From: ARS News Service [mailto:[log in to unmask]]
Sent: Wednesday, June 03, 2009 10:15 AM
Subject: Clues on Corn Yields, Weather Conditions and Climate Patterns
Clues on Corn Yields, Weather Conditions and Climate Patterns
ARS News Service
Agricultural Research Service, USDA
Ann Perry, (301) 504-1628, [log in to unmask]
June 3, 2009
--View this report online, plus photos and related stories, at
New mathematical models developed by Agricultural Research Service (ARS)
scientists and colleagues could eventually help farmers use climate
patterns to predict corn yields. Farmers could use this information,
which indicates yield cycles of about two years, to adjust their
production practices. For instance, crops grown in low-yield years may
require less fertilizer.
These adjustments, in turn, could reduce the flow of excess nitrate from
crop fertilizers into the surrounding watershed, which may help control
hypoxia downstream in the Gulf of Mexico. Corn yield variability
affects nitrate loss because small changes in corn yield may have
greater effects on nitrate loss in fields with subsurface tile drainage
Agricultural engineer Rob Malone works at the ARS National Soil Tilth
Laboratory in Ames, Iowa. He and other colleagues in ARS and at Penn
State gathered more than 50 years of data on corn production from six
high-yield corn-producing counties in Iowa to see if they could identify
key correlations among yield, weather conditions and climate indices.
Malone's modeling results indicated that high surface radiation and low
temperature early in the growing season often produce high yields when
followed by sufficient rainfall later in the growing season. This model
accounted for 89 percent of the variation in annual corn yields.
Changes in these weather variables are often associated with long-term
climate trends. So the team used established climate indices derived
from the large-scale flow of high- and low-pressure air masses and
equatorial stratospheric winds to develop models that accounted for the
variability in corn yields. This model detected an average difference
between high- and low-yielding years of 19 percent and identified an
approximate two-year cycle between high- and low-yielding years.
Malone's research helps explain the combined effect of several long-term
climate trends on long-term U.S. corn yields. In addition, these
results provide information about how the annual variation in
ground-level solar radiation during the growing season affects long-term
corn yield in the United States.
This research was published in the journal Agricultural and Forest
ARS is the principal intramural scientific research agency of the U.S.
Department of Agriculture.
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