Chicago corn and wheat lost more ground on Friday after higher than expected area estimates reinforced the prospect of more plentiful supplies in the year ahead.
Wheat was holding near a six-month low touched on Thursday following the U.S. Department of Agriculture's (USDA) acreage report, while corn was close to an 11-week low hit in the previous session.
Soybeans ticked lower after rallying in the previous session when the market focused on a smaller than expected increase in the USDA's acreage for the oilseed, shrugging off a higher than anticipated reading for quarterly stocks.
The Chicago Board Of Trade most-active corn contract, which touched an 11-week low of $3.65-1/4 a bushel on Thursday, was down 0.3 percent at $3.70-1/4 by 1208 GMT on Friday.
Wheat was down 1.1 percent at $4.40-1/2, trading close to Thursday's low of $4.36, the weakest since June 2010, and staying on course for a fourth straight weekly decline.
"The supply and demand situation is bearish for grains and more so for corn as feed wheat is going to eat into its market share," said Phin Ziebel, agribusiness economist at National Australia Bank in Melbourne.
The USDA said domestic all-wheat plantings totaled 50.816 million acres, topping analysts' forecasts for 49.869 million and the agency's March estimate of 49.559 million.
Corn seedings were 94.148 million acres, above the high end of analyst forecasts, and confounding expectations the USDA estimates would show that the corn area had been trimmed in favor of soybeans following a spring rally in soy prices.
In a separate quarterly stocks report, the USDA said corn inventories as of June 1 were the highest since 1988 while soybean stocks were the third largest ever.
Soybean futures were down 0.5 percent at $11.47 a bushel after rallying to a two-week high on Thursday.
The USDA acreage report showed farmers planted a record 83.688 million soybean acres, above the government's March forecast of 82.236 million but below analysts' estimates for 83.834 million.
Despite a bigger than expected stocks number for soybeans, analysts said supply of the oilseed was less comfortable than for corn and wheat.
"The soybean balance - despite a 1.5 million acre increase from the March estimate - is still relatively tight, and only with above-trend yields a stock reduction in the U.S. can be avoided," Rabobank analysts said in a note.