Agricultural zoning in a metropolitan county: An evaluation of the Black Hawk County, Iowa, program

Abstract

Over 400 counties in the United States currently have agricultural zoning regulations which seek to protect the local farmland base. Many of these counties either contain a large urban center or are adjacent to metropolitan counties. Yet, few studies have been conducted on the performance of county agricultural zoning programs. Such a study is of particular importance to sustaining agriculture near urban areas. If a certain agricultural zoning program is successful, we should learn why it is successful and whether it can be transferred to other counties or localities. On the other hand, if an agricultural zoning program is not achieving desired goals, we should learn why and how shortcomings might be corrected. Black Hawk County, Iowa, is a metropolitan county with over 100 000 people. The county is also a major corn, soya bean and livestock producer, accounting for $103 million in farm sales in 1982. In the mid-1970's the county instituted extensive agricultural zoning in response to urban growth pressures on farmland. The Black Hawk County program has attached national attention for its use of a Corn Suitability Rating to identify prime agricultural lands and to determine which lands in farm zones could be converted to non-farm development without significantly reducing farm output. As yet, no study has examined the performance of the Black Hawk County program. To evaluate the program, we analyzed re-zoning decisions in farm zones, changes in the number of farms and land in farms and the number of land transfers for each 256-ha section of the county between 1975 and 1985. Results indicate that the administration of the program has improved over time. Relatively little farmland has been re-zoned for non-farm uses, and several proposals for non-farm uses have been denied. The local farm economy appears stable, given the slight decline both in the number of farms and the amount of farmland. The large majority of non-farmland transfers have occurred near urban boundaries. About one-quarter of farmland transfers have also occurred near cities. These figures suggest that urban sprawl is being fairly well contained. Few farmland transfers involved land with a Corn Suitability Rating of 85 or more. This result implies that the best farmland is in quite stable ownership, and is not likely to be developed.