Latest Detailed Guide to Soybean Nutrient Deficiency Symptoms and Control Methods

Soybeans require a variety of nutrients during growth, and once a deficiency of a certain element occurs, it will cause corresponding symptoms, affecting the normal growth and yield of the plants. Below, the editor brings you the common nutrient deficiency symptoms of soybeans and their control methods. Let's take a look.

1. Nitrogen deficiency

Symptoms: When soybeans are deficient in nitrogen, the true leaves turn yellow; in severe cases, yellowing progresses from the bottom upward all the way to the new leaves at the top. The leaves are small and thin and drop off very easily, the stems become extremely thin and weak, and rust-colored patches appear on the compound leaves.

Control method: Apply nitrogen fertilizer as a top dressing in time. Foliar spraying can be used, as it takes effect quickly and works well. Generally, apply 5-7.5 kg of urea per mu, or use a 1%-2% urea aqueous solution and spray it evenly on both sides of the leaves, once every week for 2-3 consecutive times, and the plants will return to normal.

2. Phosphorus deficiency

Symptoms: When soybeans are deficient in phosphorus, the stems are thin and elongated, the leaves on the lower half are dark green, the leaves are thicker and longer, and the leaf surface is uneven. In severe cases, the veins turn yellowish-brown until the entire leaves become yellow.

Control method: Pay attention to the application of phosphorus fertilizer when fertilizing. When symptoms are found, apply phosphorus fertilizer as a top dressing in time. Apply 12.5-17.5 kg of calcium phosphate per mu, or use a 2%-4% superphosphate solution for foliar spraying, likewise once a week for 2-3 consecutive times.

3. Potassium deficiency

Symptoms: When plants are deficient in potassium, irregular yellow spots appear on the leaf edges and gradually expand over time, while the middle part of the leaf and the area near the veins remain green. The seeds also often shrivel and become deformed, forming misshapen beans.

Control method: Apply 4-5 kg of potassium chloride per mu as a top dressing, or use a 0.1%-0.2% potassium dihydrogen phosphate aqueous solution for foliar spraying. The spraying time and frequency are the same as before.

4. Molybdenum deficiency

Symptoms: The leaves are pale yellow, and the plants grow poorly, somewhat similar to nitrogen deficiency symptoms. In severe cases, the veins necrose and the leaves become severely deformed.

Control method: A 0.05%-0.1% ammonium molybdate aqueous solution can be used for foliar spraying, with good results.

5. Iron deficiency

Symptoms: In the early stage, the upper leaves turn yellow and appear somewhat curled, while the veins remain green. In severe cases, the new leaves, including the veins, all turn white, and brown spots also appear near the leaf margins, while the old leaves wither and drop off.

Control method: A 0.5% ferrous sulfate aqueous solution can be used for foliar spraying, which can alleviate iron deficiency symptoms.

6. Boron deficiency

Symptoms: When soybeans are deficient in boron, growth and development become slower, young leaves turn pale green, leaf growth is deformed, internodes are shortened, the meristem at the stem tip dies, and normal flowering and pod setting cannot occur. In severe cases, it can lead to total crop failure.

Control method: Mix 0.5-1 kg of borax per mu into the base fertilizer. If boron deficiency occurs later, use a 0.1%-0.2% borax aqueous solution for foliar spraying.

The above is an introduction to soybean nutrient deficiency symptoms and control methods. We hope it can help you. If you want to learn more related knowledge, please stay tuned to us.