* Soybeans rise on good export prospects * Corn flat, export demand supportive * CBOT wheat rises 1.5 percent, nears 50-day moving average By Mark Weinraub CHICAGO, Feb 13 (Reuters) - U.S. soybean futures jumped 1.6 percent on Thursday to their highest in more than eight weeks, spurred by technical buying and firm export demand, traders said. A U.S. Agriculture Department report on Thursday morning said export sales of soybeans fell below market expectations but showed that China, the world's top buyer of the oilseed, was still booking deals for U.S. cargoes even as newly harvested South American supplies arrive at ports. "I think it started when you didn't get cancellations to China in the export sales," said Dan Cekander, analyst with Newedge USA. "Even though it (the weekly soybean sales total) was small, they still added 300,000 tonnes to the commitments." Concerns that domestic stocks will remain tight for the next year also added further support to soybeans, traders said. "I think the main reason is because they really expect the new crop acres for beans will keep the supply side very, very tight in relation to the corn," said Mike Zuzolo, president of Global Commodity Analytics. Wheat futures also firmed, rising on a technical bounce after Wednesday's decline. Corn was close to unchanged, with traders saying that strong export demand prevented a sharp decline as the U.S. government's 10-year agricultural projections cast a bearish tone over the market. The U.S. Agriculture Department forecast the U.S. soybean crop at 3.480 billion bushels for the 2014/15 crop year, based on plantings of 78 million acres, with ending stocks rising to just 203 million bushels. That compares with a crop of 2.289 billion bushels and ending stocks of 150 million bushels in the 2013/14 marketing year. By comparison, corn harvest for 2014/15 was seen at 14.260 billion bushels, with acreage forecast at 93.5 million and ending stocks pegged at 2.607 billion. Corn production in the 2013/14 marketing year was 13.925 billion bushels with ending stocks of 1.481 billion bushels. Chicago Board of Trade March soybeans gained 21-1/4 cents to $13.44-1/4 a bushel. Prices hit their highest since Dec. 18 during the session. Concerns that dry weather in South America will curtail plantings of a second soybean crop in the coming weeks and tight soymeal supplies around the United States added further support. "We saw some rain that provided a little relief (in Brazil) but that relief is only transitory," said Sterling Smith, futures specialist with Citigroup. "We are going to fall back into a drier pattern next week." CBOT March corn settled up 1/2 cent at $4.40-1/2 a bushel while CBOT March soft red winter wheat gained 8-1/2 cents to $5.95-1/2 a bushel. March wheat found support after dipping close to its 40-day moving average early in the session, but the chart-driven buying ran out of steam as prices neared the 50-day moving average, a key technical benchmark the contract has not surpassed since Nov. 4. Prices at 1:53 p.m. CST (1953 GMT) LAST NET PCT YTD CHG CHG CHG CBOT corn 440.50 0.50 0.1% 4.4% CBOT soy 1344.25 21.25 1.6% 2.4% CBOT meal 452.80 9.30 2.1% 3.4% CBOT soyoil 39.54 0.55 1.4% 1.9% CBOT wheat 595.50 8.50 1.5% -1.6% CBOT rice 1571.00 8.50 0.5% 1.3% EU wheat 196.75 1.00 0.5% -5.9% US crude 100.29 -0.08 -0.1% 1.9% Dow Jones 16,036 72 0.5% -3.3% Gold 1299.26 8.62 0.7% 7.8% Euro/dollar 1.3673 0.0081 0.6% 0.2% Dollar Index 80.3310 -0.3480 -0.4% 0.4% Baltic Freight 1097 12 1.1% -51.8% In U.S. cents, benchmark contracts, except EU wheat (euros) and soymeal (dollars). CBOT wheat, corn and soybeans per bushel, rice per hundredweight, soymeal per ton and soyoil per lb.