Start with a level planting field
Before planting corn this spring, check how level the fields are to ensure better planting, even emergence, improved stands and higher yields, urges veteran ag consultant Kevin Kimberley. “Fields are never as level as you think,” says the owner of Kimberley Ag Consulting at Maxwell in central Iowa. He has consulted with farmers in the Corn Belt on plantability, tillage, fertilizer placement and related issues for 20 years and has been calibrating corn meters for 35 years.
It’s not enough to have calibrated corn meters and on-the-go down-pressure technology when planting, he says. “These technologies are all great, but we still need to get the field as level as possible. A calibrated corn meter and on-the-go down pressure will not fix an uneven seedbed.”
It’s also important to have as consistent soil density as possible throughout fields. “Level fields and consistent soil density, properly calibrated corn meters, and a planter that’s in top shape make an effective planting system that vastly increases the likelihood of even emergence, uniform stands and even ear placement, which maximizes yield,” he says.
• Leveling uneven fields pays off with better corn growth.
• Field-cultivating to fill holes and ruts improves emergence.
• Even emergence and uniform stands maximize corn yield.
There are holes in fields, and then there are ruts. In one field that was moldboard-plowed, ruts were so big and deep that Kimberley Ag Consulting employee Marty Morgan was able to lie down inside them.
Here’s Kimberley’s advice:
• Leveling fields. Field cultivating can help level uneven fields. Kimberley recommends following five guidelines to create a better seedbed.
1. Check to see how level the fields are by using a 2-by-4 that’s 3 to 4 feet long.
2. Aim for consistent soil density throughout fields.
3. Cultivate parallel to last year’s rows, or at an angle, depending on the depth of holes.
4. Run sweeps deep enough to push more moisture into holes.
5. Cultivate at 7.5 mph or faster if fields are quite level.
• Filling holes. Never as level as they appear from the road, fields typically have holes 4 to 6 inches deep, says Kimberley. “If you field-cultivate 3 inches deep, then you’re putting loose soil into holes that are 4 to 6 inches deep,” he says. “You want to make sure the soil in the hole and the hump has the same density. With the same soil density in the field, it’s easier to set the down pressure and have good seed-to-soil contact throughout a field. This also makes the row units run smoother on the planter.”
At times, it’s important to field-cultivate at an angle opposite to the direction of tillage to make sure soil moisture and density are consistent. “You want to bring your moisture together,” Kimberley says. “You want to be sure you have all the same soil density before planting.”
• Rootless corn syndrome. Emergence can be uneven in fields that contain both loose and firm soil. Corn in firm soil germinates first because of better seed-to-soil contact. “Poor seed-to-soil contact in loose soil causes what many people call rootless corn syndrome,” he says. “When the wind blows, the young corn plants will swirl or wobble in all directions. This leaves a hole around the bottom of plants, which lets heat get in, down to the roots. It dries the roots and makes them go dormant. Roots need moisture to grow.”
Soil that’s too loose is as bad as soil that’s too tight, he says. “Corn plants need enough moisture to start growing. But when the temperature hits 80 and 90 degrees F and the wind blows, the corn plants in loose, dry soil wobble. They wobble so much that you can see a hole around each plant. And when the plants wobble, they aren’t growing.”
This “rootless corn syndrome” was a big problem across the Corn Belt in 2012. “It happens because there’s all dry, loose dirt around the roots, and there isn’t moisture in the soil for the roots to grow,” notes Kimberley. “The corn in loose soil will resume growing if it rains. But if it doesn’t rain to cure your ills, then you will have problems.”
• Straight or angled. Usually, you field-cultivate straight with previous rows, or at a very slight angle, Kimberley says. “You want to push the humps into the hole the shanks made, so the dirt goes into the hole and soil density is consistent throughout the field. You might cultivate at a 35-degree angle. In some fields where there are ruts deep enough so a man can lie down inside them, you want to field-cultivate in an ‘X’ pattern.” Having a level field with soil that’s consistent also creates an even ride for the corn planter.
• Speed helps. Field-cultivate at a fairly fast speed. “I typically recommend starting out at about 8 mph, but only drive this fast if fields are smooth,” says Kimberley. “The effect of going fast or slow with a field cultivator is just like going fast or slow with a snowmobile on open water in a lake. If you go fast, you will not sink. The snowmobile gets on top and planes because you have momentum. However, if you go slow, you’ll sink, and then you’re trying to dig out to get on top of the water. Just like the snowmobile, we want the tractor to go fast enough so it has enough momentum to stay on top of the field when you’re running the field cultivator. You don’t want the tractor tires to spin and cause compaction.”
Field-cultivating quickly also makes a better seedbed because it brings more crop residue to the top, he says. The trash wheels on a planter can move the residue out of the row. Otherwise, corn roots will grow in it, which can cause uneven emergence. That residue can also tie up nitrogen.
Time spent leveling fields before planting can pay off. “If you have big holes in a field, it can lead to uneven emergence and poor stands,” sums up Kimberley. “Preparing fields so they are as level as possible and the soil density is as consistent as possible is crucial before you plant.”
Zinkand, an Iowa native, writes from Salem, Ore.
Patience is important
This article published in the April, 2014 edition of WALLACES FARMER.
All rights reserved. Copyright Farm Progress Cos. 2014.