GRAINS-Corn, wheat fall to contract lows, soy sags on Argentine weather

(New throughout; updates prices, adds quotes, changes byline, changes dateline from previous PARIS/SYDNEY) CHICAGO, Dec 11 (Reuters) - U.S. corn and wheat futures fell to life-of-contract lows on Monday, anchored by plentiful global grain supplies, and soybeans sagged as forecasts called for beneficial grains in Argentina, analysts said. At 12:47 p.m. CST (1827 GMT), Chicago Board of Trade March corn was down 3-1/4 cents at $3.49-1/2 per bushel after hitting a contract low at $3.48-1/4. CBOT March wheat was off 6-3/4 cents at $4.12-1/4 a bushel after dipping to $4.10-3/4, the lowest price for a most-active contract since Jan. 4. January soybeans fell 7 cents at $9.82-3/4 a bushel. Wheat posted the biggest decline in percentage terms, pressured by bumper global inventories. A higher-than-expected official estimate of Canadian output last week added to bearish sentiment, offsetting doubts over the weather-hit Australian harvest. The CBOT March wheat contract was on track for its sixth straight lower close and had a knock-on effect on corn futures. "Continual contract lows in wheat are not good news for corn," said Ted Seifried, chief market strategist with Zaner Ag Hedge. Soybeans declined on light weekend rains in crop areas of Argentina and forecasts for more moisture next week, which eased worries about dryness stressing crops in the South American country. Argentina is a major soybean producer and the world's top exporter of soymeal and soyoil. "Light showers favored Cordoba and north-western Santa Fe over the weekend, but amounts were too light to significantly improve soil moisture," MDA Weather Services said in a note to clients. "Showers should become more widespread and heavier during the 6- to 10-day period, which would finally lead to some notable improvements," the MDA note added. Additional pressure stemmed from the slow pace of U.S. soybean exports despite a record-large harvest this autumn. Export bookings of U.S. soybeans are running behind the year-ago pace, while the U.S. Department of Agriculture has projected a year-on-year increase for the 2017/18 marketing year that began Sept. 1. "We are still falling behind, and that's a growing concern. Can we hit the USDA's (2017/18 soy export) number? It's too early to say we can't, but it's becoming less likely," Seifried said. The USDA could revise its soy export forecast as soon as Tuesday, when it is set to release the monthly supply/demand report.

CBOT prices as of 12:46 p.m. CST (1846 GMT):

Net Pct Volume

Last change change

CBOT wheat Wc2 412.75 -6.25 -1.5 60777 CBOT corn Cc2 349.75 -3.00 -0.9 120634 CBOT soybeans Sc1 983.00 -6.75 -0.7 102242 CBOT soymeal SMc2 328.00 -3.70 -1.1 41380 CBOT soyoil BOc2 33.41 -0.21 -0.6 40120

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

(Additional reporting by Colin Packham in Sydney and Gus Trompiz in Paris; Editing by Gareth Jones and Jeffrey Benkoe)