Nitrogen concerns from wet spring

IVESDALE, Ill. — Is it still there for the crop? That’s the big nitrogen question after a wet spring.

AgriGold agronomists Kevin Gale and Nick Frederking, representing northern and southern Illinois, respectively, have followed the nitrogen conundrum throughout their careers. They shared their experiences at the recent AgriGold Specialty Crops Conference.

Nitrogen is a key component to corn production and grain quality, and Gale said there has always been a concern about nitrogen in areas that get excessive rainfall, but management styles have also changed.

“We’ve changed our management style drastically over the last 10 years. Whether we’re talking strip-till, putting ammonia right above the row, utilizing starter, a 2x2 program with fertility right next to the row, there’s more sidedressing, there’s more banding of nitrogen occurring today, and I think that’s going to limit a lot of the effects of the excessive rain that we had,” Gale said.

“We’re just managing for higher yields and offsetting any of the weather that’s been thrown at us over the last several years.

“Overall, yes, we’ll have some nitrogen problems. There are some with just one-and-done type programs with just fall-applied N, the loss won’t be as drastic as what we had in really wet years like 2021 or 2014-2015.

“The wettest areas are also going to have the limited roots. It all goes back to rooting environment and how deep the roots get to get the nitrogen that’s there. Denitrification could be a concern, too, on heavy soils, saturated soil conditions.”

Sampling

Frederking takes soil samples in fall-applied and spring-applied corn fields each year. The samples are in zones of zero to 6 inches, 6 to 12 inches and 12 to 18 inches deep.

“I track what’s ammonia-based. I track what’s nitrate. Obviously, nitrate form leaches. It’s gone if the rainfall comes,” Frederking said.

“I took some samples of the fall-applied anhydrous fields in the beginning of March. All of that was already in nitrate form zero to 6 inches deep. That surprised me because we’re super warm in the spring. So, the microbial activity turning it over happened successfully. With all of the rainfall I expected that to push through the soil profile.

“Normally I come back at sidedress time and take a sample of the spring-applied. I took samples at the beginning of May for March-applied anhydrous and at that point nearly all of that was in the nitrate form, as well.

“We’ve had a lot of rainfall since then. I do expect that we’ve pushed a lot of our nitrate through the soil profile. We can be sure it’s not in ammonia form anymore.

“I’m heavily promoting sidedress this year. Those that don’t sidedress, I do expect them to see some nitrogen deficiency late season.”

Better Management

Frederking concurred with Gale that farmers now have a deeper understanding and have utilized better management of nitrogen over the past five to ten years.

“Spoon-feeding, split-applying are definitely a portion of commercial production today, but at least in southern Illinois, we’re still very traditional. Anhydrous in the spring, maybe something on the planter, maybe a weed and feed, but a lot of it is anhydrous-based,” Frederking said.

“I cover a funny line because Route 16 when you get close to central Illinois is typically where you see the fall anhydrous pick up. So, I do cover some of that area and the spring-applied area.”