Corn needs nitrogen to yield really well and University of Illinois Soil Fertility Specialist Fabian Fernandez says farmers still have a bit of time left in some parts of the Midwest to apply the primary plant nutrient.
"Typically if plants are extremely deficient in nitrogen they will respond to nitrogen until about tasseling," Fernandez said. "The earlier you apply it the better chance for that plant to use that nitrogen. So first of all apply it as soon as you can; the second thing is apply it in a way that it will produce the least amount of damage to the crop and will be available to the plant."
There is definitely a right and a wrong way to apply nitrogen to corn during the growing season. Fernadez says that once roots reach a certain size injection can cause damage so surface application with drop nozzles between rows is probably the best option. However, it is an option that needs a little help from nature. Nitrogen applied to the soil surface needs to make its way into the soil profile to be used by the corn plant. That takes a rain, at least a good half inch soaking.
"That would be my suggestion," Fernandez said. "If you are applying it on the surface, make sure, if you can, to do it right before a rain event so that that rain will incorporate into the soil."
A couple of other notes: corn that is yellow at this stage in the season has already lost yield potential and putting a full rate of nitrogen on will not bring it back, so don't use a full rate. And if the corn has tasseled it's pretty much too late to apply nitrogen.