GRAINS-Corn, soy futures sag on expectations for big U.S. harvest

(New throughout; updates prices, adds quotes, changes byline, dateline, previous LONDON) CHICAGO, Aug 22 (Reuters) - U.S. corn futures fell about 2 percent on Wednesday and soybeans declined almost as much, pressured by strong yield prospects in the Midwest crop belt, traders said. Wheat futures also eased, with the Chicago Board of Trade December contract hitting its lowest in four weeks. CBOT December corn settled down 7-1/2 cents at $3.66-3/4 per bushel after dipping to $3.66-1/2, its lowest since Aug. 13. CBOT November soybeans ended down 15-3/4 cents at $8.70-1/4 a bushel. Corn fell the most on a percentage basis as traders focused on favorable weather and bearish findings from the annual Pro Farmer Midwest Crop Tour. The four-day tour so far has projected above-average corn yields for Nebraska, South Dakota, Indiana and Ohio, and scouts were expected to release a forecast for Illinois, the No. 2 U.S. corn producer, later on Wednesday.

"We are looking at a big crop, and that's what is weighing on things so far. All the yield reports we are hearing are really good, and there is no catalyst for markets to rally," said Brian Hoops, analyst with Midwest Market Solutions. A round of showers that crossed much of the Midwest this week has bolstered prospects for soybeans in particular. Soybean futures came under additional pressure from doubts that trade talks between the United States and China, the world's biggest soy buyer, would result in much progress.

"A lot of traders don't think these trade talks are going to yield anything for soybeans," said Terry Reilly, senior analyst with Futures International. CBOT wheat futures fell, with December settling down 2-1/2 cents at $5.45-1/4. The contract held above support at its 50-day moving average near $5.38-1/2 and traded higher for a portion of the session before turning lower toward the close. "On the world market, we are not competitively priced. Unless Russia or Ukraine backs off, the door is not open for us to export," Hoops said. Traders continued to mull wheat export prospects from top global supplier Russia after adverse weather reduced this year's crop. Russia's wheat exports could fall to 31.5 million tonnes in 2018/19 from a record 42 million last season, consultancy Agritel said. Wheat prices rose last week on concerns that Russia may look to curb exports, although the country's agriculture minister said on Tuesday he saw no reason for now to do so. Some traders suspect Russian exporters may speed up grain shipments in the next few months in anticipation that the government could move to limit exports sometime after December.

CBOT settlement prices:

Net Pct Volume

Last change change

CBOT wheat WZ8 545.25 -2.50 -0.5 72373 CBOT corn CZ8 366.75 -7.50 -2.0 150449 CBOT soybeans SX8 870.25 -15.75 -1.8 99583 CBOT soymeal SMZ8 323.20 -4.00 -1.2 48700 CBOT soyoil BOZ8 28.56 -0.39 -1.3 49429

NOTE: CBOT December wheat and corn and November soybeans shown in cents per bushel, December soymeal in dollars per short ton and December soyoil in cents per lb.

(Additional reporting by Nigel Hunt in London and Colin Packham in Sydney; Editing by David Evans and James Dalgleish)