From the moment it’s applied, nitrogen is at risk for loss. If not managed properly, up to 30% of nitrogen loss can happen above-ground, and up to 70% can be lost below-ground, producing serious crop quality (and therefore, economic) concerns for your farmers.
At this point in the season, you and your farmers should be able to visually identify how your corn crops are taking up nitrogen. Based on a few visual tests, along with soil tests for confirmation, you’ll be able to see how accurate your nitrogen application plan was, how spring and summer weather have impacted nitrogen use thus far, and what you might expect come harvest.
Applied nitrogen can be lost through leaching (the loss of nitrates into the groundwater) and denitrification (the escape of greenhouse gases into the environment). If a plant can’t absorb enough nitrogen through the soil, it will cannibalize its internal sources of nitrogen — draining strength from its stalk and leaves. When that happens, weakened cornstalks, stalk rot and significantly reduced yield can result.
Fields at the highest risk of nitrogen loss include fall- and preplant-applied nitrogen fields, those composed of sandy soils and fields with poor drainage.
When scouting your fields for signs of nitrogen deficiency, look for the following:
Nitrogen hunger sign is yellowing that starts at the top and moves along middle of leaf.
Healthy leaves shine with a rich dark-green color when adequately fed.
Nitrogen is essential throughout the growing season. If a plant runs out of nitrogen at critical time, ears are small and protein content is low. Kernels at tip do not fill.
A normal ear of well-fertilized high-producing corn weighs about two-thirds of a pound. It has well-filled tips.
Finding a nitrogen deficiency at this point in the season is frustrating, disappointing and can leave you and your farmers wondering: What do we do now?
“Some may consider a late-season nitrogen application as a rescue. This would only apply to V8 to V12 corn that is waist high to tasseling. But you’re gambling here,” says Scott Pringnitz, Corteva Agriscience market development specialist. “Consider applications at the first sign of loss, soil testing and visual tests. If you see deficiency, then you already have seen yield loss.”
Unfortunately, little can be done if nitrogen deficiencies are found at this time of year. It does, however, provide some key information and learnings so that you can help adjust your farmers’ nitrogen management plan for next year.
If nitrogen deficiencies are found in your fields this summer and fall, here are some tips to consider for next year:
Realizing maximum yield in the fall not only relies on nitrogen, but also benefits from a holistic approach to nutrient management. This includes making sure phosphorus (P) and potassium (K) levels are adequate to support growth throughout the entire season and protecting nitrogen (N) applications with a nitrogen stabilizer. Remember: Nitrogen remains the staple nutrient required to maximize corn yields.
Soil fertility levels for P and K are affected by:
By supporting your nitrogen applications with a holistic approach to nutrient management, you’re covering all your bases when it comes to realizing the yield potential on your cornfields.
