Urban Land Use and Agriculture
Conversion of rural lands to urban uses gives rise to
some of the most controversial land use issues.
The amount of land in urban
and developed land uses is measured in different ways.
Census-defined "urban areas" include:
-
Built-up areas with at least 50,000 people
-
Urban places with at least 2,500 people.
Census urban areas more than doubled between 1960 and 1990, from
25.5 million acres to 55.9 million acres. By these definitions,
much of the land in large-lot development and development in rural
areas is excluded.
"Urban and built-up areas" defined by the USDA's
National Resources Inventory (NRI) include those measured by
the Census Bureau, as well as developed tracts of 10 acres or more,
and tracts of 0.25 to 10 acres that do not meet the definition of
urban area but are completely surrounded by urban and built-up land.
By these definitions, the NRI captures more of the large-lot development.
NRI's "developed land" consists of urban and built-up areas, plus
land devoted to rural transportation.
Census-defined urban area grew by about a million acres (4 percent)
per year since 1960. The rate of increase dropped from 3.5 percent
per year in the 1960s and 1970s to 1.8 percent per year in the 1980s.
NRI urban and built-up area increased faster than Census urban
area in the 1980s, rising 2.9 percent. Much of the increase in NRI
urban and built-up area is in less dense, large-lot development
beyond the urban fringe and in nonmetropolitan counties. This kind
of development will not meet the population density criteria for
Census-defined urban areas for many years.
Despite doubling since 1960, urban areas still made up less than
3 percent of U.S. land area (excluding Alaska) in 1990. Developed
areas, including rural roads and transportation, made up less than
5 percent in 1992.
Although development occurs primarily on crop and pasture
land and takes that land out of agricultural production
(essentially irreversibly), our Nation's ability to produce
food and fiber is not threatened. However, in some areas,
maintaining a local supply of fresh foods, as well as
retaining the open space and scenic views associated with
farmland, is of increasing concern as the value of land
in developed uses surpasses its value in agricultural
use.
Rural Residential Development
New housing on large parcels of land exhibits different
characteristics than development occurring at the city's
edge. Instead of 4-6 houses per acre, exurban development
consists of scattered single houses on large parcels,
often 10 or more acres in size. Although this growth has
garnered much attention recently, rural large-lot development
is not new.
Growth in the amount of land area used for housing has risen in
response to increasing demand. Large lots dominate this process,
and growth in large-lot development has varied with periods of prosperity
and recession since 1970. Only about 5 percent of the acreage used
for houses built between 1994 and 1997 is on land classified as
farms, and only 16 percent is in existing urban areas within Metropolitan
Statistical Areas defined by the Census Bureau. Thus, the remaining
80 percent of acreage used for recently constructed residential
housing—about 2 million acres—is land outside urban areas
or in nonmetro areas. Almost all of this land (94 percent) is in
lots of 1 acre or larger, with 57 percent on lots 10 acres or larger.
Urbanization and Metro Agriculture
Urbanization affects agriculture in developing areas in both positive
and negative ways. Some of the effects of urbanization include:
- High rate of growth in land values—When demands for
developable land are sufficiently high, the value of land in developed
use will exceed its value in agricultural use. This enables developers
to outbid farmers for use of the land. Strong development pressures
can lead to high rates of growth in land values, which in turn speed
the conversion of farmland to developed uses as fewer farmers enter
the industry. As more land exits farming, the local agricultural
economy may suffer. However, existing farmers may welcome the increase
in farmland values, especially if they view their investment in
land as a retirement fund and do not have children who plan to continue
farming the land.
- Increased marketing opportunities—Closer proximity to
urban consumers and new output venues allow farmers to adapt their
agricultural operations to higher value or specialty crops, such
as fruits and vegetables. However, as farmland is put to different
farming uses, a shift in input suppliers may result. Suppliers providing
goods and services to more "traditional" farming operations
may fail or relocate to more rural areas, replaced by suppliers
whose products are suited to the new "specialty" enterprises.
- Increased access to labor—Closer proximity to population
concentrations means that farmers are likely to have access
to a larger labor pool. This may contribute to farmers' decisions
to shift to specialty crops that are labor intensive, but it
may lure farmers to other, nonfarm jobs.
Problems with nonfarm neighbors—Conflicts can arise
between urban neighbors using secondary roads as
commuter routes and farmers traveling to and from distant fields
with farm equipment. Other problems for farmers can include increased
incidence of vandalism and theft, including damage to crops from
urban neighbors driving through fields. Nuisance complaints may
also increase, as more neighbors voice opposition to the sounds
and smells of typical agricultural operations.
- Increased "amenity value" of farmland—As more
farmland is converted, the remaining farmland may become more "valuable" to
the local population because farmland provides open space, scenic
views, and contributes to rural amenities. These rural amenities
associated with farmland are generally not captured in the market
value of land. Because farmland owners are not compensated for
the rural amenity value of their land, but do make money from
selling for development, they do not have an incentive to delay
the conversion of farmland to developed uses.
Urbanization and U.S. Food and
Fiber Production
Shifting farmland to urban uses has posed no threat to U.S. food
and fiber production.
- Cropland acreage has remained stable over time, straying only
4 percent (plus or minus) from the 463-million-acre average
seen in 1945-97.
- Agricultural output has increased steadily, by nearly 2 percent
per year since 1948.
About half of the acres in farms are not classified as cropland,
and the number of such acres in agricultural uses has declined over
time. Most of these acres are rangeland and not suitable for crop
production with today's technology.
However, some of these noncrop acres, and others in rural uses,
could be converted to cropland if market conditions were favorable.
Estimates of the rate of conversion of rural land to urban uses
vary depending on the data source and the time period examined.
According to the Major Land Use
series, conversion averaged 1 million acres per year from 1950 to
1992. This rate increased to 1.4 million acres per year from 1992
to 1997. However, total urban area was still less than 3 percent
of the total U.S. land area in 1997.
Rural land includes a component used for residential purposes that
is not farmland or urban area. This rural residential area was estimated
at 73 million acres in 1997, an increase of 17 million acres from
56 million acres in 1980. Rural residential land occurs mostly on
large lots—20 acres and greater. Land in rural areas is generally
less expensive than urban land, which likely accounts for the larger
lot sizes in rural areas.
Conversion to urban uses is largely irreversible—land seldom
reverts back to rural uses once converted to urban. Some rural residential
land, however, could convert to other uses, such as cropland, if
commodity prices climbed.
The highest physical quality of land for agricultural purposes,
prime land, has been converted to urban uses at approximately the
same rate as agricultural land not classified as prime land. Although
conversion of rural land to urban uses is most likely to occur in
metro counties, where the proportion of prime cropland is higher
than in nonmetro counties, only about one-quarter of all prime cropland
is in metro counties. Further, fast growing areas (such as Florida
and Arizona) are not areas with high concentrations of prime land.
While urbanization is not threatening our ability to produce food
and fiber, society may choose to protect farmland for a variety
of reasons, including preserving a local way of life, safeguarding
rural amenities, or minimizing congestion.
Farmland Protection and
Nonmarket Values
Despite the relatively small fraction of the American landscape
dedicated to urban uses (3 percent or less), there is growing concern
about the disappearance of farmland in some parts of the country.
While interest in protecting farmland arises in part from desires
to maintain crop production, many citizens want to protect farmland
to preserve nonmarket benefits. These "rural amenities"
include:
Environmental Amenities
- open space
- soil conservation
- biodiversity
- wildlife habitat
- recreational opportunities
- scenic vistas
- isolation from congestion
- watershed protection
- flood control
- groundwater recharge
Rural Development Amenities
- rural income and employment
- viable rural communities
- diversified local economy
Social Amenities
- maintaining traditional country life
- maintaining a small farm structure
- maintaining cultural heritage.
These rural amenities are often a byproduct of the agricultural
production process. Ensuring the continued availability of these
rural amenities may be the most important reason for farmland protection,
especially for farmland protection near urban areas. Consequently,
information on the relative importance of these rural amenities
can be useful when considering the current state and future direction
of farmland protection programs.
The effects of farmland protection on the provision of rural amenities
has received little attention. Despite the numerous programs nationwide
to protect rural open space and to preserve farmland, very little
is definitively known about which individual rural amenities taxpayers
really care about when they support farmland protection programs.
A recent ERS report examines
farmland protection programs to see what importance the public places
on various reasons for protecting farmland.
Given that farmland protection programs can be expensive to implement,
understanding how the public values rural amenities can be crucial
in determining preservation priorities.
Some tentative conclusions as to the importance of "farming"
in farmland protection programs can be drawn. Farmland protection
programs largely focus on the protection of active agriculture,
with many programs favoring the preservation of productive soils
on which field crops are typically grown.
This strategy holds implications for the set of amenities that
are likely to be preserved in these programs. For example, emphasizing
protection of cropland versus pastureland yields different scenic
views, and has different implications for water quality, wildlife
habitat, and other environmental amenities. It also implies a tradeoff
between long-term survival of some form of agriculture, at the possible
cost of providing a mix of rural amenities that is less than optimal
today.
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