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High prices may not lower maximum return rate for nitrogen as much as you think.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

December 13, 2021

3 Min Read
anhydrous ammonia application in field
CHANGING PICTURE: Sharply higher nitrogen rates could impact how much you should apply, but perhaps not as much as you think. chas53/Getty Images

Two things ring true about nitrogen for corn in 2022, unless something drastic happens soon. Nitrogen prices will be sharply higher, and supplies will be tight.

“The quick, sharp price rise for nitrogen in the fall of 2021 was unprecedented,” says Jim Mintert, a Purdue University Extension ag economist and director of the Purdue Center for Commercial Agriculture. “We haven’t seen this sharp of a rise this quickly before.”

Michael Langemeier, also a Purdue Extension ag economist and associate director of the center, put numbers together to illustrate how higher nitrogen prices could impact how much N you can afford to apply in 2022, assuming you can get it. He used the Iowa State University Nitrogen Rate Calculator. Select Indiana and your crop district, and run your own numbers based on your nitrogen and corn prices.

“It’s a useful tool because you can quickly change parameters and see how it impacts the optimal nitrogen rate,” Langemeier says. The calculator uses data supplied by Purdue Extension agronomists Bob Nielsen, Jim Camberato and Dan Quinn based on yield trials in Indiana over the past decade and a half to calculate the nitrogen rate for maximum economic return.

You can also refer to Nitrogen Management Guidelines for Corn in Indiana by Camberato, Nielsen and Quinn, updated in October. Because it groups crop recording districts somewhat differently, the exact numbers recommended for maximum return may differ vs. the ISU calculator.

Takeaway messages

Here’s what you can take away from this situation:

Maximum return rate lower than maximum agronomic rate. The maximum economic rate when nitrogen is around 80 cents per pound, or about $1,300 dollars per ton for anhydrous ammonia, will be lower than the amount needed for top yields. Langemeier selected northwest and north-central Indiana in the ISU calculator, at $5-per-bushel corn. At 35 cents per pound for N, a possible price even a year ago, the maximum return rate is 194 pounds per acre with 100% maximum yield. At 80 cents per pound, it’s about 171 pounds per acre, with a profitable range estimated at 159 to 179 pounds. You can still expect 98% of maximum agronomic yield.

Maximum return rate still substantial. The 171-pound rate is still a lot of nitrogen, Langemeier notes. “That’s still going to take a lot of nitrogen if supplies are tight, even if farmers lower rates to where you would expect maximum return,” he says.

Corn price affects rates. If you run the same scenario again, but at $4 corn, the maximum return rate drops to 159 pounds per acre, with a range of 148 to 170 pounds. Pick the price you either expect or locked in when running rate scenarios.

Location affects nitrogen rates. Purdue agronomists discovered that more nitrogen is needed in some parts of Indiana than in others. Running the scenario at $1,300-per-ton anhydrous ammonia and $5 corn in central Indiana in the ISU calculator, the maximum return rate is 189 pounds per acre, with a range of 179 to 199 pounds. In east-central Indiana with the same parameters, it’s 208 pounds, with a range of 197 to 218 pounds. For northeast Indiana, the maximum return is at 207 pounds, with a range of 195 to 218 pounds. In west-central, southwest, south-central and southeast Indiana, it’s 166 pounds, with a range of 155 to 175 pounds.

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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