US farmers have cut an area larger than Belgium, or Massachusetts, from planting schedules this year following the steep slide in the price of agricultural commodities.

American land allocated to major crops has fallen by 7.8m acres, the US Department of Agriculture said in its first estimate of 2009 plantings. The decline is the first since 2005, before the bull market for agricultural commodities which took the prices of many crops to record highs.

Among the big four crops – corn, cotton, soybeans and wheat – wheat and cotton acreages have recorded the biggest declines, with areas planted falling by 7%. The area allocated to cotton is, at 8.81m acres, the lowest for 26 years.

The area intended for corn has fallen 1% to 85.0m acres. "Lower corn prices and unstable input costs may have slowed corn planting somewhat," the USDA said.

While area set aside for soybeans has risen by 300,000 acrea to a record 76.0m acres, this is shy of the 79.6m acres traders were expecting, according to Reuters.

Among the smaller crops also counted as "principal" by the USDA, farmers have allocated 15% less land to canola, 16% less to sorghum and 27% less to peanuts.

Crops rising in popularity include rice and sugarbeet, which are set to increase acreages by 6% apiece.