what makes biochar good or bad?

In the various videos or whatnot I've seen on biochar some of them seem to indicate that some kinds are better or worse than others, be it from how it was made or cured or whatnot but I can't seem to pin down any certain features that denigrate its usefullness though it appears they do exist in one form or another.
For a test, at a local store they sell charcoal that's just like the coals you'd pull out of a campfire, with no additives or whatnot, and I'll be testing that out in a small area. Is the process for making cooking charcoal that different (or different at all) from that of biochar?
From the methods I've seen of biochar manufacture, they seem to be either the same as how you would get woodgas, or the old timey way of setting stuff on fire, letting it burn through and depriving it of oxygen. If charcoal is made in this same way, though intended for cooking, what is the difference between it and biochar proper?

My understanding is that the time duration and temperature at which the wood is heated dictates the internal structure and surface area of the biochar. It's this surface area formed by the internal honeycomb-like shape of cells that is akin to the Edge Effect permaculture principle. Creating very long lived homes for microbes and surface area upon which to chemically react.
It's impossible to know what you're getting unless you trust the supplier or stick it under a microscope to see for yourself.

It truly depends on what you mean by "good" and "bad."

You can do everything right in the pyrolysis stage, but if your inputs are coming from clear cut forest, would that change your opinion as to what is "good" or "bad"?

The process itself is what separates biochar from charcoal, as well as biochar from activated carbon.

Many factors come into play in terms of the final biochar product. One of the best resources for understanding biochar, IMO, is the Biochar Journal. They do a very good job explaining what biochar is, what biochar isn't, and how it can be used. Like the permaculture adage "animals above plants," biochar needs to be inoculated with nutrients, water, and microbes before being applied to the soil. This can be done in many ways, such as including it in compost, vermicompost, adding feed grade biochar to livestock's diet, mixing with urine, adding it into the bedding of livestock's quarters, etc.

One of the founding entities of that journal has also played a huge role in getting the European Biochar Certificate (EBC) started. If you go to the EBC's website, you can find their requirements for certified biochar. There are only a handful of operators who have willingly undergone the process so far, but I think it will grow. Their criteria are strict, but clear and reasonable.

I have asked some biochar producers to provide me with information on the nutrients, heavy metals, pH, and other factors of their products. Some simply do not respond after you request the information. I think that having a standard- whether it be the EBC or something else- is very useful for consumers. All biochar is not created equal and, like the mycorrhizal fungi industry, there are too many people wanting to make a quick buck passing off inferior, diluted, or otherwise compromised goods.

At the end of the day: good biochar, IMO, is made from sustainable sources, in energy efficient pyrolysis systems. It is checked for contamination by heavy metals or concentrations of other potential health hazards (especially if it is to be sold). The biochar has a high surface area (say, at least 150m2/g) and has been put to at least one use before going into the soil.

Bad biochar is easier to make than good biochar. There are many deal breakers for me. Say the input source is in no way shape or form sustainable, then I'd say it is bad. If the inputs are transported over very long distances, again, it crosses a red line. If the biochar is being made on an industrial scale, say more than 2 tons a day, and there are no environmental safe guards, bad. If inputs are mixed and records for each batch are not taken. If the company producing it doesn't check for lead, cadmium, etc. or, if it does and attempts to cheat, then it is not any good.

So, as you can see, there are many ways of looking at biochar production and everyone's standards will differ.

This makes me wonder what method they used for Terra preta.

From my understanding terra preta is a very unique anthropogenic soil creation method. Because of that, I am wary of attempts to sell biochar as "terra preta" by some companies and individuals. It appears to be the result of a specific process that may or may not be so easily to replicate. Also, due to the age of these deposits, they are highly developed soils in which the soil life community has adapted through many generations. Therefore, even mixing "good" biochar with nutrients, pottery, and animal products and putting them into the soil is not, in my opinion, going to immediately yield terra preta.

While the constituents may be superficially similar, a stumbling block remains: time. It takes time for soil to structure through the work of organisms that live there in interaction with plants and humans. My stance is the same on soil creation elsewhere: sheet mulching, addition of compost, rock dusts, other natural fertilizers, and organisms will not yield high quality soil immediately either. High quality soil is the result of inputs, care, and time. Natural processes can be aided, even accelerated, but immediate realization of high quality soil is simply not possible. Roots and fungi take time to grow. It takes time for earthworms and other soil organisms to burrow through the layers. It takes time for plants to alter the soil life community in their rhizosphere. We can put the pieces in place, but it still takes time to develop.

IMO, Terra preta is more than the sum of its material parts.

Anyway,

Here is how Charles Mann, the author of 1491, begins to explain terra preta:

"As a rule, terra preta has more "plant-available" phosphorus, calcium, sulfur, and nitrogen than is common in the rain forest; it also has much more organic matter, better retains moisture and nutrients, and is not rapidly exhausted by agricultural use when managed well. The key to terra preta's long term fertility, Glaser# says, is charcoal: terra preta contains up to sixty-four times more of it than surrounding red earth. [...] But simply mixing charcoal into the ground is not enough to create terra preta. Because charcoal contains few nutrients, Glaser argued, "high-nutrient inputs- excrement and waste such as turtle, fish, and animal bones- are necessary.

Special soil microorganisms are alsolikely to play a role in its persistent fertility."

-1491, second edition, p. 355-356

#Bruno Glaser is a chemist working at the Institute of Soil Science and Soil Geography at the University of Bayreuth, Germany

Hau, Thomas; First off lets define true biochar. Biochar is organic, carbon based items that have been cooked in an oxygen missing environment all volatile compounds have been gassed off by exposure to heat.

Biochar can be made from manures, bones, woody plants, grasses, animal processing left overs and any other items that are organics.
Biochar works best when it is under the soil surface, this implicates tilling it into the soil.
Biochar has been used for thousands of years, it is not something that has been recently discovered.

"Sustainable biochar is a powerfully simple tool to fight global warming. This 2,000 year-old practice converts agricultural waste into a soil enhancer that can hold carbon, boost food security, and discourage deforestation. Sustainable biochar is one of the few technologies that is relatively inexpensive, widely applicable, and quickly scalable.

Biochar is a solid material obtained from the carbonisation of biomass. Biochar may be added to soils with the intention to improve soil functions and to reduce emissions from biomass that would otherwise naturally degrade to greenhouse gases. Biochar also has appreciable carbon sequestration value. These properties are measurable and verifiable in a characterisation scheme, or in a carbon emission offset protocol."


To make good biochar you will need to first create the biochar then inoculate it with microorganisms, the easiest method to do this is to use manure teas to wet it down before it is spread on the field and incorporated.

Good biochar will be purely organic, with no petrochemicals present.

bichar international This is the site to learn all about biochar, and the science behind it.

I have been using biochar for many years now, it works. It does require a one time tillage of soil, after incorporation you can move to no-till methods. Typically I make blends of biochar, compost, rock, bone and blood meals, these blends are then spread (rather thickly, around 2 lbs. per sq.ft.) then tilled into the top 12 inches of soil. A cover crop is then planted and grown, chopped and dropped then crop planting begins.

Biochar will increase the water uptake ability of soils, even though it does not sequester much water of its own accord. It improves soil for many years by increasing the bio activity of soil.

Having recently read "Teaming with Microbes" which describes how much micro-organisms sequester easily leached nutrients and then release them for plant roots to absorb, I agree that much of what makes Biochar useful to plants is its ability to provide good homes for microbes. When I read between the lines, terra preta was made from burning garbage in a low-oxygen manner. Since we heat our home with a high efficiency wood stove, I take metal cans with three 1/4" holes drilled in the bottom, fill them with wastes that aren't good for composting, and put one in the back of the fire box and build the fire around it. Sawdust from a friend's wood-turning hobby and bones from chickens are the two major components, but dried morning glory roots and similar are also used. This doesn't create huge quantities, but if I'm building a new bed or renovating a tired one, the biochar I've made gets added to manure layers. This is the slow process of building up that was used on the original land we now call terra preta.We have wet winters with little sun followed by dry summers, which is one type of climate were biochar is thought to be useful. I figure I'm using raw material that would otherwise be sent to the landfill, using the charring process to heat the house, sequestering a bit of carbon in the process, and that fits with the Permaculture principle of stacking. Because I can't check the temperature the charcoal is forming at, I can't say that it's at the "perfect" temperature from the agricultural test perspective, but then again, there are so many variables out there in the real world that *no* lab can control for, so long as I'm using "garbage" I can scrounge, I feel the benefits out weigh the risks.

People also make a big deal about the risks of importing non "organic" materials into processes like biochar. Again, having recently read Stamet's Mycelium Running, inoculating any area I'm planting with questionable inputs with a variety of mushrooms seems a really good approach to help Mother Nature deal with the problem. After all, it was a natural process that made the Tar Sands, and they're incredibly toxic. From all the biology I've ever read, anything that nature created has a creature (plant or animal) somewhere that calls it home and frequently undoes any toxicity in the process.

I agree that we can do things to help Mother Nature along, but time is key to much of the work we try to influence.

Besides charcoal, it contains abundant pottery shards, plant residues, animal faeces, fish and animal bones. The soil’s depth can reach 2 metres, and is reported capable of regenerating itself at the rate of about 1 cm a year. Similar sites are found in Benin and Liberia in West Africa, in the South African savannahs, and even in Roman Britain. According to local farmers in the Amazon, productivity on the terra preta is much higher than surrounding soils.

I respectfully disagree with Bryant on this one point:

It does require a one time tillage of soil, after incorporation you can move to no-till methods.

There are several ways that come to mind in which biochar could be added without mass tilling of an area.

1.) Add it to a potting mix to be used for transplants. Digging a small hole in the bed to add your transplant does not nearly do the same type of structural damage to soil as does tilling.
2.) Added to manure, or compost, which is sheet mulched onto a no till system.
3.) Placed into holes that are about to accept a transplant.
4.) Put into seedballs that are spread on the surface for seeds to utilize when they germinate.
5.) Cast on the soil surface before the exhuming of a root or tuber crop like potatoes or garlic. (I would suggest dampening the soil afterwards and then re-mulching after this disturbance for many reasons but also to protect the bio in the char.)

One of these methods might be the way the char was added to the original terra preta. Who knows? There is little known of what the"process" of the Terra Preta was, and although we do know some of the ingredients, we really are scratching the surface when you consider what biological inoculants were available in the Amazon. There also seem to have a simplified version in our Euro-schooled minds about the nature of the minds that created Terra Preta in the first place. Like the genius use of chinampas in Central America, or the connection to plant spirits that is inherent in the creation of the Ayahuasca brew, or the long term commitment of selecting a marginal wild plant food to create domestication of corn, the people who first created Terra Preta in the amazon may have known exactly what they were doing, and why. There is also the possibility that these Terra Preta beds were not consciously developed as such, but the people were simply creating garden beds in planned middens (a midden is basically a waste pile that is the organic indigenous equivalent of a garbage dump that is a common thing for archaeologists to study in a village site). The char may have simply been added because it was known to suppress/neutralize odors/toxins from excrement, urine, animal food waste, and other high nutrient additions.

Anyway: This is not to say that Bryant's method does not have merit. Indeed, a one time mass disturbance of the soil in order to incorporate a large amount of char into a large area seems to be in tune with some permacultural thought (in line with ideas like getting a big machine in to do massive earthworks once, but then set a permanent system in place). I just thought that it would be worth adding some other ideas into the mix.

Another way biochar could be incorporated into soils is worm tillage—eventually, in worm-inhabited regions, anything atop the soil surface will be incorporated by the throwing-upward of soil and disintegration of worm tunnels which happens with regularity.

Nevertheless, I am digging my biochar in this spring.

M Ljin wrote:Another way biochar could be incorporated into soils is worm tillage—eventually, in worm-inhabited regions, anything atop the soil surface will be incorporated by the throwing-upward of soil and disintegration of worm tunnels which happens with regularity.

Nevertheless, I am digging my biochar in this spring.

Worms will even ingest biochar if the particles are small enough. They love the stuff. I've seen photos of a kiwifruit orchard where they topdressed with biochar, then took some spade samples a year later. There were burrows lined with black extending 30 cm  down. Looking for that picture now....

I have to chuckle a bit at the thread title.

Nature has been making wildfire charcoal from plants in the biosphere long before humans showed up. It's not "engineered and microscope assessed" in the manner of an industrial product in a controlled reactor. Must be bad 'char then.

And yet, the deep fertility of the prairies/great plains is testament to 10,000 years of wildfires and nature's entirely imperfect methods.

There are proven ways to make bad biochar, though...like using materials that have toxic gick in them, and by using methods that fail to drive off all the volatile products and leave you with charcoal that may be good for barbecues but pretty much worthless for the soil.

But as Douglas rightly points out, prior art is all around us and if we mimic natural processes we're more likely to get it right.

If you have 10,000 years to wait, then that's fine. If you want the results sooner than that, it's worth tinkering with the process.