From the potato fields of Michigan to the high prairies of Kansas, farmers are receiving record prices for their land — but economists and banking regulators warn that this boom, like so many before it, could end badly.

Across the American heartland, farmland prices are soaring. In places like Waco, Neb., and Chickasaw County, Iowa, where the boom-and-bust cycle of farming reaches deep into the psyche, some families are selling the land that they have worked for generations, to cash in while they can.

Behind the rush is the age-old driver of farm booms: high crop prices. Corn, in particular, has been soaring, reflecting demand overseas and, domestically, for ethanol. High prices mean good profits for farmers, and many are using their growing incomes to bid for land. Sensing opportunity, investment firms are buying, too. David Taylor, of Oskaloosa, Kan., said he was saddened to sell his family’s farm but that the prices were too good to resist. Four generations had planted corn and soybeans on the 146-acre spread. But after living through the Midwest farm crisis of the 1980s, when land values plunged, and realizing that his children would not follow in his footsteps, he sold the farm at auction in December.

“I bawled like a baby,” Mr. Taylor, 59, said. His crop-producing fields sold for $10,100 an acre.

In Iowa, despite the drought last year, farmland prices have nearly doubled since 2009, to an average $8,296 an acre, far surpassing the last boom’s peak in 1979. In Nebraska, the price of irrigated land has also doubled since 2009.