(Updates weekly crop progress data, paragraphs 7-9)
By Karl Plume
CHICAGO, Sept 25 (Reuters) - Unseasonably hot U.S. weather is accelerating corn and soy crop maturity after months of concerns that lagging development could drag down yields or put some late-planted acres at risk of damage from frost, agronomists and analysts said.
Farmers around the U.S. Midwest are racing to harvest crops under mostly clear skies and temperatures more indicative of mid-summer than early autumn, with highs ranging to 90 to 100 degrees Fahrenheit (32-38 degrees Celsius) speeding up in-field grain drying.
Cash bids at several elevators and processors around the Midwest weakened in anticipation of an influx of grain in the coming days and weeks, while costs for shipping supplies by barge to Gulf Coast export terminals surged on Friday.
The unseasonable heat is almost certain to add bumper bushels to an already burdensome global grain supply that has weighed on crop prices and pressured farm incomes for four years. The strong finish to the U.S. growing season comes after a cool, wet spring stalled planting and mild summer weather slowed crop development.
“It’s been a really good harvest so far. Things definitely matured quicker with this heat,” said Kirk Liefer, a farmer in Red Bud, Illinois, who had the majority of his corn harvested and expects to begin gathering soybeans this week.
A key concern now for Liefer is getting soybeans that he grows for seed harvested quickly, before the crop’s moisture drops too much. Drier soybeans can be lost in the field during harvesting and are more prone to cracking, which lessens the value of the crop.
More than half of the U.S. corn crop was mature as of Sept. 24, up from just over a third a week earlier, according to U.S. Department of Agriculture data. The crop was 11 percent harvested as of Sunday, up from 7 percent a week earlier but 5 points behind the 10-year pace.
Soybeans were 10 percent harvested as of Sunday, up from 4 percent last week and slightly ahead of the 10-year average of 9 percent.
Analysts polled by Reuters had expected 14 percent of corn to be harvested, along with 11 percent of soybeans.
The unusual late September Midwest heat is accompanied by lower-than-normal precipitation, which will allow farmers to continue harvesting uninterrupted. Farmers will also let crops dry naturally in fields, saving them money on drying costs.
“The propane industry won’t be happy. They are always trying to anticipate what the drying needs will be, and if this continues, the drying needs will quite a bit less,” said Roger Elmore, professor and agronomist at the University of Nebraska.
Temperatures are expected to remain above normal for about another week, with a chance for rain in northern sections of the western Corn Belt early in that period, according to Commodity Weather Group agricultural meteorologist David Streit.
As of Sunday, high temperatures in Chicago, in the center of the U.S. Corn Belt, set records and topped 90 degrees Fahrenheit for five straight days, according to the National Weather Service. That followed only one day above 90 degrees in August, and two in July.
The Midwest heat wave comes amid a dry spell that has dropped river levels in the region and forced shippers to load export-bound barges with less grain to prevent them from grounding in the shallower waterways.
The U.S. Coast Guard closed a section of the Illinois River due to low water and imposed draft restrictions along a nearly 150-mile stretch of the Mississippi River from Tiptonville, Tennessee, to Memphis.
Low water may also allow the U.S. Army Corps of Engineers to continue a project stalled since 2014 to remove river-bed rock pinnacles near Thebes, Illinois.
Freight rates for hauling grain by barge to Gulf Coast export terminals over the next three weeks spiked on Friday as shippers prepared for an influx of crops.
Corn bids at elevators and processors plunged as much as 13 cents a bushel, while soybean bids were as much as 28 cents lower. (Reporting by Karl Plume; Additional reporting by Julie Ingwersen and Michael Hirtzer; Editing by Leslie Adler and Dan Grebler)