More signs of slower economic growth in China are creating worries that the world's second-largest economy may curb its huge appetite for commodities.
Prices for soybeans fell 3 percent to finish Thursday at $16.1875 per bushel Thursday. Copper, platinum and palladium also dropped.
Preliminary reports from a private business survey show China's manufacturing sector slowed in September. A separate report says Europe appears headed for a deepening recession. Europe is China's biggest export market.
China is a major importer of raw materials such as copper, oil and soybeans. Traders worry that demand will drop off if the country's economy continues to slow.
In other trading, prices are higher for silver, gasoline and natural gas. Oil, gold, wheat and corn are lower.