University of Illinois Soil Fertility Specialist Fabian Fernandez has three points of interest for corn farmers making nitrogen applications. The three points are simple. First, Fernandez says to try to make a split application of the nitrogen. It's nice to go early, but there are pitfalls.
"The only concern that I have with applications that are this early; I mean it's not extremely early but it's early enough that if we get hit with a lot of rain later you can end up losing some of that nitrogen," Fernandez said.
The second point Fernandez says is that typically corn doesn't really need that much nitrogen early on in the growing season. He says the big reason producers applying nitrogen early is so they don't have to apply during the growing season or while planting.
"In reality, until V6 when we are normally side-dressing, the plant needs only about 10% of the total nitrogen the plant needs. So if you can do a split application, it may be beneficial, and the reason I say that is the concern that we may have wet springs."
According to Fernandez popup or starter fertilizers both supply enough nitrogen for corn seedlings.
The final point Fernandez makes about nitrogen applications is about Cation Exchange Capacity, which he says is not relevant to nitrogen.
"The science as well as the practice," Fernandez said. "We have effectively applied over 200 pounds of nitrogen in sandier soils for research trials that we conduct and we see no problems. Those sandy soils have very low CEC's. If you go by the rule of thumb of no more than 10 pounds of nitrogen per unit of CEC; you know if you have a five CEC in a sandy soil that's only 50 pounds of nitrogen you could apply and that just doesn't make any sense."
So the three points Fernandez stresses: Don't apply N too early; lean toward a split application if possible and ignore the chatter about CEC's.