A Perspective on Terra Preta and Biochar

The Modern Discovery of Terra Preta, and a Brief Modern History of Biochar

In the Amazon Basin, there exists thousands of hectares of cultivated plots consisting of unusually fertile black soil, termed Terra Preta de Indio — “dark earth of the Indians” — called Terra Preta for short. These soils are many hundreds if not thousands of years old, and have remained remarkably fertile in spite of the tropical rainfall, which accelerates the weathering of soil and the leaching of water soluble nutrients. Modern scientific interest in this material began with a Dutch scientist named Wim Sombroek, whose book Amazon Soils, published in 1966, began the modern investigation into the nature of these soils and attempts to discern their secret. It was established that these soils were artificially cultivated by an established civilization that practiced agriculture, since the soils were always found with human artifacts and near the ruins of human settlements, and often had fired-pottery fragments buried in it. It was also established through analytical examinations of the soil that these soils contained pyrogenic carbon (carbon from charred materials). These soils were seemingly permanently fertile, with double the crop yields compared to surrounding soils and holding about three times as much phosphorus and nitrogen, while consisting of about 9% carbon, whereas surrounding soils contain around 1%.

Interest in the use of charcoal as a soil amendment began to grow dramatically in the 2000s, which can be credited to various publications by Prof. Johannes Lehmann, which popularized to the scientific community the concept that the production and use of charcoal could not only supply energy, but that the charcoal could improve soil fertility while sequestering carbon to fight climate change, first proposed by Sombroek. At that time, the term agrichar was variously used to specify that the application of interest was the agricultural application of charcoal, but since the term “agrichar” was the trademark of Pacific Pyrolysis company, the term biochar was coined, and the term was officially adopted at an international scientific conference in Birmingham, England, in 2009. This is not to say that charcoal had not been studied for its agricultural applications; examples of scientific study of the use of charcoal as a soil amendment go all the way back to the 1700s [See the book Geotherapy by CRC Press, Chapter 11 — “Biochar: the Field Experience”, for an account of the study of agricultural uses of charcoal in the 1700s, 1800s, 1900s, and 2000’s], but the mixed results, the lack of mature analytical techniques for the biochemistry of soil, and the lack of a distinguishing term and concept to keep agricultural charcoal research from being lost among all the other research done on charcoal conspired to keep biochar research from getting the attention and funding it deserved.

Those of you who are new to biochar may wonder why so much research was needed. Very early on, it became clear that simply adding charcoal to the soil was not all there was to it. Just as studies on the use of charcoal as a soil amendment in the 1700s and 1800s had mixed results, early attempts to simply add charcoal to soil found that in many instances of direct application, charcoal seemed to have an initially counterproductive impact on the soil, robbing the plants of nutrients as the charcoal adsorbed nutrients out of the soil too aggressively and bound these nutrients too tightly. Scientific research focused on what the difference was between modern biochar-amended soil and terra preta, and how to reproduce the amazing fertility observed in terra preta.

Since that time, academic research on biochar has exploded, in what could appropriately be called a biochar renaissance. In 2017, the number of scientific papers published on studies of biochar exceeded the papers on compost, and the pace of research has only accelerated internationally.

A shift in thinking: Should the objective of biochar research be to reproduce terra preta?

An unspoken meta-narrative that emerges from among much of the study of biochar early on in the biochar renaissance implied that the objective of this study was to reproduce terra preta. Wim Sombroek’s own challenge to soil scientists prior to his death in 2003 was to develop terra preta nova, “new terra preta”, to address the problems of soil fertility and climate change. Even if he meant it figuratively, and did not imply this as a charge to faithfully reproduce the original terra preta, the way this challenge was framed seems to me to have colored the discussions around the topic of biochar.

Although various hypotheses abound, nobody is exactly sure of how terra preta was produced. Bold claims by various proponents of cultured “effective microbes” and enthusiasts of specific preparations of biochar to have reproduced terra preta are unwarranted and baseless. There simply is not enough evidence for us to deduce how terra preta was made, and claims by anyone who is not an anthropologist with field experience in the Amazon ought to be received with skepticism. Even knowing that terra preta contained charcoal does not give us much to infer; knowing that charcoal was involved still does not tell us what feedstocks and charring processes were used, what additional processes were involved, how it was incorporated into the soil, how long it resided in the soil until it started to show benefits, and what proportions and schedule of incorporation were used. Each of these variables has an influence on the agronomic qualities of the resulting char. There are even some who dispute that terra preta is biochar amended soil, due to the observation that terra preta seems to reproduce itself.

The objective of reproducing terra preta may be partially motivated by notions of solving a mystery and recovering lost ancient knowledge, but ultimately, in light of the body of knowledge and the practical applications and benefits of biochar that have been discovered, terra preta is irrelevant, having served its role as an inspiration. The true objective is to improve long term soil fertility and resilience, especially in the face of intensified climate change. A parallel objective is to draw down and store carbon. In as much as we achieve those ends through biochar research and policy implementation, it does not matter whether or not our efforts reproduce terra preta. The original terra preta was produced in an oxisol (a soil order of highly weathered tropical soil with oxide-rich subsoil), contains charcoal made of tropical woods, and was shaped by the soil microbiome of the Amazon. In each agricultural region, differing soil parent material, differing climate, differing crops, differing soil fauna, and differing microbiome make the goal of faithfully reproducing terra preta inappropriately narrow. Exporting terra preta in order to propagate its microbiome would not be appropriate either; besides the microbiome not necessarily being well suited to other climates, soils, and crops, transporting soil brings with it the risk of introducing invasive species.

If a particular method of application of biochar yields good results, whether or not it faithfully reproduces terra preta is irrelevant; it is not possible to ever verify that any method successfully replicated terra preta nor its production method since there are no written records documenting its production. It is enough that terra preta inspired the investigations into biochar that resulted in the discovery of the known benefits and effective agronomic applications of biochar.

Is Terra Preta Charcoal Amended Soil?

The idea that terra preta is anthropogenic charcoal amended soil is not without controversy. Proponents of the hypothesis that terra preta is anthropogenic charcoal amended soil support this hypothesis on account of several findings: analytical methods examining the microstructure of the carbon in terra preta confirm that it is pyrogenic, and terra preta was often found to have pottery shards incorporated into it (whether incidentally or by design). Inferring from the thousands of hectares of land mass cultivated as terra preta, along with the depth of the terra preta and how thoroughly the charcoal is incorporated into the soil, the idea that terra preta formed by gradual incorporation of char from repeated massive forest fires seems implausible, especially given that it is found in the Amazon rainforest.

The strongest argument against terra preta being anthropogenic comes from the observation that terra preta regenerates. The late William Woods, one of the pioneering biochar researchers who contributed to the biochar renaissance, observed that in Brazil, terra preta has been mined and sold as fertile topsoil and potting mix for decades. The miners dig away the top 20cm of terra preta off the top of the mining area, and move on to another area, leaving the mined area to recover for 20 years. Over the course of time, the terra preta thickens as it regenerates itself from the forest litter that falls on it. By this account, it would appear that terra preta is merely a special form of forest litter compost. This also suggests that much of the observed depth of terra preta may not be originally cultivated material, but later growth due to the conversion of forest litter.

3 men mining Terra preta
Terra preta being mined. From the 2011 BBC Documentary on terra preta titled “The Secret Of Eldorado”.

The regeneration of terra preta from forest litter suggests that the microbiome of terra preta may have as much of an influence as added charcoal, imparting the character of the underlying material on organic material that decays upon it, analogous to the propagation of a sourdough starter “mother dough” into freshly added flour. However, it is important to point out that the charcoal content of terra preta cannot regenerate and cannot simply reproduce; pyrogenic carbon requires high temperatures to form its associated microstructures, and does not form in the decaying organic matter that builds up on terra preta. Furthermore, from the few videos and photos where terra preta mining can be observed, it appears that the material is not black like known examples of charcoal amended terra preta, but rather brown, suggesting that though this material is identified with terra preta, it probably does not contain charcoal, unless soil fauna have mixed deeper layers of soil with the new material (a process known as bioturbation), introducing charcoal into it from the underlying terra preta.

If this is so, what is going on? What is the relationship and relative contribution of charcoal and the microbiome of terra preta? And what does this mean for our theories of the origins of terra preta and our attempts to optimally use charcoal as a soil amendment?

It turns out that terra preta is not the only soil that regenerates. The regeneration of terra preta appears to be an example of negative priming.

Negative Priming

Priming describes the phenomenon of the reduction of humus from soil and a multiplication of microbial biomass upon the decay of organic residues added to the soil, such as forest litter falling upon the ground in the autumn. As the microbial decomposers begin to consume the organic residue and multiply, there is a loss of humus and an increase in microbial biomass (called the priming effect), suggesting that the decomposition of fresh residues results in further decomposition of existing humus. As the decomposition finishes, the microbial biomass gradually reduces as the level of soil humus increases, resulting in a net increase in the amount of humus. This effect is observed in forest soils, and is termed negative priming.

schematic illustration of the changes in soil carbon fractions
A schematic illustration of the changes in soil carbon fractions when new forest residues are added, taken from Figure 12.5 from the Soil Organic Matter chapter of “The Nature and Properties of Soils”, 15th ed. The priming effect is called out in this figure, but negative priming is not labeled. Negative priming is the subsequent increase in soil humus levels following the reduction in microbial biomass.

The regeneration of terra preta appears to be negative priming at work. The microbiome and charcoal are both involved, because the addition of charcoal appears to modify the microbiome of compost and soil. For example, the addition of biochar to compost (not the mixing of biochar with finished compost, but the addition of biochar at the beginning of the composting process) has been found to significantly abate the methane emissions of compost by favoring methanotrophs (methane eating bacteria) over methanogens (methane producing bacteria). Terra preta has even been found to foster mycorrhiza and host higher populations of free-living diazotrophs (nitrogen-fixing bacteria which are not bound to the root nodules of legumes). [See Geotherapy: Innovative methods of soil fertility restoration, carbon sequestration, and reversing CO2 increase, ch. 10, Geology into Biology, by David Yarrow. p. 208 and p. 219.] These are merely a couple of examples; compost and soil are home to tens of thousands of species of microbes, and biochar likely also exerts selection pressures on these microbes that result in significantly different proportions of various species, resulting in a significantly different microbiome from the surrounding soil. It would be this altered microbiome that colonizes and decomposes the new forest residue landing upon it, transforming it into regenerated terra preta populated with the same microbiome, exhibiting all of the characteristics to the parent material due to the microbiome, while lacking charcoal.

In our own field work with biochar at Gill Tract Community Farm in Albany, California, we have observed that biochar significantly alters the behavior of compost piles, resulting in compost with noticeably different characteristics. In 2018, Gill Tract Community Farm partnered with the Local Carbon Network as an early adopter of our biochar. Wary of the break-in period of suppressed plant growth incurred by adding biochar directly to soil, we decided to send the biochar through their compost piles as an exploratory application. Prior to adding biochar to their compost piles, the piles would heat up to about 130˚F, but the heat would dissipate when the piles were turned, and would not recover. After adding biochar to the compost pile, the compost would heat up to 155˚F, and would remain that hot for nearly a month. By the end of six weeks of composting, the piles would often be at temperatures over 130˚F.

Furthermore, the raised beds built using biochar compost had some notably different behavior. The raised beds at Gill Tract Community Farm at the time these photos were taken were made using an extremely compost-rich blend; each bed consisted of a blend of 20% compost made on-site, 40% purchased compost, and 40% soil. (Since then the composting program has significantly expanded, and now, hardly any purchased compost is used in the raised beds.) This mixture is packed into a frame while damp, and the frame is removed, leaving the bed unsupported, for better drainage and aeration. The raised beds made with biochar compost remained intact throughout the season, and maintained excellent aggregate stability, which appeared to be due to increased fungal activity, whereas the raised beds made with conventional compost collapsed and shrank away over the course of the season. We suspect that some of the shrinkage and collapse is due to incomplete decomposition in the compost piles without biochar.

Electron Transfer Hypothesis

Why would biochar modify the behavior or even the composition of the microbiome of the compost and the soil? In recent years, emerging research suggests that biochar’s facilitation of electron transfers among various soil microbes may play a role. For example, it was found that biochar helps abate N2O emissions from soil because of its role in transferring electrons. In 2017, it was published that biochars prepared at different temperatures were found to exhibit different mechanisms of electron transfer. In order to understand why this would have an influence on the behavior and composition of the microbiome, a bit of background explanation is needed.

The microbes in soil often carry out biochemical processes which leave them with an imbalance of electrons — in some cases, a surplus that they need to discharge, and in other cases, a deficit of electrons which they need to neutralize. These charge imbalances can build up to the point where they become bottlenecks on microbial activity. To overcome these imbalances, bacteria naturally grow microbial wires, called pili, to reach out and touch microbes carrying out electrically complementary activity in order to transfer electrons. The electrons obtained by these transfers are utilized in converting certain mineral nutrients into usable form. (For example, see this article on pili electron transfer in geobacter species.) Unfortunately, these microbial wires are materially expensive to grow, since they are made of protein. The number of complementary microbes that can be reached is limited by the length and the number of pili that can be grown, and the pili have fairly limited conductivity.

This electron transfer soil service is where biochar appears to make a difference. Biochar affords bacteria two mechanisms by which they can transfer electrons more efficiently than direct electron transfer between microbes touching each other using pili:

  • the geobattery mechanism, dominant in biochar produced at temperatures under 600˚C, which charges and discharges electron exchange chemical groups on its surface to exchange electrons with microbes that come in contact with these groups, and
  • the geoconductor mechanism, a much faster and much more prolific electron transfer mechanism, found in biochar produced at temperatures over 700˚C, which directly conducts electrons between microbes in contact with the char. A macroscopic piece of biochar visible to the naked eye can host millions of bacteria and archaea on its surface, along with contact to fungal hyphae. By directly conducting electrons among them, it serves as a microbial marketplace where electrons are the currency of exchange, removing the electron transfer bottleneck for all of their relevant biochemistry.

As charcoal is heated past 600˚C, the amorphous carbon structure begins to self-organize into more stable structures. The carbon rings form small graphene-like sheets, which are electrically conductive. As the processing temperature increases, these flecks grow and dramatically increase in conductivity as the temperature exceeds 700˚C. The following illustration (used with permission) from Biochar for Environmental Management shows the relationship between the char processing temperature and the resulting microstructure:

At the highest temperatures and longest time exposures, the microstructure of the carbon matrix of the char converts to that of graphite.

It appears that soil microbes thrive in the presence of biochar because they exploit the electron transfer services of the biochar. A quote from the news report on this discovery:

[Prof. Johannes] Lehmann and the members of his laboratory had struggled to understand why microorganisms thrived in the presence of biochar. The group removed soil phosphorus, making the environment inhospitable. They ruled out water and nutrients. They discarded the use of biochar as a food source because microorganisms cannot consume much of it. Through [Dr. Tianran] Sun’s background in environmental chemistry, the scientists found that microorganisms may be drawn to electrons that the biochar can transport.

Biochar and the Natural Selection of the Terra Preta Microbiome

In light of the electron-transfer soil service provided by biochar, I propose the following theory of terra preta’s origin and apparent self-propagation from forest litter:

The original terra preta was charcoal amended soil, and was cultivated systematically because of the observed benefits. (It seems unlikely that resources and labor would have been set aside for widespread systematic production of charcoal amended soil if the charcoal required long periods of aging to offer any agronomic benefit.) The presence of charcoal modified the soil environment, favoring microbes that best exploit the soil services offered by the charcoal (such as electron transfer), resulting in a modified soil microbiome. This modified microbiome then self-propagated up into the decaying forest litter materials that accumulated on top of it, resulting in an increase in topsoil that exhibits the characteristics of the decomposed soil organic matter in underlying charcoal-amended soil.

Co-composted Biochar

One additional confounder must be accounted for in informed speculation about the origins of terra preta: biochar is not necessarily immediately beneficial to the soil if it is directly mixed into soil as a soil amendment. In many of the early studies examining the agronomic applications of biochar, it was found that adding biochar directly to the soil was not immediately beneficial. There would be a break-in period during which biochar was found to suppress plant growth, or even repel roots and soft-bodied soil creatures like worms. This break-in period has variously been found to take as long as a couple of years in the worst instances. It is speculated that a couple mechanisms may be at work:

  • Biochars that were produced at lower temperatures, which are sometimes not fully devolatilized, start out hydrophobic, due to the presence of tar — condensed from the smoke released by pyrolysis. Until the tar is broken down (primarily by fungi that can digest tar) and the char is colonized by beneficial microbes, the tars have a preservative-like biocidal effect.
  • Biochars that are fully devolatilized, and especially biochars that have been exposed to reduction reactions (which we will look at in detail in later installments) have significantly higher adsorptivity, and behave like carbon filters in the soil, aggressively adsorbing and binding to nutrients, rather than loosely binding the nutrients like nutrient exchange sites in mature soil organic matter.

If this is the case, how might the indigenous Amazonians have prepared their charcoal for use in soil in the preparation of terra preta? Although we cannot know with certainty, we can speculate on what methods would have been accessible to them while yielding compelling benefits.

In the wake of various experiments and studies that reported that direct application of biochar to soil did not result in compelling benefits, various methods have been proposed to “charge” the biochar, “break it in”, and populate it with beneficial microbes for use in soil. Such methods include mixing char with fertilizer, manure, or compost, all of which have been more effective than direct application of biochar to soil. In the course of examining the scientific literature, and in our own experimentation, we have settled on co-composting biochar as the best practice for preparing biochar for use in the soil. Co-composting refers to the practice of mixing biochar with compostable materials, and letting the mixture go through the composting process. It is not to be confused with the practice of mixing biochar with finished compost The “co” in “co-composting” refers to the fact that the biochar is with the compost through the composting process, but does not decompose even though it influences and contributes to the process. When biochar is co-composted, the resulting biochar compost is immediately beneficial to soil. Furthermore, the addition of biochar to a compost pile reduces odor, particularly ammonia. [recently published paper by Lehmann’s soil science group at Cornell University found that charcoal has an incredible capacity to take up ammonia, both through adsorption and chemically binding to ammonia, thereby reducing ammonia odors and emissions.]

At Gill Tract Community Farm, the pilot biochar deployment site for the Local Carbon Network, co-composted biochar was tested in raised beds and compared against raised beds prepared with regular compost. The results were rather unexpectedly dramatic. Every plant that received co-composted biochar exhibited incredible fertility, though no additional fertilizer was used in any of these comparisons:

Collard seedlings

What seems to happen when biochar is co-composted is that the char adsorbs a hydrophilic porous coating of decomposition products, rich in nutrient exchange chemical sites and electron exchange sites. This coating seems to confer upon the char most of the observed benefits of char which has “aged” in the soil. Since this benefit is obtained so rapidly with co-composting, especially compared to surface oxidation by aging, it seems more plausible that this was discovered by the indigenous peoples of the Amazon. Furthermore, during the composting process, large quantities of nitrates which would otherwise be lost to off-gassing or lost through the leachate (the liquid that sweats out of compost) have been found to be captured on the biochar. These captured nitrates then serve as an abundant source of fixed nitrogen for the plants that receive the biochar, resulting in broad, deep green leaves and vigorous growth. This is the sort of compelling observed benefit that may have motivated the Amazonians to practice widespread systematic use of charcoal and compost to prepare newly cultivated land for agriculture.

Speculations on the Origins of Terra Preta

With such dramatic benefits immediately available to the crops that received co-composted biochar, here is what I suspect led to the discovery of terra preta by the ancient indigenous Amazonians.

Charcoal waste from household cooking fires were likely thrown out with household food waste and human waste. Charcoal may have even been deliberately used to control odors from manure and fecal waste. Since all of their waste consisted of biodegradable materials (with the exception of broken pottery), the mixture of char and waste essentially composted whether they intended it to or not. The observation that plants growing in and around their decomposing waste piles exhibited unusual vigor may have led to experimentation with deliberately amending agricultural soils with this composted mixture and systematically preparing compost with specially prepared charcoal for amending agricultural soils. The subsequent abandonment of farmland due to the collapse of the population resulted in the Amazon forest growing back in over the terra preta, and the accumulation of leaf litter over the terra preta then continued to increase the soil organic matter via negative priming, as the microbiome of the charcoal-amended soil propagated upwards into the forest litter, which we observe as terra preta reproducing itself.

Concluding Thoughts

Even though it is not possible to conclusively determine the method by which terra preta was produced because we have no surviving record of the process used by the ancient indigenous civilizations of the Amazon, at this point in our history, it suffices that the mystery of terra preta has inspired the scientific study of biochar, along with widespread experimentation, which has yielded so many useful applications of charcoal. With insights from soil science, we understand that terra preta is not the only soil that increases its topsoil humus/soil organic matter from plant residues (such forest litter) that accumulate upon it; this is the expected behavior of healthy soils that receive regular accumulations of plant residues. We also now understand how biochar can significantly modify the soil environment, and therefore, the conditions that favor and select for a different soil microbiome, which then propagates into organic residues that decompose upon it. With even just the agronomic benefits of co-composted biochar, produced by methods informed by these findings, we can significantly improve the fertility and resilience of our agricultural soils, and it would not matter whether or not our methods faithfully reproduced the original terra preta. What is needed now is deployment and widespread application of what we know. Whereas the ancient indigenous people of the Amazon cultivated many thousands of hectares of poor tropical oxide soils into some of the most fertile agricultural soils in the world, we in the modern developed world are destroying ours with chemical fertilizers and conventional farming practices, and those who know about biochar, though having access to mechanized farm equipment have barely matched the acreage cultivated by the ancient Amazonians. The benefit of all of our scientific insights only come from putting them to practice.

Coming up next: The right way and the wrong way to do biomass energy

Biochar and Biomass energy are intimately related through their use of combustible biomass feedstocks. In the next article, we’ll take a look at how biomass energy can be practiced in a manner that benefits the climate.

Biochar and Bioenergy 2019, Fort Collins CO

APL team member at the booth
APL team member Austin Liu at our Biochar & Bioenergy 2019 booth

All Power Labs recently attended the Biochar & Bioenergy 2019 conference held in Fort Collins, Colorado from July 1–3. Our CEO, Jim Mason, as well as biochar experts Austin Liu and Aidin Massoumi were on hand, to promote our distributed-scale biomass gasifiers, share our work with SkyCarbon Biochar and the Local Carbon Network waste-to-climate products initiative, and soak up the latest knowledge from academics, producers and practitioners in the global biochar community.

The event was hosted by the US Biochar Initiative (USBI) and featured presentations, panel discussions and poster exhibitions from more than 80 experts on major themes in the biochar space, including production and commercial application, environmental remediations, soils and agriculture, and the bioeconomy and climate change.

Our resident biochar expert, Austin Liu, gave two presentations at the conference, sharing his research on gasification’s effects on biochar properties, as well as our work with biochar co-composting and the observed benefits to plants and soils.

We also staffed a booth with videos and literature on our latest biomass-to-power/heat/biochar gasifier, the Power Pallet 30, as well as on the science behind our SkyCarbon Biochar and evidence of its impacts with our farming partners.

Biochar & Bioenergy 2019 was a very exciting opportunity for All Power Labs and the Local Carbon Network project, and we received considerable interest from attendees on our product line, on our equipment at-work in forests and on farms, and on the SkyCarbon Biochar produced through our patented gasification process. Most importantly, we met many new friends and partners to support our goal of scaling community-based carbon sequestration!

If you’d like to learn more about All Power Labs and the Local Carbon Network project, reach out!

Biochar Usage in Dairy Manure Composting

Co-composting dairy manure with SkyCarbon biochar

In the Local Carbon Network, we convert available green waste into value-added ‘climate products’ such as electricity, heat, water and biochar through a carbon negative process that combats climate change on multiple fronts.

The Local Carbon Network uses biomass gasifiers from All Power Labs in Berkeley, California, to produce SkyCarbon Biochar, a clean, porous, high-temperature char certified by the International Biochar Institute and officially listed by the Organic Materials Review Institute (OMRI). When used as a soil amendment, SkyCarbon Biochar can offer a range of powerful agronomic benefits to plant productivity, soil biological activity, water retention, pest management and mineral uptake.

We have found that these results are best achieved through combining or ‘co-composting’ SkyCarbon Biochar with nutrient-rich organic matter at the beginning of the composting process. Through co-composting, the char is biologically ‘charged’ or ‘activated’ with microbes and nutrients that enhance its benefits. In addition, compost piles containing SkyCarbon Biochar tend to reach higher temperatures and stay hotter longer, significantly reducing the processing time and allowing compost to be harvested earlier.

Ontario Agricultural Commodities

In April of this year, the LCN began working with Ontario Agricultural Commodities (OAC), a commercial-scale composting operation in Ontario, California, to implement A/B trials with SkyCarbon Biochar in dairy manure composting. Before partnering with OAC, our experience with co-composting SkyCarbon Biochar had primarily been with green waste composting, and so we were excited to see what would happen when our char was mixed with a dairy-manure composting process.

Experimental design:

Treatment and control test with two dairy-manure compost piles, approximately 200 gallons each, started at the same time. The treatment pile was composed of 10% biochar, 90% manure, the control pile of 100% manure. Total biochar added to the treatment pile was 20 gallons of biochar at start, and 15 gallons later. Moisture was added to piles every three days. Pile temperatures were measured three times a week.

The compost pile with SkyCarbon Biochar achieved and sustained higher temperatures throughout the compost process, and was ready to be harvested eight days before the control pile (indicated by black dot).

As you can see, the compost pile with biochar started hotter and stayed hotter longer than the pile without. Achieving and sustaining higher compost temperatures is particularly important for manure composting as hotter piles eliminate the threat posed by pathogens originating from animals. OAC harvests its piles 15 days after they have reached 131F, and as a result of the elevated temperatures, the SkyCarbon biochar pile was ready eight days earlier than the control pile, a 30% decrease in processing time! OAC staff also observed increased moisture content in the biochar pile, which would improve the overall effectiveness of the compost.

These are exciting results for our first foray into commercial-scale manure composting, and as we continue to combine SkyCarbon Biochar with different types of compost we look forward to testing for the additional known benefits of biochar to composting processing such as reduced GHG emissions, higher pH, enhanced organic matter, and increased nitrogen and other plant nutrients.

The LCN is actively seeking partners to demonstrate the many benefits of SkyCarbon Biochar, so if you are interested in collaborating on a solution that addresses climate change, soil degradation and world hunger, reach out!

Leave a Positive Trace Permaculture Action Day with Burning Man

Four smiling women
Photo credit: Brooke Porter Photography

On Saturday, June 22, the Local Carbon Network joined Burners without Borders, the Permaculture Action Network, and nearly 400 participants for an all-day event at Hoover Elementary School in Oakland, CA, featuring live music, arts, food and hands-on projects to improve the school’s garden and outdoor classroom. The activity was part of the ‘Leave a Positive Trace’ action weekend organized by Permaculture Action Network in partnership with the community associated with the annual Burning Man arts and music festival.

Hoover Elementary is located in a West Oakland neighborhood considered a ‘food desert’ due to the lack of access to healthy and affordable food. To address this, in 2014 the school started the Hoover Hawks’ Victory Garden to teach its students about growing food and the importance of nutrition in health and wellness. The Victory Garden is just one example of the activities in Oakland’s larger food justice movement that aims to address inequitable food access through policy and programs including management of urban farms and backyard gardens, and community supported agriculture boxes, sliding-scale farm stands, and farmers’ markets.

Participants at the June 22nd ‘Leave a Positive Trace’ event supported Hoover’s Victory Garden by digging swales, edging and weeding garden beds, planting and building furniture for the outdoor classroom located in the garden. The Local Carbon Network hosted a session in which we introduced our initiative and held a drawing to give away a SkyCarbon drawdown subscription — a compost tumbler and a year’s supply of SkyCarbon Biochar. The prize winners were Dana Frasz and Mark Matos. Franz is the founder and Executive Director of Food Shift, an organization working to address food waste and hunger.

Wide shot outdoors of about 100 people standing in a circle
Permaculture Action Day participants during the ‘Opening Circle’ activity at Hoover Elementary School (photo credit: Brooke Porter Photography)

While we are always excited to have new partners in biochar co-composting and carbon sequestration, we are especially happy to count Dana, Mark and Food Shift among the Local Carbon Network’s newest members, and we look forward to aligning our efforts to fight climate change and strengthen food resilience!

Dana and Mark
Dana and Mark with their new compost tumbler, ready to co-compost with SkyCarbon Biochar!

If you’d like to start your own backyard compost-and-carbon-storage project with SkyCarbon Biochar, contact us and join the Local Carbon Network!

Summer Solstice Char-B-Que Open House at Gill Tract

On Friday, June 21, All Power Labs and the Local Carbon Network hosted an open house at UC Gill Tract Community Farm, our regenerative farming partner in Albany, CA. More than 60 attendees were given tours of the two-acre organic farm and medicinal herb garden, and were shown the remarkable changes to soil and plant health that Gill Tract has observed since it started co-composting with SkyCarbon Biochar more than a year ago.

To further celebrate the Northern Hemisphere’s longest day, we unveiled the ‘Char-B-Que’, a wood-fired Kon-Tiki kiln and grill that produced biochar while also cooking proteins and freshly-harvested vegetables for the open house participants.

The All Power Labs’ team manning the ‘Char-B-Que’ grill

The All Power Labs’ team manning the ‘Char-B-Que’ grill

Team members from the Local Carbon Network, All Power Labs, and Gill Tract also conducted a Q and A session on integrating biochar into organic composting processes, including a walk-through of Gill Tract’s SkyCarbon Biochar compost system, and a demonstration of co-composting biochar with a household-scale insulated compost tumbler.

UC Gill Tract Community Farm is a collaborative community project between the University of California Berkeley and the local community, focused on issues of food justice and urban farming. Gill Tract is the flagship partner in the Berkeley Local Carbon Network and an active practitioner of regenerative agriculture. Since the farm began co-composting with SkyCarbon Biochar in April 2018, it has applied more than 300 kg of char to its soil, for a total of more than 9000 kg CO2e sequestered to date!

If you are an individual, organization or business interested in using our SkyCarbon Biochar to benefit plants, soil and climate, reach out! We can help assess your needs, find farm, garden and technology partners, and even help you start your own Local Carbon Network.

IBI Newsletter: June 2019

The International Biochar Initiative (IBI) is a great source for information on research and the development of biochar businesses and industry. We will be linking to their newsletters here in our News Blog posts going forward.

They recently did testing and certified our Local Carbon Network SkyCarbon biochar, the results of this analysis are shown here. This, along with OMRI certification now allows SkyCarbon to be used in certified organic farming.

OMRI logo
Click this link to access IBI Newsletter: June 2019

Co-composting with Biochar for Agronomic & Climate Benefit

Friday, March 8th, 5-7pm
FREE!  But please RSVP here


 Our monthly Open House events continue this Friday with a talk and demonstration of the agronomic and climate benefits of co-composting with biochar.  We’re convinced we’ve stumbled across a highly significant optimization for biochar usage and deployment with this co-composting scenario.  The solution is uniquely high performance in soil, easy to do, leverages the already existing infrastructure of compost operations globally (personal, commercial, and municipal), and achieves carbon impacts far beyond the raw biochar entered into the system.

Resident biochar expert, Austin Liu, will be giving a presentation on the influence of biochar on the composting process, and the influence of composting on biochar surface features.  Environmental and climate aspects such as mitigating the methane and N2O emissions of compost will be addressed, as well as the significant potential to achieve carbon drawdown multipliers through the co-composting process (i.e. further carbon drawdown beyond the raw carbon entered into the co-composting).

More practically, if you’ve had unpleasant experiences with composting (foul odors, slow decomposition, vermin, flies, angry neighbors, etc.) come see how that can be fixed.  We’ll be showing off our new in-house composting experiment, where you can see the effects of co-composting biochar vs composting without biochar in a side-by-side comparison.

 This co-composting process combines with APL CHP machinery to transform biomass residues into multiple types of value and climate impact.  Adding the co-composting scenario out the end significantly multiplies the carbon drawdown impact of the biochar generated.  The specific type of high temperature biochar produced in APL machinery uniquely enables the carbon multiplier pathways summarized in flow chart below.   Flow chart assumes the current 5% biochar yield rate of the APL electricity and heat focused equipment.  Higher yield rates are of course possible with other types of biochar focused equipment. 

Biomass to Biochar to Cocomposting Flow Rev 01

 As usual we’ll have the PP30 Cogen CS machines running onsite for your consideration.  Food and drink are free for all attendees. 

Facility tours start at 5pm.  Talk starts at 6pm.  1010 Murray Street, Berkeley, CA
Please RSVP here so we know who is coming.

For more information on the content for the talk, or for those who cannot make it, here are two documents to explore more of the technical details of co-composting with high temperature biochars.

1. “All Biochars are not created equal”.   Intro to the APL biochar scenario.

2. Austin’s presentation deck from last round of this talk.  Updates for this Friday still in process.


  Hope to see you on Friday.


We won!

We’re honored to announce that All Power Labs is part of the winning team for the Water Abundance XPRIZE 2018. APL was the technical lead for the Skysource/Skywater Alliance team, and brought gasifier based power generation, plus a unique use of water vapor from biomass, to the larger problem of making atmospheric water generation machines truly usable in the world.

XPrize Water Abundance Winners on stage

The $1.5M award was announced at the XPRIZE Visioneering 2018 event in Los Angeles, October, 20, 2018, bringing to a conclusion a 2 year long competition involving 98 contending teams from 27 countries. The prize was launched in 2016 at the United Nations in New Delhi, with sponsorship by the Tata Group and Australian Aid. Both groups are continuing their involvement to ensure this innovation gets to market and doesn’t just stop with a flurry of press releases!

The competition has aimed to alleviate global water scarcity by accelerating technologies that harvest fresh water directly from air, with 10x improved economics and usability vs current atmospheric water harvesting tech. The Skysouce/Skywater/APL team won by delivering a novel biomass gasification based high-volume water generator that can be used in any climate, meeting the competition parameters of extracting a minimum of 2,000 liters of water per day from the atmosphere using 100 percent renewable energy, at a cost of no more than 2 cents per liter.

The novelty of the Skysouce/Skywater/APL solution is the integration between the standard APL PP30 Cogen-CS power generation system, and the standard Skywater vapor compression cycle atmospheric water generation (AWG) machine. More specifically, we developed a biomass drying system placed between the two products, so that water vapor from the drying process can augment the humidity intake to the AWG machine. This enabled us to create an artificial high temp / high humidity environment for the AWG machine, meeting or exceeding the usual tropical conditions required for good AWG water yields. We did this while operating in the cold low water holding air of Berkeley, CA.

In practice, a standard AWG machine won’t really work in Berkeley late Fall air conditions. But we used “Berkeley air”, augmented with biomass, to exceed the high metrics of the competition and win against competitors working in the tropics!

All of us in the biomass powergen industry consider water in biomass a problem to get rid of. Though this contest, we discovered that it can, in fact, be a tremendous resource for co-production of potable water, while simultaneously delivering the usual electricity and sequestration of carbon through biochar. We realized that biomass is a major untapped water resource with global availability. It should be added to the list of water resources typically assumed: rivers, lakes, rain, wells, ocean, and air.

For a video summary of the competition, and some shots around APL while we were testing, see here for the XPRIZE produced video of the process.

Product Prototype: WEDEW Watertainer

Water container at Verge conference

Looking towards productization, we designed the components for the XPRIZE test rig to fit inside a standard 20′ shipping container. This container-based integration, with side wall openings for access, is the form factor we plan for ultimately bringing this Power, Water and Carbon Sequestration solution to market. The first containerized product prototype is shown above and below while being demonstrated as part of the microgrid at the Verge conference in Oakland in late October.

The WEDEW Watertainer uses the standard PP30 Cogen unit, with full utilization of its CHP features to enable the controlled drying process. All of our work on the XPRIZE project was enabled by the new CHP features of the Power Pallet: in this case applied to a highly controlled drying process for specific temp and humidity flow delivery to the AWG machine.

Development of this new product will continue over the coming Winter and Spring. We expect to start pilot projects in the later half of 2019. If you are interested in being an early customer, funder, or enabler of the first wave, please write us at: “sales@allpowerlabs.com”

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Open House: Friday, Nov 9th, 5-7pm

We will demonstrate the WEDEW Watertainer system at our next Open House, Friday, Nov 9th. We will not have the full container available (as it is currently in SoCal) but will have a second assembly with all major components operating outside at APL Berkeley.

Readouts in containerDavid in container

We invite you to join us and see more of the details of what we did to win this global technology contest.

The event is free. The food and drink are free. Please RSVP to our event page here to be part of the event and see part of our collective climate solution!

I hope to see you next week at APL

Jim Mason
All Power Labs
Founder, CEO

Local Carbon Network: Terni, Umbria- Italy launch

Kickstarter Crowdfund in process.  Join us for a 10 day learning holiday on a rural Italian farm,
with Power Pallet, biochar, and composting (and all the other Italian provincial pleasures).


This is the Valle Santa / Reiti Valley, where the APL New Farms Labs is located.  We’ve been running machinery at this site for about four years now, and using it as the headquarters for APL efforts in Italy and the EU.  With our transition to the Local Carbon Network model of deployment, we’re now recasting this site as our second major full circle “waste-to-valve, sky-to-soil” operating hub.

Those following our Local Carbon Network project will know that we’ve started to get some wonderful results at Gill Tract Urban Farm in the Berkeley Local Carbon project.  Gill Tract has switched their onsite composting efforts to now co-compost with the LCN biochar, and the results have been a step change in plant vegetable growth and vitality.  This co-composting with high temp biochar (biochar mixed in during compost making, not added post making) significantly increases nitrogen fixing, reduces N2O emissions, and introduces several multiplier effects which build soil carbon beyond the raw biochar carbon introduced.  The impacts on plants and GHG gas management are consequential.  Pictures and info can be found on the Local Carbon Network’s Facebook Page.

Now we’re bringing this biochar co-composting process to our farm in Italy, and the rest of the full circle LCN engagements to the surrounding area.  We have launched a Kickstarter campaign to fund this first EU Local Carbon Network, and hope you will help make this community based climate management demonstration possible.  Many levels of sponsorship are available: from purchasing or donating single bags of biochar, to a 10 day learning holiday for the whole family at our farm in Valle Santa.  

Local Details:  The Valle Santa / Sacred Valley name comes from saint Francis of Assisi, who visited repeatedly: the first time probably in 1209, then a long stay in 1223 and then another from the autumn of 1225 to April 1226.  While in the valley, Francis represented for the first time the nativity scene, wrote the final version of the Franciscan Rule and probably also the Canticle of the Sun, but most importantly he founded the four shrines that are located at the four borders of the plain: Sanctuary of Greccio, La Foresta, Poggio Bustone and Fonte Colombo.  https://en.wikipedia.org/wiki/Rieti_Valley.

The Sanctuary of Greccio is very close to our farm, and available on your morning walk if you choose to join us for this learning holiday.  You will have a whole country farmhouse for yourself, a private guide/driver, day trips, all meals and lessons covered. The rest of the days will be spent learning the Power Pallet operations and related co-composting with the biochar output and planting.  Or doing relatively nothing on the porch overlooking the valley.   To receive pictures of the location or discuss the details of a potential itinerary please contact silvia@localcarbon.net

There are also inexpensive memberships or learning events to support the local carbon community project without committing to a full holiday. The campaign only lasts for one more week! Please take a look and help us prove local carbon sequestration methods driven at the community level. We did it for Local Food and organic agriculture–we can do it now for local carbon management through green waste management to local soil regeneration. Click here to help us make it happen! http://bit.ly/LCNKickstarter

The Local Carbon Network Big Idea. And the Terni area specific project.

All Power Labs is now deploying our machinery through Community Based Carbon Sequestration projects to maximize climate impact, full circle resource use, and benefits to the local community.  These projects are a collaboration of People, Plants and Machines, and return a variety of social and environmental benefits to the local communities where they operate.
The Local Carbon Network uses locally sourced green waste byproducts to make clean electricity and heat, then donates the byproduct biochar to local community gardens and agriculture.   These combined actvities move carbon from “sky-to-soil” for a strong Climate Impact, improve soils for accelerated plant growth, and return commercial benefits to local participants during the process.  Think local food economy and farmers’ market; but now transacting local carbon from sky-to-soil-to-value, via the hands of local citizens and organizations.

carbon impact image 2

For our Terni project we’ve signed up local farmstay facilities, a health food store, a fair trade store, meeting spots to hold educational events, technical partners, and community gardens – all within a 20km radius of downtown Terni.  This will be the demo project and proving ground for all future Local Carbon Networks in Europe.

Funding will be used to bring over new equipment and donate at least one thousand bags of Biochar for use within the community, having a carbon impact of 20 – 40 tons of CO2e – that is the equivalent impact of 1000 – 2000 trees over a year (average is 21.77kg CO2 sequestration per year per tree)

lesson at community garden 3

And . . . we’ve already started.  In the picture below we’re doing an instructional presentation at Orti in Città Terni community garden in Terni, Italy.  They will be receiving their first load of biochar shortly.


Our current project partners are below.  We invite others who want to join us around Terni, as well as others who want to start Local Carbon Hubs in other Italian or EU regions.

The Local Carbon Network project is building a replicable, scalable, financially viable model for climate change mitigation.  If you are curious about the specifics of the process or the climate benefits, here is our FAQ.  If you are interested in starting a Local Carbon Network in your community, write to silvia@localcarbon.net or austin@localcarbon.net.

Reminder: Open House this week: Friday, Nov 9th, 5-7pm

We will demonstrate our X-PRIZE winning WEDEW watertainer system at our Open House this Friday Nov 9th.  We will not have the full container available (as it is currently in Los Angeles) but will have an second assembly with all major components operating outside at APL Berkeley. 

If you missed our annoucement about this novel biomass based atmospheric water generation solution, and our recent win of the Water Abundance X-PRIZE as a result, see here for the details.   Join us at the Open House to take a look personally at what we did to win this global technology contest.  

The event is free.  The food and drink are free.  Please RSVP to our event page here to be part of the event and see part of our collective climate solution!


APL monthly Open House continues this Friday

We’ve restarted our monthly Open House events at All Power Labs.  Now that we’ve launched the new PP30 Cogen-CS, and the Local Carbon Network is up and running, we have new reasons to gather the interested at our facility in Berkeley CA.  This month we’re having the event this Friday, Sept 14th, from 5-7pm

The Open House events are free.  The food and drink are free.  All you have to do is RSVP here.  And bring your friends.

PP30 Cogen-CS Demonstration

The Open House is an opportunity to see APL machines in operation and discuss your potential projects to use them.  We always have a PP30 Cogen-CS CHP installation up and running for the show, as well as other varying machinery throughout the year.  The “varying machinery” for this event will be a very interesting zeolite based adsorption chilling system made by Fahrenheit in Germany, which we’re powering with the hot water output of the PP30.  The new high effiency CHP solution on the PP30 makes this heat based chilling system newly interesting as an extension to the Power Pallet core electricity and heat service.APL staff will be onsite to answer questions throughout the event, as well as available for longer discussions pre and post event.  For those who have been debating a visit to have a larger strategic partnership discussion, the Open House is a good excuse to finally do it.  We do encourage longer stays around Open House days so we can schedule one-on-one extended meetings to discuss more involved projects or partnerships.  Please write us separately at sales@allpowerlabs.com if you want to arrange a dedicated discussion.

Local Carbon Farmers’ Market

 We’re expanding the monthly Open House event also host Local Carbon Network (LCN) activities.  Over time we plan to grow this into a monthly meet up we’re calling the “Local Carbon Farmer’s Market”.  This will be a gathering where you can pick up your Local Carbon Biochar, learn how to use it, and explore the related soils and climate management opportunities with other enthusiasts.  Each month we’ll have talks, workshops and other info sharing will help you to make a direct impact on carbon drawdown with your own hands and soil.
To date most LCN biochar has been going to local community gardens and schools.  If you are a participant in such, we do encourage you to join us and help grow the circle of locals actively sequestering carbon in soil.  And invite others you know from these networks. This month, Jim Mason (APL Founder and CEO) will give an updated talk on modeling climate impact of Local Carbon Network activities.  Over several years APL has developed a progressively elaborate model which relates biomass gasification and biochar machinery on the ground, to GHG impact in the sky.  This has recently expanded to encompass the directed planting and water work that is part of the LCN.  Now we’d like to present the model publicly for your consideration, opportunity to poke holes in, and input on improving it.  The talk is titled:

Biomass Gasification + Biochar = Carbon Negative Energy, Food and Water


How to reduce atmospheric CO2e levels 10-40ppm over 1 century

through a collaboration of People, Plants and Machines.

Screen Shot 2018-08-13 at 1.11.16 PM

For an abundance of clarity, the Local Carbon Farmers’ Market activities and PP30 Cogen-CS machinery demonstrations will happen at the same Open House.  This is one event, with two related but different tracks of activities.  In the future we may need to divide them into 2 separate events, but for now, it is under one tent.

We hope you can join us.

Jim Mason and APL staff

PS:  For those who missed the earlier announcements about the Local Carbon Network project, a more detailed description is reproduced below, 


Local Carbon Network

Community Supported Carbon Sequestration.
Moving carbon from “sky-to-soil” to reverse climate change

The “Local Carbon Network” is a new participatory project we’re launching at All Power Labs to put a meaningful dent in the climate problem. The project uses the carbon negative energy and agricultural machines we’ve been developing for the last decade, combined with hands in soil at local gardens and farms, to move carbon from “sky-to-soil” for Community Based Carbon Sequestration.

The project is an unusual collaboration between plants, people and machines. The plants are green-waste, which recently captured atmospheric carbon via photosynthesis, but are now a disposal problem. The machines take this “waste” and make energy and carbon biochar for soil out of it. And the people put it in the ground for improved plant growth, water conservation, and long term sequestration of carbon. Taken together, good things happen locally across Energy, Food and Water systems– which makes good things happen globally for climate by “refossilizing” sky carbon back underground.

We’re running this Community Supported Carbon Sequestration on the model of the Community Supported Agriculture (CSA) boxes you get weekly or monthly via membership. Now, the membership is for ongoing local carbon drawdown, with a physical product delivered that does magical things for your garden, house plants, farm, or vineyard.

The goal is to create a replicable model based on the common understandings and methods of Local Food and Farmers’ Market networks. We’re creating the first “proof of concept” and template for it here in the East Bay of California. We then expect the model to spread with low friction as a layover to Local Food and Local Market economies elsewhere in the US and globally.


Success in this initial East Bay capital campaign fund and deployment will justify follow-on campaigns and deployments dedicated to other Local Carbon Clusters.   APL intends to followup on the East Bay campaign with additional Local Carbon Clusters in California, Italy, Liberia and India.  These areas will be next as projects can build on business and service logistics already established by All Power Labs in these markets, and demonstration projects already operated to success.  We also invite you to consider a Local Carbon Cluster in your area, and talk with us about how to make it happen.


The goal is to fuel progressive steps towards, and long-term stewardship of, gigawatts of carbon-negative power and product deployments; with the ultimate objective of enabling a 10-40ppm drawdown in global CO2 concentration over the next century.  A 10-40ppm drawdown is approximately 10-20% of the carbon reduction that will be needed to maintain global temperature increase below 2˚C, the commonly-accepted point that will stave off catastrophic climate change.  
“Global Carbon Management through Green-waste Management” is one our most powerful tools to do something consequential about climate change with today’s technology and at-market products.  Moreover, it is a solution that can be run profitably–delivering real economic value across Energy, Food and Water systems–and therefore has a built in engine to scale.   

APL will not do this as a single company, but as a general industry enabled and pursuing the what is ultimately a market driven solution for energy and agricultural needs, we just might be able to make it happen.  Model details on the climate and financial modeling behind this scenario are in the original launch campaign on Indiegogo:  https://www.indiegogo.com/projects/local-carbon-network-community/x/18354621#/  

Yes, we have solutions to “refossilize” consequential amounts of carbon out of the sky and into the ground.  Plants + People + Machines can work together and drawdown carbon for both local value and global climate benefit.

We hope you will join us in setting this very accessible trim tab against the unrelenting fossil CO2 flow.