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Confused -- Is there a difference?

 
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I've read a couple of books on biochar, some magazine articles, and quite a bit online.  Much of the information conflicts with other information.

Two weeks ago, I made my first biochar from dry  fir branches, all finger-sized or smaller, in small batches.   The results could be divided into two kinds: pieces that could be crushed with my fingers, and pieces that couldn't.

Is there a difference between the two?  I think I read somewhere online that biochar has had the impurities burned off, and the black char on your fingers would wash off with plain water, and the other (just charcoal?) required soap and more work because the sticky residue hadn't burned off.  

So, does this residue (or lack thereof) make the difference between bio char and just plain charcoal?  Is the crushability by fingers a feature of biochar, possibly useful as a form of ID?

Perhaps in the same article, there was a reference to one of these being a fire hazard if stored in something like a plastic bucket with a lid.  I think it was the char that still has the residue.

The problem is that I'm selling my property, and I would like to take my biochar with me, for future use.

Any thoughts would be welcome.
 
pollinator
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Hi Sue, and welcome to permies! Also, welcome to the world of biochar...it sounds like you're off to a good start.

Biomass which is pyrolysed at low temperatures or for insufficient time isn't "done" for use as biochar. It's been torrefied, which means some of the volatiles have been driven off, but not all. Also, the carbon left behind is still predominantly in aliphatic bonds rather than aromatic. Symptoms of all this are chunks that you can't crumble or crush easily by hand, and soot that is a bit on the greasy side.

You can take all the bits that aren't fully charred and reprocess them. No harm done. And do take care storing biochar, whatever quality it is. Dry biochar can spontaneously ignite under the right conditions. Dampening it is a safe habit to follow.
 
pollinator
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My thoughts are that the people that created terra preta didn't have temperature gauges or the means to make biochar to very specific specifications.  They burned wood and threw it in a hole in the ground with a bunch of other trash, and came up with something awesome.  I make lots of charcoal to make biochar. Some of it comes out perfect, making that wonderful glass breaking sound when you mess with it.  Some of it comes out almost there.  I use it all.  I have read studies that said there are organisms that like to eat the stuff that doesn't get burned off entirely, studies that said for biochar to be "just right" it has to be made at a pretty specific temperature, and studies that said no one knows what is best.  Good enough for me.  I don't worry about things I have little control over because it uses up time I could be planting trees or building gardens or making new creature habitats.  My personal opinion is, don't lose sight of the big picture because you are too concerned about getting the tiniest details right. The saying that perfect is the enemy of good comes to mind.  I use to very much over-analyse everything.  I realized I didn't get much done.  Now that I just try to do my best and move on, I get lots of things done :)

I haven't heard the thing about biochar combusting, so I'll be interested to hear the answer.
 
gardener
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I'll try and separate the differences for you.

First was the third rediscovery of Terra Preta in the Amazon Basin in the 1980's, the first discovery of this "wonder soil" was back in the days of the Spanish Conquest of South America, the second discovery was in the mid 1800's when some archeologist went looking for the "Amazons" of legend.
The third rediscovery came in the mid 1900's at which time scientific study of this mysterious soil with amazing properties started being carried out. All of this led to some people trying to recreate the "wonder soil" and that is what led to what today is termed "Bio Char" or biologically activated charcoal.

There are huge differences between the burnt materials that make up the actual Terra Preta and the currently in vogue BioChar and these differences are important to understand.

Terra Preta is made up of Trash Dump materials that were burnt when the dump became full, these burnt materials were then spread over the soil and then raked into the soil so it wouldn't blow all over the village as ashes tend to do.
This was repeated every time the trash dump became full, at some point seeds probably fell onto this "field" and the seeds grew very well, which led to the people using this area of ash and burn trash for gardening space.
The gardening space was so productive that the people created even more area with their burnt trash ashes and left over particles (some were burnt pottery and so on) and this went on for around 500 years as best we can conclude at this time.
The studies of Terra Preta show that it holds water far longer than regular soil, it also has better microbiome activity and wider diversity of micro organisms as well as macro organisms which makes this soil far better for growing plants than the surrounding, non-treated soil.

Bio Char is wood that is incinerated in an oxygen depleted environment so that only the carbon matrix found in the lignin portion of the wood is left. (this stuff sounds like glass breaking when you snap a piece)
When first coming out of the "oven" the carbon matrix is barren of life forms and is called "char", it only becomes Bio Char when there are active microbes living in the matrix and there are several ways to achieve this.

In ancient times they didn't know about burning in the absence of oxygen, but parts of their trash heaps that were near the center bottom of the heap would have been this way.
Overall the results of the current Terra Preta examinations show; the material was a combination of burnt trash and ash, it was spread out away from the trash dump (burn site(s)) and that it was initially turned under the soil at the time of the spreading.
Areas larger than 5 acres in size have been located and identified in several villages along the Amazon River basin, the average thickness of the Terra Preta is around 2 feet and it is at a depth of between 6 inches and 12 inches below the current soil surface.
It has also been documented that if you dig out an area of Terra Preta and refill that hole with regular soil, in a period not longer than 5 years, the regular soil will have turned into Terra Preta. (the process by which this happens is not currently understood)

The bottom line is that both Terra Preta and Bio Char infused soil share the same traits when it comes to water infiltration/ retention and bioactivity resulting in increased fertility.

Hope that helps you understand this particular subject a little better.

Redhawk

I forgot to mention that both need to be incorporated into the soil for them to work the way they are supposed to work, using biochar as a mulch layer simply will not provide the bioactivity of the microbiosphere that is desired, making the use of biochar one of those instances where tilling it into the soil is required.
 
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Is there any down side to putting not-quite-biochar into the soil? (assuming inoculation, of course)  I get the difference between biochar and the stuff that's not quite there, but I'm not sure how to use the latter.

I have a bucketful made from the leftovers from my fire pit and experimentation with a mini-Weber kettle grill.  Some definitely goes "clink."   Some seems to be pretty well pyrolized, but probably not to true "biochar" levels. Some is clearly still wood.

I was planning to work the material in the first two categories into my compost bin and not worry about it too much - essentially thinking along the same lines as Trace, but as the OP says, there is a lot of conflicting information.

So what can a girl with imperfect biochar do?
 
Bryant RedHawk
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Just use it, the originators of the technique didn't worry about if it was populated with microbiome critters, they just spread it and worked under the soil surface.

This is one of those things that you can definitely over think, it is very simple, heap up your trash in a hole in the ground, apply fire and let burn until the fire goes out (the original people didn't have hoses to put a fire out, they had buckets but I would bet real money that they just lit the sucker and let it burn out).
Once the fire is out just get a rake or shovel and move the remains where you want them to live, spread them out and gently work them into the soil, the microorganisms will come and take up housekeeping.
You can also use the burnt remains to build a compost heap, the compost will populate the burnt stuff with the microbiome and away you go from there.

You can make Bio char as complicated as you care to but I like to use myself as an example for this. No one would ever say that I don't love technical stuff or that I would run from it.
I have used retort furnaces to make char, I have used TULD furnaces to make char. Now I use the original method, pile up stuff until I need to clear some space for more trash stuff, that's when I set the heap on fire and when it's out I spread it where I want it and use my garden fork to work it just under the surface of the soil.
Simple can be better just because you don't need any "equipment" to get er done!

Redhawk
 
Elizabeth Geller
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Thanks, Dr. Redhawk.

I can't do an open or pit burn on my little suburban property - it's both impractical and illegal - so the Weber kettle grill it is.  Luckily I got my "equipment" for free at a yard sale. I take out both grates and close the air vents, and put the kettle in my regular fire pit for safety's sake.  Then I follow more-or-less the Kon-tiki method, and then when the time seems right, I put on the lid and wait a few hours.  The results have been getting better and better.  It doesn't make much at one time, but it's a small property.

I have to say there are some advantages to my method, such as being able to toast marshmallows while I'm making my biochar. And I can use my biochar-maker as a grill too.  Plus, I have a pyromaniacal streak, so I like having an excuse to make fires.
 
Bryant RedHawk
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That sounds like a triple win to me Elizabeth, food for soil critters, food for you and no law breaking.

If you haven't already tried this, you might get better results or not (I haven't ever tried using my smoker fire box because it gets too much air) light the fire and just as it gets really going, put the lid on to limit air influx, that might give you more char than ash (or not, as I said, I haven't tried it myself).
 
Sue Monroe
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Thank you for the pointers, thoughts and comments!

I read that you let it burn until the flames stop, and then put it out.  I think I might have been a bit too anxious when I started, as the early results were the harder, least porous, and a bit heavier, and the last ones were lighter, crisper and more fragile.  I will try to restrain myself as I continue.

I did my burns in a 2-gallon steel bucket, and didn't use water for quenching, but just laid a solid plate on top for a couple of hours, eliminating the addition of oxygen.  I left it on until the lower part of the bucket was cold.

I couldn't find a good way to grind down the char with the harder bits in it, until my neighbor happened to mention grinding something in her kitchen blender.  So I ran down to my local thrift shop and bought a used one for $4.  Add char, add water, push button.  It works fine for small pieces, producing a black slurry.  

When each load is finished, I pour the batch into a container lined with a piece of aluminum window screening that sits on half a terra cotta brick.  I let the liquid drain a bit, and then lift the screen out and dump the wet mush into a bucket, and pour the liquid back into the blender for the next load, plus adding more water so it doesn't get so thick that it stresses the motor.

Yes, this is a pretty slow way to do it, but since I'm on the Learn-as-You-Go program, I can study the results as I go.

For activating it, I'm considering adding worm tea, sea minerals, and then some finished compost.  I've seen some packages of microbes at the most-local semi-organic garden shop, and thinking about that.  

Here in W.WA, they're mainly Roundup and chemical fertilizer people.  "Microbes?  You mean bugs or something?"



 
Bryant RedHawk
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hau Sue, sounds to me like you have devised a good method for making the char and getting it to smaller sizes.
Finished compost is going to be superior over the other items for activating the char, next in line would be the worm tea, sea minerals are fine but not necessary, the microbes will break down most of the organic matter they come in contact with through use of enzymes.

Keep up your good work, the others will then see how much better your soil is and they will eventually figure out that they need to learn what you do and do that themselves. (don't be surprised if it takes years for this to happen)

Going slow is better than jumping in and then finding out you did something horribly wrong and have to go back and re-do a huge amount.
Going slow is best for perfecting techniques and finding just the right combination of materials to get the best results. Kudos to you for not being afraid to go slow and make discoveries of your own.

Redhawk
 
Trace Oswald
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Once you get the technique down for creating good charcoal, the easiest way I have found to crush it is to put it in a heavy duty bag, like a chicken food bag, lie it in your driveway and run over it a dozen times or so.
 
steward
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Bryant RedHawk wrote:Terra Preta is made up of Trash Dump materials that were burnt when the dump became full, these burnt materials were then spread over the soil and then raked into the soil so it wouldn't blow all over the village as ashes tend to do.

Overall the results of the current Terra Preta examinations show; the material was a combination of burnt trash and ash, it was spread out away from the trash dump (burn site(s)) and that it was initially turned under the soil at the time of the spreading.

Areas larger than 5 acres in size have been located and identified in several villages along the Amazon River basin, the average thickness of the Terra Preta is around 2 feet and it is at a depth of between 6 inches and 12 inches below the current soil surface.


Hi Bryant, you mention "raking in" and "turning under" and then that it's currently 6-12" underground.  I presume, much like in other archeological works, that soil has built up over the original terra preta.  So would the modern day char enthusiast just need to get it under ground a bit (raked or worked in) or does it need to be deeper?  I presume the former, just clarifying.  Thanks!
 
Bryant RedHawk
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You are correct Mike, the soil over the terra preta was most likely covered over by accretion of dust and rain washed sediments. I use a standard garden rake to work my char into the soil, I'm just trying to keep it from blowing or washing away, so once I get it worked in that top inch of soil I set up a sprinkler and wet the area down (I also spread grass seeds since the areas I am working on right now are for new pasture).  I'm also planning on covering the new pasture areas with wood chips once I have some soil holding roots in place, the purpose of growing grass to be covered with about an inch of wood chips is for fungi to super populate the upper 6-8 inches of soil.

Redhawk
 
Trace Oswald
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I started experimenting with broad forking biochar and compost into new areas, and then covering with wood chips or rotting straw.  It's early to see results, but I have high hopes that I can create great soil at a faster pace this way.  Broad forking is work that I find enjoyable in cool weather, so hopefully I can do a fairly large garden area this way.
 
pollinator
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Keep in mind that what the Terra Preta was like 2,000 years ago is probably different than what we see now. As previously indicated, there would have been a range of levels of "done" charcoal from virtually in-tact biomass, to ash. We only see the charcoal now because that's what's remaining. That does not mean that there's not value in the other variances.

When a forest fire comes through, it chars living trees, burns mostly decomposed logs, and does a lot of in-between, and all of it is valuable for the regrowth of the forest.

I get "poud chabòn" or charcoal powder for free from the locals who make charcoal in large buried rings into which they carefully stack each and every useable piece of wood they can scrounge up from the constantly harvested hardwood trees that grow here (leaving only shrubby saplings behind for next year). The powder is unsellable and considered garbage, and it's in big supply if you can make the connection. It also reduces my need to crush anything at all. Mine is probably pretty close to the "correct" or "finished" biochar since the art of making charcoal has become a careful science here to get the absolute best product. But I can also quick burn brush (the spiny branches too small for charcoal and scattered everywhere to pierce my shoe and ram into my foot-bone when I dare to look up from the path) and use that. It's all beneficial.

As previously stated. I think it's best to not worry too much about it!
 
pollinator
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I wish I could find it again, but a few years ago I stumbled across a site where they published reports from the 1800s (and earlier!) written by people who hadn't heard of Terra Preta, but who discovered the benefits of biochar on their own and started experimenting.

One thing I noticed when reading those reports was that it didn't seem to matter what kind of charcoal they were using. Softwood, hardwood, crop debris, other "wastes", high firing temps, low firing temps, fully pyrolyzed, mostly pyrolyzed, etc. As long as it was charcoal, it helped. The differences between the "types" was minuscule, when there was a difference at all.

It didn't even matter if it was added directly, or mixed with the livestock's food and "deposited" that way. Although there were other benefits to that method.

What made a bigger difference was the amount. Just going by memory, I believe the reports all agreed that there was a dramatic improvement with every increase in percentage, up to 10%, then the rate of improvement slowed down. (That was measuring the amount of charcoal-to-soil, by volume, in the top 12 inches of soil.)

I hope that helps. I'll keep trying to find that website again so I can post the link.

(Edited because I said the ratio backwards. It should be one part charcoal to 9 parts soil.)
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