Considerations for NH3 Application

Guest blog by Kurt Metzger,
West Area Seed Solutions Specialist, MaxYield Cooperative

Unusually dry weather this fall has corn growers asking questions about whether or not they should wait to apply Anhydrous Ammonia (NH3).

Applying NH3 in dry soils is actually the best situation if a producer can get it to seal. The NH3 bar must be deep enough to get adequate soil separation between the point of ammonia injection and the depth where corn seed will be planted next spring, as stated by John Sawyer, Department of Agronomy, in his recent Integrated Crop Management News article entitled, “Anhydrous Ammonia Application and Dry Soils.”

At MaxYield Cooperative, we began applying NH3 nearly two weeks ago.  It was exceptionally dry then, so we made sure the NH3 bar was in the ground 6 to 7” (4-6” is typical).  We’re recommending that producers apply nitrogen deeper to help prevent damaging seed next spring.  This same point is made in Sawyer’s newsletter article.  He writes, “Shallower injection, greater movement upward from the injection point, wider knife spacing, or higher rates can lead to ammonia being in the seeding area at rates high enough to cause damage” next spring.

Fortunately, the newer NH3 bars have much better disk closers and will be more aggressive to move the soil in order to seal the in the soil.

Another point is with the dryer soils, the zone that the ammonia in the soil becomes a larger radius to attach to the clay.  This means it takes more moisture next spring in order for leaching to occur.  Remember the nitrogen moves with the soil water profile and only will move with the excess moisture.  Use of N-Serve is still very much recommended.

With that said, however, overnight rainfall will help mellow the soil and provide for better sealing upon NH3 application.  Soils are so dry that it will take many more inches of rain before it’s too much moisture is a concern.  The best analogy is that our glass is only ¼ full now, so we have a lot of room before rain fills our glass and runs it over next spring.