Nutrient Deficiency and Physiological Disorders in Soybean

ByMr. Allah Dad Khan

SymptomsPale green plants,

pale yellow leading to brown older leaves, veins are not prominent.

Nitrogen deficiency

SymptomsDark green to bluish

green leaves, often with interveinal, small lesions; drybean may have marginal chlorosis.

Phosphorus

SymptomsGreen plants with

chlorosis along the leaf margins - leading to brown interveinal necrosis in soybean; veins stay green.

Potassium deficiency

SymptomsSoybean typically requires

large amounts of potassium. Like phosphorus deficiency, potassium deficiency occurs first on older leaves. Symptoms are chlorosis at the leaf margins and between the veins. In severe cases, all but the very youngest leaves may show symptoms.

 

Potassium deficiency

Pale green to yellow leaflets without prominent veins or necrosis.

Sulphur deficiency

SymptomsPale green plants

with interveinal pale yellow mottling of the leaves followed by interveinal necrosis - or necrosis along the underside of the main veins in drybean.

Magnesium deficiency

SymptomsPale green plants;

interveinal mottling (or interveinal chlorosis in drybean) of older leaves leading to bronze necrosis; green veins.

Zinc deficiency

Symptoms are prominent interveinal chlorosis or necrosis; veins are prominent over length of leaf.

Iron Deficiency

symptomsIron chlorosis in

soybeans. The upper leaves become chlorotic.

Iron Deficiency

SymptomsPale yellow leaves

with mottled interveinal chlorosis leading to dark brown necrosis.

Manganese deficiency

SymptomsStunted plants with

interveinal chlorosis. Can be a problem in soils with high pH (>7), or on soils that are sandy or with a high organic matter content. Manganese activates enzymes which are important in photosynthesis, as well as nitrogen metabolism and synthesis. Symptoms are hard to distinguish from iron chlorosis.

Manganese deficiency

SymptomsPlants turn a light

green color due to lack of nitrogen fixation. This deficiency is not common, but can occur on acidic, highly weathered soils.

Molybdenum deficiency