CHINA BLUES: Prices for industrial metals and oil dropped after China's trade growth plummeted last month. China is a huge importer of raw materials, so slower growth there can prove worrisome to traders.

DOLLAR'S IMPACT: Most commodity prices fell because of a stronger dollar. Commodities are priced in dollars, and a stronger dollar makes them more expensive to traders who use other currencies such as the euro.

WHAT'S NEXT: The U.S. Agriculture Department plans to release an update Wednesday of its closely watched forecast of U.S. and global supplies and demand for major crops and livestock.