Farm values in America have fallen for the first time in 21 years, with the price of some pasture land slumping by 30%, official data have shown.

A triple whammy of recession, falling crop values and a drop in land demand from property developers prompted a 3.2% drop in values last year, the first annual fall since 1987, the US Department of Agriculture said.

The average farm price, as measured by the value of all land and buildings averaged across the number of acres, dropped to $2,100 an acre.

Differing experiences 

However, the overall figure masked a range of differences, with the price of Montana pasture land slumping 30% to $530 an acre while cropland in Nebraska remained in demand, appreciating by 6.3% to $2,180 an acre.

Rhode Island continued to have the most expensive farms, at $15,300 an acre including buildings, despite an above-average 8.9% drop, followed by New Jersey on $13,800 an acre, reflecting development potential.

Arizona farms remained the most expensive in the west of America, despite a 13% drop to 10,000 an acre, ahead of California, where values fell 4.9% to $9,400 an acre.

Rents rise 

The USDA added that rents for cropland had continued to rise, reflecting the hang over of the strong farm commodity prices in 2007 and early 2008, adding 5.3% to $90.00 an acre.

The increase in Northern Plains states, which includes Nebraska and the Dakotas, jumped 7.6% although irrigated California land remained the most expensive to rent, at $360 an acre, reflecting its potential for growing high value crops.

Pasture rents stayed stable at $10.50 an acre.

"Pasture rent is affected less by commodity prices and more by land values," the report said.