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It’s a cycle nearly as old as human history. Plow, plant, harvest, and repeat. It worked for our ancestors, and it’s working for us now, though with ever more problems, from obliterating soil nutrients to encouraging erosion. And things may get worse in the future, too, when climate change threatens—whether through drowning or drought—to topple our food production system at the moment we’ll need it most: In less than 90 years, the world’s population could crest between 9 and 12 billion, and that will test the limits of farming.
“Soil quality around the world has become degraded,” says Sieglinde Snapp, an agroecologist at Michigan State University. “So how are we going to feed more people with higher quality food? How will we provide more protein? And the big question is: how are we going to feed 9 billion in a sustainable way with degraded soil?”
Modifying crops like wheat could help boost yields by extending the
growing season.
There are myriad possibilities. Among the options is raising the output of current farming techniques using genetic modification, specialized fungi, or precision agriculture. But another ambitious idea is to extend the growing season, which will involve rewriting much of the book of agriculture. In other words, if we were to redo the agricultural revolution today, what would it look like?
For untold generations, farmers have plowed their fields and planted their crops in the spring, harvested them in the fall, and done it all over again the next year. But in the last several decades, agricultural experts have been experimenting with eliminating the spring planting by developing perennial crops, essentially revising thousands of years of selective breeding.
To see how perennials could help, just visit a farm in the Midwest in the dead of winter. You’ll likely find fallow fields scattered with dead plants. Some of them may be covered in snow. But under the surface, the frozen soil has locked in key nutrients and water. When the spring thaw begins—but before it’s dry and pliable enough for planting the next season’s crops—the warming fields will begin to lose some of their moisture and nutrients, which end up draining into ditches, rivers, and streams or seeping into the atmosphere. From a farmer’s perspective, the combination of these soil changes, the longer days, and the springtime rains add up to a lost opportunity. If only they could start growing sooner.
Which is why a relatively small group of scientists are developing year-round cereals and oilseeds, both key ingredients of the modern human diet. Most of these grains today are annuals, which complete a lifecycle once every year and must be replanted the next growing season. Depending on the farming method, the cycle may include tilling, sowing, and harvesting, which, when done regularly on the same plot of land, leeches nutrients from the soil and contributes to erosion. This system also requires more energy-intensive machines and materials, from fossil-fuel-burning farming equipment to synthetic fertilizers that push nitrogen back into over-taxed soil.
Perennial crops, on the other hand, could survive for many seasons, axing the annual cycle and lessening farming’s wear-and-tear on the environment. Some varieties could also have longer, lusher root systems that would sink deeper into the ground, helping maintain soil health and curbing erosion. They could even help the plants survive a drought.
Such a system would allow for longer growing seasons, too, taking advantage of the late autumn and early spring months when fields usually lay bare. Assuming that perennial crops produced the same amount as their annual counterparts—a big assumption—this would provide additional food each year from the same plot of land. A shift from annuals to perennials, or a mixture of both, could benefit both the environment and food security.
“The way in which we currently grow grains is very similar to how we started growing grains a long, long time ago, and the ecosystem of agriculture has not changed much over that period of time,” says Timothy Crews, an ecologist and the research director at the Land Institute in Salina, Kansas, where scientists have been studying perennial crops since the mid-1970s and actively breeding them since 2000. “We need to supplant purchased, high-energy inputs and mechanization inputs with ecological processes that achieve comparable or superior outcomes, which could build slow organic matter in cropping systems instead of maintaining or depleting it, which is what current agriculture does.”
The trick, however, will be coaxing crops into simultaneously surviving year-round and growing plump and harvestable seeds. Plants, as we’ve discovered over the millennia, tend to prefer one or the other, not both. Though thanks to the work of Crews and a handful of enterprising scientists, that may be changing.
Perennial Advances
Agronomists and botanists have been trying to create perennial crops since at least the 1920s, when Russian scientists started a program to breed perennial wheat. But over the past ten to 15 years or so, the field has grown significantly, says Lee DeHaan, a plant geneticist at the Land Institute. This is partly because more research groups have taken up the idea and those labs have had a chance to mature. In October, one of the first dedicated scientific meetings on the topic attracted around 50 such researchers to Estes Park, Colorado to discuss breeding and management strategies.For perennial crop researchers, advances in genetics have given them an unprecedented level of understanding and control over their subjects. “If you consider the early Russian work, they were working very blindly,” DeHaan says. “They could make crosses and observe the plants, but they had no way to know the genes or chromosomes involved.”
Today, there are two main approaches to breeding perennial crops, both of which require genetic tinkering. Both, too, are numbers games. The first is domestication, where plant breeders try to tame a wild perennial plant. This requires planting and observing thousands or tens of thousands of individual plants and then selecting those with the most promising characteristics—large seeds that hang onto the plant long enough for a harvest, for example, or ears that contain many seeds. The next step is to crossbreed these winners in an attempt to capture their positive traits in the next generation. Software that tracks which individual plants possess which traits—a tool that was unavailable to the Russian scientists in the 1920s—helps guide decisions on which offspring make it to the next round.
Shuwen Wang, a perennial wheat breeder at the Land Institute, inspects
a crossbred plant.
Still, domestication is numbingly slow and difficult work. Wild perennials tend to drop their ripe seeds earlier than tame ones, a trait plant scientists call “shattering.” It’s advantageous for wild varieties to shatter because it allows their seeds to germinate when they’re ripest, but it’s useless to a farmer who wants those ripe seeds to stay on the plant until harvest. And while many wild perennials can easily survive multiple seasons, Crews says, it has been difficult to increase their yields and grain sizes to anywhere near those of annual crops.
The second approach, and the more common one, is hybridization. Here, an annual crop is crossbred with a wild perennial counterpart in hopes that they will eventually produce a perennial crop. Hybridization offers a shortcut: annual varieties already contain the genetic recipe for high yields and big, harvestable seeds, and the wild perennials host the genetic code for longevity. Researchers can quickly identify genetic information that is linked to specific physical characteristics by using known stretches of genetic code called DNA markers. By snipping some tissue from a plant and extracting its DNA, breeders can see which genetic variations it inherited from its parents rather than waiting for the plant to grow and observing its traits, accelerating the breeding process.
Unfortunately, hybrids are often sterile, and even if they do produce offspring, they don’t always pass on the desired traits. While a few offspring will be fertile, they can also be fragile. Sometimes hybrid embryos must be coddled in a lab in a process called “embryo rescue,” which involves growing them in special nutrients to ensure their growth. Even the most successful hybrids may then need to be cross-bred to bring them up to par.
A wheat embryo, sitting on the tip of the scalpel, is rescued from an
immature hybrid seed.
Researchers across the country are trying both approaches and testing their results in the field. The Land Institute, for example, is domesticating wild sunflowers and wheatgrass—a variety they’ve named “kernza”—and their scientists are also developing a hybrid perennial wheat. Snapp, the Michigan State agroecologist, and her team conduct field research on perennial wheat in Michigan, as well as on the naturally-occurring perennial pigeon pea, a legume and a source of high protein, in Tanzania and Malawi. Still others across the world are working on rice, sorghum, corn, and mustard plants that don’t have to be planted every year.
Andrew Paterson, a plant geneticist at the University of Georgia, is among the researchers working on hybrid sorghum perennials, including a project to cross an annual domesticated variety with a wild weedy sorghum called Johnson grass, which produces an extensive underground stem system called a rhizome. When the stems of a plant with rhizomes are cut, more grow in their place. Paterson points out that there are around nine or ten genetic variations known to be responsible for perennial characteristics like this in wild sorghum, and some of the same genes are also found in rice. That these two grains diverged from a common ancestor around 50 million years ago yet still retain such similar perennial genetic traits suggests that a wide range of crops which have distant common ancestors may also share the same features.
“It looks like genetic control of perenniality is pretty similar in very different grain crops,” Paterson says. “So as we learn more about one, we learn more about all of them.”
New Plantings
Should researchers successfully develop perennial crops, it’ll be up to farmers to put them to work. Currently, philosophies differ on how crops should be planted in the future perennial landscape. The Land Institute envisions farmers sowing prairie-like fields with a mixture of perennials. And while this approach may help ward off pest insects and weeds, which more easily infiltrate a conventional field of a single crop, it complicates matters come harvest time. Currently, when a farmer cuts wheat, he knows he’s not going to be accidentally including corn in the harvest because each field grows a separate crop. Crews doesn’t think this will pose a significant challenge since the machinery to sort different seeds already exists, though it would likely need to be modified for this scenario.Paterson and others take the opposite view, suggesting that future perennial crops will simply be plugged into the current monoculture system, which would be easier to harvest with existing technology.
Still others suggest a mosaic approach, which would include both monocultures and mixed fields as well as a combination of annuals and perennials. The idea is, in part, a practical one since large-scale monocultures already exist and probably aren’t going anywhere. “There’s corn and soybeans out there on millions of acres of Midwestern landscape. They’re not going away,” says Donald Wyse, an agroecologist at the University of Minnesota. Wyse oversees several projects that aim for year-round field coverage, including both perennials and annual winter crops, such as hazel nuts that could be swapped out with an annual summer crop. “It’s going to come down to what we can put in mixtures or in perennial monocultures,” he adds.
Workers harvest crossbred wheat for analysis.
To a degree, mosaics already exist, it just depends on the scale at which you look for them. Look out of the window the next time you’re in or flying over the Midwest. There, the farmland is a patchwork quilt interrupted by occasional stands of trees and shrubs. A mosaic that includes perennials could break farmland up even more, with smaller patches containing a wider variety of plants. These perennials might be grown on parts of a farmer’s field that are usually left unplanted, where they would provide both environmental and economic benefits. For example, Wyse says, some perennials could be not only food crops, but also oilseeds for making biofuels, forage for animal feed, and raw materials for other commercial products like cosmetics. If these perennials were planted around the edges of larger single-crop field, they could recreate, on a small scale, the region’s once extensive prairies while also giving farmers something to sell.
“Deliberately planned landscapes like mosaics are the future, and perennial grains offers an option for mosaics that we don’t have now,” Snapp says. “Not all farmers can afford to have strips of prairie in their fields to provide sustainable grasses. It’s better to have practical options that also provide something they can sell or eat.”
Making Space
Regardless of how perennial fields will look—whether they’re blankets of monoculture, edible prairies, or a patchwork of both—we’ll still have to determine how they fit into our current food system. After all, we’ve been cooking and baking with many of the same grains for generations.In some places, we can glimpse this future. Kernza, the wheatgrass from the Land Institute, is already on limited menus. It’s in the pancake mix at Birchwood Café in Minneapolis, for example, which has been cooking around 50 pounds of the grain each season over the past two years. The Free State Brewery in Lawrence, Kansas made a pilot batch of a kernza saison beer several years ago, and WheatFields, a nearby bakery, has been experimenting with kernza bread for the past five or so years.
Wheatgrass heads are placed in paper bags during breeding to ensure
pollen is only transferred between selected plants.
The grain’s largest commercial debut is forthcoming from Patagonia Provisions, a cousin of the clothing company, which is rolling out a line of environmentally-conscious foods. According to director Birgit Cameron, the company is experimenting with kernza both as a whole grain and ground into flour, and they plan to have a product out within the next two years.
So how does it taste? Most people who have cooked or brewed with it want to try more, as long as they can get their hands on supplies. (The grain has a much lower yield than annual crops.) “The kernza is popular—it’s very nutritious, it cooks well, and it has good protein content,” says Marshall Paulsen, the head chef at Birchwood Café. “I hope to keep cooking with it.”
To move the crop, and others like it, from farms to more restaurants, bakeries, and breweries, however, will require a herculean shift not only in plant genetics and farming practices, but also in how grains are bought and sold. Our most common grains and oilseeds—wheat, corn, soybeans, oats, rice, and canola—are traded on the global commodities market, where prices fluctuate based on activity on various futures exchanges. Bringing a new crop into that system is virtually impossible because there is literally no button or bin for it in the grain elevator, says plant geneticist Stephen Jones, who heads, among other things, research on perennials at Washington State University.
To explore another model, Jones opened the Bread Lab at WSU around three years ago to facilitate smaller local markets that will support new perennials and other crops that don’t fit into the current system. The lab has a resident baker as well as visiting chefs, brewers, and millers to experiment with new crop varieties. It also helps pair up different businesses to speed along commercialization.
The Bread Lab model allows for more leeway in the distribution and use of perennial crops. The lab is growing, for example, a perennial wheat that has a blue-green tint inherited from its wild relatives. “It’s really pretty, but there’s no commodity stream for that,” says Colin Curwen-McAdam, a graduate student who works on plant breeding and genetics in Jones’s department. “If you’re working in the traditional commodity sense trying to make these commodity grains, now we have to put them in the commodity box, which makes your job even harder.”
In a way, the Bread Lab is a microcosm of the perennial crop world. Everything there is up for grabs, from commodities markets to the crops themselves. “It’s a brand new crop type,” Curwen-McAdam says, “and it’s completely unwritten as to what that can be.”
