The nitrogen fertilizer spread on many farms in the U.S.–part of more than 100 million tons used around the world every year–begins life in massive, energy-intensive factories that suck in air and react it with natural gas to make something that plants can use. A new startup has a different vision for the future: crops designed to fertilize themselves.
“The idea is that it would be able to let you reduce–and maybe ultimately replace–synthetic nitrogen fertilizer,” says Jason Kelly, CEO and co-founder of Gingko Bioworks, a Boston-based genetic engineering company, which partnered with Bayer, the multinational biochem company, to launch the new, as-yet-unnamed ag-tech startup.
The startup plans to harness microbes that live on a few crops–like beans and peanuts–that make those plants able to fertilize themselves and bring the same capability to plants that can’t, particularly corn, wheat, and rice, which alone make up more than 55% of fertilizer use.
When synthetic fertilizer was invented in the early 20th century, and became widely used after WWII (as nitrogen plants built during the war to make bombs began marketing their products to farmers), it transformed agriculture. Nitrogen is an essential nutrient for plants, and adding it to a field boosts growth. While a few plants, like beans, can “fix” nitrogen by working with bacteria that pull it from the air, most crops need more from the ground help to grow abundantly. As new synthetic fertilizer made it possible to grow more food, the global population swelled; the trend line for population growth mirrors the growth in fertilizer use.
It also caused problems. Runoff of fertilizer from fields causes algae blooms in lakes and streams that kill fish and lead to dead zones in the ocean, where low oxygen levels mean that most marine life can’t survive. Fertilizer production requires huge amounts of natural gas, and both production and use have large carbon footprints. Fertilizer is so overused on fields that most of it is ultimately wasted; when a farmer adds more than plants can use, that worsens problems with runoff. And when microbes in the soil digest fertilizer, they emit nitrous oxide, a greenhouse gas that traps heat 300 times more than carbon dioxide.
While farmers could reduce fertilizer use today (for example, by using technology that allows it to be applied at variable rates on a field), it’s a challenge to make that happen. “Current economics work against these practices–fertilizer is relatively inexpensive, and most farmers conclude, rationally, that it’s more profitable to offload the environmental costs to society than to spend the extra time and expense to apply it more precisely,” says Philip Robertson, a professor of plant, soil, and microbial sciences at Michigan State University.
Organic farming–using natural fertilizer like manure, and rotating crops like beans that naturally build up nitrogen (leaving the soil healthier) with those that can’t–is environmentally sustainable, but it’s more difficult and expensive to make productive enough to feed the 7.5 billion people alive today, or the 11.2 billion people that will be alive by the end of the century. The new startup aims to make crops as productive as conventional techniques today.
“Microbes that are living in the roots of the peanut plant essentially run the exact same nitrogen to ammonia gas conversion [as a chemical plant] but they do it right there in the roots–so they make the fertilizer much more efficiently, and just for the plant,” says Kelly. “Of course, you don’t need that big chemical plant, you don’t need that energy use if you have the microbe doing it right there on the spot.”
While it would dramatically reduce energy used to make fertilizer, it’s not clear yet how well it would prevent excess nitrogen from spreading. “It depends on how ‘leaky’ the plant is,” says Robertson. “Most nitrogen-fixing crops produce excess nitrogen that leaks into the environment similar to fertilizer nitrogen.”
As the new startup works on the technology, Bayer will make use of its extensive collection of microbes that it knows “play well” with particular crops. Gingko Bioworks will bring those into its lab, where it can print new DNA and design new microbes that (if all goes well) will fix nitrogen on crops like corn.
“We’re going to be changing them pretty substantially to get them to start making the fertilizer,” says Kelly. “But we have to make sure that it doesn’t make them no longer live well on the plant. That tension between these things is one of the core challenges.”
For farmers, the new plants have the benefit of reducing cost and the labor of adding fertilizer to a field. But because there’s a consumer benefit as well–consumers increasingly want to support products that reduce carbon emissions–Kelly believes that the crops may be more likely to gain acceptance than some other genetically modified food in the past.
“There is a big consumer benefit in this case, and I think that changes the dynamic quite a bit,” he says. “But communicating and helping people understand all of that is really key . . . it’s important to establish that trust, and help people understand, ‘Why should I be willing to bring a new technology in, what am I getting out of it?’ There has to be something there.”