Soybean School: Lessons learned from yield contest winners


Georgia farmer Randy Dowdy established a new world record yield for soybeans in 2019, setting the bar at 190 bushel per acre on a 3.27 acre plot. While Dowdy now reigns as the ‘yield king’, Missouri farmer Kip Cullers helped blaze the trail for contest yield winners when he put up a 160.6 bushel per acre yield in 2010.

University of Arkansas crop physiologist Larry Purcell had an opportunity to work with Cullers during this period and conducted three years of trials documenting production practices, crop growth, and yield components in Cullers’ contest fields. Earlier this month at the SouthWest Agricultural Conference, Purcell shared some of the insights he and graduate student Ryan Van Roekel gleaned from their work.

On this episode of RealAgriculture’s Soybean School, Purcell highlights production practices he feels are transferable to Canadian farmers. He does note, however, that there are many natural production advantages Cullers enjoys, including a long growing season, well drained silt loam soil and strong soil structure that offers no impediment to root development, encouraging the crop to reach deeper throughout the soil profile to access nutrients.

Feeding the crop is a key focus for Cullers and all yield contestants, says Purcell. He notes that Cullers relied heavily on chicken litter to propel his yields. A small pivot was used on the contest fields throughout the years to fertigate and feed the crop throughout the growing season. (Story continues after the video.)

Another critical aspect of Cullers’ success is early planting. “Basically, when you are ready to plant corn, you should be ready to plant soybeans,” says Purcell. With early planting comes early canopy closure, allowing the crop to optimize light interception. “That kicks off the crop producing more flowers, more nodes and setting more seeds and pods,” he adds.

Variety selection is also important. Cullers always maintains a variety trial on his farm to determine the best seed genetics for his unique growing environment. Purcell notes that Cullers’ variety trials always demonstrate a significant yield range. “Even when it comes to top performing genetics, when you have a high-yield, highly managed fertility program, some varieties do well and some don’t.”

Purcell also discusses the role of nitrogen fixation and how much supplemental nitrogen is required to produce contest yields.

Click here for more Soybean School episodes.

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