A soybean crop planted after floodwaters recede still has a chance to make a profitable yield.

“Farmers who plant in July will be gambling that there will be a late frost this year,” said Bill Wiebold, University of Missouri (MU) Extension agronomist.

“Yields will be lower, but with expected prices of $15/bu., a late crop could be profitable. It makes sense to try for something,” he said.

“We have no soybean-yield research on a crop planted this late,” Wiebold told MU regional agronomists in a teleconference. “We never thought we would be planting a first crop this late in the season.”

The best chance for success in mid to late July is with seed for short-season soybeans adapted for Iowa growing seasons, Wiebold said. Some seed suppliers said they will have seed returned after prevented plantings in flooded areas of Iowa.

Soybean varieties are rated according to “maturity groups,” with Group 1 varieties for Minnesota, while Group 2 varieties are grown in Iowa. Most years, Group 3 beans are best suited for northern Missouri and Group 4 for central and southern regions of the state.

If growers could have planted the first week of July, Group 3 beans would have been best across much of Missouri.

Wiebold has two years of research comparing soybean varieties at MU agricultural research farms at Columbia and Albany.

The Group 1 varieties grown at both locations were short and remained short throughout the season. The taller the plant, the greater the number of stem nodes where soybean seedpods attach.

In northwest Missouri, at the Hundley-Whaley Research Center in Albany, Group 2 beans performed better than the Group 1 beans. The Group 3 and 4 varieties did better at Columbia.

On the last planting at Columbia, the Group 2 beans did better than Group 1 beans. “Our last planting date was on June 16, which is not near as late as we are now, but it gives an indication that Group 2 can make a profitable yield,” Wiebold said.

The last planting date at Albany was June 6. At that location, Group 2, or Iowa beans, produced nearly 50 bu. in 2006.

There is a higher risk of frost damage on soybeans planted late. Soybean pods that are frosted before they mature produce green rather than yellow seed. “Green beans are heavily discounted in price at the elevator,” Wiebold said. “In a normal year they don’t want to buy them.”

Scott Killpack, extension agronomist in St. Charles, said first frost there is typically mid-October. “I expect growers here will stay with Group 3 varieties.”

In east central Missouri, yields from Group 3 should be higher than from Group 2, Wiebold said. However, availability of Group 3 seed may be a problem.

With short-season varieties planted this late in Missouri, Wiebold recommends planting in narrow rows and increasing seeding rate by 25%, up to 200,000 seeds per acre.

The earlier the crop can be planted the better. However, MU Extension field staff said July 15 may be the earliest that wet fields can be planted after water recedes.

Growers should check with their crop insurance agent before planting any late crop. Planting a crop might interfere with collecting payments for delayed, prevented or damaged plantings if an insurance adjuster has not seen the field.

“There will be hoops to jump through,” Wiebold said. “Failing to complete required paperwork could be costly.”

If possible, Wiebold recommends planting some crop on fields that have been delayed or flooded out. “There is something called the fallow-year syndrome, which reduces yields the following year on land not planted,” Wiebold said.

“I never thought I’d be telling farmers to plant soybeans until the end of July,” he said. “But this year changed the rules of the game.”