Mark Burrow will be hitting the shop hard this winter. The result of his handiwork will have the Altamont, Ill., farmer seeing double this spring as he converts yet another planter to a twin-row configuration.
Burrow planted his entire 2010 crop with a twin-row planter he built last winter from a conventional John Deere 1790 12/24 split-row model. He’s back in the shop again because he had the opportunity to make a good trade for a new 16/32-row John Deere 1790.
Equipment alterations. Modifying last year’s planter was no small chore. Back rows were moved 7.5" to the right. This involved moving the main seed tanks, driveshafts and gearboxes. Burrow also added rectangular tubing to relocate planting units. The sprocket that drives the transmission was modified so the seed rate was correct for twin rows. The three-point-hitch drawbar had to be moved 3.75" in order to re-center the rows.
"This past summer I ended up making additional improvements by clamping two pieces of rectangular tubing to the existing center section unit mounts. It makes the conversion much easier," Burrow says.
This tweak to his old machine put six units on the center section and avoided the necessity of moving the seed tank for folding clearance. "I use longer drive cables on the planter units to eliminate the need to move the drive jackshafts," he adds.
Burrow sees twin rows as a way to increase corn populations without causing plant and root stress and without a major change in equipment. "Twin-row technology is allowing us to safely push our populations to the 35,000 plants per acre range even on lighter soils where a more typical population would be 30,000," he says.
In a twin-row configuration, corn is planted in paired rows, usually 7" to 8" apart, on 30" centers. The idea behind this system is to gain a more uniform spacing of plants, similar to narrow-row corn. It also allows growers to use the same corn head and other equipment set for 30" rows.
Research on the advantage of twin rows vary. Farm Journal Test Plots data from the past two decades has shown a 7 bu. to 10 bu. response to narrow rows (20" and twins) when compared with 30" rows. Farm Journal continues to test both corn and soybean twin-row production.
Yet in 2010, Pioneer Hi-Bred found no yield advantage to twin rows compared to 30" rows
in 179 paired on-farm research comparisons.
However, twin-row yields differed slightly across locations. Average twin-row yield responses ranged from 4 bu. per acre increases to 10 bu. per acre declines among replicated experiments in Illinois, Iowa and Minnesota, says Mark Jeschke, Pioneer agronomy research manager. He adds that the studies did not reveal any interaction between row spacing and planting population or significant differences in hybrid response to twin rows.
University of Illinois Extension agronomist Emerson Nafziger has data from 2008 and 2009 that shows no yield response to twin-row corn in a range of populations.
"While there might be small yield increases from twin rows in some cases, the response has not been large enough or consistent enough to justify across-the-board changes," Nafziger says.
Bruce Battles, Syngenta Seeds agronomy marketing manager, expects growers in the northern Corn Belt to benefit most from narrow rows. The shortened growing season means more sunlight is used when corn shades the rows more quickly to take advantage of as much photosynthetic capacity as possible. Sun that hits the ground and is not intercepted by corn leaves means lost potential energy.
"We think there’s opportunity in using twin rows and narrow rows in a very prescriptive way," Battles says. "I’m not sure it has as much to do with increasing yield potential as it is a practice to enable the genetics of certain hybrids to capture the yield that was already there."
Do-it-yourself. Bolt-on conversion reduces the financial risk for Burrow. He wasn’t interested in buying a planter built specifically for twin rows. "I like the central fill on this planter and I’m a Deere guy," he admits. "Converting the planter was cheaper than buying a new twin planter. If I decide I don’t want to do twins, I can always convert it back to a conventional planter," he adds.
The diamond-pattern spacing often associated with twin rows is not possible with this planter. Burrow doesn’t think this is an issue because plants are spaced at least 7.5" apart at their closest point. "Plants do need to be equally spaced in the row, and at the slower meter speeds, this planter does a great job achieving that," he adds.
Nitrogen factor. Doug Pruemer of Teutopolis, Ill., modified his first Kinze planter to twins two years ago and hasn’t looked back. That first year, he turned his entire farm into a comparison trial by planting half his acreage to twins and half to 30" rows.
"That gave me a good look at the system to know that it does work and what I needed to tweak to achieve higher yields with twins," Pruemer says. "Twin rows are not for everyone. If you go into it thinking you’re just going to double up the rows, you’re going to be disappointed.
"I often recommend that growers split half their planter the first year. Side-by-side comparisons are the way to determine how the practice will work on your farm."
Pruemer thinks nitrogen is the key to making twins pay. "Our ground doesn’t hold nitrogen and we really saw that play out in wet conditions," he says. "In this area, you can pick out the twin-row farmers that have livestock and access to manure."
He’s added preplant nitrogen and sidedress applications to his practices since going
to twin-row production and increased plant populations to 38,000 plants per acre. Yield boosts from twins (compared to 30" rows) have been averaging 11 bu. per acre.
Pruemer is experiencing an average 8% yield increase on twin-row soybeans. "I really don’t know why," he says. "We don’t do anything different but double up the row. It’s a free yield boost. Some farmers in this area are planting beans that way and keeping to 30" rows on corn."
He’s modified several Kinze planters for twin-row planting for other farmers. The trans-formation takes three to four days and costs about $4,000. "All I have to do is lift the front units up and I’m back to 30s," he says.
A machinery dealership has asked Burrow to modify a planter for one of its customers. He’s offering a conversion kit on a limited basis for 2011.
Burrow was happy with the twin-row system on both corn and soybeans in 2010. Changes in 2011 will include increasing nitrogen rates in proportion to increased populations in corn.
"Spraying and harvest was surprisingly easy," he says. Burrow modified stalk stompers on all rows to twin-row configuration. He finds that the newer, more aggressive heads help feed in the additional plant material.
"We did wear out two sets of plastic wear strips on our corn-head snouts. Stainless or abrasion-resistant steel strips are not currently available, but we will make them if necessary next year," he says.