Weather assault sends soybean yields retreating

COLUMBUS – A rainy growing season and cooler-than-normal temperatures were a blessing for Ohio’s corn crop, but a thorn in the side of soybean growers.

Environmental conditions that benefited an early-planted corn crop contributed to soybean diseases and hindered the development a soybean crop, which, in some cases, was planted as late as the end of June.

The result is an average state yield of 40 bushels per acre, predicted by the Ohio Agricultural Statistics Service in its November crop production report.

Dropping more. Jim Beuerlein, an Ohio State University Extension agronomist, thinks that predicted yield may drop even further.

“The weather that was good for corn should have been good for beans. But the problem was that the corn crop got a root system established well ahead of the wet weather and the soybeans just didn’t do that,” Beuerlein said.

“The crop reporting service may be predicting 40 bushels per acre, but I think it’ll be lower than that – maybe 37 or 38 bushels per acre.”

Better than before. At any rate, the number sounds better than last year’s average yield of 31 bushels per acre.

The last time soybean growers saw an average yield that low was in 1989.

The above-normal rainfall – 25 percent to 30 percent higher – from April to October invited root rot diseases, which were so severe in some cases that average yield loss was running seven to nine bushels per acre, Beuerlein said.

“Soybeans are susceptible to a lot more root rot diseases than corn,” Beuerlein said.

“Cooler temperatures, plenty of water and sunlight are all good for yield, but with all the diseases we had, it just didn’t work out for beans.”

Phytophthora, pythium, rhizoctonia and sudden death syndrome were all present this year, as well as soybean cyst nematode.

Disease. In field trials conducted by Ohio Agricultural Research and Development Center researchers, soybean varieties planted with little or no field resistance to phytophthora root rot showed a 70 percent reduction in yields.

Varieties planted with low levels of partial resistance showed a 33 percent reduction in yields.

Soybean cyst nematode also took yields away from growers – from 5 percent to 50 percent in fields, depending on severity.

The take-home messages for next year: Test soils with known soybean cyst nematode populations to begin managing the pest early.

Also, plant soybean varieties with a combination of field resistance and high partial resistance to phytophthora root rot, to afford plants the best protection against the disease.

Weather schedule. “I think one of the big lessons we tend to learn year after year is when you can get into a field to conduct field operations, you better do it,” Beuerlein said.

“We are always subject to doing only what the weather lets us do, but we need to be ready to get those crops planted when it’s permissible so they can develop as quickly as possible.”