Iowa corn faces critical stage during heat wave

It's make or break time for Iowa's corn crop.

Following a week of Dust Bowl-style heat and drought, the crop that covers about 39 percent of the state's surface is trying to reproduce. How well it succeeds will depend upon how much and how soon it rains.

If pollen and silk fail to unite, corn yields will plummet, and consumers will pay more for food in the months ahead, according to Chad Hart, an agricultural economist at Iowa State University in Ames.

“The main impact shows up at the meat counter. When livestock producers have to pay more for corn and other feedstocks, meat and poultry supplies decline and prices go up,” Hart said.

The worst Midwest drought since 1988 has pushed corn prices up 38 percent in the past three weeks, with new crop December corn near $7 per bushel on Friday. Many ethanol plants have already stopped or slowed production, exemplifying the self-rationing that will only increase if prices rise further, Hart said.

Short supplies and higher meat prices often take from three to nine months to materialize because of the volume of animals already in the pipeline, he said.

Prices for dairy products also will increase, though perhaps less steeply because the government has more influence over dairy prices, Hart said.

Smaller price increases will be noticed for pastas, breads and cereals, he said.

While the cost of livestock can make up as much as half of the price of meat at the counter, processing, packaging, advertising and shipping account for most of the cost of a box of cornflakes, Hart said.

Hart said he thinks the Iowa corn crop has already lost 10 percent of its potential yield.

ISU corn specialist Roger Elmore said he thinks most Iowa corn has not yet suffered irreversible damage. But another week of hot, dry weather, he said, could shrink yield potential as much as 9 percent.

Though little if any rain is likely in the week ahead, a return to seasonal temperatures should slow deterioration of the crop, said Jim Fawcett, ISU Extension field agronomist in Iowa City.

Modern hybrids' improved heat and drought tolerance will be tested this year, he said.

Conditions elsewhere

As bad as conditions seem in Iowa, they are worse in much of the rest of the Corn Belt, with many cornfields already given up for lost in Indiana and Southern Illinois.

During the past two weeks, corn classified as “good to excellent” has dropped from 67 percent to 62 percent in Iowa and from 63 percent to 48 percent nationally.

Tracy Franck, 51, who raises corn and soybeans on more than 2,000 acres in Buchanan County, said he thinks a lot of corn on marginal land is already toast.

“You see those short stalks with rolled leaves turning white - that plant is dying,” he said.

Corn plants use more water during pollination and silking - from 0.35 to 0.4 inches per day - than at any other time, in part because silks have the highest water content among all parts of the corn plant, Elmore said.

A corn plant under stress during pollination loses 3 percent of its potential yield for every 12 hours its leaves are rolled to conserve moisture, he said.

Previous droughts

Under even the worst-case scenario, Elmore said he thinks this year's corn crop will be better than the crop in 1988, which is the drought benchmark for most Iowans farming today.

For the first six months of 1988, Iowa recorded a statewide average of 7.51 inches of precipitation, a record low, according to State Climatologist Harry Hillaker. Nearly twice as much, 14.81 inches, fell in the first six months of this year.

Though this year's total is less than 2.4 inches below the 17.2 inches that is normal for the period, virtually all the deficit has occurred since May 7, Hillaker said.

During the first six months of 1936, the year of Iowa's worst drought, the state recorded an average of 10.9 inches in the first half of the year. Then came the hottest July ever recorded in Iowa with an average temperature of 83.2 degrees, almost 10 degrees hotter than the 73.6 degree normal average temperature.

For the first five days of this July, the statewide average temperature has been 83.4 degrees - a little ahead of the torrid 1936 pace.

Retired farmer Ray Cook, 89, of rural Winthrop, who was 13 in 1936, said the drought that year was far worse than in 1988. His family cut oats at night in ‘36 because even the horses could not stand to work in the heat of the day, he said.

In 1988, Cook said he harvested about 100 bushels per acre on his blacker ground, though 13 acres of gravelly soil yielded practically nothing.

“This year the leaves are rolling even on the black ground. If we don't get rain in the next week, it's going to start looking a lot like 1988,” he said.