Key Considerations for Corn Planting and Nitrogen Management in Minnesota

Monday, May 29, 2023

As the field season kicks into gear in Minnesota, farmers face decisions regarding corn planting and nitrogen management. Here are some important factors to consider:

1.Prioritize planting over nitrogen application:

Planting crops should be the top priority, even if nitrogen fertilizer application needs to be delayed.

Corn's early season nitrogen requirements are generally low, and the soil usually contains sufficient nitrogen to initiate crop growth.

2.Keep urea from remaining on the soil's surface:

Leaving urea on the soil surface is not advised if broadcasting and tilling in urea before planting was the original idea but planting now takes place first.

Urea hydrolysis is encouraged by springtime soil moisture levels, which causes nitrogen loss by ammonia volatilization.

To reduce nitrogen loss, use tillage within 24 hours of rain or think about using urease inhibitors.

3.Monitor the weather forecast and use urease inhibitors:

Apply urea within 24 hours of expected rainfall or use urease inhibitors that contain an adequate amount of active ingredient, such as NBPT.

NBPT, when used in sufficient quantities, has proven effective in reducing ammonia volatilization. Aim for at least one pound (16 ounces) of NBPT per ton of urea.

4.Understand the limitations of urease inhibitors:

Make sure the fertilisers are NBPT-treated for the current growing season because NBPT degrades over time.

Depending on the soil conditions, urease inhibitors last between 7 and 14 days. Warmer temperatures and an acidic soil pH speed up degradation.

5.Explore alternative nitrogen sources:

Consider nitrogen sources like ammonium sulfate (AMS), ammonium nitrate (if available), polymer-coated urea (e.g., ESN), and UAN solutions (inject rather than surface application).

Anhydrous ammonia is an excellent nitrogen source but requires proper soil sealing and application away from crop rows to prevent seedling and root injury.

By considering these factors, Minnesota farmers can make informed decisions regarding corn planting and nitrogen management, optimizing crop growth and minimizing nitrogen loss.