John Mesko: (00:29)
Welcome back to the People of Soil Health podcast. Today, as a special guest on the podcast, Kansas State University Soil Microbiology Professor, Chuck Rice. Chuck is a distinguished professor, specializing in soil microbiology, carbon, and nitrogen cycling, and climate change. He serves as an advisor to several organizations, including the National Corn Growers Taskforce for Greenhouse Gas Emissions and Global Warming, the Board on Agriculture and Natural Resources of the United States National Academies of Science, Engineering and Medicine, where he chairs the Board as well as being an advisor to the Soil Health Partnership. And, in 2007, he received a Nobel Peace Prize for his work with the United Nations Intergovernmental Panel on Climate Change.
John Mesko: (01:17)
Chuck, it is a pleasure to have you on the podcast. Thank you for joining me.
Chuck Rice: (01:22)
Yeah. Thanks. This will be a great opportunity.
John Mesko: (01:25)
In reviewing your resume and thinking about the work that you've done in the past, and even some of our just previous conversation, it's really interesting to see the arc of your career and the things that you've done in agriculture related to soils and the environment and climate, and how that all is interconnected, but I'm really interested in learning how you became interested in this and how it turned out to be the career that it has been for you.
Chuck Rice: (01:53)
Yeah, well, I guess, growing up I was always interested in science and nature. My parents, they weren't college educated, but they gave me all, I guess, the opportunities to be involved in science, anywhere from a chemistry set to we did gardening, to other things. I even hatched eggs and watched the embryo grow inside a chicken egg. So, yeah. So that was the starting point, but I had some excellent teachers that got me interested in science and nature. And then went to college to get into science. I started out in biology, but ended up in geography, where soils and water was the major interest.
John Mesko: (02:39)
Well, it's really interesting to see how things have changed in the study of soils over the years. As we were talking earlier, before we started recording, when I was in school studying agronomy in the '80s, we looked at soil as a medium to hold on to the plant roots, mainly. And the soil solution in the soil was what we were concerned about, making sure there was enough fertilizer in there to feed the crop for the growing year.
John Mesko: (03:08)
And now we know so much more about the interconnectedness of the physical, the chemical and biological components of the soil. And you've been referring to that biological part of the soil as a black box. I think I know what you mean by that, but I'd like – for the listeners – to have you explain what does that mean to you when you think of the biological component of the soil as a black box?
Chuck Rice: (03:34)
Sure, John. Yeah. Soil microbiology is a relatively new field, a young field compared to some of the chemistry and physics components. The reason I talk about it as a black box is that we've kind of... over the time we knew what the microbes were doing in the soil, but we didn't necessarily know who they were. And even now, today, with advanced tools, we don't know everything about the biome, the microbiome of the soil.
Chuck Rice: (04:05)
That's illustrated in the fact that we can only cultivate less than 1% of the microbes that exist in the soil. We know now, with modern technology, genetic techniques, molecular techniques, that there's all these vast array of microbes in the soil, but we can't cultivate them and so we don't know their ecology. We know what some of the functions are. So that's the reason I call it in the black box. There's a huge opportunity to further understand the soil microbe component.
John Mesko: (04:41)
Well, it's certainly something that... We can see the results of a healthy soil, right? We can see when the interconnectedness is working and processing water and nutrients and making nutrients available to plants. We can see the results of that. And I think that's what's gotten the attention of... All of the work that I do in the soil health community is to see those results propagated on more and more acres.
Chuck Rice: (05:05)
Yeah. I think you got it right, is that even though we don't know who all the actors are in that soil black box, but we certainly have a greater appreciation of what the microbes are doing. And the producers, farmers, land managers are starting to understand they need a good, healthy soil, microbial activity, in order to have a healthy soil and a healthy ecosystem.
John Mesko: (05:35)
So when we think about what's going on in the soil and we think about the microbiology, what are you, in particular, studying and measuring with regard to that component of the soil?
Chuck Rice: (05:49)
Yeah, that's a good question. From the biological standpoint... Again, I've been focusing on more functionality functions, what processes, carbon cycling, nitrogen cycling, which is critical. Carbon cycling is important for storage of carbon in the soil and holding that carbon in the soil relative to the atmosphere, but also then, like the nitrogen cycling or other nutrient cycling, how is that related to plant availability and plant production whether...
Chuck Rice: (06:22)
I work in two different ecosystems. I work in the native prairie, which relies on internal nitrogen and nutrient cycling, but then in ag systems I'm trying to figure out how to be more efficient with the nutrients that are applied.
Chuck Rice: (06:37)
But then more recently, again, with the newer techniques, is trying to figure out the diversity of microbes in the soil. And we know now that how you manage that soil can change the relative abundance of different groups of microorganisms.
John Mesko: (06:58)
Yeah, absolutely. And there's the results. I mean, in the work that we do at the Soil Health Partnership, there's so many people interested in understanding how carbon can be sequestered into the soil and we can address the issues around climate change in that way. And one of the things that is a bit of a challenge, as I see it, and I don't really even have a formality for thinking about it, but it occurs to me that as we are putting carbon into the soil, and in an ag system where we're growing an annual crop on that at the same time, and we're looking to extract yield from that soil, and therefore dollars, so there's an economic component to it, I wonder, sometimes, and I have no way of really evaluating or measuring this at this point, but I see improvements in soil, I see improvements, many of our farmers see improvements in their yield, and yet we don't necessarily see a drastic change when we measure the carbon or the organic matter there. And sometimes I wonder if because we're in an ag system where we're constantly extracting value from that soil, soil might be getting healthier, but it's hard to measure it because we're taking away the improvement. We're harvesting that improvement. Do you see that happening or does that resonate at all in some of your scientific thinking on this?
Chuck Rice: (08:19)
Well, I think you got part of it right, in the sense of some of the traditional measures for measuring soil quality, soil health, like carbon, it takes a longer period of time to measure or detect that change. It would take a minimum of three to five years, and maybe even 10 years, to measure a change in carbon.
Chuck Rice: (08:47)
The way that some of the measurements we're taking now that we can detect some of those early changes, I think I've referred to it in the past or I've been accused of, I call soil health. There's three components, and I call it my Holy Trinity. It's carbon, it's some measure of physical structure, and then some measure of microbial activity or composition. And the key component of that is carbon. And the reason for that is carbon is the food, the energy source, for those microbes. So the more carbon you have, then you have a more active microbial community.
Chuck Rice: (09:35)
But the other thing is that carbon also helps to build soil structure. And the way we measure soil structure is aggregation, but you can measure water infiltration or some other component. But the reason I use aggregation is that we've found, and the reason I call it the Holy Trinity, is that we know there's a strong relationship between carbon, microbes, and structure.
Chuck Rice: (10:02)
For example, in less disturbed systems, no-till conservation ag, that we get more fungi abundance, and that fungal hyphae then helps to bind and build soil aggregates, to build that improved soil structure. And inside those aggregates, then, there's carbon that's trapped and helps sequester that carbon to build the organic matter content of the soil. So that's why it's this three-part alignment in that. And so there are practices that we know that are changing that three-way interaction.
Chuck Rice: (10:41)
Going back to the detection, carbon is kind of the centerpiece, but it does take a long time to measure that change. But we can detect earlier, within three, four years, a change and soil structure through aggregation. We can measure the microbial composition, so we can pick up changes in fungal bacteria ratios that is much quicker than, say, a carbon change.
John Mesko: (11:12)
And those changes, the aggregation and the microbes which support that fungal growth, that's going to give us those positive outcomes on the yield side and the crop quality side as well then.
Chuck Rice: (11:27)
And the other thing about that, from the soil health standpoint or crop production standpoint, if you have those three components and there's more than that, but that's kind of the basic three, if I have a microbially functioning soil, it has good structure, carbon content, then that means, from a crop perspective, I'm going to hold more water. I'm going to capture those intense rainstorm events with a better-structured soil. And so it's going to be more resilient to those dry periods or those drought years than a soil that's in a less-healthy state. And if I have more carbon, that means more organic matter, and that means more nutrients. So it provides a buffer. So you may not get higher yields, but you should get more stable yields with a healthier soil.
John Mesko: (12:24)
Yeah. Variability in any production system is a bad thing, right? Whether it's corn, soybeans or widgets or cars, we want that production system to be consistent and take out the ups and downs.
John Mesko: (12:39)
We are fortunate, Chuck, to have you serving as a member of our Soil Health Partnership Science Advisory Council. Your background and experience in microbiology have been helpful in that regard. How does the work that you do interact with involvement on our Science Advisory Council?
Chuck Rice: (12:57)
Yeah. Good question. So I guess what I bring to the table is, again, that microbial component. But I also have, over the years, experience with different management systems, how that affects the carbon-nitrogen cycling and the microbial community. The other thing that I guess, maybe, is somewhat unique is that, I mentioned earlier, is I do some of my work research on the native tallgrass prairie. And so I use that as a model. The prairie is considered climate resilient, it's nutrient efficient, it's water efficient.
Chuck Rice: (13:41)
And so, at least in my own program, and what I try to extend is, what are the components of the native prairie and can we make ag systems more like the prairie? Obviously, as you said earlier, that we have an annual crop versus a perennial, but what can we do to ag systems to make it look or to act more like the prairie, from a water nutrient-diverse system?
Chuck Rice: (14:11)
I guess that's what I bring, the 33 years of experience and then trying to look at different management systems. And I also work internationally quite a bit in South America, so I can bring some of the things they've learned in South America, as far as ag practices, to our systems here in the US.
John Mesko: (14:35)
Well, and we certainly appreciate it and benefit from it greatly as an organization. And, hopefully, by extension, our ag community does as well.
John Mesko: (14:43)
And along those lines, recently you were at one of our field days in Kansas and talked about the PLFA test. Tell us what that is and what it measures?
Chuck Rice: (14:54)
Yeah. It stands for phospholipid fatty acids. And so not a brand new technique, but what it does is tell us information about the microbial composition. One way to think of it is if you're in the TV crime show, CSI or whatever, they talk about markers and figuring out who was involved in the crime scene. But in this case, looking at the phospholipids, the fatty acids, is that it's a fingerprint. It's a biomarker for a type, a group of microbes in the soil.
Chuck Rice: (15:36)
So there's certain fatty acids that are identified with fungi. There are certain fatty acids that are identified with what we call gram-positive or gram-negative bacteria or mycorrhizal fungi. And mycorrhizal fungi are a special group of fungi that help with phosphorus uptake with the plant, but also fungi, and these mycorrhizal fungi, are key in helping develop the aggregation.
Chuck Rice: (16:06)
So, like I said earlier, we can use that test to earlier indications, to track change in management on the soil microbial community. So that's what that test is all about. And there's some of the commercial labs, some of the soil testing labs, are now starting to include that, at a cost, but farmers can submit samples and get a PLFA test for their soils.
John Mesko: (16:34)
So we're measuring microbial activity... in a shortened version of what we're doing with a PLFA test is a measurement of the amount of microbial activity.
Chuck Rice: (16:46)
Well, yeah, it's not really activity. It's telling you the composition or the diversity. What it does is, I can get several pieces of information. One is I can get the total quantity of microbial biomass, based on the phospholipid test. And then I can partition that out; who are the key members of that microbial community in that soil?
Chuck Rice: (17:12)
There are genetic tests, a DNA test. They get such great... a high resolution that it's harder to interpret, but we know from the phospholipid test they are responsible, that composition, or changes in composition, are associated with land-soil management.
Chuck Rice: (17:29)
For example, less tillage, no-till, that I see a greater abundance of fungi relative to the bacteria. And that's actually what we see in the native prairie too. In those undisturbed systems, we see a higher ratio of fungi to bacteria. So again, no-till is acting more like the prairie.
John Mesko: (17:52)
Well, when you're looking at those microbes, we know there are good microbes and bad microbes. And so when we think about the activity or the amount or, as you mentioned, the members of that community, what are some good microbes and what are the value of those microbes in the, as you say, a soil that mimics the prairie?
Chuck Rice: (18:15)
So most of the microbes are good in the soil. Actually, there's what you would consider bad microbes, the ones that cause plant or animal diseases; root rot or some other disease for those plants. But if you have a good, what I call healthy soil or microbial population, the microbes, they are degrading that organic matter, releasing nutrients for the plants. There are microbes that live along the root that are called rhizosphere microbes. Those microbes are stimulating root growth. They're also, maybe, providing nitrogen or phosphorus to the plant for plant growth and, ultimately, for yield.
Chuck Rice: (19:01)
The other thing is, if you have a well-functioning soil population, they tend to compete with the bad microbes and prevent some of those diseases. That's called biocontrol. And so there's a branch that looks at biocontrol of these diseases that would suppress these diseases with a good, healthy microbial population. Lot of the root diseases, they take advantage of a population of those microbes that are good, that are suppressed. And so they can find... get access to the roots or get access to the... and cause those plant diseases.
John Mesko: (19:43)
Well, there's a lot that goes into understanding soils, as we've been talking about, but another area of study in the environment that's grown over the most recent few years here, especially, is the whole issue around climate change. And here we are recording this podcast here at late October and, as I look out my window here in the Twin Cities of Minneapolis and St. Paul, I'm looking at about eight inches of snow and temperatures below 20 degrees for the next week or so, which even for us is way, way, way out of normal.
John Mesko: (20:22)
And we've had a severe derecho through part of Central Iowa this summer. I think most farmers that we work with can point to extreme weather events of all sorts, whether it's heavy rain or drought or early seasons and late seasons, early frosts and late frosts, over the last dozen or so years, maybe more, that is much different than what we experienced in the past.
John Mesko: (20:47)
And so how does climate change and soils and soil health interact? Are we able to mitigate the effects of climate change with healthy soils, as you were mentioning earlier about taking out the inconsistencies or the variables?
Chuck Rice: (21:02)
Well, there's a couple of different things about soil and soil health, related to climate change. One is just the direct role or opportunity to sequester carbon in soils. If we can manage that plant soil system through diverse rotations, cover crops, and less tillage, we can build up soil organic carbon. And what that means is that there's less carbon dioxide in the atmosphere.
Chuck Rice: (21:28)
So people need to appreciate that there's twice... or two to three times more carbon stored in soils than there is in the atmosphere. So if we can make some small changes in soil carbon, it can have significant influences on the atmosphere and one of the causes of our changing climate.
Chuck Rice: (21:50)
The other thing that you kind of alluded to is that one of the things about climate change is... Well, there's a couple different aspects. One is the change in temperature, but the other thing is a change in precipitation. But that change is more erratic. What you just highlighted from Minneapolis there, and this is true the last couple of days in Kansas. We went from 50 degrees, yesterday we were at 85 degrees, and then today we're at, well, I think it was 29 this morning. So we've had 30, 40 degree changes within 36 hours both up and down. And so the plants don't necessarily like that.
Chuck Rice: (22:38)
Or on the rainfall side. A couple years ago, we were dry in Manhattan, Kansas. We were down by 30% for the season. And then on Labor Day we had 10 inches of rain in about a six-hour time period. On average, we look pretty good, but the distribution, that's not very good.
Chuck Rice: (23:04)
So it's that erratic nature. And this is where building soil health is really key because, at least on the water side, a good soil is going to store more water. It's going to capture those extreme events better. It's going to infiltrate instead of running off, which means less erosion and less flooding downstream. But you capture that water, and so then when it does have these dry events, then there's more water available for the plants, and so it buffers those extremes more so than a soil that's not in good shape.
Chuck Rice: (23:46)
And then that was really born out... Let's see, I think it was 2012 in Iowa... Well, across the whole Great Plains and Midwest, we had major, major droughts, but those soils that were healthier and were in better shape, the yield declined, but not nearly as much as those soils that had poor structure and low organic matter.
John Mesko: (24:08)
As we think about the impacts of climate change and our efforts in agriculture to mitigate that, take out some of those extremes, or the effect of some of those extremes, the next question that comes to my mind always is the future and thinking about predictions that have been made over the years about the expanding population. By 2050, the world population's expected to be maybe nine or 10 billion people. And then here we also have this growing climate crisis, that doesn't seem to change.
John Mesko: (24:40)
But what kinds of advancements can we think about as we look at our continued learning around soils and their ability to grow in health and do a better job, as you say, of processing water and nutrients? What does the future look like? What kinds of things are coming down the road for us to work on and what kinds of work needs to be done and what are we looking at, the impact of these technologies and so forth?
Chuck Rice: (25:11)
I guess I'm an optimist and I think there's really exciting times right now. I've told people that there's a lot of interest in soils right now and we need to take advantage of it. And if we don't get this right, then we don't deserve a future. For soil science and agriculture, you just mentioned two of the major issues is food production for a growing population and climate change. And I think there's a lot of synergy between those two if we can employ those practices that build soil health.
Chuck Rice: (25:45)
So like conservation ag, cover crops, increasing rotations, or diversity in rotations. That's not rocket science. Those are tools we already know, but it's putting the package together. We've tended to simplify our ag systems by growing, in the Midwest, just corn and soybeans. Let's start to think about, with the Soil Health Partnership, cover crops.
Chuck Rice: (26:12)
The thing about cover crops, there's a great opportunity. If we invested a 10th of what we... for crop breeding or breeding of cover crops, that we do for corn and soybeans, we could have designer cover crops. We could design our cover crops for cool temperatures. If we wanted tuberous crops to create biopores, to alleviate compaction, we could design those root systems to overcome what we think we need to do with tillage.
Chuck Rice: (26:45)
Can we design those cover crops to fix nitrogen or capture phosphorus better, to make it better available for the grain crop or cash crop? Maybe we should be thinking about deep-rooted. Can we have corn and soybeans, or maybe even a perennial crop, in the rotation that would put carbon down deep and sequester it and take advantage of a deeper profile for water and nutrients?
Chuck Rice: (27:15)
That's just on the management side. There's some other technologies that's pretty exciting. As you mentioned, I chair the National Academy Board on Agriculture and Natural Resources. And right now we're looking at how do we develop a more dynamic soil information system? Are there ways that we... People are designing sensors to place in the soil permanently, or at least for three to five years, so that we can monitor soil water, soil temperature, nitrogen. If we can put them out in the field and have a radio signal and say, "You're low on nitrogen. Put some nitrogen in now," where we can become more efficient with the nutrients or water.
Chuck Rice: (28:02)
Are there remote sensing technologies that we can detect plant health or even soil, remotely, from above ground, either through drones or even satellite imagery? Right now, we can detect how much biomass is growing on that soil. We can actually start to detect tillage levels, how much disturbance is happening.
Chuck Rice: (28:26)
Now we're talking about collecting data. If we had soil sensors or remote sensing, we might have every square foot or every yard of soil we could collect information from. That's a lot of information, especially if we're collecting it on a daily or even a weekly basis. I did a calculation once and I forgot what it came out to be, but it was like a trillion... Over a year, you could have a trillion pieces of information just on a thousand-acre field. And then how do you store that? How do you analyze it? That's what Soil Health Partnership is trying to do, is collect this information and then analyze it and deliver it back to the farmer.
Chuck Rice: (29:17)
So that’s data, information. But then there's other things like robotics. We have auto-steer tractors, but can you imagine if we could have a robot go down, like what's the... they have that little vacuum cleaner robot...
John Mesko: (29:32)
Chuck Rice: (29:33)
Roomba. Yeah. Can you imagine that going down your field and zapping weeds or going... and things like that? Pretty interesting, cool technologies that could be applied for agriculture to make it more efficient, make it more robust in that. So I think that's some of the future opportunities, is more understanding, using those technologies, robotics, remote sensing, to better manage our soils and nutrients and water.
John Mesko: (30:03)
Well, I think you summed it up pretty nicely at the beginning of your last comment here, putting the package together. Putting together what we know and what we are learning and what we need to learn and understand better into a package that helps us evaluate the progress we're making and put that in the hands of farmers and others who are managing our soils to do better, to improve quality and the health of the soil for not only the farms, but our society as a whole, and that extends to the human health and the global population.
John Mesko: (30:38)
And so I agree with you. I don't think there's ever been a better time or a more exciting time to be involved in agriculture, and certainly the work that you're doing and the support that you lend to the Soil Health Partnership is invaluable and we certainly appreciate the opportunity to work with you and to have this conversation today. I really appreciate it and thank you so much.
Chuck Rice: (30:58)
Yeah. Thanks, John. It's exciting times and it's an opportunity to provide better information for farmers, but also the general public about agriculture and soils and soil health.
John Mesko: (31:10)
Absolutely. Let's do this again sometime, Chuck. Thank you so much.