Cut corn head casualties
Thanks to more accurate loss monitors, remote combine adjustments, and vigilant farmers, grain shooting out the back of combines has been slashed to miniscule amounts of 1% or less.
Too bad the same can't be said for corn heads. Increasing yields, tougher stalks, and more resilient shanks are challenging row heads as never before. As a result, header losses appear to be increasing, depending on harvest conditions each fall.
“Today's heads are certainly better than those of the past, thanks to improvements such as lower profile snouts, remote adjustable stripper plates, and variable-speed drives,” says Kevin Bein of Gleaner. “But, you can't assume a good header is taking in all the crop. You need to get out of the cab and look under the combine to determine header losses.”
These losses take two forms in shelled grain (most often due to butt shelling) and whole ears. Combined, they can claim 5 bushels or more per acre. And with corn at $6 or more per bushel, such losses take a big bite out of bottom lines.
For example, finding two kernels per square foot or a single ear in a row behind a combine represents a 1-bushel-per-acre loss. “In the latter case, that's the average from the loss of one modest-size ear dropping down every 50 feet of row,” says ag engineer consultant Graeme Quick.
Quick led a field research effort at Iowa State University funded by Successful Farming magazine, which purposely misadjusted combines to gauge the affects of operator error. That work, combined with field surveys by Quick, revealed that deck plate misadjustment on corn heads is a particularly troublesome problem.
Results of that research are shown in the table below.
“Certainly no one would operate a corn head with a 1⅔-inch or wider deck plate settings in an average corn crop,” Quick says. “We went to extremes in adjustments to see what happens to losses.”
The ideal setting for the corn being harvested in Quick's research was 1 inch. What he discovered was being off by just ⅜ inch (with deck plates set at 1⅜ inches) reduced the amount of crop being harvested by as much as 26 bushels an acre. That represents a $156-per-acre loss with $6 corn.
Quick acknowledges that a great many corn heads in the field today have hydraulically or electronically adjustable deck plates that allow farmers to readily adjust gaps to changing stalk sizes (which can vary by variety). But he warns that remotely adjustable plates can be plagued by spacing problems due, particularly, to maintenance challenges.
“Over time, plates can seize (from rust) and become inoperable,” he warns. “That's why it is crucial that prior to harvest you get out of the cab and measure plate gaps to confirm they are consistent with the setting in the cab.”
Quick has found heads with adjustable plates operating with gaps that vary as much as ½ inch between rows.