Sunbury, N.C., grain and cotton grower Robbie Umphlett is a self-proclaimed early adopter, so making a big change in row-widths and seeding rates in 2010 wasn’t a big surprise.

Like most of Umphlett’s innovative changes, switching to 20-inch rows on his corn and from a drill to a more conventional corn seeder on his soybeans came only after a lot of testing, some on-site observations and plenty of thinking and re-thinking.

“We thought about going to 25-inch rows from the 38-inch row spacing we’ve used for years on corn. That would give us three rows in the same space as we used to have two,” Umphlett says.

“Ron Heiniger (North Carolina State University corn specialist) said the 25-inch rows would work fine in corn. However, Jim Dunphy (North Carolina State soybean specialist) said that row spacing wouldn’t quite do it for soybeans,” the grower recalls.

Umphlett, who manages Umphlett Brothers Farms, says growing more than 3,000 acres of corn, cotton, soybeans, wheat and barley requires more precision than ever to stay profitable.

The third generation North Carolina farmer has farmed all his life and says making tough decisions is a part of farming and usually comes down to economics. An award-winning peanut farmer in the past, he says giving up peanuts was a simple matter of soybeans being more profitable.

Umphlett bit the bullet and invested in the planting equipment that now allows him to plant 20-inch rows. The economics of the move makes sense, he says.

He says a 10-20 percent increase in yield can be expected from narrow-rows. 

“We’ve been averaging 150 bushels of corn per acre. At a 15 percent increase that’s more than 22 bushel per acre increase and with $4 corn that new equipment will pay for itself in a hurry,” he adds.

On soybeans, he had been planting narrow-rows for a number of years, so planting on the new row configuration wasn’t anything new. The narrow-row spacing made it easier to drop from 70 pounds of seed per acre to 45 pounds per acre. With seed costs at roughly a dollar a pound — that’s a savings of about $25 per acre and on 2,000 acres that’s a savings that adds up quickly.   

Combining the extra income from corn and beans will allow the North Carolina grower to recoup the cost of the new planting equipment in a couple of years. “That will happen, if everything goes as planned,” Umphlett says.

Because of the different soil quality on his farm, the North Carolina grower plants grain crops using conventional-tillage, no-till, strip-till and some corn is planted on 80-inch raised beds. “Some of their land needs some extra drainage, so they plant some on beds,” says veteran Extension ag agent Paul Smith, who worked with Umphlett and Ron Heiniger to come up with the planting configuration.

“The 80-inch beds have four rows of corn. The top of the bed is flat and has a slit cut for drainage every 80 inches. The land is bedded with a hipper roller, which is fairly easy and worked really well in planting his 2010 crop.

Will standardize equipment

“Next year, they will change cotton planting from 38 to 40-inch rows to standardize all their equipment. The move allows them to standardize all their equipment on a 40-foot base. Even their new 120-foot wide sprayer fits into the 40-foot base.

“That, he says, will make life a lot simpler with standardized equipment across the board.”

Nationally, results of narrow-row spacing on corn have not been as positive. Research studies conducted by a major seed company over a 13-year period from states as diverse as South Carolina and Minnesota showed yield increases of up to 12 percent, with an average increase of only two percent.

In South Carolina, Clemson agronomist Jim Frederick says tests indicate the potential for big yield increases with narrow row planting. Comparing 15-inch versus 30-inch corn rows, the Clemson researchers found higher yields, especially in no-till versus disking plantings.

Overall, Frederick says they found yield increases ranging from 8-70 percent, depending on a number of planting variables. Realistically, he agrees with Heiniger’s assessment of a 10-20 percent yield increase using narrow-row planting.

In addition to improved yield, narrow-row corn may provide some cost savings in weed management. Narrow-rows will create a quicker cover canopy and help shade out troublesome weeds.

Of particular concern for growers in northeast North Carolina is keeping glyphosate resistant pigweed from becoming a problem.

Umphlett says that’s a problem he can’t afford. “If I find a pigweed that even looks like it may be resistant, I remove it from the field as carefully as I can and destroy it — it’s just too big of a threat to leave in the field,” he says.

While reduced number and volume of herbicide application may be reduced in narrow-row corn, physically getting into the field and spraying may be more of a challenge. The tradeoff appears to be in favor on narrow-rows.

Higher insecticide costs

Insecticide costs may be higher for narrow-row corn in the upper Southeast. Soil insecticides are applied as product per linear foot of row, so reducing the row spacing would increase the amount of insecticide that would be necessary to provide adequate

control.

Changing from a 30-inch to 20-inch row system would therefore cause a 50 percent increase in insecticide costs, while changing to 15-inch rows would cause a 100 percent increase.

One thing Robbie Umphlett, and hundreds of other growers in the upper Southeast, didn’t count on in the spring of 2010 was one of the hottest, driest spring and summers on record. Though not in the hardest hit area of the Southeast, the North Carolina grower says the heat and dry weather took a toll on his corn crop.

“We had been averaging 150 bushels of corn per acre and on most of our 500 acres we averaged about 110 bushels per acre. We had some go as high as 185 bushels per acre and some as low as 50 bushels per acre. I think the narrow-rows helped us, even with these hot and dry conditions,” he says.

“It’s hard to calculate whether we got the 10-20 percent yield increase we were shooting for, because our corn yields were so much affected by the heat and drought. Still, I think the narrow-rows did give us 10-20 percent more yield, he says.

Based on the results from his narrow-row corn, Umphlett says he still plans to go to 40-inch rows on cotton, which gives him a standard 40-inch row base for all his crops and 40-foot equipment across the board.

In addition to his planting equipment, Umphlett says he has gone to a 120-foot wide sprayer to fit the 40-inch row base. In the near future, we hope to have all our equipment for all our crops a standard size, he concludes.

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