Farmers fret as wet October hampers harvest; forecast calls for less rain but slower drying

COLUMBIA, Mo. – With potential record yields still in fields, crop farmers fret with wet weather in October, especially in northern and mid-Missouri areas that also had a wet September.

“With this much rain, it takes a week to get into fields again after the last rain,” said Bill Wiebold, University of Missouri agronomist. “That’s on deep, well-drained soils. It takes longer on claypan soils with no internal drainage.”

At mid-October, MU Extension climatologist Pat Guinan reports statewide rain averaged about 6 inches, double the average for the entire month.  A wide path along I-70 had 6 to 10 inches of rain, as did southwestern and south-central Missouri. Heaviest rains were south of Highway 36.

The Oct. 14 Missouri Crop Progress report shows the delay in harvest. Corn harvest was at 51 percent, compared to 81 percent for the five-year state average. Soybean harvest was 16 percent, half the five-year average for Missouri.

Guinan says October rain has been worse in the past. In 2009, rainfall in the state averaged almost 10 inches, the second wettest on record, topped only by 1941. The 2009 crop harvest was further behind and rains lasted all month. November that year turned dry and warm. Harvest was successful.

Now Guinan sees a change in outlook to drier weather. The Climate Prediction Center forecast shows above-normal temperatures and low precipitation for two weeks.

Wiebold pointed out state crop-harvest averages can mislead. “Most of that harvest was in southern regions.” Southern Missouri had less rain on soils with less water-holding capacity.

The most saturated areas are across central Missouri. That area was the center of the bull’s eye for rain in much of the Corn Belt, Guinan said.

With slow drying, fall rains have different results than summer rains. “Days grow shorter. Sunshine weakens. Temperatures cool. There’s no evapotranspiration from crops,” Wiebold says.

“After big rains in July, you go back in the fields in two days. In October soil takes a lot longer to dry.”

Prolonged wet weather takes a toll on unharvested crops. Dry corn stalks weaken and fall. Soybean seed swells in the pod, which causes shattering.  Wet weather can also bring rot and mold.

With the largest grain harvest on record underway, farmers were running out of grain-bin space. “They plan to store grain on the ground, wrapped in plastic, Wiebold said. “Wet weather is not good for that.”

Working in wet fields causes soil compaction, especially on clay soils.

Wiebold recalls a drive in 2009 across the claypan region of northeastern Missouri. “There were ruts 2 feet deep filled with water. It takes years to recover from that,” he said.

“I recommend going slow getting back into the fields. But I know farmers are anxious to get back to work. They might not listen.”