* Drier weather to open window for U.S. harvest -forecast
* Traders eye talks to reach interim U.S.-China deal
* U.S. sold, shipped soybeans to China last week -USDA (Adds start of U.S. trading, changes byline, previous dateline LONDON)
CHICAGO, Oct 31 (Reuters) - U.S. grain and soybean futures slipped on Thursday on expectations that weather conditions will turn more favorable for harvesting, giving a small break to farmers, traders said.
Drier weather across the U.S. corn belt from Friday through much of next week should allow growers to make better progress after rain and snow caused delays, according to weather firm Maxar. Harvests were already behind schedule after rains and historic floods interrupted plantings this spring.
Farmers are eager to bring their corn and soybeans in from the fields to avoid potential damage. They also want to know the size and quality of their late-planted crops.
"They're looking at a more active harvest pace," said Jim Gerlach, president of broker AC Trading in Indiana.
The most actively traded corn futures contract on the Chicago Board of Trade was down 3 cents at $3.87-3/4 a bushel at 12:10 p.m. CDT (1710 GMT). The most-active soybean contract was down 1/2 cent at $9.30 a bushel. CBOT wheat futures fell 5-1/4 cents to $5.04 a bushel after nearing a three-week low of $5.01.
Traders were also monitoring efforts to resolve the U.S.-China trade war, which has slowed shipments of American farm products. China is the world's biggest soybean importer and bought $12 billion worth of the crop from the United States in 2017, before the dispute.
U.S. President Donald Trump has said China could buy as much as $50 billion of U.S. farm products as part of an interim trade deal. But the demand has become a major sticking point in talks to end the Sino-U.S. trade war, according to several people briefed on the negotiations.
"Both sides claim talks are ongoing and progress is still being made, but trade is no longer interested in proposals, and wants to see actual sales rather than projections," said Karl Setzer, commodity risk analyst for AgriVisor.
Beijing could remove extra tariffs imposed since last year on U.S. farm products to ease the way for importers to buy up to $50 billion worth, rather than direct them to buy specific amounts, said the head of a government-backed trade association in China.
China purchased 481,000 tonnes of U.S. soybeans in the week ended Oct. 24 and shipped more than half a million tonnes, the most since August, according to the U.S. Department of Agriculture. (Reporting by Tom Polansek in Chicago. Additional reporting by Nigel Hunt in London and Colin Packham in Sydney; editing by Uttaresh.V, David Evans and Richard Chang)