Philip Small

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since Nov 30, 2011
Spokane, WA
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Recent posts by Philip Small

My divergent view (extremely minority opinion) is that biochar is best understood as an analog for the black carbon bits that remain after natural wildfires. Plants and soil biology evolved with and are adapted to naturally occurring charcoal.  My view is that the biochar is ideally made from plant materials native to the region and ecosystem within which the biochar will be used. Because biochar interacts with biology, and has since the beginning of plant life on the planet, presenting them with biochar in a form closest to what they are adapted to makes deep sense to me, and this practice allows me to show respect for biochar's connection with my local natural systems, this despite my ignorance of how exactly (scientifically) biochar works to increase soil health, plant disease suppression, and plant productivity in the ways that I see it working. Again, I don't get a lot of love for this apparently crazy idea that biochar is an analog for naturally occurring charcoal in soil, my lonely idea that biochar wouldn't work the way it does absent millions of years of evolution.

In practice I will use the complete available range of plant materials to make biochar for my garden: commercial biochar made from my region's softwood, hardwoods from foreign lands made from broken pallets, nutshells, almond pits. I would use bamboo, if it was handy. Because I see it working. Beyond avoiding excessive ash, woodsmoke stink, and causticity, I have loose standards in actual real life, otherwise, my soil's hunger for biochar cannot otherwise be satisfied. But I do value the locally sourced biochar the highest. There's a local outfit that sells biochar made from local grain stubble. Biochar made from grain stubble works, and it works well. Maybe that relates to the soil biology carried on the local winds is well adapted to grasses-based soil charcoal. I like to think so anyway.
3 months ago

Gray Henon wrote:I got a soil test.  It says I need 1.5 tons per acre of lime.  I need to figure out how much biochar it would take to meet this requirement.

Ask the lab to characterize your biochar for calcium carbonate equivalent (w/w percent). If 10% CCE, then need 15 tons biochar per acre to achieve the same pH raising effect as using 1.5 tons ag lime.

One of the fascinating aspects of biochar CCE levels is that the calcium, potassium, and magnesium oxides and hydroxides in freshly made ash have high CCE, like freshly kilned lime does. Over time the oxides and hydroxides convert to carbonates (like limestone, pH 8.3, no joy for making soap). For biochar, this natural conversion means losing CCE as it seasons. Freshly kilned ash (like burnt lime, pH 12, caustic enough to use to make soap) can have a CCE of 110%, but ash left exposed to nature (seasoned) will lose CCE.

If [kilned] lime is left exposed to the atmosphere, it will, over time, revert back to calcium carbonate by absorbing carbon dioxide from the air:

(IV) Ca(OH)2(s) + CO2(g) <-----> CaCO3(s) + H2O(l)

In other words, the soluble material, slaked lime, if left exposed to the air, converts to the insoluble material limestone. What we have here is the first cement! Modern cements are more sophisticated and "cure" more quickly than slaked lime, but lime continues to be a major component of modern cement. When quicklime is painted on wood, it forms a rock-hard white coating called whitewash.

Source: Caveman Chemistry

Another fascinating aspect of biochar is that the carbon component of biochar may provide a small but measurable alkalinizing effect. This effect was observed in a carbon-filtered municipal water supply study, where an alkalinizing effect long that could not be accounted for by the mineral (non-carbon) content within the carbon filtration material. I don't have the study with me, but I recollect that alkalinizing potential was small but persistent over a long period of time and the effect did not diminish with time. Add this to the very long what-we-know-we-don't-know list for biochar. I suspect we-don't-know-what-we-don't know list is long for biochar.

5 months ago
Nice TLUD design. Looks like it will hold up well.

I use a flame-cap biochar system. Not the "best" system, but certainly the most popular.

My friend Josiah Hunt's (JH in photo) initial approach to making biochar. Apparently, now most people's initial approach.

This is my main way to make biochar. It takes pyromantic intent to pull this off. The flame-cap systems are widely used around the Pacific Rim and are popular throughout the timbered western US and Canada.

Flame-cap systems are not as clean-burning as enclosed biochar systems. It is critical to the earth's health that the flame-cap charista discriminates in the fuel sizing and holds off on a flame-cap kiln burn until ideal fuel/weather (RH, moisture, temperature, wind) conditions. This attention to detail is needed to assure minimal smoke and eliminate fugitive losses of methane and nitrous oxide, invisible but powerful greenhouse gases. These can escape destruction in the flame cap due to wind stronger than the draft into the cap or insufficient draft from a cooler flame cap from cold, wet, or oversized fuel.

Done right, a flame-cap system quickly makes a bed of pure glowing embers which you then snuff with dirt, or dowse with water (or snow) to hold the char.  Very approachable, popular, scaleable, gets the job done for people who grow for a living. Satisfies that need to watch fire at work.

Josiah Hunt: How to make biochar with only a match (2013)
6 months ago
Origin of the term Biochar. Before there was "Biochar" there was "Agrichar". The Terra Preta community dedicated to achieving Terre Preta Nuova by reverse engineering the Amazonian Dark Earth (ADE) phenomenon coined the term "Agrichar" meaning charcoal you would want to use in an agricultural context. I miss those times, the term agrichar was easier to communicate than biochar is.

In 2006 some Australians members of the TP community saw the opportunity to make some money and commandeered the term Agrichar, trade marked it, restricted its use. The meaning of Agrichar became charcoal made by slow pyrolysis that has been enhanced in proprietary ways to perform well ag-wise. The rest of us had to come up with a new name, and biochar is the term we chose. It still upsets me! Fast forward 13 years to 2020, and the term "Agrichar" has disappeared from use.

Biochar, like the term scientist, can cover a wide range of qualities and qualifications. If my life hinges on understanding soil science, and I seek out the knowledge, and achieve soil success, am I not an accomplished soil scientist regardless of whether I paid for a degree or not? Maybe even more so? Yet some (me 15 years ago) would say, if you don't have formal qualifications you can't honestly present yourself as a soil scientist in formal contexts (teaching, public testimony, client reports) at least not without speaking to that detail. Does the term scientist become meaningless if we can't agree on one shared definition?  

It's kind of the same with biochar. I take the position that if I am using charcoal to accomplish improved soil health (or animal health, or compost health), I feel perfectly fine using the term biochar regardless of feedstock, ash content, volatiles content, resulting molecular state (torrefied/amorphous/graphene), process (hydrothermal-carbonization/pyrolysis/gasification/combustion), or post process treatment (seasoning, amending, activating, charging, washing, acidifying, rinsing, crushing). However what I use as biochar often will not meet the definition of biochar established by the International Biochar Initiative, nor will it meet the definition we use among ourselves locally a tribal understanding that without inoculation, biochar is just charcoal. And there are consumer protection issues when even highly caustic black ash, even char stinky with smokey smelling tar, even charcoal made irresponsibly, can be labeled biochar, thus the need to steer folks towards IBI certified biochar products, and towards the inoculated or composted variants favored within our permaculture community as the only biochar worth having. From my perspective, I see no hard and fast rules defining what biochar as a material is and isn't, but I respect anybody who has settled on a definition that works for them, that they are comfortable with.
1 year ago

Jay Angler wrote:... just add some to their feed as a powder and be done with it? Any other suggestions?

Certainly using the charcoal straight is the normal practice. I hear of chickens, of pigs, and in one case an ox, making a beeline to ingest freshly made biochar. And if the animals are having the kinds of feed challenges that one would go to activated carbon to solve, then it is best to use freshly made biochar. Freshly made would be better at keeping the ammonia levels down in the coop, one of the primary assaults on poultry health. But there is more to it than that, and it would be totally fun to compare which biochar prep your chickens prefer. You might find they do best when having access to several types at once.

Rather than grinding the charcoal down to feed grain size bits and mixing it into feed like AAFCO folks would do, gravel and stone size chunks of charcoal work just as well, maybe better. Certainly easier not to have to grind down a bunch of dusty charcoal. Let the chickens do that job. Charcoal is brittle, and can get pecked apart pretty quickly. The long standing practice with smallholder hogs is to give them a charred log end to gnaw on. In the ox incident, after a slash pile burn, the ox walked up after the fire was all out and the biochar had stopped steaming and that ox started munching directly on the chunks of recently water dowsed cinders.
1 year ago
I also would be interested to hear from folks feeding biochar. I know of several poultry producers adopting charcoal after this article:

Article conclusion: "Bamboo charcoal increased the growth performance and feed efficiency, while decreased noxious gas emission and faecal harmful microflora in fattening pigs. Moreover, such bamboo charcoal may protect pigs from infection and reduce stress due to decreased cortisol concentration and increased IgG concentration of serum or blood cell in fattening pigs. Bamboo charcoal is expected to improve swine production as a result of improved gastrointestinal environment of fattening pigs."

Charcoal as a feed additive is controversial because on the one hand, it has centuries of acceptance and demonstrated benefit, and on the other hand, a recent history of being used to pass off low quality moldy feed as high quality feed.

In toxicology, charcoal is regarded as a “universal antidote” to accidental poisonings. In moldy feed, the charcoal dials back the obvious signs in the animal that the feed exceeds established mycotoxin criteria. Because of this fraudulent activity, because of a concern for protecting the feed-purchasing public, in 2012, the USA Association of American Feed Control Officials (AAFCO) gave a ruling effectively banning the addition and manufacture of plant-based charcoal for feeding purposes.

"The [2012 AAFCO] ruling means that feed manufacturers can no longer legally add charcoal powder to feeds or supplements. The reasoning behind the removal of charcoal powder includes but is not limited to: fear of dioxin contamination in charcoal and the indiscriminate use of charcoal in pet food as a mycotoxin binder or for binding other contaminants."


This means that as of 2012 you can no longer get charcoal through an animal feed manufacturer.
As of 2012 you can no longer find charcoal as an ingredient in state approved feed mixes.
Users of charcoal in feed have had to work around this by finding their own sources of charcoal, and mixing their own feed. With the AAPCO prohibition, we won't be hearing much about it from the state, from industry, or from academic channels.

1 year ago

Priscilla Stilwell wrote:... fresh wood ash consists of a large amount of potassium, and that the potassium leaches out when it rains. ...

Note the term "spent lime" as used in this 2004 paper on CA Apple storage:

I believe the term "spent ash", like the term "spent lime" in the linked article, means the causticity has been neutralized, typically by a natural aging process whereby OH and O oxides of calcium and magnesium (and in the case of spent ash, potassium) convert to CO carbonates on exposure to atmospheric humidity and carbon dioxide. Another term that applies is mineral carbon fixation, in that atmospheric carbon is removed in the "spending" process. You can make soap using fresh ash (pH 12 or more) in place of lye, but you can't use spent ash (pH 9 or less) because the original fresh kilned causticity has been partly neutralized.

Spent ash stored outside is likely to lose potassium (K) to leaching prior to losing calcium and magnesium. At pH 9 potassium carbonate is soluble in water, calcium and magnesium carbonate is only slightly soluble. As ash pH decreases further with time, calcium (Ca) and magnesium (Mg) become more readily soluble. Among the other mineral nutrients, you can expect P, Fe, and Mn to resist leaching, and expect B, Cl, and S to be more like K: susceptible to leaching loss during storage.

edit: corrected term
2 years ago

Michael Cox wrote:Hi Folks,
The cone kilns which were first appearing two or three years ago looked promising....

I can see the benefit of a trench pit to handle longer pieces, encourage exploring that approach. The cone kin=ln better fits my situation. Some permie friends of mine, Best Biochar Kiln, in Stevens County, Washington, USA, make shippable cone kiln kits. I have two of the BBK kilns, typically running both simultaneously in a very urban backyard setting. With two and three story apartments on the downwind side, one has to deeply appreciate cone kilns for the ease with which they can maintain smokeless runs. A cone-kiln shaped pit in the dirt would work quite well also. A big wok, there are a number of ways to get the benefit of an open pan shaped firepit. I previously relied on enclosed barrel-in-a-barrel retorts, but the smoky start up, and the smoky hand off when transitioning from primary (outer sleeve) to secondary (inner vessel / retort) gases 20 minutes or so into the run. That meant I had to choose my days and times more carefully, needing to avoiding cold air temperatures and high humidity conditions that the cone kiln handles easily. That said the cone kiln is more sensitive to wind, I avoid 5 mph and above, whereas the barrel retorts were good up to 12 mph days. A windscreen can really help.

A cone kiln can throw sparks that an enclosed retort will retain. With climate disruption, and increasing incidence of red flag fire warning days of high temperatures, high winds, and extremely low humidity, open burn methods for making biochar deserve an added measure of caution.
3 years ago

Steve Jucick wrote:Has anyone tried to reburn a load that did not turn out as well as it should have?

Separating the incompletely burned "brands" to char in the next run is pretty easy if these are too stout to run to compost. The brands are the bits not easily cut with a shovel blade, just poke away at the pile of quenched embers with a shovel, the brands feel resistant, completely different than the char bits. Personally, I like seeing a bit of brands in my finished biochar because it indicates I didn't start into making too much ash, but also because it assures we'll have some low temperature amorphous carbon structured char, non-conductive to electricity. However, only as long as I know that there also hot bits that incandesced (I mean glowed) at a orange/yellow wavelength which indicates we'll have some high temperature turbostratic carbon structure, which has semiconductive surfaces, which I think is important to soil biology. Natural and neolithic fire events surely produce both low and high temperature biochar, I want my biochar type complex like how it forms in nature. Open flame backyard biochar is best for soil biological diversity (health) because it is not uniform throughout.
5 years ago

Gilbert Fritz wrote:Has anyone put biochar in potting mix?

5-10% by volume is a common target rate for soil mixes.
Use only 2-3% if you are making the well drained soil mix preferred by some horticultural growers.
5 years ago