Agronomy Talk

Agronomy Update

Spring Ammonia Applications and Corn Planting Concerns

Published on Monday, April 20, 2015

Last fall was not very conducive for applying ammonia (NH3), which brings us to our current situation concerning spring applications. Couple that with wet soils, cooler daytime temperatures this week, and the need to begin corn planting, there are areas of concern!


Here are my recommendations regarding spring applications of NH3.

Depth of Injection: If you must apply NH3 before planting corn, the depth of injection is more important than the number of days from application to planting. Target at least a 7 to 8 in. application depth. NH3 will radiate from the point of injection out 3 to 4 in. Therefore, if you can achieve a 7 in. constant application depth, the seed germination/root development zone should be safe.

Wet Clay Soils: There is one problem with NH3 applications in wetter, clay soils. The ammonia knife can “smear” the sidewalls which will actually “funnel” and concentrate some of the NH3 farther up in the soil profile, causing concern with potential seedling injury.

Dry Sandy Soils: Because you typically inject NH3 deeper in sands for moisture/sealing purposes, sandy soils that are dry now could experience nitrogen (N) loss later in the season. If large rainfall events occur, leaching of deeply-placed N and/or reduced N availability at the roots could occur. Consider sidedressing as an alternative to spring NH3 applications!

Reduce Seedling Injury Potential: Seedling injury potential is reduced when you can have 5 to 7 warm (65 to 70˚F) days from application to planting. Other things that help are moist soils, applying NH3 at a slight angle to the future rows, and most of all applying it deep!

Shallow Tillage before Planting Corn: If NH3 has been applied and corn is not planted, use shallow tillage before planting corn.

Plant Corn First: By all means, when soil conditions finally become fit, plant corn first rather than putting on NH3! Then be sure to sidedress early!



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Denny Cobb

Denny Cobb

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