Corn is falling after crop inspections in the Midwest added to evidence that the U.S. will produce a strong harvest this year.
Traders are following the annual Professional Farmers of America Midwest Crop Tour to glean more information about the prospects for this year's crop. The group said on its website Tuesday that "stellar corn yields" are forecast for South Dakota and that the Ohio crop would be better than average.
December corn fell 10 cents, or 2.1 percent, to $4.76 a bushel.
Soybeans and wheat also dropped.
Gold and copper rose, while silver fell.
The price of oil fell the most in two months, $2.14, or 2 percent, to $104.96, as traders waited for the U.S. central bank to signal when it will start scaling back its monetary stimulus.