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5 tips for avoiding nitrogen injury, loss

Follow this advice for keeping your corn healthy during early-season nitrogen applications.

Allison Lund

May 1, 2024

3 Min Read
corn seedlings in the field
HANDLE N CAREFULLY: Sidedress applications of 28% liquid N or anhydrous ammonia can result in leaf burn if nitrogen contacts plant leaves from drips or leaks. Because injury is minor, these plants should continue growing normally. Tom J. Bechman

The goal of nitrogen applications is to give your corn a yield boost, but what happens when you apply too much of a good thing? Mistakes made when applying nitrogen, such as placement and timing, can lead to injury in the form of burn. Most of the time, the plants will grow out of it. The other risk is losing nitrogen through volatilization, denitrification and leaching.

Dan Quinn, Purdue Extension corn specialist, says one of the most important things to do is keep an eye on corn after nitrogen applications to look for injuries, especially during emergence. He explains that assessing belowground plant condition should not be overlooked when looking for nitrogen injury symptoms.

“About 90% of the time, it’s the roots,” Quinn says. “That’s often where getting the shovel out and digging some plants that are in those problem areas can pinpoint where that issue is by paying attention to the roots.”

To avoid that scenario of burned roots, stunted plants and lost nitrogen, Quinn shares five tips for preventing nitrogen injury and losses during early-season applications:

1. Apply the correct rate. The most important factor to avoiding nitrogen-related injuries is knowing what rate to apply. Quinn says going too high with your rate and too close to the seed at planting can spell trouble for the growing plants. His recommendation is to apply 20% of nitrogen at planting and the remainder at sidedressing. If following up with another pass later in the season, he recommends applying 60% at sidedressing.

2. Know your placement. Make sure all application equipment is working correctly to ensure the nitrogen is getting where it belongs. If using a spreader, ensure it is calibrated correctly to avoid over- or underapplying nitrogen in certain areas. In later-season applications where drop tubes are being used, make sure the tubes reach the soil surface so they’re not splattering nitrogen on the corn plants.

3. Use split applications. Plan to make multiple passes to avoid putting on all your nitrogen at once. This relates to applying the correct rate; you do not want to apply all nitrogen in one pass too close to the seeds at planting because it can injure the plants, as well as be lost through volatilization or leaching. These split applications primarily help prevent nitrogen losses.

4. Apply nitrogen before rain. If you see rain in the forecast, try to make a pass to apply nitrogen several days before. Rain can help with the nitrogen uptake and dilute that nitrogen, thus preventing plant injuries from the application. Additionally, it can limit volatilization.

5. Don’t apply when dry. When field conditions are dry, avoid making nitrogen applications. Nitrogen injury is more common with dry conditions because there is little to no moisture in the soil to dilute the nitrogen. Moisture also helps nitrogen move through the soil, limiting losses. Nitrification inhibitors and urease inhibitors can also help prevent nitrogen loss.

With the environment being an unpredictable factor in where nitrogen ends up, it’s important to implement practices that will help counteract that unpredictability. And while most corn plants will come out of nitrogen injury, they may remain stunted and unhealthy throughout the rest of the season. It’s best to follow these key practices to avoid those scenarios altogether.

About the Author(s)

Allison Lund

Allison Lund is a staff writer for Indiana Prairie Farmer. She graduated from Purdue University with a major in agricultural communications and a minor in crop science. She served as president of Purdue’s Agricultural Communicators of Tomorrow chapter. In 2022, she received the American FFA Degree. 

Lund grew up on a cash grain farm in south-central Wisconsin, where the primary crops were corn, soybeans, wheat and alfalfa. Her family also raised chewing tobacco and Hereford cattle. She spent most of her time helping with the tobacco crop in the summer and raising Boer goats for FFA projects. 

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