Argentina soybean prices set a new high mark Thursday as drought in the U.S. continued to scorch crops and stoke worries over global supply.

Spot soybeans surged to 1,820 Argentine pesos ($400) per metric ton at the Rosario Grain Exchange on Thursday, up from ARS1,690 a week earlier. May soy sold for $325 per ton, up from $320 a week ago.

Argentina is the world's No. 3 soybean exporter behind Brazil and the U.S., and the leader in global exports of soymeal and soyoil.

"A new advance in soybean contracts in Chicago [drove] local prices to a new level, setting a record unimaginable just a few weeks ago," the Rosario exchange said.

At the benchmark Chicago Board of Trade, soybean and nearby corn futures soared to fresh record highs Thursday as traders continued to worry that the drought in the U.S. Midwest could dent the harvest. Forecasts in the U.S. for spotty rainfall and hot weather again next week are stoking those worries.

In Argentina, April 2013 corn sold for $195 per ton Thursday, up from $182 a week ago. Spot corn was traded at ARS700 per ton. Argentina is the world's no. 2 corn exporter after the U.S.

Higher prices overseas combined with strong demand from exporters following the government's announcement this week that it would clear 15 million tons of corn exports from the 2012-13 crop.

Earlier Thursday Argentina's agriculture ministry revised its forecasts for 2011-12 corn and soybean production in its monthly report, lowering the soy estimate but raising corn.

The ministry raised its corn estimate to 21 million metric tons from 20.1 million tons last month. About 89% of the harvest is done.

With the soybean harvest virtually wrapped up, the ministry slightly trimmed its estimate to 40.1 million tons, down from 40.3 million forecast last month.

Argentina is expecting a record soybean crop next season because of El Nino and as farmers shift away from corn due to the high cost of raising that crop. Corn area is likely to fall to 4.2 million hectares next season from 5 million hectares in 2011-12, according to Agritrend analyst Gustavo Lopez. Higher seed, fertilizer and agrochemical costs for corn will fuel the shift, said Buenos Aires Cereals Exchange crop analyst Esteban Copati.

Argentine farmers will plant as much as 20 million hectares (49 million acres) with soybeans in the 2012-13 season, 1 million more than during the 2011-12 season, according to analysts.

That could lead to production of 55 million metric tons, topping the previous record of 52.7 million set in the 2009-10 season--the last time El Nino showed its face, according to Agripac Consultores analyst Pablo Adreani.

Meanwhile, wheat traded for $180 a ton, unchanged from a week ago. February new-crop wheat was also unchanged at $200 per ton.

Argentina is a leading global wheat exporter, with most shipments going to neighboring Brazil.