Wheat rises on Black Sea tensions, but off three-week peak

* Traders await USDA plantings estimates due Thursday

* Soy rises on short-covering, analysts say

* Wheat swings amid technical selling, Black Sea tensions

(Updates headline, bullets and paragraph 1; adds analyst quote in paragraph 3, closing prices in 5, and analysts in 8)

CHICAGO, March 25 (Reuters) - Chicago Board of Trade (CBOT) wheat futures settled up on Monday, but fell short of the three-week high that prices hit early in session.

Soybeans also rose as dealers adjusted positions ahead of a U.S. Department of Agriculture (USDA) planting intentions report due on Thursday, while corn futures inched downward during choppy trading.

Tensions in the Black Sea region and concerns about the potential for reduced exports from top-supplier Russia spiked wheat prices before technical selling weighed on the market, analysts said.

"We traded up and hit some technical sell orders which caused everything to reverse," said Karl Setzer, partner at Consus Ag Marketing.

CBOT most-active wheat settled up 1/4 cent at $5.55 a bushel, after earlier touching $5.67, its highest price since March 4. Soybeans settled up 16-3/4 cents at $12.09-1/4 a bushel, while corn settled down 1-1/2 cents to $4.37-3/4 a bushel.

Market chatter about a disagreement between Russia and a leading private exporter helped push wheat futures upward, analysts said. Russian attacks on Ukrainian energy infrastructure over the weekend and a dry weather forecast for the Black Sea region also boosted prices, analysts said.

In the soy market, analysts attributed gains to short-covering ahead of Thursday's USDA data. They expect further positioning, while ample global supplies keep prices anchored.

Analysts surveyed by Reuters expect soy plantings of 86.530 million acres, up 2.93 million acres from last year, and corn plantings of 91.776 million acres, down from 94.641 million acres last year.

The USDA is also scheduled to report quarterly U.S. grain stocks data on Thursday.

"I expect sideways, choppy trade until the USDA report comes out," Jack Scoville, vice president of Price Futures Group, said.

Wheat, soybeans and corn are vulnerable to short-covering rallies after speculators built up big net short positions. (Reporting by Heather Schlitz in Chicago. Additional reporting by Michael Hogan in Hamburg and Peter Hobson in Canberra; Editing by Mark Potter, Barbara Lewis and Sandra Maler)