Greg Strobel and Tom Muhr have been growing narrow-row corn for several years, and neither has ever looked back.

Strobel, of Pemberton, MN, plants his corn in 15" rows, and Muhr, from Exira, IA, uses 20" rows. Both narrowed their rows in hopes of maximizing yields of both corn and soybeans.

"We wanted to go to narrow-row soybeans, but wanted to plant both corn and beans with the same machine," says Strobel. "It seemed from the research I saw at the time that we'd maximize soybean yields at 15".

After experimenting with 15" corn rows in 1997, Strobel planted 100% of his corn in narrow rows the past two years. He combines narrow rows with herbicide resistance technology, planting Roundup Ready corn and soybeans. Most fields going into corn are fertilized first with hog manure, then supplemental nitrogen is added preplant, when needed.

"Our yields are better, and we get better weed control," points out Strobel. He figures that narrow rows give him a 7- to 9- bu/acre corn yield boost.

With Roundup Ready corn he says it's easy to take care of early weed competition. And because the rows are closer together, the crop canopies quicker, so weed control stays good until the crop matures.

"My chemical costs are roughly $5 an acre, including application costs," says Strobel. "Of course, I do have to pay a technology fee for the seed. But even with that included, my weed control costs are considerably less than they were before.

"It's a simple system," he continues. "We no-till plant the beans into corn stubble and dig the fields once with a field cultivator after beans before we plant corn. We use no burndown herbicide, and we haven't needed it. And so far, one application of Roundup has given us excellent weed control."

Like Strobel, Muhr wanted to plant corn and soybeans with the same equipment.

"I knew I would gain yield in soybeans if I went to 20" rows from 30" rows," says Muhr. "From what I could find on narrow-row corn, it appeared I wouldn't lose yield planting in narrow rows, and some of the research suggested I might see better yields."

The winter before he made the switch, he spent time in the shop building a planter with 36 rows 20" apart. He couldn't buy one that fit his needs at the time. Since then, though, 20" planters have become available. He now uses a Kinze 3620.

When he made the switch from 30" rows five years ago, Muhr did it on his entire acreage. He made few other changes, though. For example, he'd already been pushing plant populations higher and saw narrow rows as a way to decrease plant spacing within the rows.

"There's less competition that way and ears are more uniform in size," he says.

With 20" rows he can still cultivate, but it seldom is necessary because weed control is better.

"I use low-cost preplant or pre-emergence herbicides to knock out weeds early," he says. "That usually holds weeds until the crop canopy develops and then they're no longer a concern."

For four years, Muhr believed corn yielded better in narrow rows than in 30" rows, but couldn't prove it. He intended to put out comparison strips each year, but that didn't happen until 1999. He had a neighbor plant an eight-row strip of 30" rows in each of two fields last spring. Both checks were more than 1/4 mile long.

"We used the same hybrids and tried to match plant populations. Fertilizer and herbicides were the same, too," Muhr says.

In the first check, Muhr's 20" rows yielded 155 bu/acre, while the 30" rows yielded 142 bu. The second check didn't show quite as much difference - 152 bu for 20" rows vs. 146 bu for 30" rows. But that's still enough to justify the cost of the narrow-row planter, he says.

"We did stand counts at harvest, and in both cases they were nearly identical for both the 20" and 30" rows," says Muhr.

Planting narrow rows is one thing. Harvesting them is another. In addition to building his first 20"-row planter, Muhr rebuilt his combine head to accommodate the narrower rows. Strobel, harvesting 15" rows, continued to use his old 30"-row head.

"We ran two rows up each row unit and it worked fine," says Strobel. "We lost very little corn."

He bought a new 15" head in 1999, largely because he needed to replace the old one.