Argentina has said that its corn harvest may surge by more than 60% to 21m tonnes, trouncing estimates from other forecasters, including the US Department of Agriculture.

The country's farm ministry said that its estimate of a crop of 19m-21m tonnes, its first guess for 2009-10 output, reflected plentiful rainfall in major growing regions.

 "The state of crops is good-to-excellent in almost all areas of production, given key rainfall during the growing cycle," the ministry said, forecasting that yields could come close to those in 2006-07, when corn production hit 22m tonnes.

Yields then hit a record 8.04m tonnes per hectare, according to the USDA.

However, thanks to drought, yields plummeted in 2008-09, cutting the harvest by some 40% to 13m tonnes.

Yield threat

The ministry's forecast is the latest of a series of upgrades for the crop, for which analysts had held some reservations after market price signals persuaded many farmer to switch to soybeans instead.

"Due to a wide range of planting dates, much of the crop still has to pass through critical growth stages, so much greater than normal uncertainty exists about the size of the crop," USDA officials said earlier this week.

"Later-planted corn… is at risk of sharper-than-normal yield declines should unfavourable weather occur during the remainder of the growing season."

The array of planting dates could also "hamper harvest timeliness due to widely differing stages of crop maturity", the department added.

'Good yield potential'

The comments were made in follow-up briefings to last week's global crop supply and demand report, which saw the USDA raise to 17.2m tonnes, from 15m tonnes, its forecast for Argentine corn production.

"Corn that is currently at the pollination stage shows good yield potential," the briefings added.