U.S. corn output may fall below 12 bln bushels: group

SIEM REAP, Cambodia (Reuters) - Corn output in the United States this year could miss a government forecast by up to 3 percent, hit by shrinking planting areas and yields crimped by excess rain at the start of sowing, an industry official said.

Production could drop below 12 billion bushels, or more than 10 percent from last year's figure of 13.3 billion, said Julius Schaaf, a representative of the Iowa farmers who grow more than a tenth of the crop in the world's largest producer of the grain.

"The range is going to be 11.9 to 12.2 billion bushels," Schaaf, chairman of the Iowa Corn Promotion Board, said on Wednesday on the sidelines of an industry conference in Cambodia.

"In my experience of 30 years of farming, looking back and looking at calculations, you don't have the full yield potential this year," Schaff told Reuters in an interview, adding that yields in Iowa could fall to 169 bushels per acre from 171 bushels last year.

The U.S. Department of Agriculture (USDA), which forecast in August corn production of 12.3 billion bushels this year, is expected to unveil new crop estimates on September 12.

Commodity brokerage firm FC Stone on Tuesday forecast the 2008 corn crop at 12.159 billion bushels, reflecting an average corn yield of 153.4 bushels per acre.

Benchmark corn prices on the Chicago Board Of Trade Cc1 have lost a quarter of their value since hitting a record high of $7.65 per bushel in June.

By 0344 GMT on Wednesday, Chicago corn futures were trading up 0.5 percent at $5.56 per bushel in Asian electronic trading.

Schaaf, who grows corn on his 1,600-hectare (4,000-acre) farm, said early spring rains had washed away fertilizer spread on the land.

"With all the rainfall we have had in Iowa this spring, we lost nitrogen applied to our fields for the corn crop and plants did not have that much ability to draw nitrogen because of the shallow root system," he said.

"Planting dates are one to one-and-half weeks later than last year and historically the planting dates relate very closely to final yields."

Corn has been planted on 84 million acres, down from 93 million acres last year as farmers switched to soybeans due to attractive prices, Schaaf added.

(Reporting by Naveen Thukral; Editing by Clarence Fernandez)