Geography Reference
In-Depth Information
economy. As early as the mid-19th century, mechanization helped offset the lack of
manpower, and American agriculture quickly became an important export.
According to the economic model of Von Thünen (1826), large areas of specialized
crops, called belts, developed based on climate, richness of soils, and the distance
from urban markets in the East, which were also gateways for exporting to Europe.
Family farming in the Great Plains peaked during the First World War. Highly
dependent on weather conditions and market prices, it then suffered from a
structural crisis in the 1920s, which led it along a path of continual restructuring.
Farmers were forced to diversify their production and to adapt to the market and
international competition, to the point where the belts were gradually dismantled and
became unrecognizable. Rural counties lost their population due to the continuous
flow of emigration, which continues today in the Great Plains. Most of the land was
taken over by large farms and marginal lands were abandoned. The agricultural
crisis which took place during the interwar period was also an environmental crisis,
as a result of land overuse and deforestation. Erosion and the decline of productivity
caused farmers to leave Oklahoma and the southern Appalachians. Meanwhile,
agriculture continued its economic development with intensive mechanization, the
introduction of chemicals, and the development of irrigation.
Instead of focusing on agricultural production or regional specializations, this
chapter will focus on settlement and land use. What remains today of the agricultural
colonization which started in the 19th century?
Today, agricultural land covers less than one-fifth of the territory of the United
States. Alaska is virtually uncultivated, as are the Hawaiian Islands (see Figure 2.2).
Just in the 48 conterminous states, agricultural land totals 1.8 million km² (see
Figure 2.1). Agriculture occupies very little space in the desert of the Southwest, or
in New England. Only the states of the Great Plains, from north to south, exceed the
national average farmland share (as a percentage of the total area). Iowa, at the heart
of the old Corn Belt, is the state with the most agricultural land. Agriculture has
declined greatly on the Atlantic coast, except in certain parts of central Florida,
southern Georgia, the coastal plain of North Carolina and the borderlands of
Pennsylvania and Maryland. Agriculture has left the Appalachian highlands, but is
omnipresent in the Midwest. The percentage of land used in agriculture decreases
west of the 100th meridian, which is nicknamed the “disaster meridian” because of
the variability of precipitation rates from one year to the next. West of the Rocky
Mountains, agriculture is concentrated in some fertile and generally irrigated areas;
the Snake River valley in southern Idaho, the Columbia River Basin and the
Willamette valley are the three main agricultural regions of the Northwest.
Agriculture in California, the richest state in the US, is concentrated in the Central
Valley and the Imperial Valley.
