer soybeans lack? How can you tell the difference? 1. Nitrogen deficiency 1. Symptoms when soybean is nitrogen deficient, the leaves turn green, grow slowly, and the leaves gradually turn yellow. 2. Remedial measures should be timely topdressing nitrogen fertilizer, topdressing 5-7.5 kg of urea per mu or foliar spraying with 1% Murray 2% urea aqueous solution, spraying every seven days or so, a total of 2-3 times. Second, phosphorus deficiency 1, the symptoms of phosphorus deficiency root nodules are few, the stem is slender, the lower leaves of the plant are dark green, thick, uneven, narrow and long; when the phosphorus deficiency is serious, the leaf veins are yellow-brown, and the whole leaves are yellow. 2, remedial measures timely topdressing phosphate fertilizer, 12.5-17.5 kg calcium superphosphate per mu or foliar spraying fertilizer with 2% Murray 4% calcium superphosphate aqueous solution, sprayed every seven days or so, a total of 2-3 times. Third, potassium deficiency 1. The symptoms of potassium deficiency old leaves appear irregular yellow spots from the edge of the leaves and gradually expand, the veins in the middle of the leaves and other parts are still green, and the grains are often wrinkled and deformed. 2. Remedial measures: potassium chloride 4-6 kg per mu or foliar spraying fertilizer with 0.1% Mel 0.2% potassium dihydrogen phosphate aqueous solution, sprayed every seven days or so for a total of 2-3 times. Fourth, molybdenum deficiency 1, symptoms of yellowish leaf color, poor growth, showing symptoms of nitrogen deficiency, severe midvein necrosis, leaf deformation. 2. Remedial measures can be carried out by foliar fertilizer spraying with 0.05% rain 0.1% ammonium molybdate aqueous solution. Iron deficiency 1. In the early stage, the symptoms are that the upper leaves turn yellow and a little curly, and the veins remain green. When there is severe iron deficiency, the new leaves, including veins, almost turn white, and brown spots soon appear near the edge of the leaves. The old leaves turn yellow and withered and fall off. 2. Remedial measures can be made by spraying fertilizer on the foliar surface of molten ferrous sulfate solution with 0.4% Mel 0.6%. 6. Boron deficiency 1. Symptoms of boron deficiency soybean grow slowly, young leaves become light green, leaves are deformed, internodes are shortened, stem tip meristem dies and cannot blossom. 2. Remedial measures can be carried out by foliar spraying with 0.1% Mel 0.2% borax aqueous solution. Click to see more soybean planting techniques click to see more food crop planting techniques