Biochar: An answer to global warming or a menace?

By Renfrey Clarke

May 21, 2009 -- Sometimes you have to hand it to capitalism. It’s sheer magic the way the system takes promising concepts, steeps them in the transformative power of the market – and turns them into howling social and environmental disasters.

Take biofuels, for example. With fossil fuels warming the planet, why not, indeed, take advantage of the fact that plants use carbon dioxide from the atmosphere to produce sugars and oils that can be turned into substitutes for petrol and diesel?

We all know where that finished up. A big chunk of the US corn crop was distilled into grain ethanol. Corn prices soared on the extra demand, increasing costs for a broad range of food production. Anyone unable to pay went hungry. When US drivers filled up with bio-ethanol, they were in effect burning the tortillas of the Mexican poor.

But is the technology the problem? Or the system?

Whatever the case, when activists of the international group Biofuel Watch noted the attention being paid to another attractive concept – sequestering carbon by turning plant matter into biochar (finely divided charcoal), and incorporating it in agricultural soils – their suspicions were raised immediately. A research paper was prepared, critically examining biochar and the promises made for it. An international appeal was circulated -- entitled “‘Biochar’, a new big threat to people, land and ecosystems” -- and opposing calls to include biochar in the international carbon trading scheme, the Clean Development Mechanism (CDM). 

So far, the appeal has been signed by more than 120 environmental organisations around the world. Among their number is Friends of the Earth Australia.


The biochar sceptics have cause to be suspicious. Enthusiasts for biochar now include Malcom Turnbull, leader of the conservative Australian federal parliamentary opposition. Considering Turnbull’s other enthusiasms – “clean coal”, for one – his championing of biochar set alarm bells ringing immediately.

Added to which, some of the proposals made for biochar sequestration are downright barmy. British writer George Monbiot records New Zealand environmentalist Peter Read as calling for new worldwide biomass plantations of trees and sugarcane covering 1.4 billion hectares, with the plant matter to be turned into biochar and ploughed into soils. Trouble is, the world’s total cropland only comes to 1.36 billion hectares.

Furthermore, and as Biofuel Watch’s appeal rightly points out, the effects in the developing world of including biochar in the CDM trading scheme would be disastrous. An assured world market for biochar would turn the substance into an internationally traded commodity. Biochar is non-perishable and easily transported; give it a further boost by allotting it carbon credits, and producing it for export would in all likelihood yield better profits in developing-world settings than growing food crops.


In ideal circumstances, the growing of tree crops for biochar could be incorporated into village agricultural systems as a superior use for degraded or marginal land used previously for sparse (and highly destructive) grazing. The biochar produced in small local kilns would be dug into soils, and its dramatic benefits for soil productivity (this is well demonstrated) would aid local nutrition and increase the food surpluses which farmers could supply to towns.

But add in carbon credits, and the world capitalist market would destroy this harmonious picture. The biochar would not be used locally, but would be exported. Large-scale commercial agriculture, often internationally based, would respond to the price signals and move in. The tree plantations, offering superior profits, would spread from the former goat pastures to occupy prime agricultural land, where they would enjoy first call on resources of water and fertiliser.

Food production would shrink. An array of economic pressures would drive small farmers off their land, and wealth in rural districts would become tightly concentrated in the hands of the richest entrepreneurs able to take advantage of the new conditions. Local communities would be ravaged.

The problem, however, would not be biochar, but capitalism.

Dodgy science

So should environmental organisations sign up to Biofuel Watch’s appeal? As things stand, no. Action is needed, but the ammunition needs to be of much higher quality. The science in the document is dodgy, and many of the arguments irrelevant or overblown. That may seem a harsh judgment, but it is borne out if we look in detail at some of the appeal’s assertions:

  • “It is not yet known whether charcoal in soil represents a carbon sink at all...”

In what is a relatively new field of research, many unanswered questions remain. This, however, is not one of them. In a set of notes posted in March, one of Australia’s most respected authorities on biochar, CSIRO land and water scientist Evelyn Krull, points out that biochar “has a chemical structure that makes it very difficult to break down by physical, biological and chemical processes”. “We know”, Krull continues, “that biochar is stable over the timescales of any [carbon] abatement scheme (100 years).”

Not all biochars are the same – their individual properties depend on the feedstock and on the temperature and duration of the pyrolysis process through which they are made. But charcoal can remain intact in nature for more than 10,000 years – it provides, after all, the basis for carbon dating. Highly fertile, carbon-rich terra preta (dark earth) soils in the Amazon region of South America indicate very strongly that when incorporated into agricultural land, biochar can persist for thousands of years. The terra preta soils are believed to have been created deliberately by ancient peoples who produced charcoal and dug it into the ground along with food scraps and other organic matter.

  • “There is no consistent evidence that charcoal can be relied upon to make soil more fertile….”

If this were the case, the Amazonian peoples would hardly have bothered. True, the evidence is not 100 per cent consistent. But will, say, 90 per cent do?

Trials of biochar in relatively carbon-rich soils in Sweden found that soil fertility actually declined, apparently because the boost to soil microbial activity provided by the biochar speeded the decomposition of existing soil organic matter. But in leached tropical soils, and also in the ancient, low-fertility soils characteristic of Australia, the experience has been diametrically different. Evelyn Krull again: “We know that biochar application can have positive results, particularly in sandy and infertile soils. Due to its chemical and physical nature (e.g. high degree of porosity and absorptive capacity), biochar has been shown to enhance soil fertility, resulting in increased productivity and in turn a build-up of organic matter in soil.”

  • “Combinations of charcoal with fossil fuel-based fertilisers made from scrubbing coal power plant flue gases… will help to perpetuate fossil fuel burning as well as emissions of nitrous oxide, a powerful greenhouse gas.”

One suspects energy companies have weightier reasons for continuing to burn coal than supplying biochar firms with extracts of flue gases. Meanwhile, there is good evidence that biochar, by improving soil structure and retention of plant nutrients, can allow crops to flourish with markedly lower applications of artificial fertilisers.

Nitrous oxide, which volume-for-volume has hundreds of times the warming effect of carbon dioxide, enters the atmosphere largely through the breakdown of nitrogen fertilisers. Not only does biochar allow the use of these fertilisers to be cut, but as NSW Department of Primary Industries scientist Annette Cowie observes, the reduction in nitrogen dioxide exceeds what would be expected from lower fertiliser use. “It seems that when you apply the biochar, that nitrogen transformation process is inhibited”, the G-Online site reported Cowie as saying in March. Studies have found that in some soils, nitrous oxide emissions decline by as much as 80 per cent.

  • “The process for making charcoal and energy (pyrolysis) can result in dangerous soil and air pollution.”

In principle, the slow pyrolysis process used to create biochar is exceptionally clean. Plant matter is heated in an enclosed, oxygen-poor environment at about 500º Celsius. Volatile carbon compounds are driven off, some of them to be condensed into a useful bio-oil. The remaining gases are burnt to provide heat to sustain the process and (in many cases) to generate carbon-neutral electricity. The exhaust gases that result from this combustion consist almost entirely of water vapour and carbon dioxide; small quantities of oxides of nitrogen that are created can be scrubbed from the exhaust stream using the biochar itself. The solid residues from the pyrolysis process are inoffensive – apart from the biochar, silica ash, plus nutrient elements including potassium and phosphorus.

Biochar, however, is a “garbage in – garbage out” proposition. If you make it out of toxic industrial wastes, you’re likely to have problems. Such practices need to be prohibited. But that is an argument for appropriate regulation, not for rejecting the technology out of hand.

No to market scams

In its handling of the science, Biofuel Watch’s appeal ignores salient facts while stretching others to make them seem to validate particular, preconceived conclusions. Thoughtful readers will spot this, and will not be encouraged to support the document’s correct and necessary criticisms of the CDM and of other market-based emissions abatement schemes.

The truth is that capitalist markets are a completely inappropriate mechanism for regulating environmental matters. Markets operate to secure profits for private entrepreneurs, not to allow optimum outcomes in dealing with complex natural systems.

Points such as these can be argued convincingly without giving strained and selective accounts of scientific findings, or creating needless prejudices against potentially valuable innovations.

[A shorter version of this article appeared in Green Left Weekly.]


One aspect of Biochar systems are Cheap, clean biomass stoves that produce biochar and no respiratory disease. At scale, the health benefits are greater than ending Malaria.
A great example;…

The biochar Fund is also doing amazing work in the developing world;

Also , I would like Rebut the BioFuelWatch folk's recent criticisms with the petition of 1500 Cameroon Farmers to the UN to recognize soil carbon sequestration;
The Biochar Fund
and to explain their program;…

Biochar Soil Technology.....Husbandry of whole new orders of life

Biotic Carbon, the carbon transformed by life, should never be combusted, oxidized and destroyed. It deserves more respect, reverence even, and understanding to use it back to the soil where 2/3 of excess atmospheric carbon originally came from.

We all know we are carbon-centered life, we seldom think about the complex web of recycled bio-carbon which is the true center of life. A cradle to cradle, mutually co-evolved biosphere reaching into every crack and crevice on Earth.

It's hard for most to revere microbes and fungus, but from our toes to our gums (onward), their balanced ecology is our health. The greater earth and soils are just as dependent, at much longer time scales. Our farming for over 10,000 years has been responsible for 2/3rds of our excess greenhouse gases. This soil carbon, converted to carbon dioxide, Methane & Nitrous oxide began a slow stable warming that now accelerates with burning of fossil fuel.

Wise Land management; Organic farming and afforestation can build back our soil carbon,

Biochar allows the soil food web to build much more recalcitrant organic carbon, ( living biomass & Glomalins) in addition to the carbon in the biochar.

Biochar, the modern version of an ancient Amazonian agricultural practice called Terra Preta (black earth, TP), is gaining widespread credibility as a way to address world hunger, climate change, rural poverty, deforestation, and energy shortages… SIMULTANEOUSLY!
Modern Pyrolysis of biomass is a process for Carbon Negative Bio fuels, massive Carbon sequestration,10X Lower Methane & N2O soil emissions, and 3X Fertility Too.
Every 1 ton of Biomass yields 1/3 ton Charcoal for soil Sequestration, Bio-Gas & Bio-oil fuels, so is a totally virtuous, carbon negative energy cycle.

Biochar viewed as soil Infrastructure; The old saw;
"Feed the Soil Not the Plants" becomes;
"Feed, Cloth and House the Soil, utilities included !".
Free Carbon Condominiums with carboxyl group fats in the pantry and hydroxyl alcohol in the mini bar.
Build it and the Wee-Beasties will come.
As one microbiologist said on the Biochar list; "Microbes like to sit down when they eat".
By setting this table we expand husbandry to whole new orders of life.

This is what I try to get across to Farmers, as to how I feel about the act of returning carbon to the soil. An act of pertinence and thankfulness for the civilization we have created. Farmers are the Soil Sink Bankers, once carbon has a price, they will be laughing all the way to it.

The USDA-ARS have dozens of studies happening now to ferret out the reasons for char affinity with MYC fungi and microbes, but this synergy is solidly shown by the Japanese work, literally showing 1+1=3

Senator / Secretary of Interior Ken Salazar has done the most to nurse this biofuels system in his Biochar provisions in the 07 & 08 farm bill,…

Charles Mann ("1491") in the Sept. National Geographic has a wonderful soils article which places Terra Preta / Biochar soils center stage.

Biochar data base; TP-REPP

NASA's Dr. James Hansen Global warming solutions paper and letter to the G-8 conference, placing Biochar / Land management the central technology for carbon negative energy systems.

The many new university programs & field studies, in temperate soils; Cornell, ISU, U of H, U of GA, Virginia Tech, JMU, New Zealand and Australia.

Glomalin's role in soil tilth, fertility & basis for the soil food web in Terra Preta soils.

UNCCD Submission to Climate Change/UNFCCC AWG-LCA 5
"Account carbon contained in soils and the importance of biochar (charcoal) in replenishing soil carbon pools, restoring soil fertility and enhancing the sequestration of CO2."

This new Congressional Research Service report (by analyst Kelsi Bracmort) is the best short summary I have seen so far - both technical and policy oriented. .

Given the current "Crisis" atmosphere concerning energy, soil sustainability, food vs. Biofuels, and Climate Change what other subject addresses them all?

Carbon to the Soil, the only ubiquitous and economic place to put it.
Erich J. Knight
Shenandoah Gardens
540 289 9750

Biochar Studies at ACS Huston meeting;

Most all this work corroborates char soil dynamics we have seen so far . The soil GHG emissions work showing increased CO2 , also speculates that this CO2 has to get through the hungry plants above before becoming a GHG.
The SOM, MYC& Microbes, N2O (soil structure), CH4 , nutrient holding , Nitrogen shock, humic compound conditioning, absorbing of herbicides all pretty much what we expected to hear.



665 - III.


Company News & EU Certification

Below is an important hurtle that 3R AGROCARBON has overcome in certification in the EU. Given that their standards are set much higher than even organic certification in the US, this work should smooth any bureaucratic hurtles we may face.

EU Permit Authority - 4 years tests
Subject: Fwd: [biochar] Re: GOOD NEWS: EU Permit Authority - 4 years tests successfully completed

Doses: 400 kg / ha – 1000 kg / ha at different horticultural cultivars

Plant height Increase 141 % versus control
Picking yield Increase 630 % versus control
Picking fruit Increase 650 % versus control
Total yield Increase 202 % versus control
Total piece of fruit Increase 171 % versus control
Fruit weight Increase 118 % versus control



EcoTechnologies is planning for many collaborations ; NC State, U. of Leeds, Cardiff U. Rice U. ,JMU, U.of H. and at USDA with Dr.Jeffrey Novak who is coordinating ARS Biochar research. This Coordinated effort will speed implementation by avoiding unneeded repetition and building established work in a wide variety of soils and climates.

Hopefully all the Biochar companies will coordinate with Dr. Jeff Novak's soils work at ARS;

I spoke with Jon Nilsson of the CarbonChar Group, in their third year of field trials ;
An idea whose time has come | Carbon Char Group
He said the 2008 trials at Virginia Tech showed a 46% increase in yield of tomato transplants grown with just 2 - 5 cups (2 - 5%) "Biochar+" per cubic foot of growing medium.

Most recent studies out;

Imperial College test,
this work in temperate soils gives data from which one can calculate savings on fertilizer use, which is expected to be ongoing with no additional soil amending.…

The BlueLeaf Inc. and Dynamotive study are exciting results given how far north the site is,and the low application rates. I suspect, as we saw with the Imperial College test, the yield benefits seem to decrease the cooler the climate.
The study showed infiltration rates for moisture are almost double. The lower leaf temperatures puzzles me however, I thought around 21C was optimum for photosynthesis.

BlueLeaf Inc. and Dynamotive Announce Biochar Test Results CQuest(TM) Biochar Enriched Plots Yield Crop Increase Ranging From Six to Seventeen Percent vs. Control Plots

The full study at Dynomotives site;…

Low Tech Clean Biochar;

Real left-wing people are more thinking along these lines:

Innovative biochar project wins major funding for protection of rainforests in Congo

Louvain - Kinshasa, May 20, 2009 – Belgium's Biochar Fund and its Congolese partner ADAPEL are pleased to announce that their project to protect tropical rainforests has been selected by the Congo Basin Forest Fund (CBFF). More than 200 organizations answered the CBFF's first call for proposals, but after what it described as "an extremely competitive selection process", only 6 projects were successful.

The Congo Basin Forest Fund is an initiative by the British and Norwegian governments, aimed at protecting the unique tropical rain forests of Central Africa and their biodiversity and ecosystem services. The fund is presided by Nobel Peace Laureate Wangari Maathai. The CBFF operates in 10 countries of the Congo Basin and is currently the world's largest fund for the protection of rain forests.

The Biochar Fund and ADAPEL proposed an innovative strategy that will help solve four of the most pressing problems in the tropics and in the developing world, simultaneously: (1) low crop yields and hunger amongst the world's poorest people, the subsistence farmers of Sub-Saharan Africa, (2) deforestation resulting from a reliance on slash-and-burn farming, (3) energy poverty and a lack of access to clean, renewable energy, and (4) climate change.

The scientific committee of the CBFF was impressed by this highly integrated concept, and granted the partners 300,000 euros to implement it in 10 villages in the Equateur Province of the Democratic Republic of Congo.

ADAPEL and the Biochar Fund's synergistic strategy is based on making the notoriously poor soils at the tropical forest margin more fertile by introducing 'biochar' into them. Biochar is the non-fuel use of charcoal and is obtained from the pyrolysis of agricultural residues and waste biomass.

When this char is added to the acidic, nutrient-poor soils of the tropics (ferralsols, acrisols), crop yields tend to increase dramatically as soil fertility, quality and productivity can be maintained. Biochar is an organic form of integrated soil management that increases the efficiency of both organic and mineral fertilizers, in particular on those fast draining soils in the tropics. By increasing crop yields amongst the poor subsistence farmers this way, both their food security and livelihoods are improved.

The introduction of biochar also helps to slow down the slash-and-burn cycle on which these farmers rely. Because their soils are so poor, subsistence farmers are forced to shift their cultivation to another plot after only a few years as crop yields decline rapidly. By slowing down the tempo of this cycle via biochar, deforestation can be prevented in a substantial way. Furthermore the project attempts to replace the slash-and-burn system with a slash-and-char concept. This will not only increase soil productivity but also conserve approximately 50% of the carbon otherwise released as CO2 into the atmosphere. As long as re-growing resources are used this would establish a considerable carbon sink.

The amendment of soils with biochar establishes a permanent, stable and easily measurable carbon sink. Char oxidizes over the course of centuries or millennia. Thus, by capturing carbon dioxide from the atmosphere in the farm residues, and by transforming these into a highly recalcitrant form that is sequestered in soils, a low cost and extremely effective type of carbon storage emerges. Carbon credits or other forms of compensation may become available for this effort, opening up a novel source of income for the farmers.

Finally, biochar helps solve another key problem amongst the poor in the tropics: the lack of access to modern, efficient and clean energy. Most households in rural Congo rely on open fires for cooking and heating. This traditional form of energy consumption puts a pressure on forest resources as it is based on the inefficient combustion of fire wood. What is more, this process not only releases a substantial amount of greenhouse gases, it is also responsible for indoor air pollution - a 'killer in the kitchen', which, according to the World Health Organization, leads to the premature death of an estimated 2 million women and children each year. By switching to a biochar-based energy system, these issues are resolved. Via a technology that combines slow pyrolysis and gasification, farmers obtain access to clean and renewable electricity from agricultural residues. The co-product of this process is biochar, which will be stored into the farm soils to improve the output and sustainability of tropical agriculture.

In short, the biochar project will help solve the hunger pandemic in Central Africa by tackling one of its root causes – rapidly declining soil fertility – , it will slow down deforestation and the destruction of biodiversity, and it solves the household energy crisis amongst the poor. Moreover, the reduction in the rate of deforestation, sustainable soil fertility management, a more efficient fuel (fire wood) use and the establishment of a stable carbon sink all contribute to mitigating climate change.

The Congo Basin Forest Fund awarded ADAPEL and the Biochar Fund's project because it scored very high on the stringent selection criteria: (1) reducing the rate of deforestation in the Congo Basin, (2) alleviating poverty and improving livelihoods of the poorest forest communities, (3) strengthening the capacity of local partners (in this case grassroots farmer organizations in Congo), (4) improving humanity's knowledge of the forest ecosystem and the factors leading to its alteration (in this case the study of tropical soil dynamics and farming systems which put pressures on the forests), and (5) the presentation of a highly innovative and creative conservation concept.

Over the next two years, the partners will implement the project in the region of Pimu, which consists of a group of around 10 villages at the tropical forest frontier in the Democratic Republic of Congo's Equateur Province. The subsistence farmers there belong to the world's absolute poorest people (making less than $150 a year from farming), and suffer under permanent food insecurity. Their fate until now has been to burn forest in order to gain new farm land, after the soils of their plots have been depleted of nutrients.

Laurens Rademakers, managing director of Biochar Fund said: "We are very excited about our successful selection by the CBFF. It means that the biochar concept is scientifically sound and may help alleviate multiple environmental, social and economic crises amongst the world's absolute poorest people, while at the same time protecting a unique ecosystem that serves humanity as a whole: the rich forests of the Congo Basin. Moreover, our strategy is innovative because it does not force people out of their traditional livelihoods in the name of conservation, as some other concepts do."

Amede Daki Bopolo, director of ADAPEL said: "The Congo Basin forests are unique ecosystems that need to be conserved. Future generations will look back on us and see how we acted. Our project may offer a pragmatic way forward to forest conservation, as it looks at the ecosystem from multiple perspectives: the interaction between the pedosphere, the biosphere, the atmosphere and the anthroposphere. The Congolese forest is inhabited by millions of people, and they are the ones who hold the key to its protection and sustainable exploitation. Conserving these forests is also a form of social justice, because the pressures of modernity not only lead to the destruction of the forest, they also marginalize entire communities. Our project may help to turn these pressures around."

Christoph Steiner, professor of Biochemistry and Biorefining at the University of Georgia, U.S., provides scientific oversight to the project. He said: "Fire accelerates the carbon cycle and biochar decelerates the carbon cycle. Carbonization conserves carbon wherever biomass is otherwise burned or decomposes for no other use than getting rid of it. The synergy with sustained soil fertility and the practice of slash and char was probably developed by the ancient population of the Amazon Basin and rediscovered in recent years. This project of carbon and soil conservation can serve as a model worldwide and displace slash and burn globally. A prerequisite for its sustainable implementation and practice is an access to the global carbon market for the poorest landowners, which requires organizations such as the Biochar Fund, ADAPEL and the CBFF. The carbon market would provide an incentive to utilize waste biomass and re-growing resources to establish a carbon sink and the means to invest into long-term soil fertility and the recuperation of previously degraded land."



Democratic Republic of Congo:

Mr Amede Daki Bopolo

Phone: + 00243 812-194-463

Email: amede.daki@terresnoires.orgThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it


Mr Laurens Rademakers

Phone: + 0032 162-263-98

Email: info@biocharfund.orgThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it

United States:

Dr Christoph Steiner

Phone: +001 706-542-3821

Email: csteiner@engr.uga.eduThis e-mail address is being protected from spam bots, you need JavaScript enabled to view it

For the press pack in English, with photos, illustrations and geographical information, please visit:…

For the press pack in French, with photos, illustrations and geographical information, please visit:…

About the project partners

ADAPEL (Action pour le Développement de l'Agriculture et de la Pêche Avec Protection Environnementale de Likende) is a Congolese NGO located in Kinshasa and Pimu, Equateur Province. It focuses on the design of highly innovative conservation agriculture and agroforestry systems that serve the needs of the world's most under-served. ADAPEL was created in 2003, and has been successful in attracting funding from some of the world's leading environmental organizations.

More information:

The Biochar Fund is a social profit organization that explores the ways in which low carbon and even "carbon negative" farming on the basis of biochar can be integrated into a development concept that tackles poverty, hunger, energy poverty, climate change and deforestation. It was created in 2008 by a group of young scientists from a diversity of fields - tropical agronomy, soil science, social anthropology and development economics. The Biochar Fund has a pilot project in Cameroon, where it works with around 1500 subsistence farmers. The organization is based in Leuven, Belgium.

More information:

Dr. Christoph Steiner is one of the world's leading researchers in the fields of biochar carbon sequestration and bioenergy systems integrated into tropical agriculture. He described the 'slash-and-char' concept and provides scientific oversight to this project. Dr. Steiner provided advice, implemented and conducted field trials on biochar production and utilization in Europe, the USA, Brazil, Bolivia, Colombia, Ghana, Senegal, Indonesia and China. He also serves as a advisor for the UNCCD with the aim to get biochar carbon sequestration acknowledged by the UNFCCC and biochar based CDM projects feasible.

More information:

About the CBFF

The Congo Basin Forest Fund was launched in June 2008 by the British and Norwegian governments. It aims to support transformative and innovative proposals which will develop the capacity of the people and institutions of the Congo Basin to enable them to manage their forests; help local communities find livelihoods that are consistent with the conservation of forests; and reduce the rate of deforestation. The CBFF will provide a source of accessible funding, and encourage governments, civil society, NGOs and the private sector to work together. It is initially being financed by a grant of £100 million.

More information:

The list of six successful projects can be found here:…

The complete list of all the applicants can be found here:…


I believe that there is much confusion over the potentials of biochar because so MANY forms and approaches are possible -- capitalist, socialist, rich, poor, centralized, decentralized, agribusiness, small farmer, more and less "developed". All can use it and, yes, all can distort it. For one recent example of a "right use of biochar" among very poor farmers in the Congo please check out the exciting approach of Biochar Fund in Africa:


I hope this it will help you
“The Biochar Revolution” with “The Biochar Solution”
I want to call this book: “All about Biochar” because “The Biochar Revolution” collects the results and best practical advice that these entrepreneurs have to offer to the biochar community.