* Traders see signs of lessening U.S.-China trade tension
* Rains fall short of expectations in dry Argentina
* Corn, wheat ease after one-week highs (Updates with closing prices, adds analyst comments)
CHICAGO, March 26 (Reuters) - U.S. grain and soybean futures touched one-week highs on Monday as fears eased that a trade war with China will take a bite out of crop exports.
The markets ultimately closed lower on technical selling and profit-taking, analysts said. However, traders were breathing easier after China's Commerce Ministry on Friday did not mention potential duties on soybeans when it said the Chinese government may impose additional tariffs on U.S. products including pork.
U.S. farmers and exporters have been worrying for months that China might restrict U.S. soy imports due to rising bilateral tensions. China imported $19.6 billion worth of U.S. farm goods last year, with soybeans accounting for $12.4 billion.
"Since corn and beans were not mentioned in the retaliatory measures, the market appears to be a bit more confident," said Tomm Pfitzenmaier, a founder of Iowa-based broker Summit Commodity Brokerage.
The most-active soybean contract set a one-week peak of $10.40-1/4 a bushel at the Chicago Board of Trade before ending down 2-3/4 cents at $10.25-1/2.
CBOT corn touched a one-week peak at $3.80-3/4, before slipping 3-1/4 cents to $3.74 a bushel. CBOT wheat closed down 6 cents at $4.54-1/4 a bushel after hitting a one-week high at $4.63-3/4.
The potential for China to impose tariffs on U.S. farm products should continue to keep the markets on edge, traders said. On Friday, soybeans dropped to their lowest price in more than a month on worries about trade disruptions.
"That's what everybody is talking about: What happens if we get into a trade war with China?" said Steve Georgy, president of Allendale, a brokerage in Illinois. "That's still looming."
Underpinning prices were lighter-than-expected rains over the weekend in Argentina, the world's No. 3 exporter of corn and soybeans. Farmers there have grappled for four months with unrelenting dryness, increasing concerns that large global supplies will tighten.
On Thursday, the U.S. Department of Agriculture (USDA) will issue data on U.S. grain stocks and estimates for spring U.S. plantings. Farmers are expected to plant more soy than corn for the first time since 1983, according to a Reuters poll.
Uncertainty about the data helped weigh on futures prices, Georgy said.
"It's a risk-off mentality from funds that may escalate going in to Thursday," he said.
The United States is the world's biggest producer and exporter of corn, and the No. 2 soybean exporter after Brazil. (Additional reporting by Gus Trompiz in Paris and Naveen Thukral in Singapore; Editing by G Crosse and Sandra Maler)