Read The Land Institute’s 2019 interview with Tim Crews, learn about his background in soil ecology, and how he came to join the work on perennial grain agriculture.

What got you into this field of work?

I became interested in agriculture and horticulture in high school. I subscribed to the Book of the Month Club from Rodale Press in the 1970s, which sparked my interest in organic gardening. Then Wendell Berry’s The Unsettling of America came out in ’77, and that genuinely had an impact on me thinking about agriculture and a broader view of how society relates to the land as opposed to the narrower, garden-scale focus of not using chemicals when you’re raising vegetables. Wendell Berry had a significant influence on me, as I chose to attend UC Santa Cruz, which had a farm and garden program. I completed the 6-month apprenticeship there, and then agroecologist Steve Gliessman arrived, and I began to pursue agroecology, which was just starting to gain traction. For my senior project, I became particularly interested in how to sustain soil fertility without relying on purchased or exogenous inputs. I ended up going to Mexico and studying a traditional farming system that had been in use for more than a thousand years, which had never used fertilizer. That experience informed the rest of my life’s work. I attended graduate school and conducted my dissertation research in parts of Mexico to gain a deeper understanding of the soil ecology that enabled traditional farmers to sustain crop production over time without the use of fertilizers.

I stopped by The Land Institute in 1981 after reading “New Roots for Agriculture” in the agroecology program at the University of California, Santa Cruz. I came out here during my sophomore or junior year and met Wes, and we toured the lab facilities they had. Then, I worked at the Windstar Foundation in Snowmass, CO, after completing my undergraduate studies. The land education program there invited Wes to give a talk at a “Choices for the Future” symposium. We all met with him and formed a connection. After that, I attended graduate school at Cornell with Wes’s daughter, Laura Jackson. Wes came through a couple of times and spoke when I was there. That was back when The Land Institute primarily offered education programs with mostly recently graduated undergrads who spent a year in the internship program. Then, I collaborated with researchers here between 2000 and 2010, attending most of the graduate fellows’ workshops at Matfield Green, and undertaking two sabbatical years, one in Australia and one in the UK, focused on Natural Systems Agriculture. After our daughters went to college and Wes was nearing retirement, I reflected on how, in all my years teaching agroecology at Prescott College, which involved traveling with students all over the West, I grew to feel like the innovations that were taking place to make agriculture sustainable were not sufficient, and I still think that. The Land Institute was the only organization striving for a solution that matched the scale of the problem.

Can you discuss some of your specific areas of focus in soil ecology?

Much of my interest in soils revolves around how soil fertility develops and is maintained. I’ve examined that question in natural non-human ecosystems, modern agroecosystems, and traditional farming systems.  Agroecology as a discipline tends to draw lessons from how nature functions and how people managed agriculture before the availability of inputs made possible through fossil fuels and other technologies. Both of those tend to be very useful in providing ideas about how we can move forward. When you’re interested in soil fertility, you tend to be interested in the stories of both nitrogen and phosphorus – two key elements that plants need a lot of. You also tend to be interested in carbon, which is the basis for soil organic matter. Soil organic matter plays a crucial role in maintaining soil fertility because it holds nitrogen and phosphorus as key components. Additionally, the matter itself helps maintain a certain tilth (texture) and aggregates (clods), which are essential for allowing air, water, and roots to enter the soil.

Throughout my research career, I’ve devoted considerable time to studying nitrogen fixation by legumes and other organisms. Legumes host the bacteria that fix nitrogen in their roots. However, there are also other bacteria, not found in legumes, that fix nitrogen and can be important in both agricultural and natural systems. I spent a lot of time trying to understand what helps and what limits those nitrogen fixers, because in a solar agriculture, that is the main way that nitrogen enters the ecosystem, as opposed to industrial agriculture, where we’ve figured out how to use fossil fuels to get nitrogen out of the air and make it available to our crops. That activity, called the Haber-Bosch process, is the most energy-intensive input into modern agriculture. People often think it is tractors, but it’s obtaining nitrogen.

Phosphorus is a whole different thing because it weathers from soils and rocks and is constrained by how much those minerals dissolve and release those nutrients. That’s the process by which all the other required elements are released: calcium, magnesium, manganese, boron, and all these elements are dissolved by the weathering of minerals. Typically, plants in natural systems get all they need of these other elements, while nitrogen and phosphorus tend to be the bottlenecks of nutrients that limit plant growth.

You talked about nitrogen fixation being a benefit of Kernza®-alfalfa intercropping – what are some of the other benefits of intercropping?

We don’t currently know how much it reduces pathogens because Kernza doesn’t tend to harbor many pathogens at present. It may be in the future, when there’s more being grown, but right now, the plant is a source of resistance genes. Conventional wheat breeders cross wheat with Kernza or intermediate wheatgrass to incorporate some of those excellent genes into wheat, thereby helping to protect it. People don’t know that a little portion of most wheat is already Kernza or intermediate wheatgrass.

There’s not a tremendous amount of insect pressure either. However, we don’t know – there could be soil pathogens, nematodes in the soil, or any number of other factors that might affect Kernza later in its life span, from year 3 to 5 or longer. Having another species integrated into the cropping system has been shown by many researchers to have a strong effect on limiting the spread of pathogens, as well as potentially herbivorous pest insects. We’re also interested in adding silphium on the margins – not necessarily every other row, but maybe every 10^th row or in some other configuration that will go deep to pull up water and nutrients, as well as provide habitat for pollinators and beneficial insects that might consume pest insects of the crop. There are more pest insects on alfalfa than Kernza, so diversifying the system further will be of interest to see what happens in that respect.

Another thing that we’re looking at right now is how alfalfa could help provide water to the Kernza in drought years. We saw evidence of this last summer. We’d gone through a serious drought and cut the alfalfa in early June. Lee noted that Kernza really took off after we cut the alfalfa, and it hadn’t rained yet. We figured it couldn’t just be nitrogen, because other plots of Kernza that had received urea fertilizer weren’t responding. Then we began to consider that perhaps it could be a phenomenon known as hydraulic redistribution, where the alfalfa root system potentially distributes water like a system of pipes, moving water from areas of higher concentration to lower concentrations. It has been conclusively demonstrated in numerous ecosystems. It’s specific to plants that have big root systems, vessels that can conduct a lot of water, so you don’t tend to see it in fine-rooted species like Kernza. In fact, there’s some thinking that Kernza probably doesn’t take up a lot of water at great depth. If it’s stressed and on the verge of death, it can probably obtain survival water from extremely deep sources, and it will remain alive. However, it seems likely that the size of the Kernza roots cannot conduct sufficient water from a meter or two down to meet its water needs. It reaches a depth of around 50 cm, or approximately half a meter. But if you have alfalfa that has roots that go down 10 or 20 feet, which is possible with alfalfa (and they’re big roots) – especially if you cut the alfalfa so it is no longer transpiring water itself – it has the pipe system in the ground that is not actively using water. If water is present at a depth of three meters, it may rise through the roots into the dry soil, hydrating it. And the Kernza might be taking it up. We think that might be what happened last year.

This year, we installed soil moisture sensors at three depths. Madeline DuBois, an intern from Northeastern University in Boston, is overseeing this as part of an Independent Study she’s doing here. Of course, this year it’s rained so much, and the soil has been near saturation most of the time; we haven’t seen anything that hints at hydraulic redistribution yet. So far, it hasn’t worked out in terms of testing that hypothesis. However, perhaps the soil will dry out sufficiently in the fall, allowing us to see some movement of water in the system. It’s still interesting to see what’s going on with soil water movement that deep. We have sensors at 30 cm, 1 meter, and 3 meters, some located in the Kernza with alfalfa and some in the Kernza without it. Therefore, if hydraulic redistribution occurs, we should be able to observe water moving up in the intercrop compared to the single-species stand.

Considering the wide hybridization efforts we are undertaking with Johnson grass and perennial sorghum, how many weeds are potentially available for consumption and utilization in the process of perennializing food? Because weeds are so prolific, are there other weedy species we could use for breeding?

Most of our annual crops are closely related to weeds. Most weeds are in the same families as crops; many are grasses or legumes. In the tomato family, the solanums, there’s a bunch of weeds. Bindweed is a member of the sweet potato family. If you selected for the seed yield of these annual cousins, they probably would lose some of what makes them such aggressive weeds. That’s kind of what’s happening with the wide hybrid in sorghum and Johnson grass – the farmers worry about us creating an invasive crop species, but we’re actually taming Johnson grass and making it less aggressive by allocating a lot of its resources to seed. If you took a wild tomato weed, such as a chokecherry, and selected for it heavily to produce big tomatoes or even cherry tomatoes, it would probably not be as prolific as a weed because of the trade-off in resources.

Will our use of wide hybridization develop crops faster in the breeding cycles than rapid domestication, because you should have more information on the parent crop and its pathogens?

It has the potential to be faster because you’re able to take advantage of an annual crop that’s been bred for hundreds to thousands of years, and thus you can maintain many of those attributes in the wide-hybrid cross. That’s exactly what’s happened in the rice project, and when you look at some of Shuwen Wang’s wheat. The challenge, of course, is to have the genetics stabilize so that the crop becomes a viable perennial. I’m hopeful that some of the recent discoveries made in both perennial sorghum and wheat at The Land Institute will help make these crops robust perennials.

Do you have any significant recent discoveries you’d like to discuss?

One of my strong interests is the amount of energy required to grow food; the energetics of agriculture are key and, I think, underappreciated by most people working in sustainable agriculture. Agriculture was originally pursued to obtain more energy for people. We lay out a large solar collector in the landscape, and we eat the solar energy it collects. But it takes energy to sow, tend, and harvest crops, and there must be more calories in the yield than you spent growing it, otherwise you would starve. Typically, there was a considerable energy return on investment in agriculture before the fossil fuel boom, which I date roughly to the advent of the steam engine. After the fossil fuel bonanza, you can spend 100 times more energy growing this head of lettuce or this grain crop than it gives you, and it doesn’t matter, because you don’t rely on that food to grow the next crop. You’re getting all these fossil fuel slaves at the filling station, and it takes nothing compared to the energy they give you, compared to human energy. That explains much of why we’re doing what we’re doing and how we do it in both organic and conventional agriculture. As we strive to reduce our extreme dependence on fossil fuels, we must address this issue and develop an agriculture that uses far less energy and yields a significantly higher energy return on investment. The work we’re doing here at The Land Institute holds the greatest promise, because humans do not need to work as much to make the ecosystem function, because the ecosystem functions on its own. People don’t have to clear the land and re-sow crops every year. If you have legumes in there, nitrogen fertility is provided. In healthy stands of perennial crops, many weeds are suppressed. All of a sudden, the ecosystem is functioning on its own without nearly the amount of human intervention that has been a ball and chain for 10,000 years for our ancestors, who have had to invest a large percentage of their time and energy in making life feasible for annual crops. A post-fossil fuel society is probably going to involve more human labor in agriculture—some people don’t agree with me. Still, if it does, there will be significant social justice implications of developing an agriculture with a much higher energy return on investment.

At The Land Institute, I’m excited about how well Kernza and alfalfa get along. Even though that seems like such a basic thing, people were skeptical when I first suggested intercropping those two. I don’t think I was the first. Jerry Glover tried it, but he broadcast the two together, and alfalfa tended to lose out in the competition to Kernza when they’re just growing in a field. I put them in rows and started managing them that way. People said, “Alfalfa’s a big water hog. In this semi-arid environment, it’s going to knock Kernza out. Or both will suffer.” Over the years, the two actually grow better and better together! This intercrop offers an exciting example of what we can look forward to in ecological intensification as we discover other combinations of species that thrive together.

As Director of Research, I am aware that you play a crucial role in our educational efforts, including selecting interns, collaborating with the new resident program, and ensuring that individuals receive a valuable learning experience. Could you talk a bit about that process?

The Land Institute was known for its intern program before it became a full-on research institute around 1998. That intern element went away for a while and got replaced by the graduate fellows program around 2000-2008 or so. Those were graduate students who would only come for one week a summer and go to Matfield Green – I was involved in that project.

When I first started working here, it was mainly hiring recently graduated high school students, possibly those in their first year of college, to work with very little actual involvement in learning about what we were doing. It was more of a summer job. They might have been interested in science or environmental science, but not specifically our work. Gradually, year after year, we began to invite older college students from schools all around the country to apply.  We are seeking students who are genuinely interested in working here and are eager to learn about our organization. We accept maybe a third to a fourth of the students who apply. We are fortunate to consistently attract outstanding students—super people. We’ve also started hiring a few high school students, or recent grads, to be farmhands. These kids focus hard on keeping weeds under control in breeding plots and maintaining equipment.

The internship program has become more developed pedagogically, and I believe the addition of Ecosphere Studies and Aubrey has further enhanced it positively. The residents’ program I don’t take credit for – it was David and Aubrey’s initiative to propose it, and they got Ebony, Brandon, and ultimately me on board. I hope we will be able to continue it – it is a more expensive program because it’s year-round. I think all the residents will attend graduate school, and their research programs will likely be related to our work. That’s a pretty amazing investment payoff, inspiring undergrads to carry it into their life’s work. I’d love to see it continue.

Meanwhile, I am working with Aubrey to initiate another graduate/post-doc fellows workshop to rekindle a slice of what happened in the summers at Matfield Green. We will organize a workshop for most students who receive support from the Perennial Agriculture Project or are pursuing projects relevant to our work in a collaborator’s lab. We would like all these early-career researchers to have the opportunity to engage in conversations to get to know each other and appreciate what The Land Institute is and does. I’ve been wanting to do this since the Perennial Agriculture Project was formed five years ago, and it’s finally going to happen for the first time at the end of October this year.

Could you speak a bit about our increasing global partnerships?

The breeding programs all have global research partners. There’s been a lot of interest and receptivity in Europe, especially. Meso-America is the area I feel is least involved, from Mexico to the tip of Patagonia. There’s a colleague of Brandon’s in Mexico, Damien, and Alejandra in Argentina works with David; we also have connections in Uruguay, but we need more. A major point of the perennial ag meeting last spring at Lund University in Sweden was to bring an international perspective to this work. In an exercise at the end of the meeting, where participants were asked to discuss what scaling up our efforts would be like globally, there was a consensus across multiple breakout groups that an international network for perennial agriculture should be formed, with The Land Institute as the hub.

The Land Institute is ready for a more formalized organizational network. We could imagine having a person who would direct it. That person would potentially help orchestrate funding for the network, even at modest levels, to support graduate students and provide seed money for new projects. A PhD student in Nairobi or Lima could apply to do a project. Perhaps that network would also be in place, so if we were to receive significant funding, we would have an organizational structure in place that would help facilitate the funding of more substantial clusters and research groups. We heard the enthusiasm for an international network loud and clear at Lund, and we’re excited about it. I see the next big step as exploring what that would look like.

With different global researchers working on grains like Kernza and perennial wheat, are they also breeding their own regional perennial crops?

Not enough. A team is working on rice in China. Then there is the pigeon pea, a perennial legume already grown in Africa, which has been used in some work in Uganda in conjunction with perennial sorghum. Anna Westerberg is working to breed barley independently. There’s a group in China focusing on buckwheat. But for the most part, no.

Groups are taking on new crops, but we would like to see more of this happening. This links to our work with the Global Inventory Project, which aims to identify wild, herbaceous perennial species that are strong candidates for pre-breeding and eventual use in perennial crop polycultures in both temperate and tropical climates. If we had an international organization, we could link it to a journal or some kind of publication that would emerge from this initiative, encouraging and facilitating different groups to domesticate new perennials in various regions. I’m excited about that possibility and thrilled by the significant increase in the number of research partners we interact with in recent years.

Do you have any specific 5- to 10-year goals that you would consider your primary focus?

My personal goal would be to develop an intercrop system at The Land Institute—a polyculture that is highly functional and relatively easy for a farmer to adopt, capable of maintaining the fertility of a high-yielding perennial grain system.  I am also looking forward to gaining a deeper understanding of the carbon sequestration potential and potential reductions in nitrous oxide emissions across all our crops. At this point, most of the work focused on greenhouse gases by The Land Institute and other groups has been centered on Kernza. I am also particularly interested in facilitating research on the environmental benefits of perennial rice.