Talkin’ Trash

02:01PM Oct 27, 2010
( )
 Cornstalks being shredded092310

Equipment companies have developed shredder and spreader attach-ments that can help you distribute your corn residue evenly.

Tough cornstalks are a mixed blessing for corn-on-corn growers. Today’s engineered cornstalks stand better than ever, often in spite of high winds, disease and insect pressure. However, strong stalks can be difficult to manage after harvest, when they clutter corn fields like rows of miniature tree stumps. To help you manage cornstalks, Farm Journal Field Agronomist Ken Ferrie and Associate Field Agronomist Missy Bauer offer the following advice.

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 rules in order to comply.

Tillage practices play a large part in determining the amount of residue you leave in fields. Because corn harvest was early this year, many growers have already completed fall tillage. Those who haven’t can benefit from considering the amount of residue they need to protect soil surfaces, especially in areas with erosion issues, Bauer notes.

“In northern areas, we try to speed up residue breakdown, but it’s often the opposite in Southern states,” Bauer says. “A lot of times, farmers there need to preserve residue to protect soils.”
Base your residue management practices on crop rotation. Ferrie says that when the crop
decomposes in a corn-on-corn rotation, it emits a toxin that can impede corn growth the following spring. In no-till corn-on-corn, his studies show that the further you can plant corn away from the previous year’s crown root growth, the better the crop is likely to perform. “You’ll need row cleaners set up on the planter next spring to keep residue away from the seedbed,” he says.

Weather conditions this fall were better than the two previous years, he adds, which helped farmers minimize compaction issues.

Strip tillage can help address light compaction, as it speeds up the decomposition process.

Distribute residue evenly. Equipment companies have responded to the increased-residue issue by developing shredders and spreaders that attach to the combine for more even distribution.
In some cases, larger headers create a trail of residue behind the machine. Check residue distribution as you harvest and adjust accordingly.

Size residue, based on your field and geography. This prepares soil for the next crop and can eliminate tillage trips and planter clogs. Smaller pieces of residue 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.

Ferrie 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. Bauer says growers need to determine whether their goal with postharvest tillage is to bury residue or break up soil density layers, and then 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.

Residue management is part of a good fertility program. Ferrie says decomposition is driven by soil microbes that are very sensitive to soil pH.

“Acid soils lead to poor decomposition, so it’s important to keep soil pH balanced,” he says.
To achieve effective nitrogen utilization for next season, he advises farmers to split their nitrogen use into preplant, weed-and-feed and planter applications, with the balance sidedressed.