Proponents of more expansive government land use policies -- from local and state "smart growth" advocates to Vice President Al Gore -- conjure up images of cropland being gobbled up by urbanization at the rate of up to 10 acres an hour.

Samuel R. Staley, a Reason Foundation researcher, points out that contrary to claims about "urban sprawl," less than 26 percent of the decline in farmland is due to urbanization.

• Most farmland conversion is to nonurban uses such as forests, pasture, range land and recreational uses, says Staley.

• Even in urban areas, most former agricultural land is being converted to open spaces, greenbelts and parks supported by homeowners seeking to maintain the semi-rural nature of their neighborhoods.

• Less than 1 percent of "prime farmland" has been lost to urban use, and although the amount of land in farms has declined, the amount of cropland -- land used to produce food -- has remained stable.

American agriculture doesn't face a significant threat from sprawl, says Staley, but government policies do encourage the inefficent conversion of land to nonagricultural uses. He recommends market-oriented approaches to land use that would promote preservation of farmland and open spaces, such as:

• Full-cost pricing and privatization of infrastructure to reflect the full costs of land development.

• Greater use of private land trusts and conservation easements to purchase the future development rights of farmland and open spaces.

• Repeal of estate taxes to allow family farms to pass to the next generation, and repeal of targeted business-specific subsidies and tax credits that distort market real estate prices.

• And finally, elimination of one-size-fits-all zoning rules that discourage mixed uses and mixed-density housing.

Source: Samuel R. Staley, "The 'Vanishing Farmland Myth' and the Smart-Gowth Agenda," Policy Brief No. 12, January 2000, Reason Public Policy Institute, 3415 S. Sepulveda Boulevard, Suite 400, Los Angeles, Calif. 90034, (310) 391-2245.