Symptoms Associated With Low Soil pH in Corn

Bob Nielsen, Extension Corn Production Specialist, Department of Agronomy, Purdue University

Low soil pH not only stunts corn growth and development, but can actually kill corn plants in extreme situations. Besides stunted plants, symptoms of
low soil pH commonly include a beaded reddish or necrotic striping of the lowermost leaves (sometimes also associated with magnesium deficiency) and brown stubby (thickened) roots. The soil pH from soil samples taken in the area of the field depicted in the accompanying images turned out to be 3.9, which would definitely be classified in the toxic category for corn. Desirable soil pH values for optimum corn growth are in the mid 6's.