Wheat on Repeat

by Emma Bryce (Anthropocene) ... A growing movement of researchers, farmers, and producers believe that perennial crops have unmatched potential to reform agriculture’s warped system, and are pinning their hopes—and research dollars—on the likes of Kernza to deliver that. The grain is now cultivated across 4,000 acres of land, by over 100 farmers across the US Midwest and as far afield as Sweden and France. Its distinct aromas have made their way into craft beers, cereals, crackers, and whiskey, and have been embraced by major brands such as Patagonia.

As a potential substitute for wheat, which covers more global land area than any other commercial crop, Kernza seems to herald a wholesome, low-carbon revolution in the vast agricultural sector. And yet 15 years since the first stands took root, the crop has only managed to capture a tiny fraction of the market, a victim of limited yields, government regulation, and a conservative farming industry. So can Kernza ever displace traditional amber waves of grain, or is it doomed to be a perennial runner-up?

If all land currently under annual grain crops were converted to perennial agriculture, the soil could accumulate almost twice the annual emissions of global aviation

DeHaan and colleagues hunt for plants that show favorable traits such as large or numerous seeds, and cross-pollinate the most promising candidates with one another. Years of this manual, non-GMO breeding has produced Kernza, a crop that retains its perenniality but produces more grain than its parent plants. Such selective breeding has doubled Kernza’s yields in 10 years.

Like other perennials, Kernza offers a tantalizing ecological alternative to industrial crops, starting with carbon use and storage. “Between nitrogen and monster tractors, and every other thing that goes into [agriculture], it is an absolute fossil fuel bonanza going on out there. And there are not very many options for backing out of that, shy of creating an agriculture that is far more like the rest of the ecosystem,” says Timothy Crews, director of the International Program at The Land Institute.

Because perennial grasses grow for many years, they develop a dense, beard-like tangle of roots that reaches deeper into the ground than annuals. Meters below ground, there is less turnover and less decomposition, locking down carbon for longer—or possibly even permanently. Perennial crops also require less tilling than annual agriculture, leaving the soil and its diverse microorganisms undisturbed, both of which help to maintain soil carbon. “Those two things—stabilizing soil structure and growing deep abundant roots—cause a greater carbon accumulation,” says Crews.

A single, firm estimate of precisely how much proves elusive, as the rate of carbon sequestration of a plant can vary drastically, depending on environmental and other factors. But some insights have come from comparing Kernza with other crops grown under the same field conditions. For example, fields of Kernza growing adjacent to plots of annual grains accumulated an average of 0.4 tonnes more carbon per hectare per year, for 10 years. (Numbers will differ by landscape and crop type—for instance higher Kernza carbon values have been shown in cooler, wetter climes, says Crews.)

According to one study, Kernza reduced the amount of nitrate leaching into the soil by two orders of magnitude, compared to maize. “It is a solution to dead zones,” says Crews. “There are many eutrophic water bodies, with phosphorus or nitrogen loss, that are curbed substantially with these perennials.”

Perennials also stabilize the soil, helping to build up layers of organic matter that accumulate nutrients and retain water, and support rich microbial communities. Additional research of Crews’ shows that the microbial communities below Kernza are comparable to wild native grasslands.

For Crews, one perk really stands out, and it is increasingly the reason why researchers and farmers from Japan to Ukraine seek out the grain: perennials help slow the erosion of critical topsoils.

So why aren’t we tearing up fields of wheat and replacing them with Kernza? Because despite the grain’s exponential yield growth in the last decade, yields are at best a quarter of wheat’s, and can’t compete economically.

Adding to the financial burden, Kernza is a smaller grain whose husk requires a different type of processing. “Processors don’t like that, so they’re gonna charge you sometimes ten times the price [compared to wheat],” DeHaan says. Overall, Kernza’s costs are roughly nine times higher than wheat.

And there’s another challenge. Kernza’s gluten content is naturally lower than wheat’s, reducing the starchiness needed to make bread and many other wheat-based foods. For the time being, “that’s going to inhibit a takeover of wheat directly,” adds Crews.

Kernza represents a vanishingly small fraction of today’s wheat market, and this plays on DeHaan’s mind: “People have tried to introduce new crops over and over again, and they have almost always failed,” he says. “That’s because it’s really hard to get something to the scale where it becomes cost-efficient.”

There are some hopeful perennial examples to look to. A guiding north star is the Chinese perennial rice, developed by Chinese scientists crossing an annual Asian rice with a perennial African relative. That work resulted in a perennial grain that now flourishes across 37,000 acres in South Asia and Africa and that, in 2022, reached the same yields as annual rice: “We’re talking six or seven tons of rice per harvest, twice a year, for four years. It is miraculous,” says Crews. Field trials across three sites in China showed that the soil has been accumulating almost one ton of organic carbon per hectare of land, per year, since transitioning to perennial rice. Farmers now spend 50% less on inputs including fertilizer, and their income increased by between 17% and 161%. “For us, it’s a wonderful case study that shows it is possible to have a perennial grain, no matter how you arrive at it. There’s not an inherent trade off in a plant being perennial and high yielding,” says Crews.

But not everyone is sure that a similar story will unfold for Kernza. “The question is, could or should Kernza be considered a replacement for annual wheat, or its own type of grain?”

But the real bullseye is crop insurance, which Kernza currently does not qualify for: “Close to ninety percent of the major crops on the US landscape carry crop insurance. That is a critical part for a crop to be attractive to farmers, especially with unpredictable weather patterns,” says Cynthia Bartels, a research scientist on the Kernza-CAP project. While crop insurance products are being developed for Kernza, those will likely take a few more years to sign off, she adds.

Internationally, there are more fundamental hurdles to Kernza’s progress. In the EU, the next major market for this crop, costly compliance testing and paperwork have so far prevented Kernza from being commercially farmed.

Alongside Kernza, The Land Institute is also developing perennial sorghum, oilseeds, and legumes. The next-closest to commercialization is the trademarked Baki bean, a high-yielding, soybean-like perennial, which the Institute is also interested in commercializing in the EU. READ MORE