5 steps to an efficient harvest
You check behind your six-row combine and find two corn ears dropped every 30 feet or so. Compound this by counting scattered kernels on the ground that average 4 per square foot.
Pretty good, right?
That depends. With a six-row machine at 30-inch rows, that 30-foot stretch with two dropped ears equals about 1∕100 acre. That’s 200 dropped ears per acre. With average-size ears, losses tally 2 to 3 bushels per acre, says Mark Hanna, Iowa State University Extension agricultural engineer.
Meanwhile, those ground kernels add up, too. Four per square foot equals about a 2-bushel-per-acre loss.
All these losses add up to 4 to 5 bushels per acre left behind with your combine. At $5 per bushel, you do the math!
“You are never going to get to zero,” says Hanna. “The American Society of Agricultural Engineers says 1% is the maximum acceptable threshing loss for corn and soybeans. In 200-bushel corn, that’s just 2 bushels. I know from experience that some combines in good standing crop have losses of under .5 bushel an acre. A good goal is to get to under 1 bushel per acre.”
Hanna gives five tips to help you fine-tune your combine and slice corn harvest losses.
1. Measure how you’re doing.
Look behind the combine and count the whole ears in a 30-foot stretch (or with a 12-row head, 15 feet is 1∕100 acre). Use this formula as a rule of thumb: One dropped ear equals 1 bushel per acre lost. If you see more dropped ears than you like, you know it’s a problem at the front end of the combine. Hanna says about 60% of corn harvest losses occur at the header.
In that stretch of harvested ground behind the combine, dig deeper -- down to ground level -- and look for scattered kernels. Count them in several 1-square-foot areas to get an average.
“It’s important to do this across the head and across the field,” Hanna says. “The variability can be high.”
If you find your total harvest loss is less than 1 bushel per acre and that’s your goal, don’t change a thing and keep harvesting, he says.
2. Find the culprit.
If the loss is unacceptable, determine where it’s occurring. If the problem is whole ears, look closely at header operation. Walk ahead into unharvested crop. You may see that most of the dropped whole ears are on the ground ahead of the combine. You can’t blame the combine for that.
To check for shelling losses on stalk rolls, combine into a section of standing crop for 15 feet to 30 feet, then back up and look at each row individually. This will tell you if you are losing kernels at the header rather than out the back of the combine due to a threshing or separating problem. You may be able to see that shelling losses are coming from one or two rows, so you can concentrate on fixing them, says Hanna.
If you determine you have a header problem, Hanna says to follow this checklist:
Set deck plates 1.25 inches apart.
Set snouts to just touch the ground.