Wet July leads to wet early August; crops, forage thrive, with warnings

Corn Field

“Wet” and “wetter.” Those words set the theme of an Aug. 2 teleconference for University of Missouri Extension agronomists.

Heavy rains on the first two days of August followed what may have been the ninth-wettest July since 1895.

Preliminary state average rainfall was 6.5 inches, said Pat Guinan, MU Extension climatologist.

He reported heavy rains started August with 3 to 8 inches overnight in a swath in northern Missouri from the Iowa line near Bethany to Carrollton then east to near Marshall and ending southwest of Columbia.

“The front just stalled there,” Guinan said. “It didn’t move all night.”

The next night, a smaller area in northeastern and east-central Missouri had 3 to 6 inches of rain. Centered on Mexico, Mo., that storm reached south through Gasconade County.

Normally dry, August started this year with flood warnings for bottomland cornfields.

Mostly, the regional specialists reported corn benefits from the rain. Some producers added aerial applications of nitrogen to replace nutrients leached away.

The time for adding nitrogen is done, said John Lory, MU Extension nutrient specialist.

A regional agronomist reported that a yield check showed that “dryland” corn might out-yield irrigated corn this year.

Soybean crops ranged from forming first leaves to start of blooms. However, farmers know that beans can start late and finish with record yields if not hit by early frost.

Reports of Japanese beetles that had dominated past calls are on the wane. Beetle populations leave crop fields and head to grassy pastures to lay their eggs.

Mainly beetles feed on edge rows of corn and soybean fields, not whole fields.

Forage production drew more discussion than field crops this week. Cool-season grasses continued to make abundant grazing.

However, an early warning came of two infestations by fall armyworms. Both had been caught early and sprayed.

Armyworm attacks start near Arkansas and work their way north. The moving mass of worms can strip pastures bare overnight.

Farmers are alerted to watch for the pest to catch them early. They require a quick response.

Ben Puttler, retired MU entomologist, said wet weather could help control armyworm invasions. A fungus can devastate the population.

Wet, warm weather favors the fungus.

Craig Roberts, MU Extension forage specialist, said past years of heavy summer rains hurt alfalfa fields. If alfalfa plants turn yellow, their nitrogen-fixing nodules may be inactive. Water-soaked soils kill the rhizobia bacteria that fix nitrogen from the air for plant use.

If the stand is thin, the alfalfa field can be interseeded with orchard grass and red clover. That boosts hay yields. If alfalfa is to be planted into the same field, the alfalfa needs to be taken out of production for a year, then reseeded.

It will be vital to inoculate the seed to re-establish the rhizobia culture in the soil.

“With thicker stands, it may be possible to add the inoculum to the soil with a drill,” Roberts said he knew of no Missouri research on that practice but had heard of it working.

Guinan’s weather outlook indicated a continued wet early August. Heat and humidity will prevail into next week.

The teleconferences between MU state and regional extension specialists help keep all up to date on new problems. Calls are made weekly through the growing season.

In normal years, most crop pests dry up by mid-August. This week, the group will decide whether to share ideas until September.