The Ruminant: Audio Candy for Farmers, Gardeners and Food Lovers - e.13: Jess Dennis on BioChar

Episode Date: August 28, 2015

This episode: University of British Columbia grad student Jessica Dennis talks about her research on biochar and its potential as both a great soil amendment for agricultural soils and a carbon sink for climate change mitigation.

This is the Ruminant Podcast. I'm Jordan Maher. TheRuminant.ca is a website dedicated to sharing good ideas for farmers and gardeners. Most of the content on the site involves me posting other people's photos of their innovative farming tools, techniques, and ideas. I'd love to have a contribution from you, so please take some photos of what you're doing and send them to me at editor at TheRuminant.ca. Okay, let's do a podcast. Hey folks, this is Jordan, and this is a rerun of episode 13, which is another one from the archive that never made it onto this newer podcast feed, which means if you are a subscriber in the last couple of years, you haven't heard it.

So I hope you enjoy it. And before we get started, I have some great news. I have booked two interviews for the next week or two, which means that we might be back into, no, we are back into new content starting next week. And I'm kind of over the hump on the farm in terms of the demands of the farm. There's still a lot of work to do, but there's there's less than there has been. So I think we're going to be back into regularly scheduled weekly episodes with all new content. So I'm really excited about that. The other thing that I hope to do next week is to talk a little bit about the Berta rotary plow, which is a common attachment for a BCS or Grillo walk-behind tractor. I have a, at least temporary collaborator, Scott Humphreys.

He is a listener, and he's been on the show once before, and he might end up doing a little bit of help for me on the podcast. And one thing he suggested is that I ask some questions of listeners who might want to participate in a conversation about different aspects of farming. So he really wants to know how people get their spacing right with their bed prep when they're using their brooder rotary plow. So I thought that was a great idea. And I think we could have a talk about the use of rotary plows in general, because I own one and Scott owns one, and I'm sure some of you own them. So if you would like to participate in a discussion, I would love to

get a recording from you. I could phone you in the next week and maybe we could put something together. Editor at theruminant.ca. If you just want to email me about that, you can get me on Twitter at ruminantblog, or you can text me or phone me 250-767-6636. So I hope to hear from one or two of you. Even if I don't, I think Scott and I will record a conversation about our rotary plows and hopefully that'll be useful to people. So we'll probably tack that on to next week's episode as well. I hope you like this episode on biochar. And I think you're going to like next week's interview, assuming that interview happens as scheduled it's with a journalist who wrote a really provocative piece on well on the philosophies we hold about food security and the camps we belong to in terms of

how we think farming should be done and why there are aspects of belonging to a camp like organic versus conventional or non-gmo or local and how these camps uh tend to limit us from making progress on food security so i think that's going to be really interesting and that'll be next week released probably on wednesday until then here is a conversation with jessica dennis about with Jessica Dennis about biochar. This episode features my interview with Jessica Dennis, aka Dennis, who graciously got on the phone with me to have a conversation about biochar. Dennis is a graduate student at the University of British Columbia who previously did some research on biochar, and in this conversation we talk about biochar's potential role as a soil amendment and maybe even a climate mitigation strategy. And if you conversation, we talk about biochar's potential role as a soil amendment

and maybe even a climate mitigation strategy. And if you don't know what the hell I'm talking about, well, just listen to Dennis. Here we go. Jessica, Dennis, thanks a lot for coming on the Ruminant Podcast. You're welcome. I'm happy to be here. So Dennis, we met at a Young Farmer conference recently, and I realized we had met before briefly at an organic conference that took place last year at which you gave or you participated in a talk on biochar. And so I invited you to come on today and talk a little bit about biochar. But before we get on to that, could you just introduce yourself?

Tell us what you're doing right now. I know you're a grad student at the University of British Columbia. Could you Tell us what you're doing right now. I know you're a grad student at the University of British Columbia. Could you tell us what you're working on currently? Sure. So yes, I'm a master's student in the Faculty of Land and Food Systems at UBC. And my thesis research is on a very different topic from biochar. And I'm working on a study around land access in BC for for farmers and my main focus is on different forms of land tenures specifically alternatives to private ownership and whether those alternative models that are popping up all over the place are working out for people and if that seems

like it's a viable way to move forward in terms of both preserving our agricultural land base in bc and creating viable small-scale farms and accessible land for the the increased number of new farmers it seems that we have in bc that sounds really cool i'm a new farmer and I think there's been an explosion of new farmers lately and I think that all of us could use more information on alternate tenure arrangements. I have a pretty interesting and complicated lease arrangement with my landlords right now. That sounds really cool. Yeah, I'll have to talk to you about that another time. Maybe we'll have you on for another episode. But today we're going to talk about biochar.

Dennis, what is biochar? So biochar is basically charcoal is the simple answer. But the definition of biochar would be charcoal that's been produced from any sort of biomass for use specifically as a soil amendment. So this word has kind of been coined within, I think around 2000 it was coined, and it does refer to the production of charcoal for use in soils. But is it different than, say, like, can I produce biochar in my wood stove here at home? Like, is it much different than throwing ashes from my wood stove into the garden? It is different in terms of the garden it is it is different in

terms of the process by which it's made only because biochar is the there's a climate change sustainability aspect of it which i'm sure we'll get into but a big component of it is to to not produce greenhouse gases in the production and so there are recommended ways of producing it. So doing it in an open fire wouldn't be a recommended way. And plus you would have incomplete combustion, so it wouldn't be ideal. Okay, so I guess we'll get into the ideal way of producing it a little bit later. But just so I make sure that I have it and that listeners understand. Biochar is the product of burning biomass like wood to produce a charcoal that you then amend your soil with to provide certain benefits to the soil,

and I'm assuming largely related to kind of soil nutrients and organic matter and that sort of thing. Have I more or less got that right? Correct. Yeah, you got that right. Okay. So maybe we can go from here by, I'll ask you, how did you get involved with learning about biochar?

Oh, that's a great question. So, like you, I didn't really know what biochar was a couple years ago, and Hannah Whitman, who is now my thesis supervisor, had put together this proposal through the Pacific Institute for Climate Solutions out of the University of Victoria to work with community farms in B.C. on something related to climate change. And she was familiar with the farmers at Fraser Common Farm and one of the farmers there, Dave McCandless, had just been experimenting with biochar on his own out of interest and wanting to be able to implement climate change mitigation strategies within their production system. And so Hannah asked Dave if they'd be interested in participating

in some research related to that, and Dave was keen to have someone help him out and do some field trials with the biochar he was producing. And so I applied to do this research internship at Fraser Common Farm, and that's how I got involved with biochar. So how does biochar relate to climate change mitigation? Biochar is – charcoal is primarily carbon. And so when you – the process by which you make biochar, which is – it's called pyrolysis. And it's basically a thermal – a conversion process in which the biomass is heated in the absence

or near absence of oxygen at a fairly high temperature. The temperature ranges from about 350 to 850 Celsius and that process results in, the carbon in there becomes condensed. You end up with less mass in the end, so you have a greater carbon-to-mass ratio. So you have sort of a concentrated carbon product. And the structure of the carbon in the biomass changes, and it becomes more recalcitrant, which just means that it's harder for the carbon to be broken down in the soil.

So if you think about adding compost to our soils, a large portion of that compost is readily decomposed by microorganisms, and the carbon that's released to the atmosphere is carbon dioxide, although there is a portion of the compost that is slower to break down and stays in the soil, and that's the more calcine-tripped part of the compost. And with biochar, because of the heating process, the carbon, the structure of the carbon that remains in there is very recalcitrant, and so it's very resistant to decay in the soil. And so when you add the biochar to our soils, the carbon won't break down readily.

And so the idea is that it will remain, the carbon will remain sequestered in the soil for quite a period of time. And so that way you're taking biomass, you're putting it in the soil, and the carbon is going to stay in the soil for a way longer period of time than it would if you were just adding compost or crop residues back to your soil. Okay, okay. So then I think that begs the question then like could we could could you take me through how this might be applied on a large scale in our society as a climate change

mitigation strategy like is the idea that theoretically dennis could you could could it could a community or society decide to grow a whole bunch of trees with the idea that the trees over their lifespan trap a lot of carbon and then eventually those trees could be could be say sustainably harvested um and burned in in this certain way to produce biochar that then gets incorporated into our agricultural soils and if done correctly a lot of that carbon is going to get trapped in the soil while there are other benefits from the biochar being incorporated into the soil. Have I got that right? You could do that.

And that's actually been one of the main critiques against biochar is that there's this potential that people are stark and growing tree plantations to make biochar and that would be it would take up land and wouldn't you know be sort of the same argument against bio fuels basically and I think that's a really important point important argument and most people who are proponents of biochar I'm not gonna say all but most people myself included the people i've worked with the idea isn't to grow something specifically to make biochar i think that would take away any potential that biochar had to for climate change mitigation through tying up land and the the resources that go into growing a crop or trees um the idea is to

use a waste stream i think it's really important that if you're talking about climate change mitigation with biochar, I think that it must come from a waste stream, or you're not going to be achieving any sort of mitigation potential if you're growing a resource just to make biochar. I'm sorry, no, I was just going to ask you if you could give an example of a waste stream that you're talking about. Yeah, so for waste, it can be all sorts of things, and I've read through a lot of literature to get a handle on what's going on, and people use very diverse waste streams just depending on where they're located,

and so it can be wood waste. At Fraser Common Farm, they have a wood lot on their site, and so we were using windfalls primarily to make the biochar. But people have experimented. You can use manure, so we could use maybe poultry manure in the Fraser Valley, which we have an excess of. I've read about in the tropics, people have used nut shells. They get mass amounts of shells left over from harvesting nuts,

which don't make good compost, although you could do other things with them, but you can make a good biochar out of it. You could use crop residues. So it can be manure, it can be green waste, it can be wood waste. And just depending where you are and what large source of biomass waste you have, you could try to redirect that for the purpose of making biochar. And then I guess if I think of it on like, you know, within the context of one farm, if you know, inevitably, you have certain organic waste that is really fibrous, and you know, prunings are a good example, that sort of thing that take a long time to compost in a normal way, I guess those would be good candidates. You know know that's where that's where the biochar production could play a role just because you can uh break those down for the gardens or the

soils benefit in in a different way than than composting that is perhaps a little more um appropriate for those really fibrous materials yeah that's a good point yeah prunings would be a good idea if you have a vineyard or an orchard. Woody biomass is a great source to make biochar with. You can also use, I mean, there's ideas of capturing, because lots of farmers don't have mass amounts of excess biomass on site. And there are other, if you're doing it on a larger scale or if a sort of a region is thinking about doing it, you could capture other waste streams from like pruning of

trees in a city in an urban area or like the green waste that's picked up in Vancouver or other districts, for instance, like there's ideas about how different waste streams could be redirected and then produced off-site. So there's both, could be, depends on the scale that you're talking about, whether on-farm or off-farm and what waste stream you could be using. And I guess when you're doing this process, it sounds like you're able to, I guess, let's call it process this organic matter much more quickly than traditional composting processes, especially with fibrous material. Is that right? Yeah, because the pyrolysis process, I mean, it doesn't take very long.

You could do it, you know, it takes about, depending on what type of reactor you have, it takes like a small one on a farm, it takes about a day to run a batch just because it takes a while to heat up and then you have the cooling down process so uh and then it's ready to go in your soil as soon as it's cooled basically so i guess you're right that it you know wouldn't take us if you're trying to make versus making compost it is a quicker process okay and before we get on to that process could I just have one more question about its benefits. Can you talk more specifically about what it can do or what you understand it can do for your soil? Definitely. So it's thought that biochar is going to increase crop yield,

and there's three main benefits to soil processes through which it might be able to increase yield. benefits to soil processes through which it might be able to increase yield. And these are improved nutrient retention and nutrient availability, improved water retention and water availability, and improved soil microbial activity. Maybe I'll just explain each of those a little bit. So to understand the benefits, I need to talk a little bit about the structure of biochar. So if you imagine charcoal, it's really lightweight because it's so porous. And so one of the big benefits from biochar is that it's a very

porous substance and something that has high porosity has a high surface area. And a high surface area in a soil is beneficial to chemical reactions that occur and that allow for nutrient availability and nutrient retention. So if you think about soil texture, soil with clay textures with the small particles have high surface area and they tend to retain water and nutrients better than a sandy soil which has a coarse texture and not as much porosity as the clay soils. So biochar would have even greater porosity and greater surface area than a clay textured soil. And so by adding biochar and increasing the surface area and porosity within our soils, it has the potential to increase nutrient retention and availability

and increase water retention in soil. And as for the soil microorganisms, it's thought that because there's all this pore space that it increases the potential habitat for microorganisms. And I've seen some cool photographs of like the mycorrhizal fungi that they sort of colonize and inhabit all the small pores within the biochar, and soil microbes colonize inside the pores as well. And so by having this flourishing of microbes in your soil, again, you get increased microbial activity, which contributes to lots of beneficial processes, including

nutrient availability in your soil. So by way of analogy, I guess, like the next time that my girlfriend points out that I've got a bunch of food stuck in my beard and kind of gives me a hard time, I can just explain that it's all about surface area and that she just doesn't understand what it's like because there's just so much, so many more sites of attraction between me and and uh you know the cottage the bowl of cottage cheese and fruit that i just ate that's true yeah yeah all right so now are there any it's it's kind of funny because just by accident last night i was reading uh i was kind of browsing farmy type articles online and i i caught one

about biochar that it was it was a really brief little blurb about some some research that's going to be done to uh explore whether there are many negative consequences uh to adding biochar to the soil and i'll just quickly ask you if you're aware of any are there any are there any um potential pitfalls of of all of us i mean our society trying this out on a large scale yeah i think there think there's lots of pitfalls, and this is, again, a great question. Biochar has a lot of hype in the media. I'd say it's portrayed in a fairly positive light. But there's definitely some negative impacts.

And in terms of soil, I think I just mentioned the benefits, and those are potential benefits. I mean, it depends on so many factors, such as your initial soil texture, your initial soil health, the amount of organic matter you already had in there, the pH of your soil, your climate, where you're located. So it's definitely not a, if you use biochar, you're going to have increased yield. It's very dependent on a lot of variables. In terms of actual negative impacts, some that, one of them is the change in pH could be a problem. Lots of biochars are rather alkaline, so have a high pH.

And there is so it could be so like lime has an alkaline pH. If you add too much of it, it might and you already have an alkaline soil or neutral soil, it could change pH to a higher level than you would like for nutrients, for crop. Crops ideally want neutral pH. Other potential negative impacts for soil is, I mean, it's very high in carbon, so some people have suggested that because it'll have a very high C to N ratio, that some of your nutrients like nitrogen might get tied up. So compost tend to have, like a poultry manure has a very low C to N ratio. A green residue compost would have a sort of moderate C to N ratio,

and a woody would have a very high. Biochar has an extremely high C to N ratio. So that is a potential concern, although that's been discredited by some people because the carbon is so recalcitrant and resistant to decay that it just doesn't end up tying up nutrients is what people argue. raised, and this is not particularly relevant to organic farmers, but if you're using pesticides or herbicides, because biochar has such a great ability to absorb and retain substances, it has the potential to absorb and retain toxic substances. So if you are using a pesticide, say, then one, it could reduce the effectiveness by absorption, and also you could have it retained in your soil which would be

even worse than if you're just using pesticides in the first place and then there's another potential that biochar itself could contain the toxic substances and that depends entirely or mostly on what you're making it out of so if you're making it from organic residues on your farm it is very unlikely that it would contain toxic substances. Although there's been some concern raised over incomplete combustion or could potentially result in some toxic substance such as polyaromatic hydrocarbons, PAHs. aromatic hydrocarbons, PAHs. However, I haven't read a lot of research on whether that is a concern or not.

Most of the few sources I have found said that any levels are so low that it's not a concern. However, there isn't a lot of research on it yet, so I wouldn't write it off as not being a concern at all. And if I remember correctly, Dennis, you talked at the conference about kind of a historical precedent for the use of biochar. This has been done before by other, you know, in history by other cultures or by other, yeah, by other cultural groups. Is that correct? Yeah, actually, it's really interesting. I started reading about the history of it. And I mean, I never thought about it too much. but maybe other people have. If you run into charcoal in your soils,

which is quite possible, you've thought more about it. So the history of it is that people found in the Amazon that there's these soils that they've been termed Black Earth now, that there's these soils that they've been termed Black Earth now, or terra preta, and they found them in the Amazon of Brazil. And there were soils that were very close to each other in location, but this in one area was way more fertile than the neighboring soils. And they realized that these highly fertile soils contained a lot of charcoal. So people started to do research on this and the charcoal is from different anthropogenic sources

such as flash and burn agriculture or like making pottery. And so there's sort of some anthropological studies on what was contained in the soil and they realized it's probably from pre-Columbian indigenous societies that there's this accumulation of charcoal that's happened over an extremely long period of time, and that's produced these really fertile soils in different locations in the Amazon. And so this was sort of an impetus for a soil scientist to be like, oh, well, maybe we should look into this.

And it kind of spurred this renewed interest in research in charcoal in North America. And in my reading, I've seen in other places as well that the idea of using charcoal and soil isn't something new in other cultures, has done it both intentionally and unintentionally over the course of history. So putting charcoal in soil is definitely not an entirely new concept. I'd say biochar is just a renewed old concept. Okay, cool. So what about you did some trials out at Fraser Commons Farm.

Can you talk briefly about what you observed? Yeah. So I worked with Dave McCandless at Fraser Common Farm, and Dave, he built a kiln on site. It's made out of a 55-gallon steel drum, so it's a fairly small kiln. And so he was making the biochar on site out of alder windfalls, and we set up a field trial where we had some different treatments. And the treatments that we decided on were we added the biochar just by itself.

We added biochar with compost, compost by itself, and biochar with compost tea. And then we had a control plot that had nothing added. And we planted beets in our plots. And to say briefly, the reason we chose these different treatments is that there's been suggestions that adding biochar with a compost or a compost tea or a source of microbial activity or something sort of to what they call activating it. So by having the compost or the compost tea, it's thought that the benefits will be greater or more immediate

than just having the biochar alone added to the soil. So we planted beets in there, and we let the beets grow from June until sort of late September, so sort of full season. And then we just harvested and weighed them. And also we had thinned the beets so that we had equal beets per treatment area. And then we just weighed them to check the yield. And we found that the biochar resulted in increased yield over the control, so not having any biochar or compost.

But the biochar and compost, or the biochar and compost tea, didn't produce a greater yield than just the biochar, so that was unexpected. And then we also found that the compost alone had the greatest yield of all of them. So the biochar did increase yield over the control, but the biochar and compost didn't end up being any better than just having compost in the trial that we did. So our trial wasn't very scientifically rigorous. It was sort of small plots. So that's what we observed from the trial at Fraser Common,

and we definitely want to do some more research to see if we do it on a larger scale what happens. Larger scale, and I would assume, too, doing it over a longer time frame, like over multiple years, would be really helpful, too, to see the effects of biochar over time. Yeah, that was something I know. They really want to keep the trials for more than one year, but it's because we had done sort of small plots within one bed. It was just a management hassle for the farm, and they ended up just – I mean, it's still in the bed that it was in,

but we don't have the separate plots anymore. But we have – Well, still, it's a great start. It's a great – I mean, it's really interesting that you two did this. And, yeah, it's a good start to playing around with figuring out the relative benefits of biochar. We actually did some little potting mix trials that were fun. We thought maybe it would be cool if we could use biochar in our potting mixes to reduce the amount of off-farm input sets that we have to buy, so to reduce buying vermiculite or something.

Yeah, or peat. Yeah. So we designed these mixes with biochar, but we'd use a relatively high rate. We tried 50% biochar and then a mix of compost and worm castings, but the seedlings did not like 50 percent biochar so it's very clear that was good to see that it was like they just didn't germinate and i think it has i think it might be alkalinity we never fully decide them i mean we can't figure

out exactly what it was but um the alkalinity would be a good guess because i know seedlings don't germinate in very alkaline soils but maybe some of the ones we had a lesser rate, like just a quarter biochar had okay germination. And we didn't get too much further with that, but I thought it would be a cool idea to experiment with trying to replace potting mix inputs that we buy off-farm. That sounds really cool too. It's too bad you didn't have more time to play around with that. That sounds really cool, too. It's too bad you couldn't didn't have more time to play around with that.

So let's let's close out this this conversation by talking about how to produce this stuff. And let's talk about it on a kind of on a I mean, this is a podcast for for generally focused on small scale farming and gardening. So let's talk about it on a small scale farm type scale. Now, one of my one of the farming apprenticeships I did a few years ago was on a farm on southern Vancouver Island, so very coastal climate. And it seems like maybe the ideal hypothetical farm to produce biochar on in that it's coastal climate, so the soils are fairly acidic from all the rain. And on this particular farm, there was a small scale sawmill. So there was a ton of wood scraps and sawdust and the kind of stuff you were talking about before can be used to produce biochar. So I just want to ask you, Dennis, if that farm or any other farmer

or gardener wants to try this, what's the most practical way that they can try this out? How would they go about trying to produce some biochar? That's a great question. So the kiln that they've built at Fraser Common Farm, I think is a pretty good design. And what it is, is it's a 55-gallon steel drum. So you can get those from different sources for no cost or cheap. And then the steel drum is where you load in your organic waste that you're using. And you have to have, when you burn, so the flame will be under the drum, so you're not directly burning your organic waste. So you would set the drum up parallel to the ground so that the length is parallel to the ground so that the length is parallel to the

ground. And then you would set a little fire underneath the drum. And when you're burning your organic waste, gases are released. And so you need to create a way for the gases to be released from the 55-gallon drum. And so what you can do is you weld a pipe, so make a small hole, weld a pipe on that comes down, comes out of the drum, and then under the drum. And then the gases will go into that pipe, and then if you perforate the bottom of the pipe, and the gases can come out. And then the gases are actually flammable, so the gases will burn once they start coming out, and then they fuel the process.

And so in this way, you have to start a fire initially, but once it gets heated and the gases are coming out, you don't need to add to the fire, so it's sort of a self-maintained process. And then it just goes until there's no more gases released and it cools itself down eventually usually overnight and that's so that's how Dave does it and there's I have pictures of it that are available online and there's also lots of sources online of how to build these 55-gallon drum-type kilns. And there's lots of different ways out there for farmers to build them,

and I think there's just like a ton of information on the Internet now. And so maybe just some recommendations if you are going to do it. There's a lot of health precautions that I recommend that you take because you're working with, you know, you're working with something that's at a very high temperature and there's gases coming out and A, if the gases don't come out, you'll have a high pressure and examine explosion. And the gases themselves are things like carbon monoxide and hydrogen gas. So A, they're really flammable, and they're also health hazards for humans to inhale. So, you need to be, make sure you design it very cautiously.

Not in your bedroom. Not in your bedroom, yeah. Okay. Don't do it in the garage. Don't do it indoors. Don't do it in your greenhouse. Don't do it in like a 1970 Volkswagen Bug. Don't do it in a 1970 Volkswagen Bug. No, no. Don't do it in your tank of fuel.

So be very thoughtful about the potential explosion and gas hazards that come along with building these kilns. Definitely do some serious reading and thought about the design before you follow, before you just build something that's out there on the internet. And another, I think it's ideal to be having the gases fuel the process. So there's designs out there where people like, I mean you can use like old techniques where you build a, dig a pit and build it up, set a fire in there, cover it all up and it certainly produces charcoal and people do that around the world.

But, I mean, if you don't want to be producing greenhouse gases, then that's not an ideal way to go about it. And so these ones where you burn off the gases, you do produce some greenhouse gases, but inevitably you're producing less by using this process. I think you also get a product. So I guess the key concepts, it sounds like, are that ideally you have a kiln-type thing because you want to have the burning taking place

in a kind of enclosed space. Ideally, you want to pipe the gas being produced back to the original source of heat so that it can be the main fuel for the burning process. Yes. And you need a really high temperature to produce higher quality biochar. Yes. And if those gases are being burned, it's going to be at a high temperature.

Your problem will be it potentially being too high, if anything, because those gases burn quite at a high temperature. So getting it up to temperature isn't such a problem if you're burning the gases. Okay. And I assume that you can provide me with some links to kind of sites that illustrate what you're talking about, and I can put those up on the website along with this podcast episode. Yeah, definitely. And another thing i want to

say that so this design that we've done is quite a simple one and there there are more complicated designs out there and i think getting trying to build some of those more complicated designs would be would be great um if you have the the time and the engineering skills to do so i think there's some opportunity for capturing heat in different ways um or capturing the gases to use in different ways because on larger scales or even medium scales people have designed systems where it's also a source of of energy and there is a lot of energy in there and if you capture it i think that would be awesome and so even on a small scale i've seen some out there they're more complicated than the one we did,

but I think they're feasible for someone who's got some engineering and building skills to make on a small farm. And you could do something like either heat water for a greenhouse or basically somehow capture energy alongside making the biochar just to even increase the efficiency. And how long does one burn take? Are we talking about a few hours or a day, or how long to produce one batch of biochar?

In the kiln that I described that we have, the 55-gallon drum, it takes a day. I mean, it burns for probably four or five hours. So it takes, there's like a little, you've got to, you set the fire, it takes a little bit for it to get going, and then it probably burns at full temperature for maybe four hours or something, and then it cools off, and then we let it fully cool until the following morning just to be safe, because you don't want to take that lid off when there's still any pressure or heat in there.

So if you start a fire and start the kiln going first thing in the morning, then the next morning you open it and it'll be safe and cool and you can take it all out and start working with it. One other thing I wanted to say is that the charcoal is dry and dusty and it's also a hazard to be inhaling or to be releasing to the air. So you need to come up with creative ways to not inhale the dust or have it released into the environment when you're working with it. So you can wear a mask when you're working with it.

I'd recommend that. And you can also try to keep it damp would be the, like, moisten it either by, by mixing it, you can just add some water or mixing it with your compost or mixing it with a compost tea or something. But if you work with it when it's damp, you can avoid the dust factor. And so it sounds like you definitely should not use biochar as a substitute for rice to throw at your best friend's wedding when they come out of the church. No. substitute for rice to throw at your best friend's wedding when they come out of the church no okay unless unless all the guests are wearing gas masks or some sort of yeah breathing apparatus yes and it may be okay yeah which which might happen in like like a post-apocalyptic wedding or something

they might have to be wearing masks anyway yeah okay good to confirm that listen uh that was really interesting i i i i'm really glad to have had you on the podcast dennis because i was fascinated when i caught this seminar at last year's conference and i think uh hopefully some of the listeners are of our listeners will find interesting too so thanks very much for for for coming on today to talk about it. Thank you so much for having me. Okay, that's it for this episode. Check out the posts of this episode at theruminant.ca if you want to look at some of the links that Dennis has provided about biochar, or if you're interested in any other delightful nuggets of information that are of general interest to farmers and gardeners.

Once again, thanks for listening, folks, and I will talk to you next time.