June 30 (Bloomberg) -- Corn plunged by the Chicago Board of Trade’s limit after a government report showed U.S. farmers planted more acreage with the grain than estimated in March. Wheat and soybeans also slid on signs of increasing supplies.

About 87.035 million acres were planted with corn, the U.S. Department of Agriculture said today in a report following a survey of farmers. That was up 2.4 percent from the March forecast on growers’ intentions and 1.2 percent higher than 85.982 million last year. The average estimate of 24 analysts in a Bloomberg News survey was 85.16 million acres.

“It’s a surprise primarily because of all the corn acres they put back into the mix,” said Jim Hemminger, a risk- management specialist at Top Third Ag Marketing in Chicago. “Another surprise was the increase in spring-wheat and durum acres. With all the planting delays we were hearing about, I expected” acreage to be lower, he said.

Corn futures for December delivery tumbled by the maximum of 30 cents, or 7.6 percent, to $3.6725 a bushel on the CBOT. In the second quarter, the price dropped 9.3 percent, the fourth straight decline.

The most-active contract has slumped 51 percent in the past year. On June 27, 2008, the price rose to a record $7.9925.

The corn report today showed “an awfully big acreage number and suggests inventories will be more comfortable,” said Tim Emslie, a research manager at Country Hedging Inc. in Inner Grove Heights, Minnesota.

The U.S. is the world’s largest exporter of corn, soybeans and wheat. Corn is the nation’s biggest crop, valued at $47.4 billion in 2008, followed by soybeans, hay and wheat, government figures show.

Soybean futures for November delivery fell 2.5 cents, or 0.3 percent, to $9.81 a bushel. Earlier, the price touched $9.435, the lowest since April 1.

June Slump

In June, the price dropped 17 percent, the most since September. In the quarter, soybeans gained 3.1 percent as Chinese demand for U.S. shipments rose amid a slump in South American output.

U.S. farmers will sow a record 77.483 million acres with the oilseed, up 2.3 percent from 75.718 million last year, the USDA said. In March, the agency said farmers intended to plant 76.024 million acres.

Wheat futures for July delivery dropped 17.25 cents, or 3.3 percent, to $5.1175 a bushel. The price earlier touched $4.9575, the lowest since Dec. 12.

About 13.77 million acres were seeded with spring wheat, the USDA said. That topped the 13 million projected by analysts surveyed by Bloomberg News last week. Total inventories on June 1 were 667 million bushels, doubling from a year earlier.

‘Profit Incentive’

“When given the opportunity and profit incentive, farmers will plant more acres,” said Dan Basse, the president of AgResource Co. in Chicago. “Farmers changed their plans and seeded more acres in the western Midwest because of favorable weather.”

Hog futures rallied today as the crop reports signaled lower costs for livestock feed. Cattle pared gains to close little changed.

“This is a great day for the cattle and hog producers and the dairyman,” Basse said. “Corn, soybeans and wheat all made their seasonal highs earlier this month. Given favorable weather for the remainder of the growing season, we should have a breathable cushion of inventories.”

To contact the reporters on this story: Jeff Wilson in Chicago at jwilson29@bloomberg.net; Tony C. Dreibus in Chicago at Tdreibus@bloomberg.net.

Last Updated: June 30, 2009 16:04 EDT