There are artificial means to imitate the above limitations, and they have been deployed with effect in some North American cities in the form of urban growth boundaries, as for instance in Lexington, KY, the state of Oregon and in Toronto, Ontario. Rarely, though, does policy directly pertain to the subsidization of the activities that the boundary is intended to protect. In Lexington, for instance, although the growth boundary was intended to preserve the area's legacy landscape of horse farms, tax subsides are offered to owners of large parcels regardless of whether any agricultural use is being made of the subject property.

The influential American environmental movement, on the other hand, has left little doubt as to the landscapes it favors protecting. The Sierra Club's website doesn't seem to have any recognition of agricultural land, instead focusing almost entirely on wilderness, although most true wilderness is not under threat of urbanization. The Nature Conservancy does mention agricultural land, but as a potential threat to natural resources. Although many of the goals of these organizations are important and praiseworthy, the focus on nature, rather than the agricultural landscape, undermines their position with respect to urban policy and planning. The Sierra Club has recently come under criticism in urban circles for appearing to support exclusionary zoning in certain contexts, while the Nature Conservancy's urban affairs expert seems to be at pains to make the case for dense urbanism to a skeptical audience.

I mention these examples, though, to reinforce the contrasting visions above. The American imagination has traditionally been drawn to wild spaces rather than to the symbiosis between food and land (represented in the French term terroir). Although the notion of "locally-sourced" food products has lately gained some traction, this has not translated into much if any public policy, and has has further been confused by cheerleading for the oxymoronic "urban agriculture" (although the very idea of local and/or urban agriculture could be interpreted as a pining for a sort of terroir). A few New Urbanist developments have emphasized the connection between agriculture and urbanism, such as Serenbe in the outer reaches of Atlanta, but these are few and far between and have not been above criticism. Local land trusts have embraced preservation of agricultural uses, but these organizations lack the scale necessary to guide policy at the regional scale.

None of this is to argue that the United States, or any other country, would necessarily benefit from European-style agricultural regulations. What may be worth exploring, though, is the question of how agricultural economics affects urban form, and to consider how public policy in this area relates to goals for urban development. Being the focus neither of urbanists nor environmentalists, agriculture has largely escaped significant land-use scrutiny in the United States. It deserves more attention.