It is too early to abandon hope for the US corn crop, the world's biggest despite delays to sowings, which have progressed at one-third of the average pace, hampered by a wet spring.

With farmers in the main growing state of Iowa proving historically able to plant one-half of their corn crop in one week, with Illinois and Indiana growers achieving rates above 45%, showed that it was still not too late to play catch up.

"A large proportion of the corn crop can be planted in a relatively short period of time," University of Illinois academics Scott Irwin and Darrel Good said.

"The majority of the 2011 corn crop can still be planted in a timely fashion, by mid-May, if weather conditions improve fairly soon."

May 10 is taken by many analysts as the cut-off date after which US corn sowings tend to result in lower yields.

'Wild card'

In fact, in many previous seasons, US farmers have managed bumper corn harvests despite slow starts to swings, Kim Rugel at Benson Quinn Commodities noted.

Two years ago, when the US corn yield hit a record 164.7 bushels per acre, only 5% of the crop was in the ground by now.

Furthermore, sowing delays have not prevented an increase in planted acres above initial US Department of Agriculture expectations, with 2009 witnessing 86.4m acres sown, 1.4m acres more than the initial forecast.

In 2007, when seedings also got off to a slow start, the final acreage was 3.0m acres higher.

"Acres are still a wild card, but historically, despite late plantings, corn tends to gain planted acres from the March [USDA estimate] to final June number," Mr Rugel said.

'Two weeks behind schedule'

However, with US weather forecasts remaining wet heading into May, both observers acknowledged risks to an optimistic outlook.

Benson Quinn said that this week's progress in US sowings may not be "much better" than the two points, to 9% of the crop, completed last week, given forecasts of two further rain systems hitting the Corn Belt.

"[This] should put the majority of the main core of the belt a minimum of two weeks or more behind schedule a week from today as we move approach the first week of May," the broker said.

Messrs Irwin and Good said that the weather outlook "provides mixed prospects" for the conditions needed to allow farmers to plant catch-up.

"It appears that planting delays will continue and may become more pronounced, particularly in the southern and eastern parts of the Corn Belt," they said.

Weak progress

The 9% of corn sowings completed as of Sunday compares with an average of 23% by now, a USDA report out overnight showed.

Last year, when farmers enjoyed dry and warm planting conditions, 46% had been sown.

The latest data showed particularly slow progress in Iowa, America's top corn growing state, where 3% was sown as of Sunday, up only 1 point on the week, and compared with an average 28% by now.

In second-ranked Illinois, farmers had sown 10% of their crop, also up 1 point over the week.