Drenching rains, low temps dampen corn planting

COLUMBIA, Mo. – It’s too early to call it too late to plant corn, says a University of Missouri cereal crops specialist.

With below-average temperatures and four months of above-average precipitation, corn planting remained stagnant statewide in the third week of April, said Brent Myers. The major exception was the state’s Bootheel region.

Planting delays don’t mean yields are in danger of dropping just yet. Plenty of time for planting corn remains and Myers recommends that nervous grain producers wait before switching corn acres to other crops.

“There is still time to put corn out there,” he said April 25 during a weekly meeting of state extension specialists.

Yield typically begins to drop when corn is planted after the third week of April, but only by 5 percent by May 5 and 13 percent by May 20, according to data from a four-year planting date study by MU Extension agronomist Bill Wiebold. Yield drops as much as 40 percent when corn is not planted by June 19.

“I would stick with corn through the end of May,” Wiebold says. “With the high price of corn, there is financial incentive to stick with corn even with some yield loss.”

Other factors, such as temperatures in July and August, often influence yield as much as planting date, Myers said.

The U.S. Department of Agriculture’s weekly weather and crop bulletin for April 14-20 reported rains of 2.78 inches statewide, with the northeastern and north central areas drenched by as much as 4 inches of rain, causing rivers and creeks to swell.

The USDA field office in Columbia reports 13 percent of Missouri’s corn crop had been planted as of April 21, most of it in the southern part of the state. This is 17 days behind the historically early 2012 crop and nine days behind the average. Nationally, 26 percent of the corn crop was planted by this time during last year’s unusually warm and dry spring, compared to 4 percent this year.

Pat Guinan, extension climatologist with the MU Commercial Agriculture Program, said levels on the Mississippi River north of St. Louis have not been this high at this time of year since 1973. “For the most part, we are saturated when it comes to moisture,” he said.

From March 1 to April 24, temperatures around the state averaged 12-15 degrees lower compared to the same period last year, Guinan said.

Average bare soil temperatures in the northern part of the state are still in the 40s and low 50s, well below optimal temperatures for seed germination. Seeds planted when soil is too cool germinate more slowly and are more vulnerable to disease.

Despite rain and below-average temperatures, Myers remains optimistic. He notes, however, that field prep, nitrogen and burn-down applications also are waiting to happen.