Too much rain over the past two months has delayed Argentina's corn planting and trimmed 1 million to 2 million metric tons from potential output, the president of corn grower association, Maizar, said Wednesday.

Early on, expectations had been for a record 28 million tons of 2012-13 corn production, but output is now likely to be 26 million to 27 million tons, Alberto Morelli said during a press conference.

That will still top Argentina's previous corn record of 24 million tons during the 2010-11 season and is up sharply from the 21 million tons harvested during the drought-ravaged 2011-12 season.

Argentina's corn exports from the 2012-13 season are expected to reach a record 16.4 million tons, Mr. Morelli said. Argentina shares second place with neighboring Brazil as a top global corn exporter behind the U.S.

A brutal drought in the U.S. this year has underpinned high global grain prices, and international markets are counting on record corn and soybean harvests in Argentina and Brazil to rebuild depleted food stocks.

High prices and wet weather due to the El Nino weather pattern have spurred South American farmers to plant as much grain as they can, but boggy fields have slowed planting, Mr. Morelli said. So far, about 40% of the corn crop has been planted, down 17 percentage points on the year. As the prime planting window for corn passes, some of the fields will be planted with soy instead, Mr. Morelli said.

Argentina is the world's top soymeal and soyoil exporter, and ranks No.3 in soybean shipments.

The U.S. department of Agriculture is expecting Argentina to grow a record 55 million metric tons of soybeans this season, up from the previous record of 52.7 million tons set during the 2009-10 season.

But muddy conditions have also slowed early soy planting.

So far, just 4% of the record 19.7 million hectares seen going to soybeans this season have been planted, down nine percentage points from a year earlier, according to the Buenos Aires Cereals Exchange.

Write to Shane Romig at shane.romig@dowjones.com

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(END) Dow Jones Newswires

November 07, 2012 12:20 ET (17:20 GMT)