GRAINS-Chicago soybeans dip on absent China buying; trade talk optimism supports

BEIJING, Sept 17 (Reuters) - Chicago soybeans eased on Wednesday as the U.S. harvest began without any fresh purchases from top buyer China, though optimism over U.S.-China trade talks lent some early support.

As of 0630 GMT, the most active soybean contract on the Chicago Board of Trade (CBOT) Sv1 fell 0.43% to $10.45-1/4 per bushel.

Prices had drawn support from news that U.S. President Donald Trump and Chinese President Xi Jinping are scheduled to speak by phone on Friday. China has yet to book any U.S. soybeans from the autumn harvest.

U.S. farmers had harvested 5% of the soybean crop and 7% of the corn crop, the United States Department of Agriculture said in a weekly progress report on Monday.

Market participants are awaiting more clarity on U.S. soybean and corn crop sizes, with some expecting the USDA to trim its national yield estimates for both crops in its mid-October report due to recent dry weather.

"Enough evidence was of declining yield potential to justify modest reductions in USDA's official September yield estimates," said Arlan Suderman, chief commodities economist at StoneX, in a note on Tuesday.

"But the bottom line is that we simply won't know this year's yields until we see the impact of late summer weather on seed size."

Despite possible cuts, U.S. corn production is still projected to be large. CBOT corn Cv1 fell 0.23% to $4.28-1/2 a bushel.

Wheat Wv1 slipped 0.23% to $5.32-3/4 per bushel, pressured by ample global supply, though brisk export demand lent some support.

On Tuesday, France's farm ministry raised its estimate of this year's soft wheat harvest to 33.3 million metric tons, up from 33.1 million projected a month ago and 29.8% higher than the 2024 crop.