For corn-on-corn: Keep it dry & don't compact
Last year was a bit of a downer for a lot of corn farmers in Illinois. Yields were lower than expected, mostly because Mother Nature just wasn't very cooperative.
The average yield, which was 4.2 bushels/acre lower than the U.S. average (a particular striking number considering Illinois' crop had averaged 13.7 bushels/acre above the national average over the previous 10 years), was even lower on continuous corn acres. Nutrient and moisture deficiencies that were common hit those acres harder than conventionally rotated corn acres.
So, if you're planting continuous corn this year again, should you expect similar yield losses? University of Illinois Extension agronomist and Agriculture.com Corn High Yield Team expert panel member Emerson Nafziger says those corn-on-corn acres won't necessarily yield less this year if you manage them right. So, what's important to making it work this year? Mainly, make sure field conditions are dry enough and you don't "undo" the fieldwork you got done last fall.
"Though we can certainly feel good about preparations we've been able to make for this spring, we know from history that a good fall doesn't always mean a good crop the following year. While the fact that soils are starting to dry out nicely in some areas of the state is a good sign as we head into April, we need to be careful not to undo the compaction relief provided by last fall's tillage by driving on soils before they're dry enough," Nafziger says. "We know that any driving we do on soils this spring will do some compaction; soils are typically at or near field capacity when we're ready to plant in the spring, and it's at field capacity that they are most subject to compaction.
"Waiting until soils are dry enough at depth (not just over the surface) will help minimize compaction effects, as will using controlled traffic, making fewer tillage passes, and lowering tire pressure," he adds.
Soil conditions should, in fact, drive all the decisions you make for your continuous corn acres, Nafziger says. That's most important at planting time.
"So should we change anything for corn following corn this year? No. Our research shows that both respond similarly to planting date and to plant population, so those should change only as soil conditions and productivity might indicate," he says. "The important things -- having good soil conditions where the seed is placed and good rooting conditions underneath the surface -- are critically important for corn no matter what the previous crop. And the crop needs to be well supplied with nutrients and protected from pests. Once we cover these basics, the crop will respond mostly to weather factors -- water and temperature -- that we don't control."