Descendants of the Maya living in Mexico still sometimes refer to themselves as "the corn people." The phrase is not intended as metaphor. Rather, it's meant to acknowledge their abiding dependence on this miraculous grass, the staple of their diet for almost 9,000 years.
For an American like me, growing up linked to a very different food chain, yet one that is also rooted in corn, not to think of himself as a corn person suggests either a failure of imagination or a triumph of capitalism.
Or perhaps a little of both. For the great edifice of variety and choice that is an American supermarket rests on a remarkably narrow biological foundation: corn. It's not merely the feed that the steers and the chickens and the pigs and the turkeys ate; it's not just the source of the flour and the oil and the leavenings, the glycerides and coloring in the processed foods; it's not just sweetening the soft drinks or lending a shine to the magazine cover over by the checkout. The supermarket itself—the wallboard and joint compound, the linoleum and fiberglass and adhesives out of which the building itself has been built—is in no small measure a manifestation of corn.
There are some 45,000 items in the average American supermarket, and more than a quarter of them contain corn. At the same time, the food industry has done a good job of persuading us that the 45,000 different items or SKUs (stock keeping units) represent genuine variety rather than the clever rearrangements of molecules extracted from the same plant.
How this peculiar grass, native to Central America and unknown to the Old World before 1492, came to colonize so much of our land and bodies is one of the plant world's greatest success stories. I say the plant world's success story because it is no longer clear that corn's triumph is such a boon to the rest of the world.
At its most basic, the story of life on earth is the competition among species to capture and store as much energy as possible—either directly from the sun, in the case of plants, or, in the case of animals, by eating plants and plant eaters. The energy is stored in the form of carbon molecules and measured in calories: the calories we eat, whether in an ear of corn or a steak, represent packets of energy once captured by a plant. Few plants can manufacture quite as much organic matter (and calories) from the same quantities of sunlight and water and basic elements as corn.
The great turning point in the modern history of corn, which in turn marks a key turning point in the industrialization of our food, can be dated with some precision to the day in 1947 when the huge munitions plant at Muscle Shoals, Alabama, switched over from making explosives to making chemical fertilizer. After World War II, the government had found itself with a tremendous surplus of ammonium nitrate, the principal ingredient in the making of explosives. Ammonium nitrate also happens to be an excellent source of nitrogen for plants. Serious thought was given to spraying America's forests with the surplus chemical, to help the timber industry. But agronomists in the Department of Agriculture had a better idea: spread the ammonium nitrate on farmland as fertilizer. The chemical fertilizer industry (along with that of pesticides, which are based on the poison gases developed for war) is the product of the government's effort to convert its war machine to peacetime purposes. As the Indian farmer activist Vandana Shiva says in her speeches, "We're still eating the leftovers of World War II."
F1 hybrid corn is the greediest of plants, consuming more fertilizer than any other crop. Though F1 hybrids were introduced in the 1930s, it wasn't until they made the acquaintance of chemical fertilizers in the 1950s that corn yields exploded. The discovery of synthetic nitrogen changed everything—not just for the corn plant and the farm, not just for the food system, but also for the way life on earth is conducted.
All life depends on nitrogen; it is the building block from which nature assembles amino acids, proteins and nucleic acid; the genetic information that orders and perpetuates life is written in nitrogen ink. But the supply of usable nitrogen on earth is limited. Although earth's atmosphere is about 80 percent nitrogen, all those atoms are tightly paired, nonreactive and therefore useless; the 19th-century chemist Justus von Liebig spoke of atmospheric nitrogen's "indifference to all other substances." To be of any value to plants and animals, these self-involved nitrogen atoms must be split and then joined to atoms of hydrogen.
Chemists call this process of taking atoms from the atmosphere and combining them into molecules useful to living things "fixing" that element. Until a German Jewish chemist named Fritz Haber figured out how to turn this trick in 1909, all the usable nitrogen on earth had at one time been fixed by soil bacteria living on the roots of leguminous plants (such as peas or alfalfa or locust trees) or, less commonly, by the shock of electrical lightning, which can break nitrogen bonds in the air, releasing a light rain of fertility.