If you struggle to manage the residue levels in your corn-on-corn acres, you aren’t alone. With the focus on using higher plant populations and narrow rows--not to mention increasingly tough cornstalks—farmers have more residue to manage than ever before. Farm Journal Agronomists Ken Ferrie and Missy Bauer provide the following agronomic tips and reminders to help you accomplish that goal this fall and in a fashion that will help you prepare for 2011.
Know your residue needs.
To qualify for government conservation programs, you need to leave a minimum amount of residue on your fields. In some cases, the requirement is upwards of 30%. Make sure you know the requirements in order to comply.
Tillage practices play a huge role in determining the amount of residue you will want to leave in fields after harvest this fall.
Ferrie says if you use no-till practices exclusively, harvest corn so the stalks left behind are no more than 24” tall. Shorter is even better.
“Those shorter stalks will be much easier to deal with when you plant next spring,” he says. “It also minimizes potential damage to your planter tires.”
At the same time, having corn residue readily available to protect the soil surface is important, especially in those areas that historically face soil and water erosion issues.
“In northern areas, we try to speed-up residue breakdown, but it’s often the opposite in some of the southern states,” Bauer says. “A lot of times farmers there need to preserve residue to protect their soils.”
Make sure your combine distributes residue evenly.
Your combine can play an important role in helping you distribute residue evenly on fields during harvest.
Equipment companies have responded to the increased residue issue by developing shredders and spreaders that attach to the combine and can help you accomplish an even distribution.
In some cases, however, larger headers on combines can contribute to a trail of residue forming behind the machine.
Check your combine residue distribution as you harvest and adjust accordingly.
Size residue, based on your fields and geography.
Sizing residue helps prepare the soil for the next crop and can eliminate tillage trips and planter clogs. The smaller pieces of crop residue that result also decompose faster than larger ones.
However, Bauer cautions: “If you do shredding, fall tillage may need to follow quickly so the residue doesn’t have an opportunity to drift. You don’t want it to blow onto your neighbors’ fields or drift into piles.
Ferrie agrees and adds: "Shredding stalks in no-till and strip-till operations comes with a risk that they'll blow away with high winds or a flood will cause them to float away.”
Know your goals for post-harvest tillage.
Bauer says growers need to determine whether their goal with post-harvest tillage is to bury residue or break-up soil density layers. Bauer adds you want to pick the tool best suited to the job.
“The type of point, shanks and spacing will play an important role in the process, depending on your goal,” she says.
Use nitrogen effectively.
Ferrie’s research shows that corn-on-corn requires a minimum of 100 lb. per acre of nitrogen surface-applied.
If the soils stay warm this fall and you want decomposition, he says between 30 lb. and 40 lb. of nitrogen should be broadcast now in the form of ammonium nitrogen (NH4). This nitrogen application helps feed microbes that are decomposing the corn residue in your fields. Plus, it counts as part of the total amount of nitrogen required to grow your 2011 corn crop. Plan on surface-applying the remaining 60 to 70 lb. next spring.