With Argentina's soybean harvest over half done, final yields are coming in lower than initially expected and production prospects have dimmed somewhat, the Buenos Aires Cereals Exchange said in its weekly crop report Thursday.

The exchange trimmed its forecast to 43 million metric tons, down from 44 million tons last week. Drought earlier in the season damaged many fields, reducing potential yields, the exchange said.

The fields have also been hit by a series of frosts over the past week, but the affected crops "don't represent a relevant amount of the area" planted with soy, the exchange said.

Yields from Argentina's soybean crop are disappointing in many areas due to drought in December and January that affected early fields and led many farmers to put off soybean planting until late January. As a result, the short growing season for much of the crop trimmed potential output.

Early in the season, many analysts predicted 2011-12 soybean output would top the 49 million metric tons grown last season.

Argentina leads global soyoil and soymeal exports, and ranks third in soybean exports. Global soy prices got a lift this year due to the mediocre crops from both Argentina and Brazil.

The exchange also trimmed its forecast for corn production by 1 million tons to 19.8 million tons as yields in many areas ended up lower than initially expected.

So far, 41.3% of the corn crop has been harvested, according to the exchange.

Estimates for Argentina's 2011-12 crop production in millions of metric tons (One hectare equals 2.47 acres):

Wheat      Soy         Corn        Sunseed 
 
B.A. Cereals Exch    14MT       43MT        19.8MT       3.6MT 
Ag Ministry          13.4MT     42.9MT      20.3MT       3.4MT 
USDA                 14.5MT     45MT        21.5MT       3.2MT 
Rosario Grain Exch   13.7MT     43.1MT      19.8MT       --

Argentina's historical production in millions of metric tons, according to the USDA:

Wheat      Soy         Corn        Sunseed 
2010-11              15         49          22.5         3.6 
2009-10              9.6        54.5        22.5         2.3 
2008-09              10.1       32          15           2.9 
2007-08              18.6       46.2        22           4.65 
2006-07              16.3       48.8        22.5         --

-By Shane Romig, Dow Jones Newswires; 54-11-4103-6738; shane.romig@dowjones.com

(END) Dow Jones Newswires

April 26, 2012 14:19 ET (18:19 GMT)