By Hugh Bronstein
BUENOS AIRES (Reuters) - Rain is expected to hit Argentina's grain belt late on Tuesday and Wednesday, helping revive soy and corn crops left panting for water after a long dry spell which raised worries about global supply.
Some parts of Argentina, which provides nearly half the world's soyoil and soymeal and about 20 percent of its corn, got scattered showers early on Tuesday. But most growers, who have already lost portions of their corn crops and are starting to worry about their soy fields, will have to wait a bit longer.
The National Meteorological Service is calling for rain late Tuesday and Wednesday in the northern part of key agricultural province Buenos Aires, as well as in the south of Cordoba, another corn- and soy-producing hub.
The showers will be crucial to Argentina's chances of producing a 2011/12 corn crop within the current estimate range of 23 million to 27 million tons, after harvesting a record 23 million tons in the previous season.
Leonardo De Benedictis, a forecaster with the Climacampo consultancy in Buenos Aires, said it will start raining in these farm areas on Tuesday night and should continue until Thursday morning.
"A cold front will move into the central growing area, provoking showers and heavy storms, delivering an average of 40 to 50 millimeters (1.6-2.0 inches) of water," De Benedictis said.
"In order to reach optimal conditions and wipe out any signs of drought, the zone needs to get about 140 millimeters (5.5 inches) of rain," he added. "But it is not necessary for optimal conditions to be present in order for crops to develop well."
Lack of water has shrunk Argentina's corn crop at a time when the world's No. 2 corn exporting country is being counted on to replenish global supplies after a disappointing U.S. harvest.
Farmers have been less worried about their soy fields, which were planted later than corn and have a longer, more flexible development period which is providing more time to benefit from January and February rains. But soy losses are mounting in some areas.
"As of now, 20 to 30 percent of soy and corn crops have been lost," said Mario Fernandez of the Buenos Aires town of Carlos Casares, who operates machines that fill and empty the long, vertical "silo bags" that dot Argentina's countryside.
The drought has halted planting of late-season 2011/12 corn and soy, which would have all been sown by this point in the season if the dry weather had not parched farmers' fields.
"The situation is critical," Fernandez said. "Late-planted soy has suffered heavy losses and early-planted soy has been reduced by about 10 percent."
World food price and Argentine grains graphic: http://link.reuters.com/suq84s
Chicago Board of Trade grains futures have been driven higher recently by supply concerns based on Argentina's weather woes.
The front-page headline in Tuesday's La Nacion newspaper said Argentina's 2011/12 soy harvest will come in 7 million tons below initial government estimates of 52 million tons. Soy industry chamber head Miguel Calvo told the paper that the crop will amount to less that 50 million tons.
The crop losses may add to fiscal and political challenges for President Cristina Fernandez. On the heels of her re-election in October, her government has been bracing for fallout from Europe's financial mess and slower demand growth from key commodities client China and No. 1 trade partner Brazil.
Grains powerhouse Argentina is in a good position to cash in on world food demand which is expected to keep growing over the decades ahead. But it lags its neighbors in attracting private capital as investors complain about Fernandez's unorthodox and hard-to-predict policies.
(Reporting By Hugh Bronstein; editing by Jim Marshall)