“Though fertiliser and fuel prices could be down sharply, the cost of growing corn is still high,” says Farm Futures Senior Editor Bryce Knorr.

“Beans look to be the crop of last resort for many US farmers, which could lead to another big increase in seedings.”

Because of the record high prices for soybeans and flooding that delayed planting in 2008, farmers planted 17pc more acres to soybeans last year.

This year, according to a Farm Futures survey, farmers appear ready to reduce corn acreage by 1pc, to 85 million acres, while increasing soybean acreage to 80 million acres, a 5pc increase.

However, the US crop mix for 2009 remains somewhat uncertain as many farmers are waiting as long as possible before making their planting decisions.