Optimizing Nitrogen Use Efficiency for Maximum Yield

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Employee driving soil optics

Article by Dale Cowan
Agronomy Strategy Manager and Senior Agronomist
AGRIS Co-operative - CENTRAL OFFICE

Nitrogen Use Efficiency (NUE) is a critical factor in maximizing corn production while managing input costs and environmental impact. NUE is defined as the pounds of applied nitrogen required to produce a bushel of corn, typically ranging from 0.57 to 1.3 lbs. of nitrogen per bushel. By improving NUE, farmers can get the most out of their nitrogen applications and maximize profitability.

Determining the Optimal Nitrogen Rate

The first step in improving NUE is applying the right nitrogen rate. Tools like Adapt-N and the Ontario Nitrogen Calculator help determine the optimum rate for each field. These decision-support tools use real-time data, such as soil conditions and weather patterns, to guide nitrogen applications and reduce waste.

The Role of Soil Nutrients and 4R Stewardship

Beyond nitrogen rates, ensuring other essential nutrients are at non-limiting levels is key to optimizing nitrogen efficiency. Following 4R Nutrient Stewardship principles—right source, right rate, right time, and right place—ensures nitrogen is effectively utilized. Regular soil testing (at least every four years) helps assess phosphorus (P) and potassium (K) levels, which play a significant role in nitrogen response.

Research presented by Dr. John Jones at the Southwest Ag Conference highlighted the impact of soil P and K levels on nitrogen efficiency. Fields with low P and K levels required higher nitrogen applications to achieve target yields. For example:

• Low P & K fields: 181 bushels per acre yield, requiring 226 lbs. of nitrogen
• High P & K fields: 245 bushels per acre yield, requiring only 204 lbs. of nitrogen

This illustrates how maintaining balanced soil fertility optimizes nitrogen application and increases yield potential.

Plant Health and Fungicide Applications

Another key factor in NUE is maintaining plant health. Foliar fungal diseases like Tar Spot can reduce leaf area, limiting photosynthesis and shortening the grain fill period. Timely fungicide applications at the correct growth stage help keep leaves green longer, increasing kernel fill and maximizing yield. More bushels harvested per unit of applied nitrogen ultimately improves NUE.

Field-Specific Nitrogen Management

Since fields vary in their natural ability to supply nitrogen, conducting on-farm nitrogen rate trials helps determine the most efficient rate for each system. Factors like organic matter content influence nitrogen mineralization, meaning some fields can produce higher yields with lower nitrogen inputs.

Take Action to Improve Your NUE

To make the most of your nitrogen applications, work with an expert to develop a customized fertility plan. Contact your local AGRIS Co-operative Crop Sales Specialist for assistance with nitrogen management strategies, soil testing, and on-farm trials.

Want to optimize your nitrogen investment this season? Reach out to our team today!