GRAINS-Soybeans firm on China demand, South America supply worry

* Soybeans hit near 1-month high

* Soybeans firm on Chinese demand, South American weather fears

* Corn easier while wheat firm on tight supplies

(Updates prices, adds Paris dateline)

PARIS/SYDNEY, Dec 6 (Reuters) - U.S. soybeans rose to their highest in almost a month on Thursday due to expectations of a jump in Chinese demand and concerns over supplies from Argentina, where rain is threatening crop yields.

Corn gave back some of its gains from the previous session, while wheat edged slightly higher, supported by tight supplies.

Chicago Board of Trade January soybeans rose 0.34 percent to $14.84-1/4 a bushel by 1220 GMT, down from a session high of $14.91 a bushel which was the highest since Nov. 9. Soybeans rose 1.6 percent on Wednesday, the biggest daily jump in more than a week.

"Soybeans are enjoying some strong fundamentals," said Lynette Tan, investment analyst at Phillip Futures in Singapore.

"There are expectations of increased exports to China and there are weather concerns in South America, which may lower production."

March corn fell 0.13 percent to $7.56-3/4 a bushel, after rising 0.8 percent the previous day.

March wheat was 0.2 percent higher at $8.61-3/4 a bushel after closing 0.4 percent up in the previous session.

In Europe, benchmark January on Paris-based milling wheat futures <0#BL2:> was 0.2 percent higher in thin trade, helped by the rise in Chicago.

The wheat harvest in Argentina is expected to be smaller than expected and of poorer quality this season as farmers slog through waterlogged fields, trying to save their crops from toxic fungi bred by too much rain.

Talk is increasing in the market that the world's fifth-largest exporter could restrict exports in the coming weeks, analyst FCStone said.

CHINESE BUYING SPREE?

Traders said market talk suggested China, the world's largest consumer of the oilseed, had acquired up to six cargoes of U.S. soybeans this week from sellers in the Pacific Northwest, and that it would soon seek more volumes.

U.S. exporters have been competing with domestic processors for soybeans on the cash market as processors are reaping high profit margins from crushing raw soybeans into soymeal, a key source of protein in animal feed, and soyoil, used in foods and soy-based biodiesel fuel.

This increase in demand comes as wet weather in third-largest soybean supplier Argentina continues to delay plantings, which could threaten yields. The Commodity Weather Group on Wednesday forecast more rain for up to the next two weeks.

Soybeans also got additional support after the senate in Paraguay, the world's No. 4 supplier of the oilseed, approved a bill on Tuesday that would impose a 10 percent tax on soybean exports despite objections from farmers.

But news that Brazil's government had confirmed its forecast for a record soybean crop of 82.6 million tonnes on Thursday, brushing off concerns over dry weather in the southern producing regions, led soy futures to pare some of their gains.

Global food markets face further volatility in 2013 as stocks and supply of key cereals have tightened, the United Nations food agency said on Thursday, even as world food prices fell for a second month in November to their lowest since June.

(Editing by Anthony Barker)