By Wayne Flanary,
Field Specialist
Rainfall has been variable from Kansas City northward to the Iowa state line. Some areas have too much rain whereas others have had normal amounts. Those areas receiving high rainfall amounts may have nitrogen deficient corn.
As I have been scouting corn fields, in many areas where ammonia was applied, the corn roots have not intercepted the nitrogen bands yet. This gives the corn uneven colors across the field where it has and has not intercepted the nitrogen bands. This has occurred in the drier counties that I cover.
However, yellow corn in saturated soil moisture conditions may benefit from having supplemental nitrogen fertilizer applied. The amount of nitrogen loss from fertilizer nitrogen is hard to predict. The corn plant with its green color has shown it is the best indicator of nitrogen loss. Yellow corn indicates a greater need for supplemental nitrogen than slightly pale colored corn. Most fields will have varying areas of yellow and green colors throughout the field.
The areas that are lighter colored will often be the most responsive to a nitrogen fertilizer application. A supplemental nitrogen application of 30 to 50 pounds of nitrogen per acre will benefit the corn crop. Different nitrogen products can be used to remedy the problem. Urea can be top-dressed over standing corn and provide less burn than other dry sources. Also, nitrogen can be applied as ammonia if knifed into the soil. Liquid nitrogen can be dribbled between corn rows by dragging tubes so the liquid nitrogen does not splash on the corn leaves.
Nitrogen losses are greater in June than in early season because of soil temperatures. The process of loss is caused by soil bacterial and bacteria are more active at 80 degree soil temperature than spring soil temperatures of 60 degrees.
If your corn is nitrogen deficient, you may want to discuss this issue with your Ag supplier. For more information, contact Wayne Flanary at 816-279-1691, Field Specialist in Agronomy, University of Missouri Extension.
