CBOT July soymeal dropped 1.3% to $347.10 a short ton and December soyoil fell 0.8% to 57.50 cents a pound.
U.S. rice futures settled lower as selling engulfed the grain markets. Wheat, which exerts the most influence on rice because both grains are global food staples, sank more than 5% to a seven-month low. CBOT September rice lost 22 1/2 cents or 1.5%, to $14.62 1/2 per hundredweight.
Ethanol futures sank as corn prices dropped by their one-day limit. Spillover pressure from corn overshadowed federal data showing ethanol production last week increased 2.3% to 901,000 barrels a day. Ethanol for December delivery lost seven cents, or 2.8%, to $2.389 a gallon. Oat futures fought off heavy selling that hit other grain markets, with the September contract slipping 2 1/2 cents, or 0.7%, to $3.59 a bushel.
-Tom Polansek contributed to this article