Don't bother asking Dan Arkels for his recipe to grow 100-bushel soybeans. He doesn't have just one. Like a master chef, the Peru, Illinois, farmer matches ingredients to each season and each field -- tweaking and shifting inputs as the crop reveals what it needs.
"The secret to growing high-yielding soybeans is to never let them have a bad day," Arkels said. A nearly perfect growing season helped Arkels top the 2014 Illinois Soybean Association Yield Challenge, with 103.85 bushels per acre. Still, he credits intense scouting and the willingness to act on the advice of his agronomist and other crop advisers for the bounty.
There are those who consider soybeans ornery -- churning out surprising yields one year and disappointing tallies the next. Arkels said the most frequent question he gets is why a soybean crop tends to stall out around 50 to 60 bpa. "Eight times out of 10, those farmers put their soybean fertility on the previous year with the corn crop," he said. "I used to be one of those guys."
Now, Arkels sets a yield goal. A typical rotation on his farm is three years of corn to one year of soybean. His fertility program starts by knowing how much each crop removes, how much it gives back (through residue) and then how much additional fertility is needed to meet the desired yield. He shoots for an average of 80 to 90 bpa across his non-contest acres.
"I know what my crop is going to take if I get the right growing season to produce that kind of yield. I make sure it's there before planting. That's not something I'm willing to sacrifice," he explained.
"Most people don't realize how nutrient-hungry a 100-bushel bean crop is," Arkels said. "The overall requirement is almost double that of a 240-bushel corn crop. Most soybeans will also run short of potassium late season. The notion that soybeans are a scavenger crop is not valid in a modern, high-yield system."
Lobbing too much nitrogen (N) out early in the season can make the soybean plant lazy. Arkels puts out 50 to 60 units of 32% N preplant with an inhibitor and follows with in-season, aerial applications split between Stoller Harvest More Urea Mate and Rosen's Sable slow-release nitrogen. "It takes 4 to 5 pounds of N for every bushel of final yield," he said. His 2014 soybean crop received an additional 150 to 180 pounds of N.
LINE OF OFFENSE
Most of his acreage is conventional till -- deep ripped in the fall with two spring passes (one to level land and one to apply preplant herbicides).
Everything in the Arkels' system is aimed at getting each seed to emerge within 24 hours. That recipe includes the latest in soybean genetics coupled with a good disease package and a premium seed-treatment package (insecticide, fungicide, inoculant), plus Stoller's Bio-Forge and Stimulate plant growth enhancers.
"My beans come out of the ground dark green and never go through that ugly phase so many farmers talk about," Arkels said.
He's moved to 15-inch rows to close the row quickly -- a tactic aimed at controlling weeds and capturing the maximum amount of sunlight. He plants on a slight angle and sprays straight on guidance. "That way, I'm only taking out a 12- to 14-inch wheel path and not wiping out an entire row, which can be another spot for a weed to emerge later in the season," he said.
"I'm all offense," he added. Some high-yield farmers like to ding the crop early, hoping to promote branching to set more nodes. Not Arkels. "If I spray with something that burns the crop back, I lose a week to two weeks of the growing season.
"I want that plant producing all the time," he added. "I like to see gigantic leaves, for example. They serve as a storage unit and are going to pack nutrients into that plant and pods later in the season." It's not unusual for his soybeans to stand 4 to 5 feet tall. He wants 20 or more nodes on each plant with plenty of clusters at each node. Taproots should run deep and be loaded with nodules, he said.
The 2014 winning plot had two ground applications -- mostly to clean up weed breaks and lay down more plant growth stimulants. Arkels followed with four aerial applications of nutrients and biologicals, starting at R2 with subsequent sprays every 14 to 22 days through the R6 growth stage. The treatments included applications of Priaxor fungicide at late R3 and late R5.
"I'm in my fields at least once a week looking for limiting factors," he said. "Tissue tests usually determine I'm fine on macros [nutrients]. It's micronutrients that are often short, and that's super easy to correct and not all that expensive to supply."
He estimated 70% of yield comes from the seeds produced by each plant. "You can possibly gain 30% more yield by packing additional weight into each seed. That's where a lot of the top-end yield is," he said.
Arkels' combine will roll later than neighboring farmers. Part of keeping that factory churning is planting Group III or later varieties. His winning entry, Pioneer 34T07RR2, was a 3.4 variety (planted at 182,000 ppa).
Sweating the details is critical, but Arkels says growers can start with one simple step: "Beans can be made more predictable by having the fertility in place to grow what you want to grow," he noted.
Arkels' tips for success include the following:
1. Set a yield goal at the beginning of the season and fertilize to match it. Consider what the crop is going to take up and what it is going to leave.
2. Seed treatments are insurance you can't afford to be without. Arkels wants every seed emerging at the same time. Those that arrive two to three days behind the rest are nothing but weeds, he said.
3. Narrow up your rows -- the 15-inch spacing affords a quick crop canopy and lowers weed pressure.
4. Keep the factory growing as long as possible.
Editor's Note: The United Soybean Board has set the ambitious goal of reaching a 60-bushel-per-acre national average by 2025. Many U.S. soybean growers have already surpassed that milestone and set their sights on reaching 100-bushel yields. In this seven-part series, DTN/The Progressive Farmer looks at some of these top producers and their practices. This is the sixth story in the series.
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