The debate about the likely size of USDA's final estimate of the 2014 U.S. average corn and soybean yields continues, with the market apparently anticipating those estimates will exceed the August forecasts, particularly for corn. At the margin, the size of the crops will also be influenced by the magnitude of harvested acreage.
The first acreage issue is the magnitude of planted acreage, and the second is the magnitude of harvested acreage. The current planted and harvested acreage forecasts are based on June USDA surveys, adjusted for any new information revealed in the August crop production surveys. The August forecasts were unchanged from the June forecasts. History suggests final acreage estimates will differ from current forecasts, with the direction and magnitude of those changes being the issue.
Since 1996, when agricultural policy changed to accommodate more planting flexibility, the final estimate of corn planted acreage ranged from 2.014 million acres less (2013) to 750,000 acres more than the June forecast. The difference exceeded one million acres in only four of the 18 years from 1996 through 2013.
The average difference was a decline of 432,000 acres, statistically not different from zero. However, the final estimate was below the June forecast in 13 of the 18 years. The larger declines were in years of late planting, but not all late planted crops resulted in large declines from the June forecast to the final estimate.
During that same time period, the final estimate of soybean planted acreage ranged from 1.464 million acres less (2010) to 1.185 million acres more (2008) than the June forecast. The difference exceeded one million acres in six of the 18 years. The average difference was a decline of 141,111 acres, statistically not different from zero. However, the final estimate was below the June forecast in 11 of the 18 years from 1996 through 2013. The difference between the June forecast and the final estimate of planted acreage during that period was not correlated to either the lateness of corn or soybean planting.
For the current year, a larger-than-average percentage of the corn acreage in the 18 major corn producing states was planted late (defined here as after May 20). Much of the late planting was in northern and eastern states. A late planted crop, along with the historical tendency for the final estimate of planted acreage to be less than the June forecast, suggest the final estimate this year will likely be below the June forecast of 91.641 million acres.