GRAINS-Soy and corn ease as traders await US crop report

By Renee Hickman

CHICAGO, Sept 10 (Reuters) - Chicago soybeans and corn dipped on Wednesday as traders squared positions ahead of the U.S. Department of Agriculture's global supply and demand report due on Friday, analysts said.

Meanwhile, wheat dropped on falling global demand.

The USDA is expected to trim U.S. soybean and corn yield forecasts on Friday, though production is still projected to remain high.

In its previous outlook, the USDA pegged corn output at a record high and soybean harvests at bumper levels.

"There's a real concern that the government could lower exports because Chinese business is non-existent so far," said Don Roose, president of grain and livestock investment management company U.S. Commodities.

U.S. farmers are missing out on billions of dollars in soybean sales to China halfway through their prime marketing season as stalled trade talks halt exports and rival South American suppliers fill the gap, traders and analysts said.

In Brazil, the world's top soybean producer, soy exports are forecast at 7.43 million tons in September, up from the 6.75 million tons projected a week earlier, according to Brazilian grain exporters' association ANEC.

On the Chicago Board of Trade (CBOT), the most active soybean contract Sv1 slipped 6-1/4 cents to $10.25 a bushel by 12:41 p.m. CST (1741 GMT).

Corn Cv1 dropped 2-1/2 cents to $4.17-1/4 a bushel and wheat Wv1 was down 4-1/4 cents at $5.16 a bushel.

Roose said wheat demand was low because too many countries - from Australia to Russia - have just enough stocks.

In Russia, the world's biggest wheat supplier, export prices continued to decline last week as some farmers stepped up harvest sales.

Friday's USDA report is expected to show a slight decrease in U.S. wheat ending stocks while world wheat stocks are forecast to rise, a Reuters poll of analysts showed.