Floods have swamped much of Argentina's soy crop, causing heavy losses to one of the world's top grains suppliers.

Argentina's Rural Society said Thursday that about 4 million metric tons have been ruined. The losses are estimated at up to $1.3 billion.

Rains stemming from El Nino weather phenomenon have hit farmers in the grain belt of northeastern Argentina particularly hard. Some farmers have opted to stop the harvesting of soy while fields dry out.

Grains are the backbone of Argentina's economy. The South American country is the world's third-biggest exporter of soy and a major supplier of corn and wheat.

The Argentine Red Cross estimates more than 2,000 people have been evacuated and more 30,000 people have been affected after the rains swelled rivers, swamping fields and towns nationwide.