Wires

GRAINS-Soybeans drop on U.S. harvest, worries over interim China trade deal

Karl Plume

* Soybeans sink as interim U.S.-China trade deal delayed

* Progressing U.S. harvest weighing on corn, soybeans

* Traders positioning ahead of Friday USDA crop report

* Wheat firms on southern hemisphere crop worries (Rewrites throughout with U.S. market open, adds quote, updates prices, changes byline, previous dateline PARIS/SINGAPORE)

CHICAGO, Nov 6 (Reuters) - U.S. soybean futures slumped on Wednesday on rising supplies from the ongoing U.S. harvest and concerns about a delay in finalizing a "phase one" trade deal with China that could speed imports by the world's top buyer.

Corn also weakened on harvest pressure and dull demand for U.S. supplies, while wheat firmed on technical buying and short-covering as adverse weather has reduced wheat production prospects in the southern hemisphere.

The market's focus has been on Friday's monthly supply and demand report from the U.S. Department of Agriculture (USDA) for a fresh indication on this year's rain-disrupted U.S. corn and soybean crops as well as drought-hit southern hemisphere wheat production.

But news that a meeting between U.S. President Donald Trump and Chinese President Xi Jinping to sign a long-awaited interim trade deal could be delayed until December triggered selling at midmorning, pushing soybeans to session lows.

"Any delay is obviously not a good thing," said Jim Gerlach, president of A/C Trading.

"To be fair, China has been buying U.S. beans and it looks like they will continue. But if you're looking for an acceleration, you're going to need a deal."

A largely favorable harvest weather forecast for the U.S. Midwest over the next two weeks and improved rains in Brazil, which have soothed worries about early planting-season dryness, also weighed on corn and soy.

Chicago Board of Trade (CBOT) January soybean futures were down 5 cents at $9.29-1/4 a bushel at 11:33 a.m. CST (1733 GMT), while December corn was down 1/2 cent at $3.81-1/4 a bushel.

CBOT December wheat rose 3-1/4 cents to $5.18-1/2 a bushel, a 1-1/2 week high, after holding technical chart support at its 20-day moving average.

Wheat prices were supported by concerns about crop output in Argentina and Australia as a tighter grain supply could boost export prospects for U.S. shipments.

Commodity brokerage INTL FCStone said a poll of its clients estimated Australia's 2019/20 wheat crop at 15.54 million tonnes, 19.1% lower than Australia's official estimate of 19.2 million tonnes.

A weaker dollar also lent some support to wheat futures as it makes U.S. shipments cheaper for buyers holding other currencies.

(Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by Aditya Soni, Chizu Nomiyama and Richard Chang)