BUENOS AIRES (Reuters) - Heavy downpours have ruined the harvest of nearly 5 percent of Argentina's soybean farms and could damage even more of the 2015-16 crop if rains extend into next week as expected.
Grain experts still forecast a strong harvest once the rains let up, however, due to robust production in regions unaffected by the precipitation. Argentina is the world's No. 3 exporter of the oilseed and the leading supplier of soyoil and soymeal.
"The longer it takes for the weather to change, the worse the damage. But there are areas doing very well, which is supporting the harvest outlook," said Cristian Russo, head of forecasting for the Rosario grains exchange.
Rains are lashing almost half of the 20.5 million hectares (50.7 million acres) planted with soy in Argentina, delaying the harvest, flooding dirt roads carrying grains to port and threatening diseases due to excess humidity.
Soy futures in Chicago <0#S:> surged to eight-month highs on Tuesday, due partly to concern with Argentina's delayed harvest.
"If it keeps raining, it could be a disaster," said Stella Carballo, a specialist at the Climate and Water Institute.
Most experts said it was too early to evaluate the full impact on the crop, but at least 800,000 to 900,000 hectares of planted soybeans will go unharvested this year due to the heavy rains tied to the strongest El Niño weather pattern in decades.
On Monday, just 612 trucks of soy arrived at docks in the key agricultural port of Rosario, down sharply from 4,273 trucks delivering soy on the same day last year.
(Reporting by Maximiliano Rizzi, writing by Brad Haynes, editing by G Crosse)