Scout to ensure even playing field
Corn that emerges unevenly can easily cost growers $50 per acre or more, but investing time before planting can pay off big time at harvest, says Kevin Kimberley, Kimberley Ag Consulting. Based at Maxwell in central Iowa, he’s been working with farmers in the Corn Belt for more than 20 years.
“We’ve got great technology with autosteer and GPS and other tools like variable-rate technology,” Kimberley says. “But it’s still important to stop the tractor when you’re planting and get off and check things. Precision ag tools aren’t bulletproof. Satellite connections can drop, which is something I see happen every year on farms.
“You need to be looking at the sidewall in between the gauge wheels and the closing wheels and check your ‘Tru-Vee’ furrow. Look to see if the root mass on corn plants has been retarded in its growth, which is something that happens between 300 and 350 psi [pounds per square inch]. Check for sidewall compaction. Can you cave the furrow’s sidewall down to your seed? Also, check to see if there are fracture cracks in your furrow sidewalls.”
• Uneven corn emergence can mean a $50 loss per acre.
• Check the furrow’s sidewalls for compaction and cracks.
• Examine the seedbed for valleys and loose dirt.
The cracks in the sidewalls of the furrow should be angled going to the back. If the cracks are straight up and down, then the down pressure most likely needs to be increased because the sidewall is lifting. “To check for this problem, you need to stop the tractor and get out and look for it in the soil,” he says. “Your planter monitor can’t make these decisions for you. Instead, you need to let the soil tell you what you need to do.”
During the past two growing seasons, Kimberley has also seen problems throughout the Midwest with closing wheel alignment. If the wheels aren’t aligned properly, that can cut corn yields by 15 to 25 bushels per acre. Even at $3.50-per-bushel corn, those losses amount to $52.50 to $87.50 per acre.
“Having your closing wheels properly aligned is crucial to achieve even emergence of corn seedlings,” Kimberley says.
Check seedbed before planting
Check the seedbed for valleys and loose dirt. It’s not only important to stop periodically while planting to check for sidewall compaction, it’s essential to check fields before you begin planting. Fields may look level from the road but may be uneven.
Kimberley recommends taking a 4-foot board and laying it across several rows. Check for high spots and low spots. Also, check the density of the soil in the high and low places.
If valleys between the ridges are 4 inches deep or more, using a field cultivator will push loose, dry dirt into these lower places. “This will create a pattern of loose, dry dirt in the valleys and firm dirt in the ridges,” says Kimberley. “You want the seedbed to be level and the soil to be uniform in density.”
Creating a level seedbed with uniform soil density may require field cultivating across the old rows. If the old rows run north and south, you want to run the field cultivator pretty much east and west, but not at an exact 90 degrees to the rows, he says. Instead, cultivate about 10 or 12 degrees off from a 90-degree angle.
“You want to put moist soil into the low spots,” says Kimberley. “The key is to get off the tractor and make sure the dirt is all the same, firm and moist, behind the field cultivator. It’s very important to fix this problem, which was caused by poor fall tillage before planting corn this spring. I’ve seen this problem occur with some of my clients, but it is something that can be resolved before planting.”
If the problem of low spots with loose, dry dirt and ridges with firm soil remains when the corn is planted, then emergence could be uneven.
Leveling the ground and making sure the closing wheels are aligned properly can also help reduce or eliminate another major problem, which is “cold water inhibition.” Kimberley says, “You want to plant the corn seed into the soil tight, so the cold water in the first spring rains doesn’t get to the seed and chill it.”
Checking fall strips
Corn growers who strip-tilled their fields last fall also can benefit by checking the strips before planting this spring.
“See if the soil structure and the moisture in the strip or zone that you will be planting into is the same,” says Kimberley. “You can use a spade to peel off the top of the strip, mimicking how the trash wheels on the planter scrape off the top.” The soil needs to be both firm and moist. If it’s not, go out with your strip-till rig and use a narrow knife and a ripple coulter and till down 4 to 5 inches, he advises. This will bring the soil back together so you have consistent soil structure to plant your seeds into. Freshening up the strip in spring can make it 10 to 12 degrees warmer than a strip of soil you don’t freshen up.
“Freshening up the strip to make the soil moisture and density uniform will give your corn a more even emergence pattern in spring,” Kimberley says. “This will give you more bushels and higher test weight at harvest in the fall and put more dollars in your pocket at the end of the year.”
Even emergence will allow maximum sunlight to get to the corn, resulting in maximum bushels and test weight. Late-emerging corn plants are shaded and act like a weed, competing for sunlight and moisture with the earlier-emerging corn.
Zinkand, an Iowa native, writes from Salem, Ore.
This article published in the March, 2016 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2016.