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Packing them in

It's all about higher plant populations and 12-inch rows in this seed company trial.

Contributors:  Manufacturer, Des Keller

Myron Stine will be the first to admit that researchers at the Iowa-based seed company that bears the family name can't tell you why corn with certain genetics performs better in a high-plant population environment.

That hasn't stopped Stine Seed Company from pushing full steam ahead to identify as many corn lines that thrive at higher populations as possible.

“There are variables we can't see,” says Stine, the firm's vice president of sales and marketing. “We do believe the only way in the future to hit the high yield levels desired is by planting higher populations. That just so happens to involve narrow rows to make it work right.”

Narrow as in 12-inch rows – 3 inches less than what most anyone is farming right now. “If you want, in Iowa, to average 300 bushels per acre consistently, the realistic answer is more plants per acre,” Stine says. Corn planted at traditional levels on super high-fertility ground and spoon-fed nutrients can get high yields, he says, but not with the regularity that could be accomplished with higher populations per acre and the right hybrid.

How high?

Stine is talking populations up to 60,000 plants per acre. This year, the company is putting its money where its research is – getting producers to try higher population corn.

“If you're willing to dabble with high-population corn, we'll pay for any corn over 38,000 plants per acre,” says Stine.

The incentive will likely be necessary. As of 2009, U.S. farmers grew just 4% to 5% of corn in 15- or 20-inch rows.

Such extreme narrow-row corn doesn't mean the individual plants have less room to grow. In research at Stine Seed Company, plants are spaced 10 to 12 inches apart in the row, as opposed to the 5 to 7 inches apart in more traditional 30-inch rows.

One of the company's new 2013 hybrids, 9733 VT3 Pro, is a 112-day corn bred for planting at higher populations. The company will also be conducting trials on more than 600 of its existing hybrids at populations of 45,000 to 65,000 plants per acre. Such trials will help the firm determine which of its hybrids are adapted to high populations, says Stine.

Shorter plants and upright leaves

Stine Seed Company is one of about six corn-breeding companies in the U.S., and it screens more than 60,000 unique lines of corn germplasm each year. Originally a soybean seed company (and still the biggest provider of soybean genetics), Stine Seed Company began breeding corn in the 1970s. Founder Harry Stine (Myron's father) is the research director responsible for the company's emphases.

The new high-population corn bred for 12-inch rows does look a bit different than typical hybrid plants. The plant is shorter than usual – by as much as 1½ feet – and its leaves are more upright than outstretched.

45,000 The number of acres Stine Seeds expects its new high-population 9733 vt3 pro hybrid to be planted to in 2013.

The Stines grew 2,300 acres of the corn on their own farms last year. Though dry, their average overall yield was 143 bushels per acre. Their best field overall, planted in 12-inch rows, yielded 233 bushels per acre.

“That farm did get some rains other places didn't,” says Stine.

The Stines planted the new 9733 VT3 Pro hybrid at 51,000 plants per acre last year, but they'll adjust down to 44,000 on highly productive ground this year.

“We decided that was a little too high,” says Stine.

Stine believes there is support among other seed companies for corn planted in higher populations. Other breeders have tried to take hybrids not selected for high populations and plant them that way, with predictably mediocre results.

Because the high-population plants tend to be shorter with smaller tassels, this corn doesn't leave any more residue than traditional hybrids. As the breeding progresses, high-population corn may likely get even shorter – only as high as 5 feet, according to Stine.

Narrow combine head

The company has been able to harvest 12-inch rows using a new combine head from specialty manufacturer Calmer Corn Heads, based in Alpha, Illinois. The firm uses a prototype planter from John Deere that features staggered and offset row units on a narrow frame. The Stines recommend wider flotation tires to reduction compaction, an even bigger concern in such narrow rows.

Calmer Corn Heads built its first production 15-inch corn head in 2002. It has now built the first production corn head designed for 12-inch rows in 20- and 30-foot-wide heads for 12-inch rows.

Farmer and founder Marion Calmer agrees with the Stines' approach to getting high-yielding corn.

Narrow-Row Location Matters

Geography has played a role in order for narrow corn rows to boost yields in university trials.

“In corn, 15-inch and 7.5-inch double rows have shown no response compared to 30-inch rows in Missouri,” says Bill Wiebold, University of Missouri Extension agronomist. He adds, though, that latitude likely plays a role in more favorable responses that have occurred in northern states.

On-farm trials from 2009 to 2011 in northwest Minnesota show yields and economic returns maxed out for 22-inch rows planted at 40,000-plus-per-acre populations. Yields were 4% to 5% higher at these upper populations, says Jeff Coulter, University of Minnesota Extension agronomist.

Narrow rows canopy earlier than wider ones. This helps manage weeds by preventing sunlight from penetrating the soil surface. Early canopying can also conserve moisture by shielding the soil floor from sunlight. •

“The future in agriculture of consistently growing 300-bushel corn or better means we're going to have to be in the 12- to 15- or the 20-inch rows,” he says. “We're going to have to have the genetics that like high populations to make it happen.”

Most of the farm equipment industry will be waiting and watching for those hybrids. Until then, 30-inch rows remain the norm.

“While many people are talking about different and narrow-row spacings, very few farmers are actually doing it,” says Rhett Schildroth, Kinze's product manager. The Iowa-based manufacturer introduced a new planter this spring, the 4900. The planter is set for only 30-inch rows.

“The vast majority of the market will continue to plant at that width, we predict, for the short term to midterm,” says Schildroth. He's talking about the next two to five years. After that, the development of hybrids for higher populations –and narrower rows – may well cause them to rethink, he adds. •

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