The surprise from USDA’s October WASDE (released last Thursday) was the reduction in the estimated U.S. national average corn yield from September’s 181.3 bushels/acre (BPA) to 180.7 BPA. It was not so much the amount of the change that was unexpected but rather the direction. Big crops get bigger, as the saying goes, and when the corn yield estimate rises from August to September, which it did this year, there is also most often another increase in October. However, this big crop did not get bigger. With acreage estimates unchanged, the October yield reduction took estimated production from 14.827 billion bushels in September to 14.778 billion bushels. In hindsight, the variability of harvest yield reports from producers in nea...