Fundamentally Speaking

IL April Weather Conditions Impact on Corn Seedings

One of the coldest winters in memory has Illinois soil temperatures well below normal as corn planting season is just around the corner.

Readings four inches below the soil are reportedly in the mid 30 degree range, well below the 50 degree threshold needed for germination.

This suggests that corn plantings in Illinois, the second largest corn producing state will at best get off to a normal start and that seems optimistic.

If this is the case, that would be the second year in a row and four of the past six where Illinois corn seedings proceeded at a below average pace.

This graphic shows the percent of the Illinois corn crop planted by April 30 from 1984 to 2013 along with the difference of Illinois April temperatures and precipitation from the 1984-2013 averages that are respectively 52.6 degrees Fahrenheit and 3.90 inches of rain.

The five year average pace of corn seedings by April 30 in Illinois is 36%, 46% for the 10 year average, and 38% for the whole 1984-2013 period.

Last year a mere 3% of the crop was in the ground by the end of April, the slowest pace since 1993 when there was no IL corn planted by April 30 and the 2% seen in 1984.

In addition to these three years, 2009, 1999, and 1995 were all years where the amount of Illinois corn seeded by April 30 was less than 10%.

No surprise that of these six years, all but one saw below average April temperatures and all experienced above average April rainfall.

Last year April Illinois temperatures averaged 49.7 degrees, the third coldest relative to average over the past 30 years while rainfall of 7.1 inches was the third highest since 1895.

Though late plantings are often associated with below trend yields, that was not the case for Illinois at least last year and in 2009 where very good yields were posted, as summer weather conditions are much more of a factor.

On the other hand, final planted area was lower in all but one of the six years from what Illinois farmers intended to plant ranging from unchanged to down 700,000 acres with an average decline of 283,000.



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Mr. Brandy
3/31/2014 | 2:17 PM CDT
Another plot for your graph would be Average Yield or % of trend yield for each of those years.