Minnesota Ag Connection - Early fertilizer applications

Minnesota Ag News Headlines

Early fertilizer applications - risks and recommendations
Minnesota Ag Connection - 03/08/2024

As the winter of 2023 unfolds with record warmth, the agricultural community is abuzz with the possibility of early spring fertilizer applications. Experts from the University of Minnesota, including Dan Kaiser, Fabian Fernandez, and Jeff Vetsch, share crucial insights into the risks and considerations associated with applying nutrients during this period.

Most fertilizers, being water-soluble, can dissolve and interact with unfrozen soil, posing little risk of loss for phosphates and potash if not subject to runoff. Nitrogen fertilizers present more complexity.

In colder soils, under 50Â°F, the risk of nitrate accumulation and subsequent loss is lower, yet ammonia volatilization from urea, especially when not incorporated, becomes a significant concern.

The specialists recommend incorporating urea at least three inches deep within four days of application to minimize volatilization risks. They caution against early applications of urea and UAN (urea ammonium nitrate), particularly in liquid forms, due to volatility and the potential for nitrate loss.

Urease inhibitors can mitigate ammonia volatilization for a brief period, but their effectiveness is limited if urea is applied too early and left on the soil surface without sufficient rainfall for incorporation.

For anhydrous ammonia applications, the inclusion of a nitrification inhibitor may be beneficial if applied in March, as it could reduce nitrogen loss over the extended period before crop uptake.

The experts also suggest soil testing, especially in continuous corn or manured fields, to account for potential nitrate carryover and recommend not to rush into urea or UAN applications given their greater loss risk.

With the current low nitrogen loss potential and potential nitrogen already present in the soil, they advise waiting until closer to planting for nitrogen applications, providing flexibility and possibly reducing the need for immediate nitrogen applications.

This guidance underscores the importance of strategic planning and soil health considerations in nutrient management, ensuring that crops receive the nutrients they need without unnecessary loss or environmental impact.

Other Minnesota Headlines