GRAINS-Soy climbs to one-week high on U.S. yield worries, corn firm

(Recasts; updates prices, adds quotes; changes byline, dateline) CHICAGO, Nov 1 (Reuters) - U.S. soybean futures rose to a one-week high on Wednesday on concerns that the U.S. Department of Agriculture (USDA) might lower its forecast of the domestic soybean yield in a monthly report next week, traders said. Corn firmed along with soybeans, with firm cash markets lending support. Wheat drifted lower but the bellwether December contract held above a contract low set a day earlier. As of 1:05 p.m. CDT (1805 GMT), Chicago Board of Trade January soybeans were up 6 cents at $9.90-3/4 a bushel after reaching $9.95, the contract's highest since Oct. 20. CBOT December corn was up 2 cents at $3.47-3/4 and December wheat was down 3/4 cent at $4.17-3/4. Soybeans climbed on technical selling and fears the U.S. crop, while still a bin-buster, might not be as large as the USDA projected in October. "The yields just are not out there, not quite as high as the government says they are," said Mark Gold, managing partner at Top Third Ag Marketing. The USDA last month lowered its forecast of the U.S. 2017 soybean yield to 49.5 bushels per acre, and some expect the government to trim its estimate again in its next monthly supply and demand reports on Nov. 9. Several private analysts are expected to release updated crop estimates in the coming days, ahead of the USDA's reports. CBOT corn futures were modestly higher on short-covering, but hovered near life-of-contract lows, a factor that has encouraged farmers to store a portion of their harvest and hold out for a rally. "Cash corn in the heart of the Midwest is hovering around $3 (per bushel), and the producer really isn't interested in selling. For the most part, unless you had monster yields, you are below the cost of production," said Don Roose, president of Iowa-based U.S. Commodities. CBOT wheat fell, hovering near Tuesday's contract lows with pressure from abundant world supplies and hefty Russian exports. "The background picture is still bearish, with record large Russian wheat exports still entering the world market with no signs of serious Russian logistics problems." said Matt Ammermann, commodity risk manager at INTL FCStone. "The market is perhaps starting to realize that Russia needs exports to run at record levels every month to clear out its available supplies and this means intense competition for U.S. wheat in export markets."

CBOT prices as of 1:08 p.m. CDT (1808 GMT):

Last Net Pct Volume

change change

CBOT wheat WZ7 417.75 -0.75 -0.2 55842 CBOT corn CZ7 347.50 1.75 0.5 168935 CBOT soybeans SF8 990.75 6.00 0.6 92339 CBOT soymeal SMZ7 313.50 1.70 0.6 44704 CBOT soyoil BOZ7 34.89 0.14 0.4 54562

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

(Additional reporting by Michael Hogan and Naveen Thukral; editing by Elaine Hardcastle and G Crosse)