A record late planting and a record cool July have created a lot of confusion it the farm community. In a normal year there is nothing better for corn than a cool July with timely rains. That is normally the formula for a guaranteed bin-buster, but with a really late planting date a cool July means slow growth and delayed harvest with risk of frost. At the Macon County plot meeting last week Dr. Darrel Good shared that a yield model used by the Ag Economics group at the University of Illinois shows that the yield penalty from late planting was offset by the favorable July weather. Good news but only if the first frost date is average or later than average.

Yield surveys are a way the ag industry tries to get a handle on the size and condition of the crop. This week I helped with a corn survey in Coles County. A group of volunteers went to every township and sampled random corn fields. A total of 54 fields were sampled with yields ranging from 67 bushels to 224 bushels per acre. Based on the standard yield formula, a county average yield of 154 bushels was estimated. This is 9 bushels below the 10 year average for the county.

Pro-Farmer did their Midwest Crop tour this week; results can be viewed on-line at http://www.agweb.com/croptour.aspx. In a nutshell they reported the Iowa corn crop is huge and Illinois looked better than expected but is very late.

This week, TopFlight Grain Co-op will conduct their crop tour in the Macon, Piatt, Champaign, Moultrie and Douglas county areas. The market focuses a lot of attention on public and private crop yield forecasts. Each announcement brings a corresponding adjustment to the price. Higher prices can bring the hope of higher incomes but if yields are low that opportunity is reduced. Many farmers and consultants are walking fields now to determine how local fields are fairing. The task is a little more difficult this year because of the unevenness of the crops. More areas need to be sampled to get reliable results.

The formula for estimating corn yields is easy to remember. Take the average number of kernels per ear times the average number of ears in a thousandth of an acre and then divide by 90. Do not put too much faith in these yield estimation techniques. These formulas make a lot of assumptions. The elevators buy based on weight not number of kernels and beans. When test weights are low and seed size is small these formulas tend to over estimate yield.