US farmers could raise corn plantings 3m acres while still keeping the US market in a "comfortable" balance, an academic has said in a note flagging the potential for growers to opt to leave fields fallow too.

Sowings could hit 89.5m acres this spring while still trimming inventories to the 1.5bn-bushel level which would represent "neither shortage nor surplus", Darrel Good at the University of Illinois said.

His analysis assumes a drop to 158 bushels an acre in yields, lower than last year's 165.2 bushels an acre, but in line with historic trends.

It also factors in a rise of 180m bushels to 13.25m bushels in consumption, with increasing purchases by bioethanol plants offset in part by flagging demand from livestock farmers, as they turn increasingly to distiller's grains, a byproduct of the ethanol refining process.

Harvest hangover

Mr Good's estimate of plantings required for an in-balance market is in line with many analysts' forecasts for actual sowings, signalling that a jump in corn acres may not necessarily result in a collapse in prices.

"There is some concern that the late harvest has resulted in the need for more than the usual amount of spring tillage and fertilizer application," Mr Good said.

"Planting corn and corn may be particularly challenging in some areas due to the lack of [autumn] tillage and the rough field conditions due to harvesting under wet soil conditions.

"An early, open spring would he helpful for catching up with field work."

Sowings gap 

His analysis also suggested headroom for a further drop in areas planted with principal crops, after last year's 5.7m-acre decline from a 2008 peak.

"High prices and generally good returns resulted in a 9.4m-acre increase in total plantings from 2006 to 2008," Mr Good said.

However, over the last decade, the area of plantings had varied by 13.1m acres,

"Planting decisions for individual crops in the spring will be influenced by crop prices, prospects for net returns for competing crops, and spring weather conditions," he added.