The price of corn dropped as weather conditions remain favorable for the crop.
Corn for July delivery dropped 1.5 cents, or 0.3 percent, to $4.43 a bushel.
The price of the grain has plunged in the last two months as rains in the corn growing regions of the U.S. have been light and temperatures remained moderate. The U.S. Department of Agriculture is forecasting a record crop this year.
"The main part of the corn belt looks very good," said Todd Hultman, a grains analyst at DTN.
In other trading of agricultural products, wheat and soybeans also fell.
Wheat dropped 8.25 cents, or 1.4 percent, to $5.81 a bushel and soybeans fell 9.25 cents, or 0.7 percent, to $12.25 a bushel.
Most metals climbed, led by platinum. Gold and silver also ended the day higher.
Platinum for July climbed $15.30, or 1.1 percent, to $1,471.90 an ounce. Palladium for September rose $7.75, or 0.9 percent, to $830.40 an ounce.
Gold rose $2.90, or 0.2 percent, to $1,321.30 an ounce. Silver for July gained 12.70 cents, or 0.6 percent, to $21.04 an ounce. Copper was little changed at $3.15 a pound.
The price of oil fell 14 cents, or 0.1 percent, to $106.03 a barrel as traders monitored the insurgency roiling Iraq for any signs it could affect the country's oil production and exports.
In other energy trading, wholesale gasoline rose 2 cents, or 0.6 percent, to $3.13 a gallon, natural gas gained 9 cents, or 2 percent, to $4.54 per 1,000 cubic feet. Heating oil rose 1 cent, or 0.3 percent, to $3.04 a gallon.