The least expensive way for Milledgeville, IL, farmer Curt Dambman to get to narrow-row corn was to stay with 30" rows. “I had to keep my existing corn head because I need it for custom harvesting,” he says.
So Dambman built a planter to double up his corn rows with twin rows, 8" apart on 30" centers. “I built a double toolbar frame so I could mount two Buffalo slot planter units 31" apart, front to back, in each row, with an 8" space between them,” he says. A Case IH Cyclo 500 seed module sends seed to each planter unit.
Dambman planted 500 acres of twin-row corn last year and saw mixed results. “On good soils I got a 5% yield increase with the twin rows,” he says. “On poorer soils I didn't see the same benefit. But that was an equipment problem, not the twin-row system. My single-row planter just does a better job of getting the seed in the ground.
“I think there's a lot of potential in the twin-row system. But for right now, I'm going to stick with single rows on corn, because of the equipment issue.”
University of Nebraska research shows no consistent yield advantage for twin-row or narrow-row corn, according to extension ag engineer Paul Jasa. “We just haven't seen the yield increases here that have been reported in other parts of the Midwest,” he says.
Jasa did see yield decreases in his plots with narrow-row and twin-row corn due to ear loss at harvest with a standard 30" head.
“Ear loss was less in the higher-population plots because adjacent plants tended to hold each other up,” he says. “At the higher populations, losses from the twin rows were about the same as from 30" rows.”
Dambman didn't see those problems when he harvested his twin-row corn with a 30" corn head.
“Harvest went fine. I was really pleased,” he says. “There's a lot of action going on in front of you, however. Each stalk has to bend at least 4" to go in the head. I was very cautious and selected a hybrid that didn't tend to drop ears. I had some twin-row popcorn and did see more ear loss there.”
Soybeans looked good in Dambman's twin-row trials last year and he plans to plant all his soybeans with the twin-row planter again this year. “I didn't get any yield advantage, but I planted 175,000 seeds/acre that all grew, vs. 225,000 seeds/acre with my drill and maybe 120,000 of them grew,” he says.
Dambman also likes the quick canopy he gets with the twin-row beans compared to 30" beans.
“I'm going to try some population experiments with soybeans this year. I think we tend to plant too high of a population. I'm going to increase rates on light soils and decrease them on heavy soils.”
Jasa cautions farmers considering narrow rows.
“Consider all variables affecting profit, especially machinery costs. Our research suggests that a standard corn head probably will be unacceptable for harvesting narrow- or twin-row corn that is down or has weak stalks. If there is little or no yield advantage, narrow- or twin-row corn may not pay for major modifications, unless it's time for machinery replacement anyway.”