"The average U.S. corn yield will obviously be the most
important factor in determining crop size, but the magnitude of
acreage harvested for grain will also influence crop size," Good
Good said the likely magnitude of harvested acreage starts
with the magnitude of planted acres. The USDA's National
Agricultural Statistics Service June Acreage report estimated
corn acreage planted for all purposes this year at 96.4 million
"History suggests that the final acreage estimate will
deviate, at least slightly, from this estimate," Good said. "For
example, in the previous 10 years, the final estimate of planted
acres deviated by as little as 37,000 to as much as 1.345
million acres from the June estimate."
The positive deviations (four) averaged 293,000 acres, and
the negative deviations (six) averaged 650,000 acres. The
recently released USDA Farm Service Agency report of planted
acreage of corn in 2012 by those participating in government
programs has been used to judge the potential change in the NASS
estimate of planted acreage this year. That report showed
planted acreage by program participants at 93 million, or 96.5
percent, of the NASS June estimate.
"Some have suggested that this report points to an increase
in the NASS estimate of planted acreage," Good said. "However,
in the previous five years, the ratio of FSA acreage to the NASS
final estimate averaged 97 percent in a range of 96.7 to 97.5
percent. The ratio based on the June estimate this year is
slightly smaller than that of the final ratio of the previous
five years. If anything, then, the lower ratio points to the
potential for a slight reduction in the NASS final estimate of
planted acreage rather than an increase," he said.
Good said acreage of corn harvested for grain in a given year
is equal to planted acreage minus acreage harvested for silage
minus non-harvested acreage. Acreage harvested for silage has
declined over time. Acreage harvested for silage averaged about
9.2 million acres in the 1970s and about 7.6 million acres in
the 1980s. That acreage has been relatively stable since 1990,
averaging just under 6.1 million acres and in a range of 5.3 to
7.1 million acres.
"Acreage harvested for silage, however, tends to spike in
years of dry weather like that of 2012," Good said. "Compared to
the previous year, for example, silage acreage increased by 1.3
million acres in 1980, 2.3 million acres in 1988 and just over 1
million acres in 2002. This 'spike' pattern was not observed in
1983 or 1995, however, when harvested acreage of silage was less
than in the previous year," he said.
[to top of second column]
In the case of non-harvested acreage, Good reported an increase from
the previous year of 780,000 acres that occurred in 1980, 460,000 in
1988, 258,000 in 1995 and 1.65 million in 2002. The outlier in the
pattern of an increase in acreage not harvested for grain in recent
dry years was 1983. The pattern that year may have been influenced
by the 21.6-million-acre year-over-year decline in planted acreage
in response to government programs aimed at reducing the corn
surplus, according to Good.
So what about harvested acreage of corn in 2012?
"We are anticipating that due to the severity of this year's
drought, the difference between planted acreage and acreage
harvested for grain will be at least as large as in 1980, 1988 and
2002," Good said. "Differences in those years averaged 10 million
acres, in a range of 9.47 (million) to 11.1 million acres. If
planted acreage was also slightly less than the NASS June estimate,
that experience points to acreage harvested for grain of about 86
million, nearly 1.4 million less than the June NASS estimate," he
Under this acreage scenario, Good said a national average corn
yield near the August forecast of 123.4 bushels would result in a
crop near 10.6 billion bushels.
"If the average yield is also 4 to 5 bushels lower than the
August forecast, as we suspect, the crop may be near 10.2 billion
bushels, almost 600 million bushels less than the NASS August
forecast," Good said. "A crop of that size would require a
year-over-year decline in consumption of U.S. corn of nearly 1.8
billion bushels, or about 14 percent.
"Corn prices would likely have to remain high for an extended
period in order to motivate such a large decline in consumption,"
Good said. "The USDA's Sept. 12 Crop Production report will provide
an important update on the likely magnitude of harvested acreage,
yield and production, and bring the rationing question into clearer
focus," he said.
[Text from file received
from the University
of Illinois College of Agricultural, Consumer and Environmental