What to Do About Soybean Nutrient Deficiency? A Detailed Guide to Symptom Identification and Control Methods

Soybeans require a variety of nutrients during growth. 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 spreads from the bottom upward, reaching 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 iron-colored patches appear on the compound leaves.

Control methods: Apply nitrogen fertilizer promptly as a top dressing. 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 water solution and spray it evenly on both sides of the leaves, once a 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 become slender, the lower leaves are dark green, the leaves are relatively thick and long with an uneven surface, and in severe cases the veins turn yellowish-brown until the entire leaf turns yellow.

Control methods: Pay attention to the application of phosphorus fertilizer when fertilizing. When symptoms are found, apply phosphorus fertilizer promptly as a top dressing. 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. The middle part of the leaf and the area near the veins remain green. The seeds often shrivel and become deformed, forming misshapen beans.

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

4. Molybdenum deficiency

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

Control methods: A 0.05%-0.1% ammonium molybdate water 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 appear near the leaf edges. The old leaves wither, yellow and drop off.

Control methods: A 0.5% ferrous sulfate water 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 slow down, young leaves turn pale green, leaf growth becomes deformed, internodes shorten, the meristem at the stem tip dies, and the plants cannot flower and set pods normally. In severe cases, it can lead to total crop failure.

Control methods: 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 water solution for foliar spraying.

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