Farmers must deal with rain to harvest corn that grew in deep-drought season

COLUMBIA, Mo. – The Missouri corn crop can’t get a break from the weather. Drought slowed growth most of the season. Now moisture from remnants of Hurricane Isaac delay harvest of that corn.

This may not be the year to let the crop dry in the field, says Bill Wiebold, University of Missouri Extension agronomist. Early harvest can pay, even it increases costs.

“Timely harvest is essential to harvest as much yield as possible, even if it means more drying and aeration costs,” Wiebold says.

Delays can lead to broken stalks and dropped ears from a drought-weakened crop.

“Poor stalk quality leads to increased preharvest and harvest losses,” Wiebold adds.

In August, USDA estimated the Missouri corn yield at 75 bushels per acre.

Wiebold, using a 30-year-yield trend line, calculated the 2012 Missouri corn yield should have made 141 bushels per acre. “That’s a yield drop of 47 percent,” he says.

Harvest will verify actual yield.

“With that drop in production, farmers may be cautious to sink additional expenses into the crop,” Wiebold says.

“Harvesting a larger portion of the low yields may outweigh additional costs associated with early harvest,” he says. “Timely harvest as soon as fields are dry enough to withstand combine and wagon traffic is important to reduce harvest losses.”

There are many reasons stalk quality drops following a droughty growing season, Wiebold says.

Some disease-causing fungi, such as charcoal rot, grow well in heat on drought-stressed cornstalks.

Also, potassium builds stalk quality, but uptake was reduced on dry soils.

Stalk diameters of plants are smaller this year. The lateral expansion was limited by reduced turgor (water pressure) in the plant cells, Wiebold says.

Many corn plants died early, allowing fungi to attack the dead cells and break down cellulose and other structural strengths.

The results can be cornstalk breakage below the ear. “It will be difficult to gather those ears into the combine,” Wiebold says.

While rains were needed, storms increase stalk breakage and delay harvest. Gulf air masses meeting a series of cold fronts bring more moisture while temperatures remain high.

High dew points result in fog and damp plant tissue. That stimulates growth of fungi, which further weakens cornstalks.

All the corn that can be harvested, stored and dried will likely be worth more than any prices seen before, Wiebold says.

“The harvest should be worth the extra effort.”