Urbana, Illinois
July 16, 2008
A new study by
University of Illinois
agricultural economists projects that average 2008 corn yields
could be reduced by 2.9 bushels per acre in Illinois, 3.5
bushels in Indiana, and 6.3 bushels in Iowa due to
later-than-normal planting and above-normal precipitation in
May. Soybean yields may be down 1.1 bushels, 0.4 bushels, and
1.0 bushels per acre, respectively, in those same states for the
same reasons.
"The purpose of our study was to evaluate 2008 yield potential
for corn and soybeans in Illinois, Indiana, and Iowa using
previously developed crop weather models that estimate the
impact of technology and state average monthly weather variables
on state average yields," explained Scott Irwin, a professor in
the U of I Department of Agricultural and Consumer Economics and
lead author of the study. Department colleagues Darrel Good and
Mike Tannura were co-authors.
The study, "Forming
Expectations About 2008 U.S. Corn and Soybean
Yields--Application of Crop Weather Models that Incorporate
Planting Progress" is available on U of I Extension's
farmdoc website.
"In the current environment of strong domestic and export
demand, relatively low world stocks, and historically high
prices, the expected size of the 2008 U.S. corn and soybean
crops takes on added significance," he said.
"The market's expectation about the prospective size of the
crops will have a major influence on prices for the next three
months."
Typically, acreage expectations are "solidified," he said with
the USDA's June Acreage report.
"That is not the case this year, however, due to widespread
flooding and replanting in Illinois, Indiana, Iowa, Minnesota,
Missouri, and Wisconsin," Irwin said. "A special USDA survey in
those areas this month will provide a clearer picture of planted
and harvested acreage in the USDA's August Crop Production
report."
The magnitude of the expected yield declines due to slow
planting progress in 2008 is relatively small due to the fact
that May precipitation, while high, was not extremely high. The
magnitude of late planting, while above average, was
considerably less than highs recorded in previous years.
"It is important to keep in mind that these estimates do not
take into account the impact of replanting due to flooding in
some areas of Illinois, Indiana, and, especially, Iowa during
June," Irwin said.
The various models used by Irwin and his colleagues in
projecting 2008 yields resulted in a wide range of forecasts of
U.S. average yields for both crops.
"Corn yield forecasts range from 129.3 to 163.8 bushels per acre
and the soybean yield forecasts range from 37.8 to 45.3
bushels," he said.
"Production expectations for both crops, however, remain very
uncertain for at least three reasons."
First, he noted, the magnitude of harvested acreage is not yet
known. Second, remaining summer weather is an unknown.
"Finally, the crop yield models have relatively large forecast
errors," he said.
Irwin said that with the exception of the unfavorable July and
August weather forecasts used in the models, these yield and
production expectations exceed those of the USDA's World
Agricultural Outlook Board.
by Bob Sampson |
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