The price of corn is falling ahead of a key government report that may show supplies of the grain are abundant because of a record crop last year.
Corn for March delivery fell 5 cents, or 1.2 percent, to $4.12 a bushel, its lowest price since August 2010.
U.S. farmers produced a record corn crop last year and the U.S. Department of Agriculture will release its latest estimate of crop supply and demand on Friday. Forecasts for a strong harvest in Brazil are also weighing on prices.
Wheat for March delivery fell 4.5 cents, or 0.8 percent, to $5.84 a bushel. Soy beans for the same month rose 4.5 cents, or 0.4 percent, to $12.74.
Gold, silver and platinum all rose. Copper and palladium fell.
Oil edged lower.