Managing old-crop residue is one component of a crop production system. It sets you up to grow a uniform crop—and uniformity is one of the building blocks of higher yield.
Our residue management system is based on the advice of our crop consultant, Ken Ferrie.
With residue management, our ultimate goal is to have uniform soil moisture and temperature conditions to plant into the next spring. That requires sizing residue and distributing it evenly.
Residue management starts when a crop enters the combine head because tillage can't fix uneven residue distribution. If you don't spread residue uniformly, you'll have streaks of residue next spring when the crop comes up. The corn growing in the streaks will be yellow and less uniform because soil microbes expand to decompose the residue. They tie up nitrogen in the soil, making it unavailable to the new crop.
From a planting standpoint, you can clear away the residue with row cleaners, but you still tie up nitrogen. And the soil will be cooler where there is more residue.
On our combines, we use knife-roll corn heads to chop the cornstalks. Then, we spread the residue as it leaves the combine. Experience has shown us there's a lot of difference between machines.
We want to spread residue evenly with the width of the header. One combine we used only spread residue the width of the rear tires, even though it was equipped with both a chopper and a shredder. It left streaks of residue and bare soil.
Of the two combines we own now, one does fine in corn residue and pretty good in soybean residue but is horrible in wheat residue. Our other combine, a Claas Lexion 575R equipped with a Redekop MAV straw chopper and a chaff spreader, does a good job in all three crops. It has a 35' grain platform and a 30' corn head.
The right tools.
After harvest comes tillage. For fall tillage in continuous corn, we switched from a standard ripper to a Sunflower 4511 disk-chisel tool. It is equipped with a gang of disks, followed by chisel shanks and another gang of disks. Our goal is to incorporate corn residue and roll out root wads.
Studies by Ferrie showed that in continuous corn, uniform mixing and incorporation is more important than tilling deep. In the spring, we run a McFarlane Reel Till, with some modifications that we made, or a Great Plains Turbo-Till. We pull 8- or 9-bar harrows behind each implement.
These are not tillage tools; their purpose is to size the residue and level the surface. Smaller pieces of residue will decompose faster.
Prior to planting, we broadcast nitrogen. The nitrogen feeds microbes that decompose the residue, so they do not deplete nitrate in the soil.
We prefer the McFarlane tool if the soil is soft or holding more moisture.
We like the Turbo-Till when the ground is crusty or we have more residue to chop. Sometimes we run both tools, one after the other.
In a corn/soybean rotation, we sometimes no-till the soybeans. But we like to run the Turbo-Till in the fall; it distributes the corn residue more evenly, so we have more uniform moisture in the spring.
We also run the Turbo-Till when we plant wheat into corn residue. We think sizing the corn residue makes it flow through the drill better.
There's no one-size-fits-all residue management technique. You have to find what will work best in your conditions.
Geography plays a huge role in residue management. Here in southern Indiana, residue management is a little easier than it is for farmers farther north because we get more decomposition in the spring and fall. Wherever you farm, residue management—like every aspect of farming—is a continual learning process.