Argentina's 2011-12 soya crop could suffer if it does not rain soon in key growing areas, the Buenos Aires Grains Exchange said on Thursday.
Soya seedings in the world's top exporter of soyaoil and soyameal were delayed in the last week due to limited precipitation in many areas, linked to the La Nina weather phenomenon.
The forecast for rain in the coming days "does not cover critical regions like southern Cordoba and most of Buenos Aires province, regions where conditions could worsen once northern winds and a heat wave return," the exchange said in its weekly crop progress report.
Buenos Aires province is the biggest soya-growing district in Argentina.
By Thursday, farmers had seeded 75.6 percent of the 18.85 million hectares earmarked for the crop, advancing 2.7 percentage points from a week earlier and outpacing last season's sowing tempo by 0.9 points.
"The amount of rain and the temperatures seen in the coming weeks will determine how much area is ultimately planted (with soya)," the exchange said.
Agriculture Ministry authorities have estimated this season's soyabean production at between 52 million and 53 million tonnes.
No official output estimate has been released by the government or the grains exchange.
The US Department of Agriculture forecasts Argentina's 2011/12 soya output at 52 million tonnes, up from 49 million tonnes in the prior crop year.
With regard to the corn crop, farmers had seeded 74.6 percent of the 3.74 million hectares estimated for planting with commercial-use corn by Thursday, advancing 3.3 percentage points from a week before.
Argentina is the world's No 2 corn supplier after the United States.
Rains in some areas improved the crop's condition in the last week, but elsewhere moisture is lacking.
"Early-seeded corn in much of the central region, have already seen their potential yields reduced, and there have been plots lost as well," the exchange report stated.
Local government officials have estimated the 2011/12 corn crop at up to 30 million tonnes, which would be a record high.
The USDA foresees an Argentine harvest of 29 million tonnes.
Warm, dry weather has been a plus for the wheat crop, which is in its final development stages or is being harvested.
The grains exchange forecasts 2011/12 production at 13.6 million tonnes.
Argentina is also one of the world's biggest wheat suppliers.
By Thursday, growers had gathered 65 percent of harvestable areas planted on a total of 4.6 million hectares.
This shows progress of 14.5 percentage points in the last week and puts the harvest pace 12 points ahead of last season's.
The Agriculture Ministry forecasts wheat output at 12 million tonnes, while the USDA estimates 14.5 million tonnes.