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


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.