This article was written by Dr. Ron Heiniger an NC State Cropping Specialists. This article discusses nitrogen in corn; and, ways to get the most out of your nitrogen in your corn crop.

As we reach the end of the growing season there is always one question that comes to my mind when it comes to growing corn. Do I have enough (N) nitrogen to finish the crop? This question is particularly pertinent in a season like this where in many places in North Carolina timely rainfall has occurred and the crop is finishing in excellent condition. Did I leave some yield in the field because I didn’t apply enough N? There is ample evidence that tissue concentrations of N in the ear leaf at dent stage are directly related to yield potential. Such that 2% N equals 200 bushel per acre corn yield, 3% equals 300 bushels per acre, 4% equals 400 bushels per acre, and so on. Therefore, having enough N in the corn is important at this stage of the season. So, how do I make sure that I have enough N to finish this crop?

The first step in having enough N is making sure that the corn plant is finding all the N that is in the soil or that you have applied as fertilizer. This means having a strong, massive root system that is exploring the entire field both vertically and horizontally. Such a root system has its foundations on quick, uniform emergence, good management of seeding rate and row configuration and excellent vertical distribution through reduced soil compaction. Root health must be maintained throughout the growing season by maintaining good drainage and meeting the nutritional needs of the plant. Nitrogen fertilizer should be applied near the root system of the plant and protected against losses from volatilization, denitrification, and leaching. The second step to having enough N is a good assessment of crop yield potential. When the crop gets off to a good start and then has excellent environmental conditions growers should consider adjusting N rates to match the condition of the crop. The final step is finding ways to mine more N from the soil (or the environment) during the grain fill period. Farmers on organic soils know that these soils have the potential to release N late in the season, farmers on sandy soils utilize manure or litter to release N during grain fill and some of the new technologies such as N-fixing biologicals have the potential to fix more N right up to physiological maturity. These are the steps to answering the question – Do I have enough – and finding that you are covered!

Along with knowing that you have enough N the other important question is  – Am I capturing all the light I can? A positive answer to this question depends on three things: a full, healthy canopy of leaves, good soil moisture to maintain leaf function, and the right atmospheric conditions that maximize light intensity. A full healthy canopy of leaves means having the right plant density (plant population) and utilizing hybrids with optimum leaf angles. Good soil moisture, moderate temperatures, and optimizing the metabolic systems of the leaf are essential to good leaf function. Finally, the right atmospheric conditions – crystal clear skies – are important. While we can do something about canopy cover and leaf function there is very little we can do about atmospheric conditions. Recent hazy skies due to smoke contamination from wildfires or to higher humidity are concerning but not something that we have any control of.

As this season wraps up we should consider these two “do I have enough” questions and make sure these areas of plant needs are always covered. We have an opportunity this season to have one of the most successful corn crops ever. Lets make sure to take advantage of that opportunity.