Dan Kamla chuckles when he says that he might get more corn silage next fall than will fit in his bunker silos.

Barring a poor growing season, he'll definitely produce more tons of silage this year, but not by planting more corn acres. For the first time, all 100 of his silage-corn acres will be in 15" rows.

Kamla, of Arcadia, WI, is part of a trend toward narrow-row corn silage production. More and more dairy farmers are abandoning 30" and wider rows for their silage acres, opting instead for 15-22" rows.

Higher yields are the big drawing card, but farmers who've tried it cite other benefits, too, including better weed control. And dairymen with big herds like the fact that higher plant populations suck up more nutrients from manure, helping them avoid groundwater pollution problems.

Seed company representatives are less enthusiastic, however. They point out that not all hybrids perform well in narrow rows, and the ones that do have not been identified yet. Also, narrow rows usually mean higher plant populations, and research shows that, as plant numbers increase, silage digestibility drops, negating some of the yield-gain benefits.

Interest is high in west-central Wisconsin, Kamla reports. Several other dairy farmers in his area grow narrow-row silage corn, and more would try it if they had Kemper non-row-specific heads for their forage harvesters. That's the piece of equipment that makes it possible. Kamla has one, and does custom silage harvesting for a few narrow-row neighbors, but isn't able to fill all the requests.

He grew some 15"-row corn the past two years, and got significant yield increases compared with corn in 30" rows. Last year he had 25 acres in narrow rows.

"We had good-to-excellent yields considering the dry July weather," Kamla reports. "We had over 31 tons/acre, and we figure we gained about 26% over wide rows."

A neighbor did some calculations for Kamla and came up with a $100/acre increase in net profit. That was figuring the value of milk produced with the added silage.

Planting the crop is the biggest drawback for Kamla. Using a 30"-row planter, he plants each field twice. On the second trip, the planter drops seeds midway between the previously planted rows. That trip is more difficult than the first.

"I almost get blurry-eyed watching the marks," Kamla states.

He plants silage-specific Mycogen hybrids that range in maturity from 94 to 108 days. He figures the maturity range will widen his harvesting window in case of wet fall weather.

His planted seed population: 43,000/acre. He says Mycogen reps watched his narrow-row fields closely last summer. They recommend that their hybrids be planted at 24,000-27,000 seeds per acre. At those populations, they say each stalk should have two good-sized ears.

"We had one large ear on each stalk, and we're satisfied with that," says Kamla. "Some hybrids have small ears so they don't get as much grain in the silage."

The dairy farmer uses the same per-acre starter fertilizer rate when planting narrow rows and wide rows. The weed control program is the same, too - one postemergence application. But the narrow-row corn has fewer weeds.

Gary Dvoracek, Mycogen district sales manager in Kamla's area, thinks narrow-row silage corn is worth considering.

"I'm excited that farmers are looking at how to increase production off an acre of land," says Dvoracek. "This definitely is an avenue to check out."

But more research and farmer experimentation are needed before he'll recommend that farmers jump into narrow-row production.

"My biggest concern about narrow rows is that we've only been looking at it hard the last couple of years," Dvoracek adds. "And we've had two good growing years. I wonder what's going to happen in a cool year when we don't get much sunshine. Maturity may be delayed, and there's the possibility of increased stalk lodging."

Another consideration for growers who use corn insecticides at planting: Per-row rates may have to be reduced to avoid applying more than the per-acre labeled amount, Dvoracek cautions.