The Corn That Grows Itself

How microbes could upend America’s toxic dependence on nitrogen fertilizer

Crabs, clams, and worms die almost immediately. Fish, shrimp, and any animal that can swim quickly enough make valiant, though often doomed, efforts to flee. There are few places to go in a dead zone that can reach the size of New Jersey.

The Gulf of Mexico hypoxic zone — or “dead zone,” as it’s more commonly known — is a stretch of seawater where vast swaths of slimy algae bloom annually. When the algae eventually die, they decompose, sucking up so much of the water’s oxygen that all nearby aquatic life suffocates. In 2017, this dead zone measured 8,776 square miles, the largest since scientists at the National Oceanic and Atmospheric Administration began recording it in 1985. This summer’s dead zone is expected to be the second-largest on record at 8,717 square miles, according to scientists at Louisiana State University.

You can find the source of the dead zone by traveling north out of the Gulf, up the Mississippi River, and through its tributaries as they branch out into the agricultural nervous system of the U.S. In the rich, black soil of the Midwest, you’ll find the culprit: nitrogen fertilizer, the backbone of modern industrial farming.

Farmers around the world use 120 million tons of nitrogen fertilizer each year. (Another 54 million tons is added in the form of things like manure and atmospheric deposition.) In the U.S., much of the fertilizer goes into the Corn Belt — an area stretching from Nebraska to Ohio, Minnesota to Missouri. There, 6 million tons of nitrogen fertilizer are spread across farmland every year.

Close to 100 million tons of nitrogen added to the world’s crop fields are lost to the environment every year, either as gas emissions or as runoff.

While nitrogen fertilizer deserves considerable credit for driving a century-long global increase in crop yields, it’s also nasty stuff. The chemical factories that produce the material expel as much greenhouse gas into the atmosphere as all of the houses in America combined. Fertilizer is finicky and its application is often wasteful. Because it’s easily washed away by rain, farmers are often forced to spend more time and money applying more fertilizer.

And, as the hypoxic zone indicates, nitrogen fertilizer is a huge environmental hazard: Close to 100 million tons of nitrogen added to the world’s crop fields are lost to the environment every year, either as gas emissions or as runoff. Nitrogen feeds the algae that blooms in the Gulf: more runoff equals more algae, which equals a bigger dead zone. According to the International Nitrogen Management System, a project led by UN Environment, the world must halve its usage of the agricultural chemical by 2050, or else prepare for poisoned water that creates more dead zones across the world’s oceans.

But what if farmers didn’t need nitrogen fertilizer? What if they could fertilize their crops, increase their yields, continue to feed a growing population — and do it all without putting a single atom of nitrogen in the soil?

More than 100 years after the last breakthrough in nitrogen technology, we’re on the precipice of finding out. Pivot Bio, a Silicon Valley startup, believes it can convince farmers to swap out nitrogen fertilizer in favor of specially-fermented soil bacteria that can fuel crop growth organically, without the waste and ecological hazard of traditional methods. The eight-year-old company is armed with more than $86 million in financing from the likes of the Gates Foundation, DARPA, and Breakthrough Energy Ventures, an investment fund that includes bigwig billionaires like Jeff Bezos and Richard Branson.

There’s one obstacle, though. Creating a next-gen fertilizer, says Pivot Bio CEO Karsten Temme, “is the hardest problem in agriculture.”

Trials show that the startup’s nitrogen-producing bacteria is tenacious, and can deliver a steady stream of nutrients across an entire growing season. When mixed in with traditional fertilizer, Pivot Bio’s microbes can increase production by nearly eight bushels per acre. For someone like Indiana farmer Jake Misch, who tries squeezing at least 170 bushels of corn out of every acre, that’s 448 more pounds of crop he can turn into cash. Misch is Pivot Bio’s first customer.

After a year of beta tests and five years of field trials, the startup is selling its product on the open market, just another step toward its ultimate goal: completely replacing chemical nitrogen fertilizer. Misch says that for about $100 apiece, he purchased 16 boxes of microbes, enough for 80 acres.

“I hope it works,” says Misch. “I hope we see good results. I think we will. But time will tell.”