GRAINS-Soybeans firm ahead of USDA data; weak China demand caps gains

BEIJING/PARIS, Nov 12 (Reuters) - Chicago soybeans rose on Wednesday as traders adjusted positions ahead of the release of official U.S. data on global supply and demand on Friday, the first update in weeks, but prices were capped by a lack of large Chinese purchases.

The most-active soybean contract on the Chicago Board of Trade (CBOT) Sv1 was up 0.4% to $11.32 a bushel at 1120 GMT.

China has made modest U.S. agricultural purchases since the leaders of the two countries met last month, but traders are awaiting major soybean deals after the White House said Beijing had pledged to buy 12 million tons by year-end.

Meanwhile, the oilseed unit of China's COFCO said on Monday it has signed agreements to buy over $10 billion worth of Brazilian soybeans, soybean oil, palm oil and other agricultural products. The statement did not mention any U.S. purchases.

China is grappling with a glut of soybeans after months of record imports, clouding prospects for large U.S. purchases.

"To see stronger support for U.S. beans, we will need to see China book some business. But rallies will likely be capped with South American sales already made, and ample stocks," said Josh Lawrence, adviser at IKON Commodities in Sydney.

Corn Cv1 edged up 0.1% to $4.32-1/2 a bushel on concerns that dryness and diseases during the growing period for the U.S. corn crop significantly affected yield and quality.

Wheat Wv1 eased 0.7% to $5.47-3/4 a bushel.

"Everyone is awaiting the USDA report and adjusting their positions ahead of it," a European trader said.

A Reuters poll of analysts projected that the USDA will lower its U.S. corn yield estimate to 184.0 bushels per acre (bpa) from 186.7 bpa in its previous September 12 forecast.

It pegged the U.S. soybean yield at 53.1 bpa, down from 53.5 bpa previously.