Symptoms of Plant Malnutrition--Visual Symptoms and Incipient Malnutrition

Abstract

Corn was grown across a gradient created with increasing doses of urea fertilizer. Comparison of a photograph of the corn row with a plot of the yield of fresh husk sweet corn revealed that disappearance of visual N deficiency occurred well before maximum yield was reached. This illustrates the need for more sophisticated means of determining optimal fertilizer levels than can be obtained by mere visual observation, which fails to detect "hidden hunger" in plants.