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Practical anhydrous application tipsPractical anhydrous application tips

Remember to wait for soil temperatures under 50 degrees F and adhere to safety measures.

Kevin Schulz

October 24, 2023

3 Min Read
Tractor applying nitrification inhibitor to a field
PREVENT LOSS: Using a nitrification inhibitor is good insurance to keep fall-applied nitrogen in place to be available for next spring’s crop. Farm Progress

As harvest winds down, farmers’ thoughts turn to fall application of fertilizer, including anhydrous ammonia.

Brad Carlson, University of Minnesota Extension educator working out of the regional office in Mankato, reminds there are considerations before calling the custom applicator or hauling the nurse tanks to fields. “Fall application of anhydrous ammonia, with a nitrification inhibitor, is considered an acceptable practice for most of Minnesota,” he says.

The key word there is most of Minnesota. Carlson refers to a Minnesota Department of Agriculture map where it is safe to fall apply anhydrous ammonia — but maybe more importantly, where it is not only ill-advised, but also illegal.

“Use of a nitrification inhibitor, such as N-Serve, is really kind of a hedge against extreme conditions that would lead to nitrogen loss in between the time of application and the time of the crop is up and using it,” he says. “The period of high use for next year’s corn crop is probably going to be about the first or second week of June next year. So that’s an awful long time for the nitrogen to be sitting in the soil.”

Research has shown that historically anhydrous ammonia “is probably the only product that is really acceptable for fall application,” he says. “Our best management practices still do say that urea is acceptable in western Minnesota, but the research over the last couple of decades has shown that it really has been underperforming anhydrous. Some of that is water-quality-related, but we also feel that we’re possibly losing some of the nitrogen through volatilization into the atmosphere, and particularly when the soil is really dry. … so we’re really not recommending fall urea at all.”

He does add that the risk of water-related loss lessens as one gets to Morris, Minn., and up the Red River Valley.

Nitrogen loss from leaching and denitrification both occur when soils are completely saturated, “so when the soil profile is as dry as it has been, the risk really isn’t all that high,” Carlson says.

This interview took place Oct. 16, and rains had finally come to drought-stricken regions, but will it be enough? “We don’t have a crystal ball,” he admits. “I mean, last year was really dry, and we ended up at field capacity by the time we got into planting season, and so that’s possible again this year. We just don’t have a good way of knowing that.”

As always, Carlson reminds farmers to be patient, and wait for the soil temperature to get below and stay below 50 degrees F at the 6-inch typical depth for anhydrous application. View MDA’s interactive map to find the current 6-inch soil temperature and the past week’s history.

Safety first

Whenever anhydrous applicators take to the fields, the MDA reminds applicators to remember safety measures, both when applying anhydrous as well as working on equipment and transporting.

  • Always wear NH3-rated goggles and gloves. Never wear contact lenses.

  • Be sure to have a clean and accessible emergency water supply of at least 5 gallons available.

  • Exercise caution when making connections and disconnections of transfer lines, treating them as if they always contain NH3.

  • Stand upwind when connecting, disconnecting, bleeding lines or transferring NH3. Also, close, bleed, disconnect and secure valves and transfer lines when taking breaks or disconnecting lines, and be sure to handle hose end valves by the valve body.

  • Position equipment away and downwind from homes, people and livestock.

  • Never assume NH3 lines are empty.

  • Always wear the required protective safety equipment.

  • Have access to safety water (NH3 storage facilities must have a minimum of one open-top container holding 150 gallons of clean, accessible water or an accessible emergency shower with a plumbed eyewash. A 5-gallon container of clean, accessible water must accompany NH3 nurse tanks).

You can find more safety, storage and transportation information on the MDA website.         

Minnesota Department of Agriculture contributed to this article.

About the Author(s)

Kevin Schulz

Editor, The Farmer

Kevin Schulz joined The Farmer as editor in January of 2023, after spending two years as senior staff writer for Dakota Farmer and Nebraska Farmer magazines. Prior to joining these two magazines, he spent six years in a similar capacity with National Hog Farmer. Prior to joining National Hog Farmer, Schulz spent a long career as the editor of The Land magazine, an agricultural-rural life publication based in Mankato, Minn.

During his tenure at The Land, the publication grew from covering 55 Minnesota counties to encompassing the entire state, as well as 30 counties in northern Iowa. Covering all facets of Minnesota and Iowa agriculture, Schulz was able to stay close to his roots as a southern Minnesota farm boy raised on a corn, soybean and hog finishing farm.

One particular area where he stayed close to his roots is working with the FFA organization.

Covering the FFA programs stayed near and dear to his heart, and he has been recognized for such coverage over the years. He has received the Minnesota FFA Communicator of the Year award, was honored with the Minnesota Honorary FFA Degree in 2014 and inducted into the Minnesota FFA Hall of Fame in 2018.

Schulz attended South Dakota State University, majoring in agricultural journalism. He was also a member of Alpha Gamma Rho fraternity and now belongs to its alumni organization.

His family continues to live on a southern Minnesota farm near where he grew up. He and his wife, Carol, have raised two daughters: Kristi, a 2014 University of Minnesota graduate who is married to Eric Van Otterloo and teaches at Mankato (Minn.) East High School, and Haley, a 2018 graduate of University of Wisconsin-River Falls. She is married to John Peake and teaches in Hayward, Wis. 

When not covering the agriculture industry on behalf of The Farmer's readers, Schulz enjoys spending time traveling with family, making it a quest to reach all 50 states — 47 so far — and three countries. He also enjoys reading, music, photography, playing basketball, and enjoying nature and campfires with friends and family.

[email protected]

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