Controlled-Release Nitrogen Fertilizer Under Contrasting Soil Drainage Conditions for Corn Production

Study author(s): Fabian Fernandez, University of Minnesota
Growing season(s): 2026, 2027, 2028, 2029
Minnesota location(s): Wells

Note: Complete reports with figures and tables will be made available for download.

What is this project about?

Wet spring weather can lead to high nitrogen losses from pre-plant urea, reducing both farm profitability and environmental health. While tile drainage helps manage excess soil moisture, many Minnesota fields or field areas still lack adequate drainage. Split-applying nitrogen can help in wet years, but getting equipment into wet fields in-season can be difficult and adds extra costs.

This project, led by researchers at the University of Minnesota, evaluates whether polymer-coated urea (PCU) or PCU-urea blends can protect nitrogen investments, boost efficiency, and improve yield economics in poorly drained vs. tiled soils.

Key Project Goals & Farmer Benefits

  • Tailored Guidelines: Refine University of Minnesota Nitrogen Best Management Practices (N-BMPs) specifically for tiled versus untiled soil conditions.
  • Optimal Application Strategies: Determine the best nitrogen application rates, timing, and fertilizer blends to hit the economic and agronomic optimum yield.
  • Nitrogen Efficiency: Measure nitrogen uptake in crops and lower the risk of nitrogen loss to the environment.
  • Practical Knowledge: Share clear, actionable research updates directly with growers and crop consultants through UMN Extension programs.

How the Study Will Be Conducted

  • Location: Conducted over 4 growing seasons on a long-term research plot in Wells, Minnesota.
  • Drainage Comparison: Compares performance across 8 research blocks containing side-by-side tiled (drained) and untiled (undrained) soils.
  • Fertilizer Treatments: Tests 200 total test plots comparing 5 different nitrogen application strategies across 5 application rates (0, 60, 120, 180, and 240 lb N/acre):
    1. Pre-plant urea
    2. Pre-plant blend (2/3 urea + 1/3 PCU)
    3. Pre-plant blend (1/3 urea + 2/3 PCU)
    4. Pre-plant PCU
    5. Split application (60 lb N/acre PCU pre-plant followed by a V6–V8 sidedress of urea with a urease inhibitor)
  • Measurements: The team will collect soil samples (down to 3 feet) before sidedress and after harvest, test plant biomass and grain for total nitrogen content, and record final yield data.
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