The government data also showed a mild reduction in the US soybean crop production forecast, which was expected but did offer slight support to the soybean futures market. Wheat futures saw selling pressure mainly due to the sharp losses in the corn futures market.

Traders expected the government to lower the US corn crop size slightly, but instead USDA raised production by 80 million bushels from August's report, to 13.843 billion bushels. The average US corn yield was raised to 155.3 bushels per acre, compared to 154.4 in August's USDA report. USDA also reduced old-crop corn carryover to 661 million bushels, which was lower than market expectations.

Soybean futures prices were given a slight boost in the wake of a neutral to mildly bullish USDA monthly crop report. The USDA trimmed the size of the US crop to 3.149 billion bushels versus 3.255 billion bushels in the August report. The average US soybean yield was pegged by USDA at 41.2 bushels per acre, versus 42.6 in August. USDA left its 2012-13 soybean carryover level at a tight 125 million bushels.

December soft red winter wheat futures prices were lower at midday Thursday and hovering near the contract low of $6.35 1/2 a bushel scored in August, following the USDA report. Wheat continues to be a follower of corn and soybeans. USDA left its all US wheat crop carryout estimate unchanged at 718 million bushels.