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Research Highlights
Soybean Maturity Group Study in Northeast North Dakota Helps Grower Seed Selection

Plot of soybeans planted on May 21, 2020, just prior to harvest. Photo: Bryan Hanson

By Carol Brown

In terms of crop production, soybeans are a relatively recent addition in North Dakota rotations. And in the northeast part of the state, they are even newer to the scene. With the shorter growing season so far north, there weren’t too many cultivars to choose from in the maturity groups suitable for the area. Over the last few decades, the growing season has lengthened, and more adaptive cultivars have been developed – now there are more choices for northern farmers.

“In northeast North Dakota, three counties on the Canadian border have seen soybean acreage increases from about 86,000 acres in 2011 to 417,000 acres in 2017,” says Bryan Hanson, research agronomist at the Langdon Research Extension Center. “It’s now around 300,000 acres, but still, that’s tremendous growth.” 

With acreage increases like this, research on crop productivity and other issues can lag behind production, or not come about at all until needed. This was the case of Hanson’s current project, funded by the North Dakota Soybean Council. For three years, Hanson has been comparing soybean maturity groups, cultivars and planting dates to determine best soybean performance. 

“In 2017, two counties in my area received hail damage on June 9 that impacted about 100,000 acres,” Hanson says. “June 10th is the final planting date for RMA (risk management agency) insurance. I started getting inquiries from insurance companies asking about replanting scenarios.”

Figure 1. 2020 Seeding date and cultivar maturity group effect on soybean yield.

If a grower loses a crop after June 10, they had 25 days to replant, which brings that date to July 5. But intuitively, Hanson says, most people know soybeans can’t be planted that late in his part of the world, thus launching the idea for the research project.

“In the northeast part of the state, farmers are using the earliest soybean maturities — 00.5 to 0.7 or 0.8,” says Hanson. “If you live in the southern part of the state, where they’ve used 0.6 to 0.8 maturities, and you had some catastrophe, you had a lot more options on finding seed for replanting. Up here, we’re at the bottom of the options already — there’s nowhere to go.”

In 2018, he started the project, comparing several cultivars in maturity groups 00.5, 00.9 and 0.1, seeded on May 15, May 24, June 4, 14 and 25.  He measured yield, effect on protein and oil, as well as other agronomic traits including plant height and test weight for each planting date, cultivar and maturity group. 

“That year was the most normal, as far as normal is defined. In 2019, we lost most of the trial data because of a 20-inch snowstorm in October,” says Hanson. “Last spring was really wet, and we had a frost-freeze on Sept. 8. Fortunately, we still had good yields last fall.”

Figure 2. 2018 Seeding date and cultivar maturity group effect on soybean yield.

From the three years of data comparisons, Hanson says that for most years, if farmers can plant soybeans in the middle of May to May 20th, the earlier maturity groups such as 00.9 and 0.1 would probably produce the best yields. 

He has shared his findings with the state RMA office and hopes they can put the information to good use. 

“June 10 is the final planting date for the entire state, and they did modify the replant requirement date for 2018 to replanting 10 days after final date, if practical,” he says. “Maybe they will be a little more lenient when weather events like a hailstorm occurs in our area again, now that they have our data.”

Farmers can find Hanson’s results on the North Dakota Extension website and in their annual report: https://www.ag.ndsu.edu/langdonrec/annual-research-reports1-1/2020-annual-research-report/view

To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.