(Updates prices, recasts lead; changes dateline from previous LONDON, changes byline)
* CBOT corn futures down 40 percent for the year
* CBOT wheat set for biggest annual loss in 5 years
* Soybeans on track for annual loss of around 7 pct
CHICAGO, Dec 31 (Reuters) - U.S. soybean futures fell to the lowest level in a month on Tuesday on end-year liquidation and improving prospects for a bumper South American crop, traders said, and were on track for a 7-percent loss in 2013.
Corn slipped to a two-week low and was on course to fall nearly 40 percent for the year, its biggest annual slide on record, as a record-large U.S. harvest replenished global inventories following a historic Midwest drought in 2012.
Wheat prices turned up after the spot contract on the Chicago Board of Trade dipped below $6 a bushel for the first time in more than 19 months, pressured by ample world supplies.
At the Chicago Board of Trade as of 11 a.m. CST (1700 GMT), most-active March soybeans were down 13-1/2 cents at $12.95-1/4 per bushel. March corn was down 1 cent at $4.22-1/2 a bushel and March wheat was up 2 cents at $6.02-1/2.
Soybeans tumbled ahead of the New Year's Day holiday as much-needed rains fell in crop areas of Argentina. Beneficial rains also fell in Brazil, where the harvest of a likely record-large soybean crop is under way in a few areas.
Argentina should harvest 55 million tonnes of 2013/14 soy, above the previous year's production of 48.3 million tonnes, on an increase in the area planted with the oilseed, the Rosario exchange said in a report on Monday.
Prospects for rising global soy inventories have hung over a soy futures market that has been propped up by firm U.S. cash values amid robust demand from China.
"South American weather is easy, and there is not a lot of trade," said Dan Basse, president of AgResource Co in Chicago.
"It's worth noting that the soybean-corn (price) ratios are out to record highs. Everybody sees the bear market in corn and wheat, and they see soy as over-valued," Basse said.
Soymeal posted the day's biggest percentage losses at the CBOT, pressured by falling cash prices for dried distillers grains (DDGs), a corn byproduct that competes with soymeal as a protein source in animal feed.
The U.S. cash market for DDGs has plunged in the last week after China rejected two U.S. cargoes of the feedstuff after detecting the presence a genetically modified strain not yet approved by Beijing.
As a result, U.S. supplies of DDGs are starting to build.
"The back-up of DDGs in the United States is going to cause some pressure and likely will affect meal prices also," Basse said.
Corn has come under pressure this week after crop-friendly rain fell over much of Argentina's corn and soybean growing region over the weekend and more rain is expected in the northern two-thirds of the country.
"Rains in Argentina have pressured the price of corn and soybeans... New rains are expected in Argentina this week, thus limiting the impact of high temperature on crops," French analysts Agritel said in a market note.
Wheat edged higher on short-covering after falling to its lowest level since May 2012. CBOT wheat is down 22 percent on the year, its biggest slide since 2008, while spot wheat in Paris has fallen around 18 percent.
Dealers said rising global stocks had weighed on values. Commodity funds hold a large net short position in wheat, leaving the market vulnerable to short-covering at year's end.
Bitter cold temperatures in roughly the northern half of the U.S. Midwest this week may cause some wheat winterkill in areas that do not have a blanket of insulating snow.
"We'll definitely see an uptick in icing on rivers, and some wheat in west central Illinois and northeast Missouri may see some winterkill," said Don Keeney, meteorologist for MDA Weather Services.
Keeney said Midwest temperatures would fall to zero degrees Fahrenheit (minus 18 Celsius) or a few degrees colder by New Year's Day. A slight weekend warm-up should be followed by another round of extremely cold air next week.
Prices at 11:32 a.m. CST (1732 GMT)
LAST NET PCT YTD
CHG CHG CHG
CBOT corn 422.50 -1.00 -0.2% -39.5% CBOT soy 1314.00 -14.25 -1.1% -7.4% CBOT meal 439.80 -10.50 -2.3% 4.6% CBOT soyoil 38.62 0.00 0.0% -21.4% CBOT wheat 604.00 3.50 0.6% -22.4% CBOT rice 1552.00 8.00 0.5% 4.4% EU wheat 207.75 -0.25 -0.1% -17.0% US crude 98.54 -0.75 -0.8% 7.3% Dow Jones 16,557 53 0.3% 26.3% Gold 1206.91 10.91 0.9% -27.9% Euro/dollar 1.3768 -0.0035 -0.3% 4.4% Dollar Index 80.1210 0.1210 0.2% 0.4% Baltic Freight 2277 30 1.3% 225.8%
(Additional reporting by Nigel Hunt in London, Colin Packham in Sydney and Michael Hogan in Hamburg; Editing by William Hardy and Marguerita Choy)