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Six steps to better soybean yields

Those of you who are stymied by slumping soybean yields this fall aren't alone.

Just check out USDA's November crop production report, which tallied average U.S. soybean yields at 41.3 bushels per acre. That's down 0.1 bushels per acre from October's USDA estimate, and 1.4 bushels per acre from 2006's average yield.

Still, not all is dismal on the soybean front. Kip Cullers, Purdy, Missouri, broke his own world soybean production record of 139 bushels per acre with a 154.7 bushel per acre yield in 2007.

Cullers' purpose for participating in yield contests is to test new soybean-growing techniques.

"We really don't use it for a profit center," he pointed out at a mid-November press conference sponsored by the Missouri Soybean Association (MSA) regarding his world record yield. "We try and learn from it."

He takes what he learns from the contest to the approximate 600 acres of soybeans that he raises across his farm. "This year, our farm average for both dryland and irrigated, across the board, was 74 bushels per acre," says Cullers. "That to me is a lot bigger feat for me than the contest. It took what I learned (from the yield contest) and applied it to the rest of the farm."

It's possible to boost soybean yields by stepping up management intensity, says Greg Luce, a Pioneer Hi-Bred International agronomist who works with Cullers. "If soybean are managed like corn, we can do a lot more with them," says Luce.

Here are some management practices Cullers did in his contest fields to set the world's soybean yield record.

  1. Select the right variety for the right field
    Cullers' variety selection strategy is simple: plant the best genetics for the area. "I run extensive on-farm research on my farm with seed from a lot of different companies," says Cullers.

    The variety that set the world record was a Pioneer 94M80 soybean. This Group 4.8 Roundup Ready variety packed excellent yield potential, along with resistance to diseases like sudden death syndrome and resistance to soybean cyst nematode.

Treat for pests
"We are far enough south where we have disease," says Cullers. He manages soybean fungal diseases by applying Headline fungicide. His fungicide strategy for the 2008 contest will be the same as in 2007 -- a fungicide application at podding followed by another application 21 days later.

Cullers controlled soybean aphids, a new pest in Missouri, with Warrior insecticide with Zeon technology in the contest field.

Reduce stress through frequent irrigation
Cullers irrigates his contest soybeans. "It used to be that you'd wait until the soybeans were about to croak, and then you'd put an inch of water on them," says Cullers. "We water every day."

Frequently irrigating with low volumes of water helps slice plant stress. "This comes from green bean production, where you're trying to cool the plant and alleviate stress," says Luce.

Equidistant spacing with twin rows
Cullers planted the yield contest soybeans with a French-made Monosem twin row planter. He credits the planter with creating more equidistant spacing between plants. This helps plants capture more sunlight, which generates more photosynthesis and ultimately more yield.

Build roots
Cullers applied Optimize, a soybean growth promoter, to enhance root development. This seed-applied product is touted as giving improved vigor and stand emergence, and an improved root system for boosting nutrient and water uptake. In the contest field, it doubled root mass size, says Cullers.

Ask questions
Cullers cultivates a wide circle of soybean industry and university experts for advice. "I'm not scared to ask questions, to try new things," he says.

"We've probably taken yields as high as the current system will allow," says Cullers. "The beans are getting too tall. We're going to try and shorten the plant structure."

So are 200 bushel per acre soybeans in the future? "The genetics are there," says Cullers. "We just have to figure out how to do it."

Those of you who are stymied by slumping soybean yields this fall aren't alone.

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