South America's weather poses a greater risk to corn than soybeans, a leading crop scout said, amid a fresh wave of crop revisions for the region - including an Argentine forecast of a jump of up to 40% in corn output.

Michael Cordonnier, at Soybean and Corn Advisor, said that a record South American soybean crop looked in the bag, especially after major central Brazilian growing regions received their "best rains of the season so far" last week, with "more rain forecast for this week".

"That helped dry areas of Mato Grosso and Goias," in Brazil, at a time when much of the crop was in the sensitive pod-setting phase, Dr Cordonnier told Agrimoney.com.

"The Brazil crop looks like setting a record by 5m tonnes. I cannot see it losing 5m tonnes or more."

'Situation is more iffy'

However, for corn, for which the crop currently looks like being only 1m tonnes up from last year, "the situation is more iffy", Dr Cordonnier said.

"There is downside risk in Brazil and Argentina. It may be a record. It may be not."

Brazil farmers are planning to get more than half their corn from the so-called safrinha crop sown on land vacated by the soybean harvest, and for which sowings have only just started.

"This is a high risk crop," with its success depending largely on how far the rainy season extends into the growing season, he said.

"If it ends in June, you could have a huge crop like last year. But if it ends in March, you will get a diminished corn crop."

'Worried about pollination'

Argentine prospects, meanwhile, had been curbed by the planting delays, caused by persistent rains, which meant that 350,000 hectares were still to plant.

"Everything planted late, you do start to get worried about pollination," Dr Cordonnier said.

The comments tally with those of Gail Martell, at Martell Crop Projections, who cautioned over conditions in Argentina's Buenos Aires province, where "relentless rains in December caused widespread flooding on corn farms, setting back crop development and washing fertilizers out of farm fields.

"Delayed seeding dates and a lack of sunshine further hampered corn development. A sharply reduced corn harvest is anticipated," Ms Martell said.

'There is a lot of corn'

However, Oscar Solis, Argentina's deputy agriculture secretary, on Tuesday lifted expectations for the country's corn crop, pegging it at 28m-30m tonnes.

"There is a lot of corn, and in exceptional condition," Mr Solis said.

The US Department of Agriculture on Friday lifted by 500,000 tonnes to 28.0m tonnes its forecast for the harvest in a move which surprised many observers, including Dr Cordonnier, who pegs the crop at 22.5m tonnes.

Separately, Oil World, the German-based consultancy, said that in Brazil, "soybean crop prospects have improved in many soybean growing areas with improving weather conditions.

"The Brazilian crop may turn out above our December estimate of 81m tonnes if favourable weather conditions prevail."