Perennializing Row Crops

The first perennial grains are now available to farmers

Annual crops have distinct advantages over perennial ones. Quick maturation, more management tools and higher yields are reasons annuals play a major role in our agricultural system.

Yet it’s not hard to believe that the balance has skewed too far toward annuals. Perennial crops offer great benefits that most American farms are currently foregoing.

The Land Institute is one organization that is seeking to restore perenniality to our acres. Its researchers have been working for several decades to breed species of intermediate wheatgrass, legumes, oilseeds and sorghum that can be grown for multiple seasons — reducing erosion, improving soil and producing competitive profits for growers. The first of these to become commercially available is Kernza perennial grain — an improved variety of intermediate wheatgrass that was planted on nearly 4,000 acres in 2021.

Tessa Peters is The Land Institute’s director of crop stewardship and works with growers to troubleshoot production and economic issues. She has a Ph.D. in plant breeding and plant genetics from the University of Wisconsin-Madison.

As Wes Jackson, the co-founder of The Land Institute, says, “If your life’s work can be accomplished in your lifetime, you’re not thinking big enough.” Peters and her colleagues certainly have huge goals — but they’re starting to see the fruits of their labors as well.

Acres U.S.A.: I want to get to some of the specifics on how farmers can get access to Kernza perennial grain seed and how they can grow it, but first, can you explain some of the history of the breeding programs at The Land Institute and why it’s important to develop perennial grains?

Tessa Peters: Sure. The Land Institute was founded in the 1970s as an educational organization. The co-founders, Wes and Dana Jackson, had this idea of creating agricultural systems that mimicked natural systems. 

The idea is that these systems are capturing the two principles that we see again and again in nature: perenniality and diversity. That was something they were really excited about, and they started thinking about how we could have these agricultural systems. 

One of the things that started to become obvious to them was that we really need grain crops as part of the human diet to meet caloric needs, and the Central Plains is a place where a lot of those grain crops are grown. Thinking about how to add perenniality and diversity led them to the idea of having perennial grain crops that would be grown in polycultures — mixtures of perennial grain crops — that would be grown together and harvested and then used to feed humans.

That was the founding idea behind what is happening with The Land Institute, which is now focused on perennial grain crop breeding. We also develop systems to grow those perennial grain crops — in polycultures, but also understanding disease management and pest management for grain crops. 

Acres U.S.A.: Can you describe some of the systems that you’re developing right now? It’s not just Kernza, correct?

Peters: Right. Kernza is one of the grain crops that we have, but we’re working on a host of others. We have five breeding programs at The Land Institute. One of them is now in Georgia, and that’s perennial sorghum. 

We also breed perennial wheat, intermediate wheatgrass for Kernza grain production, silphium — we particularly work on Silphium integrifolium, which is a future oilseed crop — and then perennial legumes. Our legumes program works on sainfoin and on perennial ground covers and some other potential crops as well, like lupine.

Acres U.S.A.: What’s the difference between Kernza and perennial wheat? —intermediate wheatgrass versus wheat? 

Peters: Intermediate wheatgrass is Thinopyrum intermedium. It’s a grass that was used in the U.S. for more than a hundred years, primarily as forage. It has also been used for things like CRP (NRCS’s Conservation Stewardship Program). 

Then the Rodale Institute started looking at different perennial grasses as potential grain crops and they identified Thinopyrum intermedium as a potential. Their initial work on breeding transferred to The Land Institute in about 2003. Lee DeHaan, the lead breeder for the Kernza program, focused in on this as a potential grain crop and started making selections for things like bigger seed size and the ability to de-hull it more easily. That work has been going on now for close to 20 years.

So Kernza is a different species than annual wheat. They’re distantly related; they share two of the three genomes.

Acres U.S.A.: Why should farmers be interested in growing Kernza? 

Peters: I think we all recognize that soil erosion is a problem and that the best method for preserving soil is to keep a living root in the ground for as many months of the year as possible. With a perennial grain crop, that is expanded to 12 months a year and beyond. So, we’re talking about years without having to till or go in and disturb the soil. That is huge in terms of a reason that growers should be interested in Kernza. To me, that’s the number one thing.

Companies are really interested in carbon sequestration as well, and there’s great potential for that with perennial grain crops, which have long and deep root structures, like Kernza. Thinopyrum intermedium, even if it’s grown as a forage intermediate wheatgrass, still has that great root structure. 

It also has huge potential to improve the water quality for communities where it’s grown, because there’s potentially less nitrogen being applied, and nitrogen that is applied is being taken up at a much higher rate than on equivalent crops, like annual wheat. Kernza is absorbing something like 95 percent more of the ammonium than annual wheat, which only absorbs 50 percent of what is applied. So, it helps to prevent fertilizer runoff into water sources. The state of Minnesota has been really forward-thinking in terms of trying to use Kernza in particular as a way to preserve or enhance drinking water quality.

Acres U.S.A.: Does Kernza use less water than annual wheat — would it help in that regard in the West or more arid places?

Peters: It’s not a low-water-use crop, but it is pretty drought tolerant. The reason that it’s drought tolerant is because those roots go down so far. It can get water from different parts of the soil profile compared with some of the annual crops. 

Acres U.S.A.: About how many acres or how many farmers are growing Kernza this year?

Peters: In 2021 there were 3,951 acres and 36 growers who harvested grain. 

Acres U.S.A.: And it is a trademarked product, correct? What does that mean for a farmer who wants to grow it?

Peters: It is, yes. What that means is that you have to have a trademark license in place to be able to buy Kernza seed. You can buy intermediate wheatgrass seed, but if you want to buy the improved varieties that have better grain production, you do have to have a license in place. 

The reason for the license is twofold. First, early on, the license was really important in creating a legal definition for what Kernza was. You couldn’t just go sell annual rye and call it Kernza. You need to have an actual legal definition of what it was to ensure that it was actually a perennial grain crop that was being sold under the name. 

The other part of the motivation is market differentiation. Also, it’s really important for growers to be able to have input on how the grain supply is built. On the food manufacturer and production side, the trademark allows us to be able to ask people questions around supply and demand. We can ask growers how many acres they’re growing and how much they harvested this year. There would be no requirement for anyone to provide any of that kind of information to help us develop a market without the trademark. It’s really important for us to be able to build a market to be able to collect that kind of information — essentially a research activity. 

It’s also allowed us to scale the market at the same time as we build supply. Rather than having supply greatly outpace demand and then having the price fall out on growers — and every grower sitting with bags of it in their shed that they can’t sell or that they can only sell for pennies — because we’ve been able to do this stepwise supply and demand growth, because of the trademark, that has allowed the price discussion between growers and buyers to continue, hopefully, in an equitable way.

Acres U.S.A.: Would growers who are just growing a small amount be able to direct market Kernza themselves?

Peters: Yes. 

Acres U.S.A.: Let’s talk about the growing practices for Kernza. How different is the growing process compared to a regular wheat crop?

Peters: It’s quite different from growing a regular wheat crop. The establishment period is a lot more difficult. It’s a perennial crop, so it takes a little bit longer to get going. It’s not going to be as competitive as an annual wheat right away. 

In the first year, weeds can definitely be a problem. That’s something that growers have had to deal with. Until recently, the only way to deal with it was mowing. There was recently one product that has an herbicide label for use on intermediate wheatgrass as a grain crop, but that was very recent — in the last month or two. So, no one has used any chemicals, and mowing the weeds that have grown up above it has really been the only way to do any kind of weed control, until now. 

But even in what seemed like pretty dire weed circumstances, there are growers in year two who have had really good yields. Once well established, Kernza is very competitive with annual weeds — even with perennial weeds. 

Acres U.S.A.: Has anyone experimented with maybe growing a cover crop together with it, like an annual oat?

Peters: They have. An annual oat or an annual barley — that has been done in Canada. They’ve planted the nurse crop and the Kernza in the spring. Then, you get that nurse crop during a summer establishment period. You could mow it or you could harvest it. I think folks have tried to do both. Then, the following year, you would have your first Kernza harvest. 

The other thing is that we’ve had a lot of growers use it as a dual-use crop. They plant it in the spring and then just use it as a hay crop that first year, because if you plant in the spring you will not get a grain yield that first summer. It does have to have that dormant period before it will flower and head out. It depends on the timing of their moisture as well — if they’re not going to get any moisture in the fall, then they need to establish in the spring. Then, after they’ve used it as a forage or a hay crop for the first summer, they come back the following year for a grain crop. 

Acres U.S.A.: What does fall sowing look like?

Peters: You would sow maybe the first week of September. The establishment takes place in September, October, November. Then it will go dormant over the winter. Most growers are doing this — trying to get it to establish really well. Then they have that first harvest the following summer. 

Acres U.S.A.: You’re establishing it into a tilled field, correct? You’re not trying to no-till this?

Peters: There are lots of folks who have no-tilled. Growers have done both. One of the big things is that following another winter annual is not a good idea because you’ll have a lot of volunteer winter annual grain. That will be really difficult to separate from the Kernza. So, that’s not a good idea. 

Acres U.S.A.: Can you talk a little bit about fertility management? 

Peters: We have organic growers who are using a chicken or turkey litter or something like that. Some growers also have a source of cattle manure. It does need nitrogen and will certainly produce more with good nitrogen application. 

Acres U.S.A.: Perpetually or just in the beginning?

Peters: Perpetually. Year after year, it does still need some kind of fertility. One of the experiments we’ve done at The Land Institute is frontloading nitrogen through planting into an alfalfa crop, or following alfalfa. That has worked really well here in Kansas. But that’s primarily been on small plots. I don’t know at large scale, necessarily. But that idea seems to potentially be a good one. 

What we have seen is that the fertility management is probably somewhere in the range of 60 to 70 pounds an acre. We’re not seeing any yield bump beyond that kind of fertility added, whether it’s organic or chemical fertilizer. 

Acres U.S.A.: And irrigation? You said it’s a heavy water user, correct?

Peters: I wouldn’t say it’s a heavy water user — I just don’t want people to think that it’s a crop that can grow with no water. It does need water to grow. But we have growers who are doing dryland in eastern Wyoming. Again, they’re planting in the spring because that’s when their water comes for establishment. It can be grown dryland in pretty dry climates, particularly if it’s cooler. Of course, eastern Wyoming is at a pretty high elevation, so it’s cooler than it would be in central Kansas. In central Kansas, you need more water. 

But again, there it’s being grown almost entirely dryland. I think I know maybe one or two systems where they’re using irrigation.

Acres U.S.A.: I’m sure you’ve done soil tests before and after. Is Kernza improving the organic matter, soil organic matter?

Peters: Yes, definitely. It is improving organic matter, primarily from the addition of all of the root exudates.

Acres U.S.A.: And how different is harvesting compared to annual wheat? 

Peters: It’s probably a little bit later in the season — a week or two after a wheat harvest. Which is kind of nice for growers; they’re not trying to do everything all at the same time. 

Overall, it isn’t too different. You can use your combine. We have growers who are swathing and then coming back with a pickup header, and that seems to work well, especially in places where you don’t have to worry about catching a rain, but where the grain might be still kind of green and you can get everything dried down really nicely. 

A lot of the growers now, though, are using a stripper header. Stripper headers were designed for forage grass-seed production. They work really nicely on something like Kernza. But there are also a lot of growers who don’t have a stripper header and they’re using whatever combine header they have. That also seems to work. 

It’s a small grain, smaller than wheat — about a third to a half the size of wheat. You’re going to have to adjust your combine to make sure that it compensates for that and that you’re not just blowing it out the back. 

Acres U.S.A.: What are yields typically?

Peters: The average yield this year was 409 pounds at the farm gate, which translates to maybe 200 pounds an acre clean and de-hulled. We are not in a bushel market at this point. The bushel weight when the hull is on is going to be completely different from the bushel weight when it’s de-hulled. We’re still really figuring that out.

Acres U.S.A.: But, it’s fair to say, the yield is quite a bit lower than your cereal wheat.

Peters: Yes. And the price is quite a bit higher because of that. Our main goal is to increase yields. Over the last three years we have seen yields increase. Last year’s yield was down a little bit from what we had the year before, primarily because of drought conditions in a lot of the growing areas. But you have years like that.

The yield is low, but our main goal at The Land Institute with all our breeding programs is to improve yields. I expect that we’re going to see new varieties in the next year or two that are going to hopefully increase the yield substantially.

We’ve also seen grower experience and agronomic knowledge helping to increase yield. I think we’ve more than doubled yield from when I started in 2019. We’re on the path.

Acres U.S.A.: “Perennial” in this case doesn’t necessarily mean you’re never going to have to replant, correct? When does that occur? 

Peters: Right. We know that you should have at least three years of good grain harvest. You may get more than that. Last year was really the first year that we had any substantial acreage that had been in for four full years, and it was a very droughty year, so it’s unclear whether the lower yield on those fourth-year stands was due to drought or due to their age.

We accept and know that yield decreases with stand life. That’s another one of the breeding goals — to increase stand life. 

Acres U.S.A.: But the way things are going right now, if you’re coming out with new, better varieties, replanting every three or four years probably isn’t a bad thing anyway, at this point.

Peters: Right, at this point. We recommend planning on three years of grain harvest and then maybe another year or two, if you have a use for the forage. The forage will remain really robust for at least five years.

Acres U.S.A.: Can you talk about the taste?

Peters: Yes. The flavor is great, I think. It’s not as bitter as whole-grain wheat flour. It’s primarily being used, at this point, as a whole-grain flour. Processors are generally not separating the bran from the germ at this point. It has more of a nutty, or sometimes almost a cinnamon-y or graham-type, flavor. I think it’s very good. We use it a lot at my house. 

It does bake differently than wheat. It has high gluten — it’s almost 20 percent protein, compared to 12 to 15 percent for hard red wheat and 10 percent for white wheat. But the high gluten doesn’t translate to high gluten strength for baking, which is interesting. We don’t totally understand why, but we know that for bread baking, the gluten just isn’t as strong as a hard red wheat. It performs somewhere between a soft white wheat and a rye in terms of its baking quality. But it’s great in things that are unleavened, like cookies or pastries. It’s great for a lot of applications. 

For leavened baking, at about a 15 to 20 percent addition you won’t notice much of a difference. But above that it takes a more experienced baker than me to make a good loaf.

Acres U.S.A.: Have you done any tests on nutrient density between regular wheat and Kernza?

Peters: We have a nutrient sheet on Kernza.org. It’s a little bit lower in carbohydrates than a white wheat or a refined flour, but high in fiber — 18 percent. That’s way higher than you find in an all-purpose white flour, which is about 3 percent.