If you want to plant corn and soybeans no-till in narrow rows, it's a challenge to handle the heavier amounts of crop residue. Some farmers buy a new narrow-row, no-till planter. Others modify existing equipment.
Carl Molgaard, farming with son Kyle near Peterson in northwest Iowa, spent less than $5,000, including labor, to convert their planter into an 18-row machine they use to plant corn no-till in 19-inch rows. For soybeans, they use an 8-inch-row-width no-till drill.
Carl bought two plate-planting units for $500 and bought a used four-row air planter for $1,000. He put these planting units on the 12-row planter he already owned.
Mechanic Swede Erickson of Feekes Farm Center helped Molgaard build the narrow-row, no-till planter. They started with the Molgaards' model 800 International 12-row air planter set on 30-inch rows and added the four air planting units.
They set the 16 units on the toolbar at 20-inch spaces, then moved all units closer for a 19-inch spacing. That allowed them to add two more planting units, one on each end of the toolbar. Those are the ground-driven, plate-type units.
The result is an 18-row planter that can be used for corn or beans on 19-inch spacing. Molgaard modified his six-row, 30-inch-row-width corn head for his Case IH combine. It's now a nine-row corn head set on 19-inch row spacing.
Cut residue, don't bury it
Molgaard doesn't cultivate corn or beans; he plants, sprays and harvests. However, he added another operation in 2004 to handle the larger amount of crop residue left by bigger yields. He hits fields with a specially modified "straight blade" disk before planting corn.
Unlike a regular tandem disk, this tool doesn't do tillage. It slices crop residue on the field surface so the planter can plant without plugging. The disk cuts residue into smaller pieces without burying it, leaving it on top for erosion control.
Iowa has had big corn yields recently. And the new corn-borer resistant hybrids produce healthier stalks that don't deteriorate as fast. There's a larger amount of crop residue lasting for more than a year in a no-till corn-soybean rotation.
After being sliced with the modified disk, the smaller pieces of residue break down faster than large pieces so you don't have excessive buildup. Smaller pieces flow through the planting equipment better.
Carl took an IH 490 tandem disk and set both gangs (front and back) to run straight instead of angled. He also replaced the regular disk blades with wavy coulter-type blades, 17 inches in diameter.
Corn residue carries over
Blades are spaced 8 inches apart on front and back. He positioned the blades so those on the front gang don't run in the same place on the field as the blades on the back gang.
"When the disk goes across a field, crop residue is sliced about every 4 inches," Carl says. "The blades on the back gang run between the marks in the ground made by the blades on the front gang."
He uses this tool before he plants and only on bean ground to be planted to corn. His fields coming out of beans and going into corn have a significant amount of corn residue present. "This disk with the blades running straight works great," Carl says. "We don't have to lift it when turning at the end of a field. It turns easy and doesn't tear up the ground. We pull it fast, 9 to 11 miles an hour depending how rough the ground is, and it can do 300 acres in a big afternoon."
The planter doesn't have trash whippers. "We took them off because with the narrow rows we were getting such a deep furrow," Carl explains. "Deep furrows between rows can lead to washing of soil on slopes in a heavy rain."
The planter's disk openers handle the residue, but if you don't have trash whippers on the front of the planter, the closing wheels in back can plug and the seed furrow doesn't get closed. Carl solved that by using only one closing wheel.
To handle cornstalks when drilling beans, the Molgaards have a coulter caddy on the front of the no-till drill. "We don't chop stalks with a rotary cutter," he says. "We pull into cornstalks and put in beans."
Rotary mowers and stalk cutters are high maintenance and take power and fuel, so the Molgaards avoid them.
Tips for staying on course
No-till farmers sometimes find it hard to see the planter marker's mark in a field with a lot of crop residue. Carl Molgaard does two things to stay on course when planting.
Chain link: He doesn't have a GPS guidance system, so he simply hangs a short piece of chain on the end of the planter, dropping it down over last year's row. "I can look back and see if the planter is planting directly over my old rows," he says. "On sidehills the chain shows how much the planter is drifting. If it's over too far, I can compensate."
Wheel assist: Most farmers look ahead over the tractor hood, using the center of the tractor as a guide to follow the planter marker's mark in the field from the previous trip. Instead, Carl shortens his planter markers so he runs a front wheel of the tractor over the mark made by the marker. With a wide front-end tractor, he alternates - one time it's the front wheel on one side of the tractor and the next pass it's the front wheel on the other side. "This system is easier to see," he says.
Odds better with beans
Soybeans respond more consistently to the narrowing of rows than corn.
"For soybeans in Iowa, we generally see an average of about a 4-bushel-per-acre yield advantage for 15-inch compared to 30-inch rows," says Palle Pedersen, Iowa State University Extension soybean agronomist.
"We don't see a lot of yield difference between 7.5-, 10-, 15-, 20- and 22-inch row spacing, but they are all yielding greater than the 30-inch soybean rows," explains Pedersen.
You may not see a yield advantage every year. "And when you have optimum canopy development, you don't see the same advantage as when the crop is under stress," he says.
"We are still collecting data on row spacing choices in Iowa. But it looks like narrow rows such as 15 inches will help farmers in many ways, not just with a better yield."
The narrower the rows, the quicker the soybean canopy closes to help control weeds. The 15-inch rows have less yield reduction in stress conditions compared to 30-inch rows, because 30-inch rows don't get the canopy closure.
"We see much higher plant mortality in 30-inch rows compared to 15-inch rows," adds Pedersen. "Comparing the number of seeds we put in the ground to the number of plants at harvest, we can see we lose more plants in 30-inch rows. That's because the plants are very close to each other within a 30-inch row and there is a lot of competition compared to 15-inch row spacing."