Healthier stalks at harvest, thanks to insect-resistant corn hybrids and fungicides, contribute to higher yield—which is positive. On the flip side, tougher stalks can be harder on tractor and implement tires, especially in no-till situations where all the residue remains on the soil surface.
"Cotton, canola and corn are some of the worst crops on tires,” says Wayne Birkenholz, manager of global field engineering for Firestone Agricultural Tires. "But soybeans and wheat can also be abrasive.”
"I've had a number of flat tires from soybean stubble—stalks seem to go right through them,” says Lance Hansen, who farms with his son, Nick, near Guthrie Center, Iowa. "With corn, you notice today's tougher stalks are harder to combine, so I'd guess they're tougher on tires, too.”
Although it usually doesn't get that bad, "it is possible to destroy a set of tires in a couple hundred hours, if conditions are right,” says Birkenholz's colleague Ken Brodbeck, Firestone's original-equipment sales engineer.
Weather-hardened stalks. Conditions that increase tire damage include hot, dry summers, which create hard, brittle stalks, and dry, open winters, which result in less decomposition.
"These conditions create stubble that easily shatters into very brittle spear points capable of penetrating rubber tires,” Brodbeck says.
Dry conditions and short stalk height create the most severe conditions for equipment tires, Birkenholz adds.
- Healthier stalks at harvest time, resulting from insect-resistant hybrids and increased use of fungicides to reduce disease, increase hazards to combine, tractor and implement tires.
- The single best solution is low-tech: stubble shoes on the combine or a stalk stomper on the tractor.
- Running tires between rows, rather than across them, also helps reduce damage.
Tests conducted with a durometer tool prove stalks are almost always harder than tires, Brodbeck says. Tire companies are fighting back by adding compounds that make rubber harder and more resistant to damage. "But you can't make a tire too hard or it becomes subject to cracking,” points out Firestone marketing manager Tom Rodgers.
While higher-ply tires will provide an increased resistance to stubble damage, they can't completely eliminate the problem. However, there are a few things you can do to reduce the extent of tire damage.
"The best solution to protect tires from stubble damage is a low-technology one,” Brodbeck explains. "Lean the stalks over at a 45° angle.” This can be accomplished by using stubble shoes on the combine or, for tractors and implements, building what many farmers call a stalk stomper. The stomper is usually a length of iron, often along the lines of 2"-diameter well pipe, that can be filled with sand and mounted in front of tractor tires to knock stalks over during tillage.
If you have a chopping head on your combine, you may be able to adjust it so that the chopped stalks result in a less spearlike configuration, Brodbeck advises. And, when possible, run tractor and implement tires between crop rows, rather than over or across them.
You may also be able to reduce damage a bit by buying new tires well ahead of harvest season and giving them some time to toughen up. "Rubber compounds need time to age and harden,” Brodbeck says. "They are most vulnerable to damage during their first year. If you have a choice of tillage tractors, run the one with the older, harder tires.”
You can e-mail Darrell Smith at firstname.lastname@example.org.
- February 2009