The worlds largest grid. The story of the American Corn Belt
If you open Google maps and take a closer look at the American Midwest, you will discover one of the most profound examples of man's conquest over nature. Covering fifteen American states, and parts of Canada, the American Corn Belt stretches from the Appalachian mountains in the east to the Colorado mountains in the west. It forms a seemingly eternal field of 1 x 1 mile squares of farmland, only interrupted by the occasional natural landmark, town or road. This is the story of the world's largest human made grid.
A rough outline of the American Corn Belt.
In the late 18th century much of the Americas was still covered in prairies, with bison roaming the grasslands. The land was exceptionally fertile and formed the basis for the American expansion in to the west, where upon thousands and millions of settlers reaching American shores each year would be allotted pristine farmland and start a new life. Over the coming centuries 99% of the American prairies would disappear, to be be replaced by the largest agricultural area in the world.
What remains of a an early American prarie homestead.
In the early days of the American colonies land was allotted on a British system of dividing by topography and natural landmarks. This however required careful surveying of the land and became confusing and inefficient as trees were cut down, or erosion changed the paths of rivers. A new system was needed to distribute the lands of the west. Preferably without having to survey the site up close.
Following the Land Ordinance Act of 1785 a grid system was developed, dividing the land in to a series of square townships, based on a baseline and meridian for each state. Each township was made up of 35 sections. Each section was 1 x 1 mile long (1,6 km). Where the land was fertile a farm could encompass a single section, but in the drier lands further west a single farm might encompass several sections. Section 16 was always reserved for a school district, based on an entirely unprecedented idea of civic engagement and education for the farmers. Sections 8, 11, 29 and 26 would be reserved by the federal government, to be sold off later when the land value had increased. Providing much needed revenue for the American state.
A diagram of the township system, with the school district of section 16 in the middle.
The townships system as it looks today (somewhere in Iowa).
Roads and train lines would usually follow the grid system precisely. Section 16 would some times form the basis for the establishment of a small town, which would grow from the school district.
The small town of Hull, Iowa, with a school district.
This mathematical approach to land surveying, while extremely effective, was not without consequences. In the 30s a series of dust storms known as the "dust bowl" seriously damage the ecology and agriculture of the United States, and terrorized the inhabitants of the Midwest. The reason for this ecological collapse was a lack of knowledge of wind erosion. The deep grass roots of the original prairie had originally trapped soil and moisture in the ground, even during periods of droughts. Because the farmers of the Corn Belt conducted extensive deep plowing, the unanchored topsoil was carried by winds when an extended drought period began in the 30s. The problem was further exacerbated by plowing in the straight lines of the grid, rather than following the contours of of the land, which exposed the topsoil. The solution was to implement techniques of dryland farming, including shallow plowing, following the contours of the land and resowing the fields after harvest season.
A storm during the "dust bowl" of the 30s. The phenomenon caused a major health issues, including dumping 5000 tonnes of dust on the city of Chicago, as well as thousands of bankruptcies and a refugee crisis.
The grid of the American Corn Belt had a profound impact on the cities of the Midwest. They would develop from the township system, with major roads extending from the country sides to form city block of 1 x 1 mile.
The Chicago grid grew from the townships of Illinois.
The Chicago grid as seen from the sky.
When driving through the Midwest before the Second World War, the countryside could be seen be full of farmers, working the land. In the 60s and 70s the farms were forced to adapt to new techniques of industrial scale farming, employing the use of combine vehicles. The need for labor was quickly reduced and those who refused to adapt would quickly run out of business. The ancient technique of crop rotation, which lets the ground heal by employing different crops in regular intervals was abandoned, because fertilizers and pesticides allowed farmers to grow the economically most valuable species of corn and soybean, year after year. As a result the farmlands were severely depopulated and the number of sections per farm substantially grew. This meant that you could suddenly drive for hours on end without seeing a single human being.
Industrial farming
One of the many abandoned farms in the Corn Belt (Montana).
Another example of mechanization which contributed to depopulating the American countryside and changing the land is the central pivot irrigation system. These automated sprinklers rotate along a pivot, creating a circular pattern, so easily recognisable when flying above the Midwest.
The pivot irrigation system is usually based on dividing a section in four. This means that each sprinkler is usually designed to be exactly 1/4 mile, or 400 meters long.
The exact size of the Corn Belt is not agreed upon, but it covers at least the states of Iowa, Illinois, Indiana, southern Michigan, western Ohio, eastern Nebraska, eastern Kansas, southern Minnesota and part of Missouri. It forms the world's most productive area of agriculture and is truly the world's breadbasket. In 2010 the United States exported 316 metric tonnes of corn. China, the second largest supplier exported 177 Mt (though China is a larger exporter of rice). In dollar value the US is by far the largest food exporter in the world.
A NASA satellite image measuring plant florescence during growth season in America.
A map of the Corn Belt of America.
Roads showing the outlines of the sectors of Illinois.
The Corn Belt has made a profound impact on American ecology and geography. It is truly one of the most remarkable and crazy examples of human engineering of natural landscapes. For this reason it has also captured the imagination of American society in film, literature, music and architecture.
The cornfield chase in Interstellar
The final scene of Cast Away
Frank Lloyd Wright's dream of a decentralized, utopian city (Broadacre city) was probably inspired by the Corn Belt and the township system.
Sources:
https://lib.dr.iastate.edu/rtd/1827/
https://modernfarmer.com/2014/04/nasa-shows-u-s-corn-belt-literally-glowing-productivity/
http://www.encyclopedia.chicagohistory.org/pages/410050.html
https://en.wikipedia.org/wiki/Public_Land_Survey_System
https://no.wikipedia.org/wiki/Dust_Bowl
https://en.wikipedia.org/wiki/Township_(United_States)
https://en.wikipedia.org/wiki/Prairie
https://en.wikipedia.org/wiki/Center_pivot_irrigation
https://www.investopedia.com/financial-edge/0712/top-agricultural-producing-countries.aspx