Fill the Yield Gap

Research identifies ways for soybean growers to add bushels to every field.

Shawn Conley (Progressive Farmer image provided by Shawn Conley)

Farmers in the north-central U.S. are looking for lost soybean yield.

Shawn Conley, a soybean specialist at the University of Wisconsin, says the genetic yield potential of America's most widely planted legume is 110 bushels per acre or more in most states, depending on climate and soil conditions. But, most farmers average 50 to 55 bushels per acre.

"Where are the other 50 to 55 bushels?" Conley asks. "We're working to minimize that yield gap."

The completion last year of a three-year study Conley co-led with University of Nebraska agronomist Patricio Grassini called "Benchmarking Soybean Production Systems in the North Central U.S." can help farmers do just that. It identifies factors that preclude soybean farmers from obtaining yields that should be potentially possible on their farms.

Production and management data from more than 8,000 fields covering about 600,000 acres was collected and analyzed. The North Central Soybean Research Program (NCSRP) -- a collaboration of 12 Midwest state soybean associations -- spent more than $1.3 million in soybean checkoff funds on the multistate project. Other universities and state soybean research programs also contributed to the effort.

Researchers examined what high-yielding farmers are doing compared to low- and average-yielding contemporaries with similar soil types and environments. The project team pinpointed the most critical yield-limiting factors, such as planting too late.

Industry officials say the project's return on investment could be significant, possibly in the billions of dollars, if producers implement various soybean-management and production practices highlighted in the study.

"We're looking to put more bushels in the bin with less cost per acre," says Cecil Demott, NCSRP president and Rock Port, Missouri, farmer. "I think there's a lot of value in that."


The study pointed out at least 10 management practices farmers can implement, which vary among states, to boost yields and minimize the yield gap. Conley highlighted several practices that cross state lines.

> Plant early. Soybean yields decrease 0.2 to 0.5 bushels per day when seed is planted after April 25,
give or take a few days depending on location,
Conley explains.

> Control weeds. Keeping weeds at bay requires a two-pass herbicide program that includes a preemerge with residual and a postapplication.

> Manage pests. Apply a foliar fungicide and insecticide at the R3 growth stage.

> Cut seeding rates. Many farmers still plant 150,000 seeds or more per acre, which can lead to disease problems such as white mold that thrive in a high-plant-population environment and dense crop canopy. Conley says reduced seeding rates, especially in high-productivity fields, will maintain and can increase yields, as well as save on seed costs.

> Install tile. The study shows farmers with drained fields can plant five days earlier than in nontiled fields. Plus, soybeans don't like "wet feet," Conley says. Both can boost productivity.

Conley and other researchers say it's probably not realistic that the entire yield gap can be wiped out by eliminating a few yield-limiting factors. Different soil types, fertility, weather and other uncontrollable conditions affect production.

"But, we're always going to be chasing it (genetic yield potential)," Conley says.

Increasing yields by 20 bushels per acre or more is possible, he contends, by fine-tuning management practices that are cost-effective and logistically feasible.

"Many farmers still think they can plant soybeans on May 15, and it doesn't hurt yields at all. That's easily worth 10 bushels right there in some environments," Conley says. "The study also showed anywhere from a 0- to 7-bushel-per-acre increase with a blanket foliar fungicide and insecticide application based on climate and soil characteristics.

"It's pretty eye-opening how many farmers are just realizing this [at least one fungicide and insecticide application] over the last year or two," he continues. "If farmers can squeeze out an extra 5 or 10 more bushels per acre, that's significant."

Keith Kemp is trying to make his West Manchester, Ohio, fields more productive. He's participating in the research effort and using project results to become more efficient.

Kemp, an NCSRP board member, is committed to planting soybeans as early as the weather and soil conditions allow. He cut his seeding rate by 30,000 to 50,000 seeds per acre to 130,000 and is contemplating going as low as 100,000 seeds per acre next year.

Kemp estimates he's already saving about $25 per acre in seed costs. Yields have also increased by 10 to 15%, he cites, by planting in mid-April, if conditions allow, instead of early May.

"We discovered we need to plant soybeans before corn, but it's hard for some farmers to realize that," Kemp says. "The more sunlight plants take in, the more pods. The research we're doing is changing our whole industry."


The U.S. is awash in soybeans primarily because of reduced Chinese exports, which is suppressing values. The projected average farm price for the 2019-20 marketing year is $8.40 per bushel, according to USDA.

That doesn't change NCSRP's mission, executive director Ed Anderson explains. Its farmer leaders invest soybean checkoff funds in programs via university research and Extension to improve yields and profitability.

"Even when prices aren't very good, farmers are still paid per bushel," says Anderson, who also serves as senior director of research for the Iowa Soybean Association.

U.S. soybean farmers are expected to average 47.9 bushels per acre this year, according to the USDA September "Crop Production Report." Production is estimated at 3.63 billion bushels. The north-central region accounts for 82% of soybean production in the United States, data shows.

If the nation's soybean farmers could increase the average yield by 10 bushels per acre, that would be another 760 million bushels. Even at $8 per bushel, that's an extra $6 billion in revenue.

"The project isn't just about producing more bushels, which is important," Anderson asserts. "A key piece is looking at ways to maximize inputs and production practices to drive profitability."

Yield Gap Analysis Continues:

The benchmarking study determined several agronomic practices that, for a given soil-climate context, can be fine-tuned to close the yield gap and improve profits for soybean producers.

The North Central Soybean Research Program (NCSRP) decided to finance a new project this year -- "Boots on the Ground: Validation of Benchmarking Process Through an Integrated On-Farm Partnership" -- that focuses on showing how the producer survey data can be used to identify and strategically evaluate management changes in on-farm research settings. The first year of the proposed three-year project costs nearly $450,000.

"Now, we're taking information learned back to farms to test and make sure the math is correct," University of Wisconsin soybean specialist Shawn Conley says.

"It further helps us hone high-priority research trials that we should be doing to increase profitability and productivity," NCSRP executive director Ed Anderson adds.

All soybean checkoff-funded research can be found at


> To see the full benchmarking report and individual state results, visit

> Follow Matthew Wilde on Twitter at @progressivwilde.


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