By DAN ZINKAND
Before setting out to till fields black after harvesting corn and soybeans this fall, you should think ahead about making the best seedbed for planting next spring, advises Kevin Kimberley.
“Tillage is a marriage with your planter, and tillage is one of the most overlooked factors in farming,” says Kimberley, founder of Kimberley Ag Consulting at Maxwell in central Iowa. He consults with farmers throughout the Corn Belt on tillage, planting and fertilizer placement.
To handle crop residue at planting in spring, many farmers still want to turn their fields black in the fall, he says. They say poor tillage is better than nothing at all. However, approaching fall tillage with the same focus as planting can reduce problems that routinely cost corn growers at least 12 to 20 bushels per acre, Kimberley says.
“Every year when I travel through the Corn Belt and Great Plains, I see uneven emergence of corn and soybeans being the biggest robber of yield. Uneven ear placement indicates the corn emerged at different times in the field,” he notes. And many times, the bushels lost due to uneven emergence can be staggering.
Several years ago, Kimberley found a field of corn where uneven emergence cost the grower 63 bushels per acre. While that was back in the days of $6 corn, it’s still $220.50 per acre with $3.50 corn. On 1,000 acres, that’s $220,500.
“An amount which would cover input expenses or cash rent, or could be your profit for the year,” he notes.
Till right, plant right
Done right, fall tillage will result in better soil structure and soil consistency, as well as level the fields, he says. Done wrong, tillage turns fields into high, hard ridges of soil and holes filled with fine, loose dirt.
“So many farmers want the ground to be black in the fall, and it doesn’t need to be black,” Kimberley says. “With black ground, it’s been loosened. If your crop residue is all buried, that means you have gone too deep. You’ve run wings.”
He adds, “When we blow the soil loose and apart every year with wings on the tillage implement, we just keep repacking the soil. Blow it apart to a depth of 12 inches deep and the tractor tires will fall down 12 inches. The insanity is repeating this year after year.”
When scouting cornfields in late summer to estimate the yield potential, check the soil and think ahead to fall tillage and strip tillage, as well as to planting next spring. By doing tillage right, growers can improve their yields and the test weight of the grain, and harvest corn with a lower moisture content.
Tillage done right and tillage done wrong shows up in ear placement, Kimberley says. Ideally, the ears should be at the same height. A roller-coaster pattern with up and down ears indicates the corn seedlings emerged at different times and pollinated at different times, he says. The ears mature at different times. Depending on the amount of heat and the fall weather, ears on the late-emerging corn plants may be wet when the field is harvested.
Keeping ears even
“Corn tassels can all be the same height, but ear height and size can be uneven,” he notes. “Moisture levels will be different in the ears when the earliest-emerging corn matures and that will create problems.”
The late-emerging ears will be wetter, have lighter test weight grain and will be a higher moisture content to dry and store. Most of all, the small, late ears will yield less.
“In the past, we always tried to make the ground loose through the use of wings, twisted shanks and covering boards, which made the field look black,” Kimberley says. “But if you check the soil, you’ll see holes, chunks and swells. So the next spring when you field-cultivate or vertical-till, you will have loose dirt in the holes. Where the ridges are, the soil is tight. The corn will come up on the tight dirt first because of seed-to-soil contact. Water will run off the firm soil in the ridges.”
Tillage guidelines
Kimberley offers these recommendations if you’re planning to do tillage.
• Disk-rip and vertical-till at opposite angles, making an X.
• Don’t run the disk-ripper blades too deep.
• Run the blades 4 inches or a maximum of 5 inches,
• Pop the root ball, but leave it in place.
• Run a harrow behind the disk-ripper blades.
He says if you vertical-till fields of corn on corn you should do it at a 45-degree angle opposite to the direction it will be disk-ripped. The two tillage passes across the field will form an X.
“Our goal is to flatten the crop residue and stalks that are sticking up, and pop the root ball loose,” Kimberley adds. “When the disk-ripper or chisel plow comes through the soil, you don’t want to pop a big chunk out otherwise you’ll have a big hole for loose dirt to go down.”
Running the disk-ripper blades deeper than 5 inches will make the topsoil too loose, he says. Removing corn root balls instead of popping them results in voids, which fill with loose soil.
Kimberley prefers running a harrow instead of rolling baskets or spiked teeth at the back of the disk-ripper, for several reasons. “The harrow drags dirt into the holes that the disk-ripper may make. We want the ground level for planting next spring. We’ve found that a Gates harrow works well.”
In contrast, rolling baskets will beat and pulverize clods and root balls, but they won’t fill holes in. And sometimes the rolling basket can make waves in fields. That happens when the baskets push down and spin, then push or drag soil, and then spin again. “The same tillage problems can occur in soybeans following corn,” says Kimberley.
Visit kimberleyagconsulting.com.
Zinkand writes from northwest Iowa.
Fall-tilling bean stubble
If there’s little soybean residue left on the field after harvest, the field may not even need to be disk-ripped, says ag consultant Kevin Kimberley. “Whether you disk-rip or not depends on the amount of crop residue from the soybean harvest. The goal is leave as much residue on top of the field, stuck in the dirt.” You want to protect the soil against wind and water erosion.
If you decide to disk-rip soybean stubble, run the disks shallow so they barely cut the straw, he advises. “We like to run points on the tillage tool because we want to have the soil fractured and firm, not blown apart.”
These guidelines create good water infiltration and provide a good start for next year’s seedbed. “In soybean stubble, we like the harrow on the disk-ripper because it levels the holes, but it pulls bean straw and trash to the top,” he says. “If you’re doing fall tillage in a field of corn on corn, you’ll still have crop residue on the top when planting soybeans.”
This article published in the July, 2015 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2015.
Conservation Tillage