Me again!
So, are you sad that you didn't get to go to the
Permaculture Voices conference? Did you go but you can't remember what was said? Well, I am an obsessive note taker (most of the time) and I took notes at most of the talks I attended.
I will share them here with you!
Please note that this is in no way a transcription. These are my notes, taken in real time, on the fly, whilst trying to look at the slides and follow along. I find that note taking helps me synthesize information. None of this
should be construed as an accurate quotation, even when I put it in quotes. (For example, I'm pretty sure not a single speaker used the utterance "Yo.") Much of the time, I am trying to summarize and it's entirely possible that I've gotten some things wrong.
My next notes document is Peter Hirst. The topic this time was "Biochar Basics"
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Peter Hirst
New England
Biochar, LLC
Following Laura Ingham is really something - she is the world’s leading authority on soil. Wow.
I’m learning lots of new terms as I spend time in the biochar world. Biodynamic, beyond organic,
permaculture, etc. I think what we’re doing is really just going back to “food.”
I’m sure you know this: it’s all about the soil. What biochar does, it does in the soil.
The atmosphere is 200 miles thick and covers all of the earth’s surface. The ocean is on average 12000 feet deep, and covers 70%. The soil is on average 6” thick and covers ***% of the earth’s surface.
What we’re really talking about peak soil and what to do about it. (Computer fail delay)
So, C, E flat and G walk into a bar. The bartender says “we don’t serve minors here” (Ba-dum-bump!)
So, peak soil, the concept that we are running out of soil. It was first raised in 1898 as an issue by Sir William Crookes. The fixation of atmospheric nitrogen is one of the great discoveries, awaiting the genius of chemists.
Two Germans perfected the synthesis of nitrogen from air: Haber and Bosch. Thanks a lot, guys.
Biochar can be a tool for
land forgiveness and remediation. It is a multipurpose tool. It does a lot of things really well.
It’s just charcoal, of a quality that makes it useful as a soil amendment. You can even burn it, if you want to. I came into this because I was a blacksmith and I needed charcoal as a fuel. I came up with a good method to make fuel, and I ended up making biochar.
A good biochar is made at a higher temperature and it has no flavor. It’s relatively pure
carbon. Activated charcoal has a surface of plain, pure carbon. It has a high cation exchange capacity.
A gram of charcoal has about 400 sq meters of surface area. It can soak up 5 times it’s weight in
water and life.
The Terra Preta soils of South America: indigenous anthropogenic soil. You can find topsoil that is 6 feet thick. It’s so amazing it is being mined and sold to people in the
city for their houseplants. This stuff was discovered in 1985, hundreds of years after the people who made it disappeared.
The “Preta” in terra preta, which means dark, does not come from the biochar. That’s from the humates. Humic acids from the fungi. If you mix biochar with white sand, it won’t be that dark.
Pic: Peter standing behind extra tall corn, planted in really crappy soil with the addition of biochar.
Pic: here’s the microscopic structure of biochar. It’s the cell walls from the
wood. It looks like coral, and it acts like a coral reef for the soil. There’s places for everything, for bacteria, nematodes, for air bubbles. It’s the ultimate microbial condominium.
When you just add biochar to the ferralsol in south america, you don’t get a lot of color change nor much pH change. It is when you add waste that the color changes and the pH comes up to 5.3-5.7.
The really impressive gains are seen when you start with really poor soils. If you’ve got good soils the limiting factors are more likely to be sunlight and water. Still, you’ll see better retention of organic matter in your soil.
Yes, it’s expensive to put in, but it will last forever in the soil. (As long as it doesn’t erode away.) It’s a one time investment that will last.
It increases retention of all the good stuff in your
compost and soil. And, by the way, just making biochar is sequestering carbon.
A complete life cycle analysis of making biochar will show you how cool this is. 20 tons of CO2 for every ton of carbon in the ground, well, that’s the potential. Still, it has much greater value in saving fertilizer, improving soil, providing (heat)
energy as it is made. . .
Biochar is the only carbon sequestration technique that is adding value as you use it.
Q: what does it do for
trees?
A: there has not been
enough study with trees. They are currently testing biochar with city trees and it does seem to be a boon to them, living it difficult conditions as they are.
A lot of
greenhouse operators are using it as a 1:1 replacement for vermiculite in their potting soil. It helps make soil fluffy.
It reduces leaching of nutrients into groundwater or surface water.
You can mix it in a slurry with compost tea, you can mix it in with compost if you top-dress with compost.
For us, we only use wood that was headed back to the atmosphere anyway - waste wood. There is no need to purpose-grow wood to turn into biochar.
Biochar is made by pyrolysis. When you do this, 50% of the carbon is saved in the biochar, the other half goes to CO2.
Pyrolysis is done by heating the woody material in an oxygen free environment. We are pulling out the wood gases and burning those completely, the only thing leaving our furnace is CO2 and H2O.
An ancient way to make charcoal is in mud kilns, where you pile up the wood and have it smolder for days and days. Lots and lots of smoke, highly inefficient.
Whenever you burn a wooden match, you make some charcoal.
Wood does not burn. It’s gasses that are burning. What’s happening to the wood is reduction. The wood is turning into carbon, carbon monoxide, methane.
Heat doesn’t rise. Hot gasses rise. A candle in space burns blue in a sphere. The yellow color is glowing bits of stuff.
To make charcoal with an open burn, turn the usual procedure around. Put the big stuff on the bottom, smaller stuff on top, light the fire on top. You will get a very hot fire with much less smoke. You can reduce the particulates by 90% with this technique.
Pic: kiln for making charcoal. An Adam Retort. It’s got two chimneys. You burn in an enclosed chamber and it reduces smoke by 80%.
Here’s a metal one which captures ALL the smoke. It’s close to wood gasification, but different. You are making biochar when you do wood gasification, though.
What we do, we go into a customer and analyze what biomass they have, what we can do with it. Quick, he ran through several projects they did.. But, I’ve got to go see
Alan Savory.