With expectations of record yields across the US grain belt, US corn and soybean futures traded near the lowest level in four years on September 4, according to Investing.com.
A day earlier, corn prices tumbled 3.23%, or 11.6 cents, to settle at US$3.5200 a bushel after a pair of private-sector reports reinforced expectations for a record harvest.
Prices fell to a four-year low of US$3.4800 a bushel on August 12 after the USDA estimated the corn harvest at 14.03 billion bushels, which would break 2013's record of 13.93 billion bushels.
The agency also said that it expected average corn yields of 167.4 bushels per acre, above an all-time high of 164.7 bushels in 2009.
The November soy contract fell to US$10.1240 a bushel on September 3, a level not seen since September 2010, as ongoing expectations for a record US harvest weighed.
According to the USDA, this fall's harvest will reach an all-time high of 3.82 billion bushels.
Elsewhere on the CBOT, US wheat for December delivery slumped 0.42%, or 2.27 cents, to trade at US$5.3313 per bushel, the lowest since August 14.
A day earlier, wheat futures plunged 3.47%, or 19.2 cents, to settle at US$5.3560 a bushel, as continued strength in the US dollar and receding concerns over a disruption to supplies from the Black Sea-region weighed.
A stronger dollar makes domestic wheat less competitive on the world market.
Corn is the biggest US crop, followed by soybeans, government figures show. Wheat was fourth, behind hay.