In Iowa and the three other states covered by Farm Credit Services of America, farmland prices have risen 20 percent or more in the past year, said Kirk Manker, chief appraiser of the bank.

Iowa farmland rose 22.6 percent in 2007, Manker said. Nebraska farmland rose 19.6 percent in a year, South Dakota showed a 22.6 percent increase and Wyoming had a 20.9 percent increase.

Farm Credit Services tracks real estate values by making semi-annual appraisals of 68 farms, Manker said. It also has followed 7,500 sales of farmland in the four states.

Manker credited profitable prices and increasing yields of corn, soybeans and wheat, relatively low interest rates, and ethanol production, which is increasing the demand for corn. [Read the full story in the Des Moines Register.]