Increases in world grain stocks and estimated 2011 total corn yields surprised grain markets expecting decreases — especially in corn, Purdue Extension agricultural economist Chris Hurt said.

The U.S. Department of Agriculture released its January Crop Production and Stocks reports Thursday (Jan. 12). The bearish report caused corn futures prices to drop to the daily limit of 40 cents. This marks the sixth straight year that the government's January crop updates jolted markets, Hurt said.

"The biggest surprises were the corn production and stocks reports, both of which were higher than expected," Hurt said. "There was a lot of anticipation that both stocks and production would be down."

Estimated corn yields increased from 146.7 bushels per acre in the Nov. 1 report to 147.2 bushels per acre in Thursday's report. The increase of 0.5 bushels per acre represented a total increase in U.S. production of 48 million bushels.

In Indiana, corn yields totaled an estimated 146 bushels per acre, up one bushel per acre since the November report. Ohio, however, was down one bushel per acre, to 158.

U.S. soybean production largely followed the same trend. Final 2011 soybean yields increased 0.2 bushels per acre, resulting in 10 million more bushels of U.S. soybeans than were projected in the November report.