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“Biochar has the high potential to increase resource efficiency — saving fertilizer, saving water, providing better nutrient retention and hosting more microbial populations — in addition to direct carbon sequestration.”
— Michael Kaiser, Assistant Professor of Agronomy and Horticulture, University of Nebraska Lincoln
Biochar, an ancient soil amendment similar to charcoal, is showing new promise for improving carbon sequestration and resource efficiency in modern farming operations.
In today’s episode of the podcast, brought to you by SOURCE®️ by Sound Agriculture, contributing editor Dan Crummett talks with Michael Kaiser and Britt Fossum from the University of Nebraska Lincoln about biochar and the university’s biochar, which currently make up one of the largest in-field biochar studies in the U.S.
Related Content:
Biochar Has Potential to Save Water, Fertilizer
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Full Transcript
Michaela Paukner:
Welcome to the No-Till Farmer Podcast, brought to you by SOURCE by Sound Agriculture. I'm Michaela Paukner, managing editor at No-Till Farmer. In today's episode of the podcast, contributing editor Dan Crummett talks with Michael Kaiser and Britt Fossum from the University of Nebraska Lincoln, about biochar and the university's trials with this ancient soil amendment, which currently make up one of the largest infield biochar studies in the US.
Dan Crummett:
We're here today discussing agriculture and environmental benefits of biochar in agriculture. I'm Dan Crummett, a contributing editor for the No-Till Farmer Magazine, and with me here are Michael Kaiser, assistant professor of agronomy and horticulture at the University of Nebraska in Lincoln. And doctoral student Britt Fossum. They're involved in one of the largest infield biochar studies in the US. Welcome, Michael and Britt.
Britt Fossum:
Hello.
Michael Kaiser:
Hello. Thanks for having us.
Dan Crummett:
You bet. I appreciate your time. First, let's begin explaining what is biochar and why is it useful and how is it different from a charcoal briquette?
Britt Fossum:
Yeah, so biochar is essentially one of the products that comes out of pyrolysis. So it is produced by heating some form of biomass. It can be wood, it can be residue from crops. And heating it without oxygen, which ends up producing a lot of this very carbon rich material. So in a way, there's some similarity with charcoal, except you are kind of tailoring this production process to make as much of the biochar material as possible. And a lot of times there are specific temperatures and specific feedstock, and all of that can influence the properties of biochar.
Michael Kaiser:
Just wanted to add, because you had a question about the charcoal briquette. The charcoal briquette is basically produced by the same technique, so it is pyrolysis, so combustion under oxygen limiting conditions. And what they do before, they use sawdust, maybe the particle size is different. And sometimes they press it before the pyrolysis process into a briquette.
But basically the material that comes out is similar, because the feedstock is similar. So for biochar, we are using all kinds of waste, organic material, and for the charcoal briquettes, they're using sawdust or specific wood material that is requested by the buyers or by the consumers. For biochar, we are basically looking for any organic waste material that we can transform into biochar. But basically the production process and also the material characteristics are similar.
Dan Crummett:
Very good. Well, why is biochar important to agriculture, and why is there an interest right now?
Britt Fossum:
I think that does tie into the production process as well. Because it's a very unique form of a carbon amendment that you can add to soil. So it doesn't decompose very rapidly. So you can basically apply at one time and see the effects over a long period of time. And because of what it's produced from and how it's produced, it has a very, very high surface area. So when you add it into the soil, you're increasing all kinds of structural properties. And doing so over a long period of time.
Dan Crummett:
Okay. The addition of carbon to the top soil, and we're talking about growing things, there are more benefits than just the application of carbon to the soil. And you mentioned the high surface area. How does this interact in the soil and what benefits would a grower look at? My audience of course is no-till farmers and others, they're going to be interested in why this is something they should be interested in. What does it do? I know there's some link with bio microbes and such. Can you address that?
Michael Kaiser:
So what we know from a couple of long-term feed experiments worldwide, so as Britt mentioned, the first purpose was we put biochar in soil because we have a source of carbon. It's 60 to 80% organic [inaudible]. So we have a high [inaudible] immediately in the long term. What we figured out, and a lot of research as well figured out, biochar can improve nitrate retention, which is good for storing nitrogen in soil and reducing groundwater contamination. We see an improved cation exchange capacity, because of the high specific surface area. We see an improved water holding capacity. We see an improved soil structure, and the lower bulk density. Biochar is not really a fertilizer, but biochar is also inhabited for microorganisms, so it can improve the living conditions for microorganisms. The effect of biochar on agronomic benefits are getting bigger as poor as your soil, so as more sand you have.
And biochar is also a strong amendment to increase soil pH. So if you have an acidic sandy soil, your effects are bigger than in a fertile silty soil with a lot of organic matter. But nevertheless, we do have this benefits and effects in almost all soils, but the magnitude of an effect is bigger in the poorer soil. And so we see especially increased in yields in tropical poor soils, not as much in more fertile soils. But biochar does have a high potential to increase resource efficiency. So meaning saving fertilizer, saving water, getting better nutrient retention, having more microbial habitats. So there are a couple of core benefits, agronomic core benefits to the long-term carbon sequestration.
Dan Crummett:
Is one application of biochar sufficient or is this something that needs to be done over time? Does the effect wear off after a while?
Britt Fossum:
So there is not a lot of long-term studies on biochar in a contemporary agronomic context. It's still fairly new. So I can't make any promises basically, about how long you'll see the effect. But a lot of it depends on your application rate initially, as well as the baseline state of your soil. So like Dr. Kaiser said, if you have a very poor soil, you'll notice the effect of introducing a lot of carbon more. It'll be more noticeable. And it also depends on your application method, so how deeply it's incorporated into the soil and what kinds of disturbance come after. So it is resistant to decomposition, but it can be lost from the soil via other pathways. It can blow away, it can be washed away. And so again, no promises, but theoretically you could observe the benefits for multiple years after application.
Michael Kaiser:
We do have two global long-term feed experiments in biochar. That are the terra preta soils in the Amazon and that are the old charcoal kiln sites in Europe. So in Europe they produced in the heavily wooded areas, charcoal for centuries. And there are experiments looking into agricultural fields [inaudible] since over 200 years.
And you still see from aerial photographs, the old kiln sites that are basically black spots. And if you analyze these black spots, you see that the carbon content is still higher, the pH is still higher, the cation exchange capacity is still higher. And the Amazon, the indigenous people applied... So incorporated charcoal 6, 7, 800 years ago. And we still see this differences between this terra preta, these Amazonian dark earths. And the natural soils, which are [inaudible] soils. [inaudible] soils are very old, very acidic, very poor in nutrients. And you still see the differences.
If you excavate a soil pit and you have an adjacent terra preta soil to a [inaudible] soil, you still see it's much darker, it does have much more carbon, it does have better nutrient retention. So this is clearly an indication that this is a long-term effect.
But as Britt says, for us it depends on how much you put in, especially if you're on a no-till system, you just want to put it one time. And then look at the most efficient rate, which is part of our research looking into that. As I said, it's especially in Nebraska with our soils, we want to increase or maintain yields by reducing resource input. Means nutrients, fertilizer, water. Mineral fertilizer, the costs are going through the roof over the last two years. So if you save fertilizer, right and save water, that makes your entire system more efficient and more environmental friendly.
Michaela Paukner:
I'd like to take a moment to thank our sponsor, SOURCE by Sound Agriculture. Welcome to a better source of fertilizer. SOURCE from Sound Agriculture unlocks more of the nutrients already in your fields, so you can add less fertilizer while getting the yield you're counting on. By activating soil microbes SOURCE provides more of the existing nitrogen and phosphorus to your crops. It's such a solid backup plan, you'll probably find yourself wondering why SOURCE wasn't the plan all along. Visit sound.ag to learn more. Now let's get back to the conversation.
Dan Crummett:
This to me, I think would be very applicable to deep banding, with banded fertilizer as well as at plant through the planter near the expected rhizosphere. Is that something that, am I correct on that or does it need to be broad cast and tilled in? What about banding?
Britt Fossum:
So I couldn't find any information about people who have tried that and done research comparing it with just a broad cast and tilling. But I know from even speaking with some producers at field days in Nebraska, they do find that the idea of doing a full tillage across the whole field was kind of not appealing after they've been doing so much work with no-till for years. And so I think a lot of work needs to be done too to try some of these methods for applying biochar.
So for us, we are trying to use a minimal tillage method just using disking, focusing on a one-time application. So trying to reduce the amount of tillage, but doing experiments with, like you said, doing strips of biochar. And even one producer in Nebraska who's been making his own biochar had met me and started talking about wanting to experiment with making a slurry and applying it in that form with some other components. So I think I can't give you an answer because there isn't one yet, but a part of it is trying out these different methods. And seeing how it works, what works best, what it's best for. A method like banding might be useful for reducing loss. But yeah, I can't give you a solid answer just because it hasn't been tried.
Dan Crummett:
Okay. Well that leads us into your project that's going on there. Explain what it is, what you're doing, what the hypothesis might be. And where we are going with trying to find theories behind it.
Britt Fossum:
All right, so there are currently two main projects. I mentioned earlier that the one that we're focusing on right now is the large scale biochar application combined with biosolids. And so the rationale behind that is, looking at biochar's ability to increase the efficiency of applying this form of organic fertilizer. So biosolids do contain more nutrients than the biochar does. And so our thought process in designing this experiment is that by applying biochar and biosolid together, you can hold onto more of those nutrients and increase water efficiency and overall just improve the outcomes after using this amendment.
And so the design was developed with members of the Lincoln Biochar committee, I think mostly with partners in the city of Lincoln who have a pretty large biosolids program. And also helped source our field site. And so it is about 16 acres in total of field, of which we have control with nothing applied to it besides conventional management. A biochar for four acres of just biochar, four acres of just biosolid, and four acres with that combination. And so the idea is that by looking at these different combinations, we can determine is the biochar addition actually increasing the efficiency of applying the biosolids?
And we're looking at a number of different parameters, not just soil carbon, but also nutrient content. And the previous project, which is still ongoing, is much smaller in scale, but it is again looking at biochar in systems that are really relevant to Nebraska. And so for that project there are two field sites, and in those cases it's only applying biochar with conventional fertilizers. But there, at least one of the areas I'm interested in is that one of the sites is rain fed and one is irrigated. And so we're able to look at how it can improve efficiency of irrigation and also unfortunately in drought years, how it impacts water use in this rain fed system.
Michael Kaiser:
What might be very interesting for the No-Till community. So in this second project, what [inaudible] described, we are working at UNL Research and Extension centers close to [inaudible] center. And here we combine biochar with cover crops. And we do have plots where we did simulate one-time tillage. So we used an existing no till cover crop experiment and apply it a one-time tillage that we need to bring in the biochar. And then we measure nitrogen, carbon.
So based on this onetime tillage, we didn't see any changes in nitrogen and carbon contents. Also not in nutrients. We didn't check aggregate stability, but we don't see big differences in having a one-time tillage event after four years no-till and cover crops. We just wanted to see if this no tillage event does have any big effects on our soil properties. Because we need this one-time tillage or disking, the minimum tillage what Britt described, to bring the biochar in. Otherwise, you are running into problems losing the biochar via erosion, wind or water. And the biochar effects are biggest if the biochar is mixed into the soil. So we need to bring it in to have the benefits and to avoid losses. And the biosolid and biochar experiment is totally under no-till and cover crops. So here we combined in total four climate smart management practices, so biosolids, biochar, no-till and cover crops. And want to see here, as Britt described, synergy effects.
Dan Crummett:
How long do these projects last? What do you expect? How long do you expect these to be ongoing?
Britt Fossum:
Well, at least three years for me. But I think especially with the larger scale biochar application, depending on what we see as far as biochar losses, this could hopefully be a site that's studied for a long period of time. Because again, one of the areas of interest definitely for me is seeing how long the effects last, and how they change over time. Just because, I mean, there are long-term studies that show biochar can last in soil for a very long time, but not much if it's under contemporary management in Nebraska. And so getting to see how all of these inputs and the intensification of agriculture, if that changes anything about the durability. But I don't know if you have any other thoughts.
Michael Kaiser:
As long as possible, but that depends on funding. So once a biochar is in, you can resample 20 years after, you just need to know where it was. So we did this in Germany with a field experiment established 20 years ago. Then it was just transformed into a normal farmland operation, but we still knew where the biochar plots were. So we resample 20 years after.
The same as with the biosolid biochar experimental side. We just need to reapply every four years of biosolids. Everything else stays the same. So that's an excellent collaboration with Lincoln Biochar Initiative and with the City of Lincoln, funding from University of Nebraska Center of Energy Science Research and Nebraska Forest Service. So they are supporting this biochar, biosolid, each program is supporting the other one. So we try to... To run the experiments is okay management wise and also effort wise. We need to get funding on a regular basis for analyzing the soil sample.
So we try to get this going as long as possible because we need the long-term data. And what we can also measure is biomass, grain yields and cover crop biomass to see how all this management effects result in productivity. Because this is, if Britt and myself, if we are talking to the farming community, I mean that's a big point. So we need to keep up with productivity. We don't want to see a loss in productivity. What we want to see is same productivity or higher productivity by less input. So making the system more efficient. And more environmental friendly. I mean that's a big part of our motivation as well.
Dan Crummett:
Well, I've read about preloading biochar with various humates, that sort of thing, to improve the habitat for microbes. Is that what the wastewater or municipal waste would be doing in this case?
Britt Fossum:
Biochar, when it's first produced is very bare of nutrients. It's, like we mentioned, basically just carbon. And all of that surface can really absorb and hold onto nutrients, water, all of that. And so I think some of the ideas with trying to preload biochar is trying to kind of get that surface started a little bit early. I think with just materials that are, I've definitely heard of maybe adding an inoculant and mixing it with something like compost, or in this case biosolid.
Here, they were not premixed. The biochar was applied to the field and then the biosolid was applied a little bit later. But this would be something that we would look at, is kind of how addition of biosolids changes that biochar surface. And whether it loads the biochar with nutrients. But that was not a primary part of the experimental design. It was applied separately as just biochar and just biosolid. And at our previous project that was also just biochar with no additives, no anything else.
Michael Kaiser:
The biochar, what Britt explains, the biosolids are substrate, right? So it's water, it's organic material, it's nutrients, it's good for microorganisms. So we will measure microbial biomass, fungi, bacterial. So we will have information about if biochar plus biosolids is increasing microbial abundance. But usually biochar in soil, it's not really decomposing. So it's not only to a lower rate transformed into carbon dioxide to a really lower rate. Because it stays forever on soil. But the pores are actually adding habitat. And if biochar over time is absorbing water and nutrients, that are perfect living conditions for microorganisms. And the pores building basically a surface area where they can attach to and then they're waiting for food and water. And biochar over time gets smaller. And we see an increase in so-called functional groups on top of the surface of biochar. And that's a sign for microbial life.
So microbial activity is increasing the so-called oxygen containing functional groups, which make them more [inaudible] and higher... So it's an oxidative breakdown or transformational of the surface area. And that shows that biochar, even if you apply it without any preconditioner, over time, it gets charged, it gets colonized, it gets used as a habitat. In general, we see an increase in microbial abundance and activity once we have biochar in the soil. And from my perspective, if you put it in the soil, you just wait a bit and the soil is doing its job. The temperature as lower you go with the production temperature, is higher are the volatiles. And the volatiles can be used as a substrate. But as Britt said, in our case, we mix it with the biosolids. And our hypothesis is that we have an higher abundance and higher microbial activity in the biochar biosolid plots.
Britt Fossum:
And I think I'm remembering some questions I've gotten at field days before too, that were just concerns that there was a lag time after adding biochar, before it was really integrated into the soil. But we are seeing that... We're doing some, again, analysis of the biochar surface and we're seeing that it is pretty rapidly associating with soil particles and soil minerals. The preloading process is not really necessary. It kind of does it on its own when it's added to soil, especially when it's mixed in really well.
Dan Crummett:
It's an amazing product apparently. Let's veer a little bit here from the project, to the work you're doing overall. And how it applies with others. I know there is a Nebraska Minnesota Biochar Initiative. And I'm wondering how this, your project fits in or dovetails with that. Is there any connection between the two?
Michael Kaiser:
The Nebraska Biochar Initiative was kind of a program that was funded by the Nebraska Forest Service, which is meanwhile not funded anymore. But the Lincoln Biochar Initiative is kind of a child of the Nebraska Biochar Initiative. So the Nebraska Biochar Initiative supported the Lincoln Biochar initiative in the first place.
So basically the Nebraska Forest Initiative is ceased, but now we have the Lincoln Biochar Initiative, which is combining most players, the City of Lincoln, the Nebraska Forest Service is involved, UNL is involved. So that's our playing ground right now. Right? Our network, our connection.
And Minnesota, so Minneapolis was one of the cities that also received the funding from Bloomberg. So the City of Lincoln received funding from Bloomberg, $400,000, one of seven cities globally. So they got funding from Bloomberg to build their own biochar program, which includes a biochar plan. And there is close interactions and discussions between Minneapolis and Lincoln, because both cities received the funding from Bloomberg. And there are interactions, especially on the city level, that the cities exchange information and application details and so on. So there are relationships, interactions between the Lincoln Biochar Initiative and the Nebraska Biochar Initiative, the biochar initiative led in Minneapolis.
Dan Crummett:
Where would you suggest growers interested in this find further information? Where do they look to educate themselves?
Britt Fossum:
Yeah, so there are some resources that have been developed in Nebraska. We have some resources developed by the Forest Service and also some information provided by extension. And with the Lincoln Biochar Initiative, hopefully putting out some more information as well.
A lot of these resources are focused on making biochar. That's something that I've come across. Or using it in smaller scale applications. And so I do know that there are some fact sheets being developed right now looking at guidelines for larger scale, field scale application, using some of the information that we got just from the application process for this project. But again, this is something that our research will hopefully help develop. A lot of these methods need to be tested out and tried in order to write these kinds of materials for application.
But yeah, as far as if there are producers who are maybe interested in making some, if they have a lot of wood waste or anything like that, probably the best place to go for information about that would be your state forest service or extension.
Michael Kaiser:
And any farmers, so we also have a US Biochar Initiative, they do have a pretty cool homepage. And if farmers are interested in information about production or where they can maybe get some biochar, or how the application process is going, they can always reach out to us. So to Britt or to myself.
They can also, we have a Lincoln Biochar Initiative homepage. So all people involved in this network in Lincoln, we do have some experiences. So we are more the research side and application, large scale application. The colleagues from the Lincoln Biochar Initiative from the city have more information right now on about setting up a biochar plant. And what you need to do about different production conditions or different production tools. We do have some contacts to regional producers in Nebraska, so we are more than happy to help. So they can reach out to Britt or to myself, or to the Lincoln Biochar Initiative. So there, I think for Nebraska is a lot of expertise, a lot of information, a lot of first recommendations. So we have a pretty good network with a lot of expertise on different areas. So we are more than happy to help and provide information or to provide contacts or make contacts. So that's always an option.
Dan Crummett:
Okay. Well, thank you very much. This is an exciting time and an exciting process, and you seem to be on the cutting edge of it. I appreciate your time. With that, we'll let you get back to studies, so thank you.
Britt Fossum:
Great. Thank you.
Michael Kaiser:
Thank you very much for having us.
Michaela Paukner:
Thanks to Michael Kaiser, Britt Fossum, and Dan Crummett for today's conversation. I encourage No-Till Farmer Magazine subscribers to check out page 58 of the August Conservation Tillage Guide to read Dan's full story about biochar. Or, go to no-tillfarmer.com/podcast for a link to the article. You'll find the transcript and a video of this podcast episode at that link. Too many thanks to sound agriculture for helping to make this No-Till podcast series possible. From all of us here at No-Till Farmer, I'm Michaela Paukner. Thanks for listening.
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