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Soybean Watch: Field yields well despite a very late, wet start and dry finish.

Tom J Bechman 1, Editor, Indiana Prairie Farmer

November 8, 2019

3 Min Read
combine harvesting soybeans
PROOF IS IN HOPPER: How would soybeans fare with a super-late start in a tough year? The guessing is over in this field. Average yield was above the projected state average yield.

Think back to early June. Things looked dire for many of you. If you didn’t have soybeans planted yet and someone said you would harvest 55 to 60 bushels per acre, you might have questioned their judgment.

Yet that’s what happened in the Soybean Watch ’19 field. It was no-tilled into cornstalks using a John Deere 750 drill on June 12. The 51-acre field in central Indiana consists of primarily silt loam soils with internal drainage that’s somewhat poor. There’s tile, but it’s not a complete pattern system.

“We said all year that we wouldn’t know what we had in any field until the combine ran,” says Steve Gauck, a Beck’s sales agronomist based in Greensburg, Ind. Beck’s sponsors Soybean Watch ’19.       

“That’s proving true,” he says. “Yields are all over the board, depending on planting date, soil type, when it rained and how much it rained. This particular field looked pretty good all year, once soybeans emerged and got going.”

The elevator scales proved Gauck correct, with the entire field averaging 57.5 bushels per acre. Several passes weighed using the grain cart scales yielded in the range of 60 to 65 bushels per acre.

2019 challenges

The Soybean Watch ’19 field encountered some major challenges:

Planting date. Based on history, soybeans planted June 12 are at a sizable disadvantage, Gauck says. There’s at least an 8% loss in expected yield potential due to planting date, according to the Purdue University Corn and Soybean Field Guide. Data indicates that for a midseason variety planted June 10, expect no more than 92% of yield potential compared to planting May 20. For a full-season variety, expect 90% of yield potential.

Related:Seed size a major factor in soybean yield

The two varieties in the Soybean Watch field were mid- to full-season for the area. Yield expectations drop off quickly — by June 20, you’re looking at 82% and 78% of full potential, respectively.

Wet start. Starting June 15, it rained 10 straight days, totaling 5 inches. Temperatures were cool. Emergence was slow, but two weeks after planting, it was clear the field wouldn’t need replanting. The stand count for one variety with full seed treatment averaged 124,000 plants per acre, while the other variety treated only with Ilevo averaged 107,000 plants per acre.

Dry finish. The area couldn’t buy rain after Labor Day. Soybeans were still in a critical reproductive phase. “One more rain in mid-September would have added yield,” Gauck says. “We found several aborted beans within pods when we made a final visit.”

What went right

So how did the field yield as well as it did?

Enough plants. “If you have 80,000 plants per acre and soybeans are fairly evenly spaced, you shouldn’t see a yield loss,” Gauck says. “We were well above that population here.”

Improved genetics. Two distinctly different varieties from two companies were planted. “Compared to earlier times when we had late, wet starts, genetics are much improved,” Gauck says. “Most varieties handle these less-than-ideal conditions and still produce reasonably well.”

Few disease, weed and insect issues. “Compared to 2018, we’ve seen much less disease and insect pressure overall this year,” Gauck says. “We found a few plants with disease symptoms here, but in general, the field was pretty clean for disease. It was also free of weeds. A few stinkbugs came in late, but not enough to be significant.”  

About the Author(s)

Tom J Bechman 1

Editor, Indiana Prairie Farmer

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