July 1, 2009

Key to Nutrient Deficiencies of Corn and Sorghum

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    


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

Iron deficiency Iron deficiency in corn


Symptoms begin as lesions, broad bands, or marginal leaf tips of chlorotic tissue or as generalized yellowing; veins are not prominent

Go to F    


Pale green plants; chlorosis or necrosis advance from the leaf tip along the midrib.

(Courtesy of the International Plant Nutrition Institute)

Nitrogen deficiency Nitrogen deficiency in corn  


Dark green plants; dark yellow chlorosis advancing along leaf margins; purple color


(Courtesy of the International Plant Nutrition Institute)

Phosphorus deficiency Corn with phosphorus deficiency  


Dark green plants with chlorosis along the leaf margins developing to brown striping and necrosis


(Courtesy of the International Plant Nutrition Institute)

Potassium deficiency Potassium Deficiency


Green-yellow plants with dark yellow interveinal chlorosis advancing to rust-brown necrosis

Magnesium deficiency Magnesium deficiency of corn  


Pale yellow plants; uniformly yellow leaves without necrosis

Sulfur deficiency Sulfur deficiency in corn Sulfur deficiency in corn


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 Zinc deficiency in corn zinc deficiency in corn