A two-week rally in U.S. soybean futures ended Monday as traders decided to book profits amid concerns over the strength of Chinese demand.

Soybeans for May delivery, the most actively traded contract, ended down 8 cents, or 0.6%, to $13.25 a bushel at the Chicago Board of Trade. March soybean futures fell 9 cents, or 0.7%, to $13.19 1/4 cents a bushel.

Soybean futures had climbed for the previous 10 straight trading days, surging on drought damage to the Brazilian crop and expectations for growing U.S. export demand.

Yet new concerns about the strength of Chinese demand for U.S. soybeans emerged after Chinese Premier Wen Jiabao Monday said the country aims for economic growth of 7.5% this year, compared to its target of 8% in past years, though the target is largely symbolic. China is the world's largest importer of soybeans.

Further support came from traders selling soybean futures to exit positions speculating the market would rise and book profits from the recent rally. In addition, analysts said a disappointing crop in South America is already built into prices, setting the market up for a potential sell off if the U.S. Department of Agriculture's monthly crop report out Friday isn't as grim as expected.

"The market looks like it might've been getting a little bit tired," said Anne Frick, senior oilseed analyst at Jefferies-Bache.

Corn futures gained Monday. The contract for May delivery, the most actively traded, rose 5 3/4 cents, 0.9%, to $6.60 3/4 cents a bushel. March corn ended up 7 1/4 cents at $6.66 1/4 cents, the highest level since September for front-month contract.

Analysts said market participants were buying back futures contracts for corn, exiting so-called spread trades in which investors were speculating prices for soybeans would rise at the same time corn futures fell.

Corn futures also found support from tight supplies in U.S. cash markets where prices are rising to provide farmers an incentive to sell more corn.

"They're trying to pry corn out of the farmer's hand," said Linn Group analyst Jim Riley.

Still, ongoing concerns about South American production is likely to limit declines in soybean futures, while the upside in corn futures is capped for now by expectations farmers will plant a massive crop this year.

Meanwhile, wheat futures ended mixed Monday, pressured by the declines in soybean futures and ongoing strong global supplies.

"Fundamentals in terms of wheat still remain relatively bearish with the world amply supplied," says Dan Basse of AgResource.

CBOT March wheat futures fell 3 cents to $6.67 3/4 cents a bushel while March futures at the Kansas City Board of Trade dropped 5 cents to $7.05 1/2 cents. March wheat rose 3 1/2 cents to $8.31 1/4 cents at the MGEX in Minneapolis.

-By Owen Fletcher, Dow Jones Newswires; 312-750-4120; owen.fletcher@dowjones.com