Investing.com - U.S. corn and soybean futures extended losses from the previous session on Tuesday to trade close to four-year lows amid ongoing expectations of record yields across much of the U.S. grain belt.
On the Chicago Mercantile Exchange, U.S. corn for December delivery slumped 0.25%, or 0.88 cents, to trade at $3.4713 a bushel during U.S. morning hours.
A day earlier, the December corn contract tumbled 2.18%, or 7.6 cents, to settle at $3.4820.
Corn futures hit $3.4360 a bushel on September 4, a level not seen since June 2010.
Corn prices have been under heavy selling pressure in recent months as expectations of record yields across much of the U.S. grain belt drove prices lower.
According to the U.S. Department of Agriculture, the corn harvest will total 14.03 billion bushels, which would break last year's record of 13.93 billion.
The USDA is set to update is forecast on September 11. According to market analysts, the agency could raise its U.S. production estimate to 14.27 billion bushels.
Meanwhile, U.S. soybeans for November delivery dipped 0.4%, or 4.0 cents, to trade at $10.0400 a bushel.
The November soy contract lost 1.27%, or 13.0 cents, on Monday to end at $10.0840.
Prices of the oilseed fell to $10.0120 a bushel on September 4, the lowest level since September 2010, amid ongoing indications this year's crop would be by far the largest in history.
The USDA could say that this fall's U.S. harvest will reach an all-time high of 3.89 billion bushels, up from a previous estimate of 3.82 billion bushels in August.
Elsewhere on the CBOT, U.S. wheat for December delivery slumped 0.57%, or 3.02 cents, to trade at $5.3038 a bushel.
The December wheat contract hit a five-week low of $5.2420 on Monday as continued strength in the U.S. 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 U.S. crop, followed by soybeans, government figures show. Wheat was fourth, behind hay.