Stine Seed Company planted more than 2,500 acres of corn in 12" rows using a custom-built John Deere/Bauer planter that used staggered rows for trash clearance and special floatation tires.
Improved corn genetics might favor high seeding rates and ultra-narrow rows, helping boost yields
Special floatation tires on planter
What has kept the strategy of planting corn in 20" rows or narrower from gaining wide acceptance?
"A 325-lb. NFL lineman wouldn’t make a very good race horse jockey," says Harry Stine, owner of Stine Seed Company near Adel, Iowa. "Just like you can’t interchange athletes between sports, you can’t put corn hybrids bred for 30" rows in narrow rows and expect them to excel."
The impetus to experiment with 20" or narrower rows comes from extensive research at universities across the Corn Belt that indicate corn yields often benefit from higher planting rates. But higher populations crowd plants within the row.
"When intra-row spacing gets to 5" or less it begins to constrain yields," says Kess Berg, Integrated Farming Systems lead corn agronomist with Monsanto Company. "Narrow rows are one way to push plant populations beyond 35,000 without crowding them too much in the row."
For example, at 33,000 plants per acre in 30" rows the plants are 6.3" apart, but in 20" rows their average spacing is 9.4".
When harvesting 51,000 plants per acre in 12" rows, automatic header height control and autosteer is necessary, says Steve Luther, Stine Seed Company field manager.
Yield push. While Stine acknowledges there are challenges to growing corn at elevated populations, he thinks final stands higher than 45,000 plants per acre are necessary to reach yields of 250 bu. per acre and beyond.
"On the average, farmers harvest 0.3 lb. of dry grain per stalk," Stine says. "In the 1940s, they planted 8,000 plants per acre. Take 0.3 lb. of grain times 8,000 stalks, divided by 56 lb. per bushel and you should yield 43 bu. per acre.
"Today we’re planting corn at around 35,000 population, and still averaging 0.3 lb. of grain per stalk," Stine says. "0.3 lb. of grain times 35,000 plants per acre, divided by 56, figures out to around 187 bu. per acre, which is an average yield across the Midwest."
Using Stine’s formula, it requires 46,500 plants per acre to average 250 bu. per acre at harvest.
Both Stine and Berg emphasize that simply narrowing rows and increasing populations doesn’t guarantee higher yields.
"It’s important to remember that high populations are just part of the picture," Berg says. "In many fields, plant population isn’t the limiting factor. Going with higher populations in narrower rows without optimizing soil fertility and other variables may not increase yields."
Steve Butzen, DuPont Pioneer’s agronomy information manager, says corn yields don’t always increase when rows are narrowed.
"Our data from the previous two decades didn’t show an interaction between row width and hybrid," Butzen says. "The same hybrids that won in 30" rows also won in narrow rows. But things are rapidly changing. If our current or future data begin to show that a specific hybrid is better in 15" or 20" rows than other hybrids in 30" rows, we’ll focus on optimizing that opportunity to achieve higher yields."
Genetics are key. Alpha, Ill., farmer Marion Calmer has grown corn in 15" rows for 15 years. He says history predicts that different seed genetics will be the catalyst that optimizes higher seeding rates.
Harry Stine, owner of Stine Seeds, vows to never plant another crop in rows wider than 12".
"Think about it," Calmer says. "If you plant the old open-pollinated corn they used to hill-drop in the 1930s in today’s 30" rows at 33,000 plants per acre, the yields would be miserable. You can’t just switch to narrow rows and higher populations and still use the same corn genetics you did in 30" rows."
Stine is convinced that the potential of higher populations planted in narrow rows will only be reached if the hybrid is designed to thrive in that challenging environment.
- Mid February 2013