Argentine growers could gather bumper soy and corn harvests next season as forecasts for wetter weather bring hope to drought-hit farms, a senior U.S. Department of Agriculture official said on Wednesday.

Dryness from the La Nina phenomenon walloped the Pampas farm belt in December and January, reducing yields and slowing supply from the world's No. 3 soybean exporter and No. 2 corn provider. On top of that, some growers have had to suspend harvesting after uncommonly heavy May rains caused flooding. The extreme weather swings have prompted a raft of 2011-12 harvest forecast cuts for a country being counted on to help meet rapidly rising global food demand.

But the 2012-13 season, which starts with October and November soy and corn plantings, looks promising, Melinda Sallyards, agricultural counselor at the U.S. Embassy in Buenos Aires, told the Reuters Latin America Investment Summit.

Forecasters see ample rains late this year due to the El Nino phenomenon, just in time to support 2012-13 sowing. "You could have soy and corn bumper crops in the 2012-13 season, if rains from El Nino hit at the right time, after planting and then during the flowering period in December and January," Sallyards said.

Caused by a warming of the tropical Pacific Ocean, El Nino tends to bring rains to South America, while La Nina, caused by a cooling of those same waters, tends to squeeze off rainfall. Steady precipitation would bolster the agriculture sector and increase export tax revenue at a time when Argentina's economy is slowing under the weight of Europe's financial troubles and slackening demand from No. 1 trade partner Brazil.

So not only export companies that operate in Argentina, such as Cargill, Bunge and Noble Group, are interested in the crop outlook, but the international financial markets are as well. "Usually El Nino means more production and higher yields for Argentina," Sallyards said. "Right now, we see corn area down in 2012-13, at 3.5 million hectares, but we expect production to rise to 23.6 million tonnes."

The Argentine government expects a corn crop of 20.1 million tonnes and a soy take of 41.5 million tonnes in the current 2011-12 season.

"We're looking at a stable number of hectares planted with soy in 2012-13, but with much greater production," Sallyards said. She cited her office's projection of a 52 million tonne 2012-13 soy harvest from a projected 19 million hectares planted with the oilseed.

Forecasts from the local USDA office are factored into the estimates published by the agency's main office in Washington, which currently expects 55 million tonnes of 2012-13 soy output and 25 million tonnes of corn.

Argentina is the world's No. 1 exporter of soyoil, used for cooking and in the booming biofuels sector. It is also the top supplier of soymeal, used as cattle feed particularly in China, where the emerging middle class is clamoring for beef steak.

The crop estimates reflect most of the effects of the December-January drought, but not the flooding that has blighted parts of key grain province Buenos Aires, Sallyards said.

"We haven't yet factored in the damage done by the flooding, but when we do over the next month or so, we expect that damage to be little compared with that done by the drought," she said.

Some 500,000 hectares in Buenos Aires province have been inundated by water over recent weeks. But considering that the entire Pampas, including grazing areas, comprises 60 million hectares -- more than the size of France -- the impact of the floods on overall exports should be small.

The Argentine USDA office estimates wheat plantings of 4.0 million hectares in the upcoming crop year, a forecast in line with that of the Argentine government. But Sallyards said the estimate might face downward pressure.

"This is our initial estimate based on the planting intentions of wheat farmers," she said. The Buenos Aires Grains Exchange also expects 4.0 million hectares for wheat this year; planting has already started.

Wheat growers, who sowed 4.6 million hectares in the 2011-12 season, have been shifting to other crops in a bid to skirt government export curbs that undercut wheat farm profits.

Reforms to Argentina's export rules have not revived interest in growing wheat, while worries mount that faltering investment in the sector is making the world's sixth-largest wheat exporter less competitive. Algeria rejected an offer of Argentina wheat last month, citing quality concerns.

"What we've seen in the past two years is a shift from wheat production toward barley production," Sallyards said. "Factors including weather, prices, production costs and any changes in government policies could impact final planted area."

(Editing by Lisa Von Ahn)