After wet spring, another fear stalks Wisconsin's corn farmers: an early frost

Colleen Kottke
Wisconsin State Farmer
Each fall its a race against time as farmers try to get the crop off at its peak quality.

Farmers across the Midwest had a rough start to the year with a winter that refused to quit and a spring that wouldn't start. Cold and damp conditions tested even the most patient among them.

"It was as if Mother Nature was battling us every step of the way," said Kathy Miller who runs a farm in southwest Wisconsin. "We finally got our last field of corn planted in early June. Now we sit and hope for a late frost."

Constant rain showers in May and June kept many farmers' planting ambitions at bay, forcing some to leave fields unplanted. Much of the corn that was planted is now behind schedule, fueling fears that an early frost could spell disaster for the crop.

DTN ag meteorologist Bryce Anderson said crops in general across the Upper Midewest are about two weeks behind schedule in terms of progress.

"Corn needs about 60 days after it tassels to go through the post-pollination stages of blister, dough, dent and final maturity," he said. "When you have corn first pollinating the first of August, you're looking at the middle of October before things get killed off by frost in order for the grain to have a fighting chance of making something."

According to the University of Wisconsin, typically in a normal year, corn should be "silking at the end of July and denting on Labor Day." After corn silks, it normally takes about 55 to 60 days (1000 to 1200 Growing Degree Units GDUs) for it to mature. 

Normally during September, growing degree units in Wisconsin accumulate at the rate of 12 to 19 units per day for a total accumulation of 400 to 450 units.

While summer warmth and scattered thunderstorms across the state created another excellent week for crop development, crop progress remains behind average. Plenty of warmth and a late frost are needed to make sure corn and soybeans fully mature by harvest time.Greg Blonde, a University of Wisconsin Extension agent in Waupaca County, notes that the Marshfield Research Station indicates the area is 200 GDU's below normal.

"The good news is that during the month of August, we may have been at or above normal given the daytime highs and nighttime temperatures that helps accumulate more growing heat units," Blonde said. "To make up a couple of weeks of Growing Degree Days, we definitely are going to need a later than normal killing frost."

Last year farmers faced plenty of obstacles trying to get their crops out of the fields, including snow.

Frost fears

Corn is killed when temperatures are near 32 degrees F for a few hours, and when temperatures are near 28 degrees F for a few minutes. The average first freeze happens from early to mid-October in the southern half of Wisconsin — a week later for areas near Lake Michigan. Farmers in northern Wisconsin could see the first killing frost the last week of September.

According to models that he has been following, Anderson says he doesn't expect an early frost.

"We are looking at the average first date around October, putting late planted crops in a position of coming down to the wire in terms of maturity," he said.

Blonde says the variations of soil across his county has had a variety of effects on the corn crop this year. 

"Crops located on the western side of the county near the Central Sands region look phenomenal. But as we go from west to east, where we have heavier soils and lower land, the bigger the implications we're going to see," Blonde said. "But the killing frost will impact the sandier soils more because lighter soils give up the heat quicker. so we often see a killing frost the last week of September in the Central Sands regions."

Mike Ballweg, a University of Wisconsin Extension agent in Sheboygan County, expects to see an extremely variable corn crop this year due to a wet and cool planting season which resulted in delayed planting dates. He estimates Growing Degree Days are 7-10 days behind the 30-year average.

"For eastern Wisconsin I would estimate that 75-80% of the corn crop should reach physiological maturity by the time we have the average first frost dates," he said. 

Reaching the finish line

Despite constant rain showers, corn pollination across the state was relatively successful said University of Wisconsin Agronomy professor Joe Lauer. 

"There wasn't a lot of stress during pollination, so we have a lot of kernels going out there," Lauer said.

Wet weather conditions haven't impacted pollination in Wisconsin this year, although it may be occurring two weeks behind scheduled in fields experiencing delayed planting.

Many farmers who experienced a delayed planting season are hoping to harvest good, quality corn silage. Lauer says there are two forage-quality peaks for corn silage. The first peak occurs right after the plant tassels. The second peak is near maturity during the milk stage.

"If we have a killing frost when the corn plant is at tasseling, you can still get a pretty good quality forage. The downside is you don't have a lot of yield, maybe 3-4 tons of dry matter," Lauer said. "If you have a frost after the plant has tasseled, the quality goes down but the yield continues to go up because the grain is starting to come on."

All in the timing

Lauer said the key to harvesting quality feed is all in the timing (and a little luck from Mother Nature).

"It all hinges on when the tasseling occurs in the field, If farmers note that date they can start to make plans for later on," he said. 

They also need to keep track of which fields are further along in maturity, especially if they use the services of a custom harvester.

This fall farmers will be faced with the challenges of a corn crop in different stages of development, sometimes in the same field.

"They usually come on your farm and want to take everything off at once. And this year there's going to be a lot of fields at different stages of development," Lauer said. "The best thing the farmer can do is work closely with those custom operators and be sure you know when that field is going to be ready so they can time the harvest better."

Although the corn crop was ready for harvest, a rainy weather pattern set up by a developing El Nino in the Pacific kept farmers from getting into the field and harvesting the crop last fall.

"It looks like the El Nino has run its course and we're now seeing an El Nina effect, and one of those reactions is a prospect for a drier trend in the Midwest during the fall season," Anderson said. "And that would be helpful for harvest with drier air helping to dry grain out in the field."

Anderson predicts that most corn harvested this fall will contain a moisture content at 20% or higher,

"Buying a little propane now might not be a bad idea to help handle some of those drying costs," added Lauer.

Quest for forage

Blonde said feed inventories are going to be of concern to farmers heading into the winter months, not only for Wisconsin farmers but those across the Upper Midwest.

"Hay inventories were at record lows earlier this year. We've had some harvest in trying to bring the supply back into the market, but I don't expect we've been able to build back much of that inventory," Blonde said. 

A lot of folks are pinning their hopes on a good quality corn silage harvest, but there are no guarantees.

Although hay prices have dipped recently during the harvest season, he predicts good, quality forage crops will be hard to find this winter.

"A lot of folks are pinning their hopes on a good quality corn silage harvest, but there are no guarantees," Blonde said. "If we have an early frost and grain farmers are stuck with an inventory of corn, instead of harvesting those crops for grain it could possibly become a forage crop for silage and in some ways make more feed available to farmers."

Ballweg says that some farmers have opted to plant some of the prevent plant acreage in east central Wisconsin after July 1 in cover crops for additional forages needed on the farm. He estimates that 15-20% of corn acres were prevent plant and 10-15% of the soybean acres.

Anderson hopes that farmers will be able to harvest those crops they've worked so hard to get planted this spring.

"To a large extent, a lot of producers had the wet fall just compounded by the heavy rains this spring. Those wet fields and wet condition problems once they started never went away," he said. "I've felt a lot of stress and anxiety on the part of producers because of weather issues. It's been a tough 12-month period. And so any easing of key weather patterns at key times when producers need to be out in the field would be a welcome change for them."