U.S grain and soybean futures ended higher Wednesday, rallying for the second straight day, with a weaker dollar and global crop concerns fueling advances.

Soybean futures continued to recover from declines earlier in the week, with buyers energized by confirmation of fresh Chinese export demand and lingering uncertainty about South American crops.

News that China purchased 120,000 metric tons of U.S. soybeans was welcome news for the market, said Mike Zuzolo, president Global Commodity Analytics and Consulting. "The announced sale was confirmation of the U.S.'s number 1 export demand base returning after the Lunar New Year holidays," Zuzolo said.

Analysts had anticipated fresh demand arising from a jump in export basis levels Tuesday and needed that validation, he added. Cash basis levels at the Louisiana Gulf rose by 3 cents Wednesday, sparking new talk of additional export business taking place.

Soybean futures were also buoyed by supportive external market influences, with weakness in the U.S. dollar attracting broader based buying across commodities.

Meanwhile, there remains enough uncertainty about South American yield losses to keep prices underpinned, particularly with well-known private forecasters continually lowering crop estimates for South America, Zuzolo said.

Otherwise, futures remain within recent trading ranges. Investors are not shaken by recent price moves, as the nearby March contract stays within a month long wide trading range from $11.85 to $12.35 a bushel.

CBOT March soybeans ended up 16 1/4 cents to $12.15 1/4 per bushel.

U.S. wheat futures rallied to an over-four-month high, driven by concerns about possible production losses from frigid temperatures for crops with protection of snow cover in Russia, Ukraine, France, Germany and Poland. Analysts are hopeful U.S. export demand could pick up if output from those nations is curtailed by cold weather.

Meanwhile, lingering talk of Russia possibly implementing an export tax on grains aided the bullish enthusiasm. Russia has been a leading supplier of wheat to the world market, providing stiff competition over the last year for U.S. farmers.

U.S. wheat export demand has picked up somewhat recently, and the government announced fresh sales Wednesday, reporting 120,000 metric tons of soft red winter wheat sold to unknown destinations.

CBOT March wheat ended up 8 1/4 cents to $6.74 1/4 per bushel, March KCBT wheat ended up 7 cents at $7.22 1/2, and March MGEX wheat ended up 9 cents at $8.36 3/4.

Corn futures ended higher, buoyed by spillover support from wheat, weakness in the U.S. dollar and concerns about the extent of yield losses from heat, dryness in South America.

CBOT March corn ended up 3 cents to $6.42 a bushel.

-By Andrew Johnson Jr., Dow Jones Newswires; 312-347-4604 begin_of_the_skype_highlighting 312-347-4604 end_of_the_skype_highlighting; Andrew.johnsonjr@dowjones.com