In its monthly world supply and demand (WASDE) report, USDA pegged this year's corn crop 556 million bushels lower than previous estimates, taking into account a slight reduction in harvested acreage as well as lower expected yields.

This year's crop will average 153 bushels/acre, according to USDA. That's down 5.7 bushels/acre from last month's estimate "as unusually high temperatures and below-average precipitation during July across much of the COrn Belt sharply reduced yield prospects," according to Thursday's WASDE report.

Corn use is also pegged lower, for both feed and fuel. "Feed and residual use is projected 150 million bushels lower reflecting the smaller crop and higher expected prices. Corn use for ethanol is projected 50 million bushels lower with tighter supplies and lower forecast gasoline consumption for 2011 and 2012," according to Thursday's report.

That adds up to an ending stocks number 156 million bushels lower than last month's estimate, at 714 million.

• See more from Thursday's WASDE report