Background:
Nitrogen can have a great impact on a grower’s success and identifying nitrogen deficiency in corn and soybeans and its cause can be critical. Severe nitrogen deficiency will result in a yellow-colored V on the leaves of the corn plant. Since nitrogen is a mobile nutrient, symptoms will begin in the lower leaves and move up the plant. Soybean leaves will also appear pale green to yellowish with dark green veins.
Favorable Conditions:
Nitrogen deficiency in corn and soybeans is often seen in cold or saturated soils, dry soil, particularly after the mid-season. Large amounts of low nitrogen residue, sandy soils, inadequate fertilization, leaching from heavy rainfall, excessive rains, and ponding/flooding are also favorable conditions for nitrogen deficiency.
What to look for:
Nitrogen deficiency in corn causes stunted, spindly plants with light green or yellowish color. It also causes V-shaped yellowing of the lower leaves starting at the leaf tips, and the entire leaf will eventually turn brown and wither.
Nitrogen deficiency in soybeans causes poor modulation of roots and stunted spindly plants with a light green color, which will appear on the first leaves.
Sources:
Nutrient Deficiencies and Application Injuries in Field Crops