Corn

I was going to research and write about wheat, but alas. Corn likewise started out as one thing, and is now something very different. Though that’s true for a lot of domesticated plants. Corn is in fact so domesticated that it can’t even grow without our help at this point since the seeds won’t fall off (they’ve been bred that way since it’s very convenient for harvesting).

Those seeds, aka kernels (which is an etymological sibling of “corn” which in Old English meant a single seed of a cereal plant like wheat, barley, or rye), each develop distinctly by pollination of the silk, each silk being tied to one kernel.

Alongside the distinctness of each popcorn kernel, corn as an aggregate is produced in rather large quantities. It is the most produced cereal grain in the world by weight, and the second most produced crop (after sugarcane whose production is as much as corn and rice, the number three spot, put together). One corn plant can produce between 600 and 1000 new corn plants (the “multiplication ratio”) and corn currently has the highest potential for carbohydrate production per unit area per day, and the highest grain yield per hectare.

The vast majority of that corn isn’t for human consumption, though, but goes toward producing ethanol and feeding livestock. The history of the ethanol market in the United States, and the production of corn to meet it, finds its story in the Energy Tax Act of 1978 followed by the Clean Air Act of 1990, the Energy Policy Act of 2005, and the Energy Independence and Security Act of 2007. Tldr: the US wanted to rely less of foreign oil, began mandating oxygenated gasoline for a cleaner burn (ethanol helps), and required that all gas have at least 10% ethanol.

The production of corn into ethanol is a net energy-positive process–we get out 34% more than we put in according to the USDA’s “The Energy Balance of Corn Ethanol: An Update”, to say nothing of the externalities of producing it (like how much nitrogen from fertilizer finds its way into the Gulf of Mexico or how the Ogallala aquifer is being overdrawn and wells are running dry due to the water-intensive nature of corn farming).

This fast-burning nature of the corn energy cycle has been in development for a while. Pre-domesticated wild corn has much higher protein content than subsequent varieties which have been bred for sugar and starch. Domestication is estimated to have taken a couple hundred years in Mexico some nine thousand years ago, but genetic selection really began to take off in 1933, at which time less than one percent of the corn grown in the US was a hybrid variety, increasing to over 90% by 1945. These hybrids were produced by a breeding program which began by creating pure inbred varieties. Turns out when you self-fertilize corn most of it is so genetically un-diverse that it dies out. The ones which survive, though, called “selfed lines” (they’re much worse than average corn for production) can be used to pollinate one another making a “single cross”. If you take two single cross lines and use them to pollinate each other you get a “double cross”. Many of these crosses were made and their properties compared and selected for. (In fact, many states now have their own performance trial infrastructure which companies use to test new varieties.) Some of these double-crosses were so productive that average grain yield per hectare doubled within 30 years. Later techniques made comparably productive single-crosses which were preferable for farmers because they have more uniform ears.

Turning corn into a more uniform product for consumption has been a thing for thousands of years, with the invention of masa flour in Mexico which is made beginning with a process called nixtalamization, a word from Nahuatl made up of “nextli” (lime ashes) and “tamal” like tamales (the tasty corn snack), which involves cooking and soaking the kernels in a basic solution (hence the lime ashes). (They may have figured this out by cooking kernels in a limestone bowl, but the jury’s out.) Conveniently this process makes a more viable dough than if you just grind corn up with water since it gelatinizes some of the starch, plus it makes available the vitamin B3 which is otherwise not accessible in digestion. The same process is still used today to make tortillas (the average consumption in Mexico is 350-500 calories of tortillas per day) and other snacks like Doritos (which sell about $2 billion per year). There’s an entire industry around processing dry masa flour (DMF) as well as experiments in speeding up nixtamalization like using ultrasonic probes to jitter the solution (at small scales resulting in a 10x speedup in soaking time).

How much these things are about corn, and how much corn happens to be a convenient avenue for capital, concentration, compression, and extraction, who knows. Perhaps it is a mirror.

Or perhaps it’s that corn is so adaptable that these things have all come to pass. That within a dozen years the entire genetic distribution can be changed over and increase yields, that it can be bred towards burning in a car, fattening up a cow, or popping in the movie theater. That it can grow as far north as Canada and as far south as New Zealand.

The diversity of corn has even resulted in a variety called olotón (or Sierra Mixe) in Oaxaca, Mexico, which grows over 16 feet tall and has aerial roots which secrete mucus supporting bacteria which fix nitrogen, meaning that it requires no fertilizer to grow. It may be the only nitrogen fixing cereal crop in the world to date, and is under study at UC Davis. Which is all to say that in these changing times, perhaps we’d best look to corn for tips on how to adapt, evolve, and thrive. It’ll give us an earful.