July 1, 2009
Plant symptoms can be used to differentiate and identify crop nutrient disorders. Symptoms of nutrient deficiency vary with variety, growing conditions, and plant age and similar symptoms may be caused by other abiotic or biotic stresses. Use the following key to help identify seven nutrient disorders observed in Nebraska corn and sorghum.
For more information on these and related topics, also check the UNL Extension publication, Nutrient Management for Agronomic Crops in Nebraska, EC155, available online or in soft cover through your local Extension office.
| Symptom identification key for nutrient deficiencies in corn and sorghum. | ||||
| A1. | Symptoms appear first or are more severe on older and/or fully expanded leaves | Go to B | ||
| A2. | Symptoms appear first or are more severe on younger leaves | Go to C | ||
| B1. | Symptoms advance from leaf tip towards the base; no interveinal chlorosis | Go to D | ||
| B2. | Symptoms begin as interveinal or marginal chlorosis | Go to E | ||
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C1. |
Symptoms are prominent interveinal chlorosis or necrosis; veins are prominent over length of leaf |
Iron deficiency |
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C2. |
Symptoms begin as lesions, broad bands, or marginal leaf tips of chlorotic tissue or as generalized yellowing; veins are not prominent |
Go to F | ||
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D1. |
Pale green plants; chlorosis or necrosis advance from the leaf tip along the midrib. (Courtesy of the International Plant Nutrition Institute) |
Nitrogen deficiency |
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D2. |
Dark green plants; dark yellow chlorosis advancing along leaf margins; purple color
(Courtesy of the International Plant Nutrition Institute) |
Phosphorus deficiency |
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E1. |
Dark green plants with chlorosis along the leaf margins developing to brown striping and necrosis
(Courtesy of the International Plant Nutrition Institute) |
Potassium deficiency |
 |
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E2. |
Green-yellow plants with dark yellow interveinal chlorosis advancing to rust-brown necrosis |
Magnesium deficiency |
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F1. |
Pale yellow plants; uniformly yellow leaves without necrosis |
Sulfur deficiency |
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F2. |
Pale green plants; white to pale yellow bands in the lower half of the leaf which advance to pale brown or gray necrosis (Left photo courtesy of the International Plant Nutrition Institute) |
Zinc deficiency |
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