The Future of Corn Production May Be Underground

Corn as a commodity is pretty wacky in the United States. The US grows more than any other country on Earth, but some very large piece (the largest) of that goes to ethanol production and is subsidized by the federal government. This fixes prices across the globe, and can be implicated in disastrous, riot-fostering food price spikes in the developing world. If the planet is going to keep producing new humans and/or keep shoving corn into gas tanks, we're going to need more corn—a critical staple food so far irreplacable—one way or another.

One way to produce more corn is to take up more land, but that's not as easy as it sounds. Corn, even as a last-ditch staple, has some preferences about where it grows. The American Midwest offers flat land and fertile soil, along with a favorably long growing season and lots of daylight, which is why you'll find most of the country's corn crop growing in states like Iowa, Nebraska, and Minnesota.

Before continuing, there are demand-side solutions to corn. One of those is just eating the damn stuff rather than carving out a huge piece of the production pie for a waning would-be green technology and lots and lots of animal feed. Meat, in the grand scheme of food system efficiency, is miserable. If we're not going to give up eating meat, the practice of which consumes just under a third of yearly corn production, we'll need more land. One interesting solution, laid out in a study released today in the journal Industrial Crops and Products, is to start growing corn underground.

The US (and other countries) have quite a bit of underground land, at least more than you'd think. The country is porous with old mining tunnels and natural caves, the natural response to which has been sealing them up or otherwise ignoring their existence. And it turns out that corn can be more flexible in its growing preferences than might otherwise have been thought; it's possible to create a simple hybrid crop just by limiting the temperatures that a corn cultivar is exposed to for two hours a day. The result is a shorter (by about two feet) hybrid variety of corn that produces the same volume of seeds as normal, non-stunted corn.

The researchers, based at Purdue University, point out that this might be one way to keep high value transgenic corn varieties—such as those producing compounds used in the pharmaceutical industry—seperate from other corn varieties, thus preventing cross-breeding.

Obviously, these aren't dark mines and caves. There would need to be artificial light sources. The main difference for the plants is in terms of temperature and atmosphere (less O2, more CO2). The Purdue researchers actually tested this out in an abandoned limestone mine supplied with some insulation and high-intensity discharge lamps, with the result being plants that did too well. "We coddled the plants with such luxurious conditions that the corn was touching the lamps before it had even tasseled," notes study co-author Yang Yang in a press release.

While the discussion so far is limited to growing super-specialized transgenic corn in these environments, there's no reason for that to be the end of it. While a means to increase productive land and segregate hybrid/transgenic cultivars here on Earth, one might also imagine applications for underground farming on other planets where the surface isn't suitable for crops. In this way, underground farms could one day become terraforming machines, converting high levels of underground carbon dioxide into oxygen, to be released on the surface. On Earth, that's one of the reasons for the super-success of underground crops in the very first place: a relative abundance of CO2.

Cary Mitchell, the paper's lead author, adds, "Productivity in a controlled environment is superior to that in the field, and you can raise more than one crop per year." So imagine continuous rotating harvests of most any crop imaginable. That's more than adding production capacity, it's cutting back on the absurb feats of global transportation we rely on to keep currently seasonal things like apples and spinach in grocery stores year-round. Needless to say, whether it's a matter of sponging carbon dioxide from the atmosphere or cutting global shipping fuel costs, this idea should also be considered a climate win, at the very least as a nice side effect.