GRAINS-Corn nears one-week low as U.S. harvest weighs

* Harvest pressure, soft cash market pressures corn

* Soybeans rebound after CBOT November nears three-week low

* Wheat higher in technical bounce after three-session skid

(Recasts throughout; updates prices, adds quotes; changes byline, dateline, previous PARIS/SINGAPORE) CHICAGO, Oct 3 (Reuters) - U.S. corn futures fell to their lowest level in nearly a week on Tuesday, pressured by the ongoing harvest and softening cash markets, analysts said. Soybeans were modestly higher, with the November contract rebounding from a near three-week low. Wheat futures firmed in a light technical bounce following a three-session sell-off. As of 12:22 p.m. CDT (1722 GMT), Chicago Board of Trade December corn was down 2 cents at $3.49-1/2 per bushel after dipping to $3.48-3/4, its lowest since Sept. 27. CBOT November soybeans were up 1-3/4 cents at $9.59 a bushel and December wheat was up 3-1/2 cents at $4.48-1/4 a bushel. Corn drifted lower on supply pressure and ideas that the U.S. Department of Agriculture might raise its forecast of the U.S. 2017 corn yield in its next monthly supply/demand report on Oct. 12. The government pegged the corn yield at 169.9 bushels per acre (bpa) last month. "First yield reports are showing for the moment better potential than expected," consultancy Agritel said regarding the corn and soybean harvest. Commodity brokerage INTL FCStone late Monday raised its forecast of the U.S. corn yield to 169.2 bpa, from 166.9 a month earlier. The firm also raised its forecast of the U.S. soybean yield to 49.9 bpa, from 49.8 previously. Additional market pressure stemmed from softening cash values resulting from rising costs for river barges due to low water levels and the expanding Midwest harvest. "It's hard to see the futures market rally when the cash market is weak. Until they get some of these problems resolved and we get some rain, that is weighing as much as anything," said Jim Gerlach, president of Indiana-based A/C Trading. CBOT November soybean futures turned higher after dipping to $9.52-1/2, the contract's lowest since Sept. 13. CBOT wheat futures firmed as the market tried to stabilize following a three-session slide. Plentiful U.S. supplies anchored futures after the USDA last week raised its estimate of U.S. 2017 spring wheat production. Egypt's state grain buyer, the General Authority for Supply Commodities, bought 180,000 tonnes of Russian wheat in an international wheat tender.

CBOT prices as of 12:21 p.m. CDT (1721 GMT):

Last Net Pct Volume

change change

CBOT wheat WZ7 448.00 3.25 0.7 68089 CBOT corn CZ7 349.50 -2.00 -0.6 134595 CBOT soybeans SX7 959.00 1.75 0.2 63706 CBOT soymeal SMZ7 314.20 0.60 0.2 28880 CBOT soyoil BOZ7 32.65 0.13 0.4 35936

NOTE: CBOT December wheat, December 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 Naveen Thukral in Singapore and Gus Trompiz in Paris; Editing by Dale Hudson and Diane Craft)