With high nitrogen fertilizer prices and low corn prices, can you decrease your nitrogen rate for 2026?

By: Brad Carlson, Extension educator

The University of Minnesota uses the Maximum Return to Nitrogen (MRTN) method for helping corn growers pick a nitrogen fertilizer rate. This method uses a database of results from many research trials around the state and then factors in the price of corn and the price of nitrogen fertilizer to find the most profitable nitrogen fertilizer rate for Minnesota corn growers.

Understanding the “price ratio” is key. The price ratio is the price of nitrogen fertilizer per pound to the value of a bushel of corn.

 For example, if N fertilizer costs $0.40 per lb. of N (or $656 per ton of anhydrous ammonia), and corn is valued at $4.00 per bushel, the ratio would be 0.40/4.00 = 0.10. Historically, the price ratio has hovered around 0.10 but in recent years high nitrogen fertilizer prices have resulted in higher price ratios.

What is the price ratio looking like heading into 2026?

The University of Minnesota’s corn fertilizer guidelines (z.umn.edu/cornfertilizer) use four standard price ratios. In the table below, you can see that the nitrogen rate that maximizes profitability for corn after soybean at the 0.10 price ratio is 150 lbs. N per acre, with an acceptable range of 135 to 160 lbs. N per acre. However, with current low corn prices and high nitrogen fertilizer prices, the price ratio is likely closer to 0.15 for most growers. This means that a nitrogen rate of closer to 135 lbs. N per acre (with an acceptable range of 125-145 lbs. per acre) would be better to maximize profitability.

Table 1: Suggested nitrogen rates for non-irrigated corn following soybean

Prior crop	N price/crop value ratio	Optimal rate	Acceptable range
Soybean	0.075	155 lbs. N/acre	145-170 lbs. N/acre
Soybean	0.100	150	135-160
Soybean	0.125	140	130-155
Soybean	0.150	135	125-145

Using the calculator, you can calculate your own price ratio based on the nitrogen fertilizer price you are paying and the corn price you are getting (or expect to get). Just go to cornnratecalc.org and click on the “calculator” tab at the top.

There, you can select your state, rotation, and nitrogen source. Then, input the price you paid (or expect to pay) for nitrogen fertilizer and the corn price. For the example below, the local cash delivery price for corn on October 17, 2025 (when I was writing this blog post) was $3.76 per bushel. I called a Minnesota co-op and they quoted me a price of $850 per ton for anhydrous ammonia, which equates to $0.518/lb. N. With fall application, I’m going to add in the cost of a nitrification inhibitor, which is about $0.10/lb. N, so the nitrogen price climbs to $0.618/lb. N.

Hit “calculate” and you will see your results. As you can see below, for my example, the price ratio is 0.164, off the chart in the U of M’s corn fertilizer guidelines. The calculator suggests a nitrogen rate of 133 lbs. N/acre with an acceptable range of 121 to 143 lbs. N/acre. I’m still getting 98% of max yield but I’m saving money because U of M research suggests that adding 10-20 more pounds of nitrogen to get those last few bushels is not worth the high cost of the N fertilizer. If the fertilizer were cheaper and/or corn prices were better, adding a little more fertilizer would be more likely to pay off.



If you consider your “normal” N application rate to be at the 0.1 price ratio, the recommendation for corn following soybeans is 150 lbs. N/acre. The recommendation drops to 136 lbs. N/acre when the price ratio of 0.15 is used. This equates to a savings of $7.25 per acre.

It needs to be noted that the top of the return to N curve is relatively flat, so while these reductions may seem risky, the data suggests it is not. The acceptable range at the current price ratio is between 128 and 150 for corn following soybeans. The acceptable range is N rates that return plus or minus $1.00 for fertilizer expense, or, at current prices, 0.27 bu. of corn. I think all would agree that a difference of 1/3 of a bushel of corn per acre can probably not be accurately measured, meaning the risk is not as great as one might think.

 
The remaining open question is regarding what prices will be heading into next year. At this time, I have not been able to get a reliable price quote for fertilizer for the spring. Everyone I have spoken to agrees that there should be no issues with N fertilizer availability, however, everyone expects the price to be higher than where it is today. Stay tuned, and we will give an update over the winter as those factors become clearer.

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