On the concrete floor of a greenhouse in rural Kansas stands a neat grid of 100 plastic plant pots, each holding a straggly crown of strappy, grass-like leaves. These plants are perennials – they keep growing, year after year. That single characteristic separates them from soya beans, wheat, maize, rice and every other major grain crop, all of which are annuals: plants that live and die within a single growing season.

“These plants are the winners, the ones that get to pass their genes on [to future generations],” says Lee DeHaan of the Land Institute, an agricultural non-profit based in Salina, Kansas. If DeHaan’s breeding programme maintains its current progress, the descendant of these young perennial crop plants could one day usher in a wholesale revolution in agriculture.

The plants are intermediate wheatgrass. Since 2010, DeHaan has been transforming this small-seeded, wild species into a high-yielding, domesticated grain crop called Kernza. He believes it will eventually be a viable – and far more sustainable – alternative to annual wheat, the world’s most widely grown crop and the source of one in five of all calories consumed by humanity.

Elite Kernza plants selected from 4,000 seedlings in the Land Institute’s perennial grain breeding programme. Photograph: Ben Martynoga

Annual plants thrive in bare ground. Growing them requires fields to be prepared, usually by ploughing or intensive herbicide treatment, and new seeds planted each year. For this reason, Tim Crews, chief scientist at the Land Institute, describes existing agricultural systems as “the greatest disturbance on the planet”. “There’s nothing like it,” he says.

The damage inflicted by today’s food system is clear: one-third of global greenhouse gas emissions; ocean dead zones covering thousands of square miles; and 25bn-40bn tonnes of fertile topsoil lost each year.

Replacing annual plants with perennial varieties would massively reduce agriculture’s environmental impact. Soil erosion would drop; perennials would instead build soil health, limiting runoff of nutrients and toxic farm chemicals, cutting fertiliser and pesticide use, and storing climate-heating carbon within farm soils.

There is just one problem. Reliable, high-yielding perennial grain crops barely exist.

The inspiration for the Land Institute’s push to develop perennial grains came from its founder, Wes Jackson, 89. For Jackson, the health of soils that generate 95% of human calories should be a primary concern for all civilisations. “Soil is more important than oil,” he says in a recent documentary. “Soil is as much of a non-renewable resource as oil. Start there, and ask: ‘What does that require of us?’”

Lee DeHaan at the Land Institute in Salina, Kansas. Photograph: Ben Martynoga

Jackson hit upon an answer during a visit to a native prairie reserve in Kansas in the late 1970s. Prairies are highly productive and biodiverse perennial grassland ecosystems. They don’t erode soils; they build them. Indeed, the rich soils that make much of the US midwest and Great Plains such prime agricultural lands were formed, over thousands of years, by prairie plants working with underground microbes.

Why is it that we cannot have perennial grains that grow like prairie plants, Jackson wondered. “That was the epiphany that set me off,” he said in a recent interview.

DeHaan, 52, learned about Jackson’s mission while he was a teenager in the early 1990s. Having grown up on a Minnesota farm, he was immediately inspired. “I would love to try to create the first perennial grain crop,” he resolved. “That became my dream.”

Though still under development, Kernza is already a viable crop, grown at modest scale in 15 US states. Kernza seeds and flour are used in a range of products, from beers to breakfast cereals.

The key challenge is yields. In Kansas, the best Kernza yields are about one-quarter those of annual wheat. But DeHaan says this is changing rapidly. “My best current extrapolation is that some Kernza plants could have wheat-like yields within about 15 years.”

“We have to go fast,” he says. To hit this target, his breeding scheme deploys DNA profiling, computer modelling and far-red LED lighting to push the experimental plants through two full breeding cycles each year.

But yields are just one metric of success. Whereas annual wheat roots are about half a metre long and temporary, Kernza’s roots are permanent and can plunge 3 metres deep. Such roots unlock a whole suite of environmental and agricultural benefits: stabilising and enriching soils, gathering nutrients and providing water, even during droughts.

A comparison of wheatgrass (left) and wheat roots at the Land Institute. Photograph: Ben Martynoga/The Land Institute

Perennial plants also tend to have far stronger in-built resistance to pests, diseases and weeds than annual plants, especially when grown in mixed plant polycultures.

The Land Institute is working with collaborators across 30 countries to develop many new perennial crops: oil seeds, wheat, pulses, quinoa and several other grains.

The potential applications are diverse. In Uganda, researchers are developing perennial sorghum for drought tolerance. In war-torn Ukraine, where supply chains are disrupted and rich soils are degrading, Kernza is being tested as a low-input crop. As DeHaan, Crews and colleagues write in a recent scientific paper, perennial grains represent “a farmer’s dream … a cultivar that is planted once and then harvested every season for several years with a minimum of land management.”

Success is far from guaranteed. But perennial rice, grown in China since 2018, provides crucial proof of concept. Led by Yunnan University with Land Institute support, the work took just 20 years. Perennial rice now matches the yields of elite annual varieties, with research demonstrating significant greenhouse gas reductions.

Perennial rice grown in a research trial in Yunnan. Photograph: Ben Martynoga/The Land Institute

DeHaan believes perennial grains are uniquely capable of rebalancing what he calls the “three-legged stool” of agricultural sustainability, whereby productivity, farm economics and environmental impact must be in balance.

This metaphor is not abstract for DeHaan – he has lived it. During the 1980s, his family’s Minnesota farm produced plenty of grain but the economics failed. Spiking interest rates forced them to sell, along with thousands of other midwest farms. The environmental costs – eroding soil, contaminated water – did not appear on any ledger, but they were visible in the landscape.

Current agriculture, DeHaan argues, is supported by $600bn in annual subsidies worldwide, which too often prop up production, while farming communities struggle and ecological damage mounts.

Perennial grains could eventually deliver on all three fronts simultaneously. But formidable challenges must still be solved to achieve that.

Kernza growing on the Land Institute’s research fields. Lee DeHaan estimates the crop’s yields could match wheat within 15 years. Photograph: Ben Martynoga

Yields must improve substantially. The problem of harvests tapering off, year-by-year, must also be solved. Farmers will have to develop new methods for growing and harvesting these crops. Markets present another hurdle. Current supply chains are optimised for a narrow range of staple crops, grown in monoculture, making processing costs prohibitive for new crops with different properties.

Kernza grain – smaller than wheat – ready for milling. Photograph: The Land Institute

For all these reasons, DeHaan firmly rejects the idea that perennials are a “silver bullet”. “The reason is that it’s difficult,” he says. “The trade-off is time and investment. That’s why they don’t exist yet. It’s going to take decades of work and millions of dollars.”

Remarkably, DeHaan does not paint the current agricultural-industrial complex as the enemy. “Every disruptive technology is always opposed by those being disrupted,” he says. “But if the companies [that make up] the current system can adjust to the disruption, they can play in that new world just the same.”

The Land Institute’s strategy is redirection rather than replacement. “Our trajectory is to eventually get the resources that are currently dedicated to annual grain crops directed to developing varieties of perennials,” says DeHaan. “That’s our [route to] success.”

There are signs that this is already working, with the food firm General Mills now incorporating Kernza into its breakfast cereals.

Back in the Kansas greenhouse, DeHaan strikes a reflective note. “When I started working here in 2001, these ideas were regarded as very radical. It was embarrassing to even bring up the ideas we were working on. It was laughable.”

That, he says, is no longer true. Major research institutions, businesses and an expanding network of global partners are now engaging with perennial grain development.

DeHaan points to his “winners” – the 100 young Kernza plants before us. Within a human generation, their descendants could be feeding millions while repairing soils that took millennia to form. “We don’t just have our head in the clouds,” he says. “We’re not just dreaming of this impossible future.”