(Adds U.S. market activity)

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Chinese purchases of Argentine soy loom over US prices

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US farmers advance soy and corn harvests

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CBOT corn and wheat futures ease

By Tom Polansek

CHICAGO, Sept 26 (Reuters) - Chicago Board of Trade

soybean futures were unchanged on Friday, headed for a second

weekly loss after China made large purchases of Argentine

supplies this week at the expense of U.S. crops.

The market was unchanged after falling hard earlier this

week on concerns about China's lack of demand for U.S. soybeans.

Wheat and corn futures were trading lower.

After Buenos Aires briefly suspended grain export taxes this

week, around

40 Argentine soybean cargoes were registered for export in

November and December, mostly headed to China, two traders told

Reuters. On Thursday, Argentina reinstated export taxes.

Still, the buying frenzy by Chinese importers was a fresh

blow for U.S. soybean farmers, who have been shut out of exports

to top market China during the current harvest season as trade

war tariffs make their beans prohibitively expensive for Chinese

buyers.

"That news has been digested and the taxes have been

implemented, so soybeans should have seen the bulk of selling

from that news item," said Brian Hoops, president of Midwest

Market Solutions.

The most-active soybean contract on the Chicago Board of Trade

was unchanged at $10.12-1/4 a bushel by 12:25 p.m. CDT

(1725 GMT).

When asked if China would purchase U.S. soybeans, a Chinese

commerce ministry spokesperson said Washington

should remove

what China described as unreasonable tariffs and create

conditions to expand bilateral trade.

The advancing U.S. soy and corn harvests have put further supply

pressure on prices, though doubts over the size of corn yields

have lent support to that market.

The U.S. Department of Agriculture is slated to issue a weekly

update on harvesting progress on Monday.

"Corn is facing an active harvest weekend ahead with

weather turning warmer and drier," Hoops said. "The window

should be wide open for corn and soybean harvest."

CBOT wheat was down 8 cents at $5.19 a bushel, and

corn dropped 4 cents to $4.21-3/4 a bushel.