Biochar From the Ground Up recap

Last week I visited a small slice of heaven; The Farm in Summertown, TN.  The Farm is the oldest intentional community in the country and has been home to Albert Bates, author of The Biochar Solution amongst other books, for decades.  Biochar experimentation at The Farm spans the gamut from soil amendment to building material to humanure additive which then moves over to worm bins for some final processing.  Just walking around the various natural buildings and permaculture filled ambiance was enough to inspire, but actually getting my hands dirty making biochar plasters, cement mixes, bricks, filtration devices with other like-minded folks was soul boosting.

We visited a nearby farmer that feeds his livestock (pigs, goats, poultry) an earthy blend of biochar mixed with lightly fermented whey and grains which they gobbled up greedily. We used rather grand outhouses that mitigated odors and reduced nutrient leaching with a blend of biochar and sawdust. And we shared stories of our mutual journeys, lessons learned and best practices along the biochar continuum.  What I really enjoyed about this experience, especially compared to attending biochar and other related conferences which tend to pack an enormous amount of information into back to back 15 – 20 minute sessions all day long for 3 days, was the more relaxed pace, the ability to get to know everyone there and hear about their own particular biochar experiences. The other fun part was leveraging everyone’s tools and backgrounds to take certain ideas further – such as the chardboard paper which I wrote about nearly 3 years ago.  Albert had a contraption that was able to measure the electromagnetic shielding of the chardboard which was pretty substantial, roughly 90% reduction! 

For those of you that have the time and desire to experience truly sustainable living, I highly recommend a visit to The Farm.  Staying in the Fairy House, a cozy earth bag building with a living roof provides the quietest sleep you could ever dream of…

Biochar Plaster

 

In preparation for an upcoming workshop on Biochar From the Ground Up to be held at The Farm in Summertown, TN this week I have been experimenting with the use of biochar and different materials. While I’ve been researching biochar and cement for a few years and have blended char with other synthetic and organic materials, I haven’t had much exposure to plaster.  Then I stumbled upon lots of different plaster and stone materials from my father’s former orthodontic offices and asked him to school me in the ways of making different plaster and stone composites. Once I had mastered that, adding in a bit of biochar was a no brainer.

To kick things off I made a 100% plaster sample and a 50/50 biochar plaster sample (see below) first blending the dry ingredients thoroughly before adding water.  (Biochar particle size was <1/20”.) A few things are already interesting to note.  The exothermic reaction that normally occurs with plaster during curing seemed completely absent with the biochar plaster which  didn’t heat up at all.  Also the volume of the blended model is smaller so the swelling which typically happens with plaster seems to have been minimized.  And finally the weight of two samples was significantly different.  When finished the all plaster sample weighed 5.2 ounces whereas the biochar plaster was 3.4 (it lost .2 ounces overnight), 34.6% lighter – not a bad thing when it is used in various building materials (e.g. gypsum drywall).

It would be interesting to test various other properties of this composite such as fire, mold and sound resistance, insulation, hardness as well as curing time. To be continued!

The 1G Mission

Late last year the Board of the International Biochar Initiative (IBI), of which I am honored to be a member, decided it was high time to get ambitious when it comes to biochar production.  We set a goal to help try to build an industry capable of producing 1 G [i.e. one billion metric tonnes] of biochar within the next 50 years.  This is what’s known in the business world as a BHAG – a big hairy audacious goal.  Given the recent alarming elevation of both temperatures and atmospheric CO2 levels, we felt that it was time for the biochar industry to step up and show the world how and how much biochar can help rebalance carbon.

Since that time the notion of how to reach that goal has been on my mind a lot.  There is an ever increasing variety of new technologies coming on line that can carbonize all sorts of organic material including fast and slow pyrolysis, gasification, hydro-thermal carbonization, low tech kilns, and even micro-wave pyrolysis (just attended a ribbon cutting event on one of those today at RIT). From small, nearly free kilns, to multi-million dollar industrial furnaces, the industry finally seems poised to pyrolyze plenty of organics.  The ‘how’ is no longer the constraint to reaching 1G.

The ‘what’ still needs to be identified and quantified, at a global, country, state and local level.  After a very (and I stress VERY) preliminary look at just a few potential feedstocks, I’ve come to conclude that 1G is not going to be a problem based on available supplies of unloved biomass.   The world has more than enough organic matter that is currently being landfilled, burned or otherwise underutilized which, if carbonized, could bring many benefits beyond rebalancing carbon (as I’ve recently blogged about here).

Let’s look at the residues from just 2 of the world’s biggest crops: rice and corn. According to the USDA Foreign Agricultural Service, preliminary reports show that global milled rice production in 2016/17 was 481.5M tonnes. Rice has two distinct residues: rice straw and rice husks. The amount of rice straw produced (by weight) as compared to the amount of milled rice produced is variable from 1.0 – 4.3 the weight of milled rice.  Much of this straw is burned in-situ so that farmers can get on with the business of planting their next crop, even if this practice is banned!  Nowadays, thanks to small, mobile kilns like the Kon-Tiki and Warm Hearts Trough, carbonizing rice straw can be done in fields which would not only reduce air pollution but would prevent enormous amounts of CO2 from becoming airborne. If, by some miracle, we were able to carbonize all of this straw it could produce from 157M – 675M tonnes based on a typical yield for this particular feedstock of 32.6%.  The rice husks could generate an additional 44M tonnes of char based on typical yields from this particular feedstock.

Corn is an even more ubiquitous crop with an estimated 1,065Mt produced per year.  As with rice, corn also has two residues; stover (stalks, leaves, etc. which weighs about the same as the harvest corn) and cobs which weigh about 15% of the corn.  Corn residues amount to 1,225Mt of underutilized biomass which could produce more than 350Mt of char.  Combined these two crop residues alone could potentially sequester more than 400Mt of carbon (or 2.776Mt of CO2e), and that is only looking at the carbon in the char and excludes the reduction in GHG that the production of biochar could provide if heat is harvested or electricity produced, or soil or manure-generated GHGs that could be lowered if biochar is sequestered in soils or added to manure compost or lagoons.

Obviously carbonizing 100% of these residues is a highly unlikely scenario, but this does show that the world produces enormous amounts of biomass every year that could be used to generate not just biochar but heat and/or electricity at the same time. Crop residues are but one big bucket of biomass.  Forestry by-products (thinnings, culling, branches, sawdust, papermill waste, etc.), excrement (both human and livestock), urban waste (e.g. municipal solid waste, industrial, etc.) and invasive species also provide enormous opportunities to help us reach and surpass 1 billion tonnes of biochar.  Imagine how far that could help countries (or apparently in the US it will be up to States, Cities and companies!)  reach their Paris Agreement goals.  Once the collective ‘we’ sharpen our pencils and calculate each of these available categories, I suspect biochar could be one of the best tools for not only reaching their climate mitigation targets, but also helping to improve soil resiliency, food security, while also providing renewable energy and boosting local economies.  

Carbon Farming & Biochar Workshop Recap

Last Saturday we had the first of what may, if there is sufficient help and interest, be an annual event for the region; a gathering of those interested in carbon farming and biochar.  Thanks to our gracious host Peter Arena, the event was held at the beautiful Boathouse Beer Garden which has spectacular views of Cayuga Lake.  On the agenda were folks representing government, academia, industry and consumers. The quadruple helix as I like to call it. Nearly 50 people gathered to hear about the status and strategy of the recently proposed NYS Assembly bill on carbon farming and learn all about biochar.  Technology vendors and newbies to biochar met and mingled with regional biochar ‘experts’.

NYS Assemblywoman Barbara Lifton kicked things off with a discussion on the NYS proposed legislation.  While there is not currently a twin bill in the Senate, she explained that at least this gets the conversation started.  Miranda Phillips from the Ithaca chapter of the Citizens Climate Lobby spoke about the types of citizen advocacy needed to get bills such as this funded and forwarded.

Dr. Michael Hoffmann, Executive Director of the Cornell Institute of Climate Smart Solutions (CICSS) provided a great perspective on what NY farmers can expect in terms of climate change, both negative and positive, and described various adaptation tools and strategies that Cornell has been working on .  Dr. Johannes Lehmann, one of the world’s leading biochar researchers, spoke about how biochar can actually help mitigate climate change by way of rebalancing atmospheric carbon levels. Johannes is a tough act to follow but I did my best to provide what I call the layman, not Lehmann perspective on biochar.

Technical demos from Biomass Controls, Acorn Biochar, America Sequesters and my biochar buddy Dale Hendricks demo’d a small TLUD stove. I was supposed to demo a Kon-Tiki kiln but was juggling a bit too much to strike a match.  We also had GreenTree Nursery there to show some of there biochar enriched horticultural products and talk about soil matters.  Local organic farmers Gerard Dumphry and Jennine Huber who have been using biochar for nearly a decade showed how they are incorporating it into a soon to be planted organic hop yard.

After a rather unexpectedly long lunch period, which one kind soul said provided ample opportunity for people to meet many interesting attendees, we heard from one of my research buddies at RIT, Steve Barber, on using biochar for filtering food & beverage industry effluent.  Following this was a very interesting perspective on using biochar in a fixed bed biodigester.  This research was managed by Bruno Xavier in Brazil but Bruno is now working in the Finger Lakes – always good to have more people in the region!

Our workshop attracted a number of Canadians including Rasmus Kiehl who told us about the Open Source Biochar Wiki page that he has been curating since 2009!  This is a great resource which I encourage everyone to check out!

Wrapping it all up was a panel of carbon farming and biochar users: Gerard Dumphy of Danby Farms, Dale Hendricks from Green Light Plants who spoke about its use in the horticulture industry and Suzanne Hunt from Hunt Country Vineyards who spoke about building soil resiliency by boosting soil carbon.

We were fortunate to have 2 videographers shooting video for the day so at some point we will have more pictures and video available.

Overall I was very pleased with the variety and enthusiasm of attendees and presenters.  Mother Nature cooperated by providing perfect burn weather.  We even had an exceedingly rare on-site visit by a white deer which must have escaped the nearby shuttered Seneca Army Depot.  Although I’ve seen plenty of white deer within the Depot, I have NEVER seen one outside of the 24 miles of fenced in area.  I think it was a sign, so thanks white deer and thanks also to our host, Peter and all the others that helped make the event a success!

How Biochar supports the UN Sustainable Development Goals

The 17 Sustainable Development Goals (SDGs) adopted by the United Nations are focused on ending poverty, protecting the planet and ensuring prosperity for all by 2030.  These are what are sometimes called BHAGs (Big, Hairy, Audacious Goals) in the business world. Big aspirational goals are exactly what is needed to reimagine, reinvent or in some cases retrofit our precariously unbalanced world.

Wide scale adoption of the production & use of biochar could materially help achieve at least 12 of these goals.  While I could (and may!) do a full blog post on each of the SDGs that biochar could influence, here is a brief overview of which goals biochar can impact with some examples of how it is already working:

Goal #1: No poverty – making biochar from crop waste & blending with animal urine & manure decreases the need for subsistence farmers to purchase off-farm fertilizers and boosts yields.  Farmers in Nepal improved yields by more than 100%

Goal#2: Zero hunger – growing more food, especially in poor soils with increasingly erratic climate, reduces hunger. (see Nepal example above)

 Goal #3: Good health & well-being – using biochar in soils can immobilize certain metals and toxins and reduce the need for chemicals in soils.  Using biochar to filter storm water can reduce E.coli and other bacteria. See the Warm Hearts example in Thailand on replacing chemicals in agriculture with biochar.

Goal #6: Clean Water & Sanitation – using biochar as a low cost water filtration medium can reduce negative impacts of unfiltered effluents.  Carbonizing sewage sludge is a way of reducing volume and immobilizing toxins.

Goal #7: Affordable & Clean Energy – a growing number of biochar production technologies can be used to produce heat and/or electricity and/or syngas.

Goal #8: Decent Work & Economic Growth – carbonizing underutilized biomass which is commonly burned in open fields creates economic opportunity for farmers and other rural inhabitants.

Goal #9: Industry Innovation & Infrastructure – new biochar uses include building materials (e.g. concrete, bricks, asphalt) and other composites. Incorporating biochar has been shown to improve various properties of both concrete and asphalt thereby extending the potential lifespan of the materials.

Goal #11: Sustainable Cities & Communities – biochar has been shown to benefit storm water management, green roofs and urban tree planting. It could also be used to remediate urban brownfields.

Goal #12: Responsible Consumption & Production – converting waste into biochar and using the char to displace high carbon footprint or non-renewable or expensive materials will lead us away from a linear economy to a more circular one.

Goal #13: Climate Action – this would be a long list starting off with the ability to stabilize carbon pulled out of the air via photosynthesis.  Biochar production can also displace fossil fuel based energy.  Fed to cows or added to landfills or manure slurries it can lower CH4 emissions. The list goes on…

 Goal #14: Life below Water – adding biochar to soils can reduce nutrient leaching which is responsible for significant eutrophication around the world. 

 Goal #15: Life on land – reclamation, remediation, restoration are all ways that biochar can improve life on land!

Char putty

DIY slime is all the rage these days.  It’s fun and funny and just plain weird. You can kneed it, bounce it and break it over and over yet it always returns to a gelatinous blob. My teenage daughter has made all sorts of variations of this easy-to-make polymer using just three simple ingredients: glue, borax and shaving cream.  It’s the XXI century version of silly putty which is made with just two ingredients: silicone oil and boric acid.  As I have an insatiable desire to add biochar to almost everything, I decided to fold in some char to my first attempt of DIY slime.  The pictures show the slime before and after adding char (I used particle size <1/20” and a lot more char than is shown in the picture).  It is rather beautiful especially compared to the bland, milky-white pre-char substance. 

But might it have any practical value?  The inventor of silly putty asked this question for years and the best they came up with was a toy; a multi-million dollar toy mind you, but still just a toy.  Might there be some benefit to adding carbon to this particular polymer?  After adding biochar to various materials, my next favorite thing to do is chat with Master Google about big questions such as this, so off I went on my cyber quest.  Lo and behold researchers in Dublin recently blended graphene, biochar’s more sophisticated and expensive carbon cousin, with homemade silly putty.  Alas my idea was not so crazy – nor original!  Dubbed ‘g-putty’, this polymer turns out to be a highly sensitive sensor which may just have bio-medical applications.  Researchers claim that g-putty could, amongst other possible uses, be used to track human vital signs.  Its ability to conduct electricity is what appears to be the basis for its high level of sensitivity.  Fascinating!

One thing I’ve pondered ever since a good friend battled chemo-induced neuropathy is whether biochar could somehow help expunge or pull out the toxins pumped into the body during chemotherapy.  Could char putty draped around the affected limbs help detoxify their systems once the chemo has done its duty? Would magnetized biochar, the new darling for sorbing heavy metals and other toxins, make this work?  Or are the pores clogged with the other substances in the char putty?

Therapy putty is already ‘a thing’.  Its prescribed for those with anxiety.  But perhaps char putty could reduce more than anxiety.  It’s worth considering.  Hears to hoping this not-so crazy idea might inspire a few researchers to put this putty through its paces! 

It is Not the Critic Who Counts

Recently someone claiming to have ‘spent years’ researching biochar wrote a rather lengthy blog/report about his viewpoint on the prospects for biochar as a viable solution for climate change mitigation. I won’t mention the title as it seems to have changed a few times, perhaps in an effort to garner further attention.  Not surprisingly though there has been some interesting conversation within the biochar community about said article. One of the main complaints was that the site that published the article never allowed comments, which seems a little thin-skinned.  That is a tactic that our new President and certain cabinet secretaries have been using, so perhaps it is becoming something of a new norm to discourage dialogue.  To quote a frequent late night twitter abuser – ‘SAD’! 😉

But what is so glaringly obvious to anyone that is actually inside the industry and has actually spent a lot of time on biochar research or at least reading broadly and deeply on the topic, is that the article is so out of date.  If it had been published 2 – 3 years ago, the last time the author seems to have spoken to anyone in the industry, some of what he wrote would have been more relevant.  However in the past few years much has changed in the world of biochar. Not only has the breadth of biochar research expanded in terms of a wide variety of potential new uses and a better understanding of the nuances of biochar production and the best ways to use it in different growing systems, but also the number of companies that are beginning to produce thousands of tons of biochar is increasing every quarter.  Hardly what I would consider a ‘standstill’ for the industry, which is what the author claims

Another odd point is that the author chose to focus almost exclusively on biochar’s ability to sequester carbon for the long term, something for which he claims there is dubious research – without really backing that up with recent peer reviewed citations.  He claims that for the past several years there has been an effort to get biochar included in carbon markets.  By and large that effort ended a few years ago and while it is true that it was unsuccessful, the fact of the matter is that the whole carbon market industry has been something of a disappointment.  Prices per ton of CO2e on the carbon markets have been hovering around $12 in the U.S.  whereas the lowest price per ton of biochar is around $600 (and often much higher).  Needless to say with such a huge disparity, the carbon market side of things doesn’t really get too many folks in the biochar world all that excited these days, at least not in the U.S.  That is not to say they wouldn’t welcome additional income, but this is not something a lot of people are actively working on.  The focus has been on documenting biochar’s value proposition in agriculture, in remediation, in wastewater treatment and other areas.  There is acknowledgement that biochar doesn’t make economic sense everywhere given the current price, but the quest for identifying viable markets has definitely moved beyond carbon markets.

This article also resuscitates an old yarn claiming that the only way for biochar to make a significant impact in rebalancing atmospheric carbon, is if substantial food bearing land is converted into growing biomass for carbonization.  I call a hearty BS on that one. To clarify what I mean by BS, I am talking about not just bull manure, but all human and animal excrement as just one stream of waste that when carbonized, has the potential to significantly reduce current GHG emissions related to large animal and human poop processing AND sequester carbon at the same time.  I’ve blogged about lots of other waste that is currently either being out-right burned (e.g. crop waste, invasives, etc.), or landfilled (e.g. food waste, green waste, etc.) or otherwise underappreciated that can take us a long, long way before ever entertaining the needless notion to convert land used for crops into land used for biomass.

Then there are claims that ‘in many instances’ the biochar industry has teamed up with the Oil & Gas industry looking for ways to mitigate their emissions or remediate the harm they have done to eco-systems. Many compared to what? I have seen or heard of very little financial investment from the fossil fuel folks (FFF) outside of funding some academic research. Of course the FFF are beginning to hedge their bets into renewables and other climate friendly technologies, so it would be naïve to claim they have invested nothing, but I would love to hear more facts instead of unsubstantiated innuendo.  This type of hack job reporting is what has made Fox News famous. 

It is disappointing to see biased articles like this that purport to have spent so much time on an issue, when it is clear the goal was headlines and not balanced reporting. Balance requires following all the threads, not just the titillating ones.  Those of us ‘in the arena’ as Teddy Roosevelt so famously said, with our faces marred by dust (perhaps he meant biochar?), are hard at work trying to find the bright spots of where and how and for how long biochar can help rebalance carbon while also helping humanity to adapt to the ominous perils of climate change, toxified soils and other environmental calamities.  It is far more productive for all of humanity to build something up, rather than to tear something down.  That doesn’t mean we can’t admit to the flaws and failed attempts to build an industry, but we need to focus on what works and how to replicate it quickly, economically and sustainably if we are to have any chance of making an impact with biochar. 

Join me at the Carbon Farming & Biochar Workshop!

Exciting news!  Legislators in the NYS Assembly recently introduced the ‘Carbon Farming Act’ (A3281) which seeks to reward farmers for practices that maximize carbon sequestration in New York.  The bill acknowledges that ‘soil & vegetation management can significantly enhance soil & carbon sequestration’ while at the same time improving soil health, crop yield and water quality. 

To help educate the public on what this really means and build support for the bill, I am helping to host a one day workshop on May 20th which will provide an overview of carbon farming methods, including a focus on biochar of course!  The workshop will review the proposed legislation and its potential impact on farmers and will include sessions led by students and faculty from Cornell University and Finger Lakes Biochar on carbon farming and biochar.  You will leave the event knowing how to make biochar, different kinds of equipment available to make it and a few ways to use it at home or on your farm.

I’ve rattled the cages of other biochar experts in the region and am happy to say that many of them will be on hand to provide demonstrations on how to make biochar and talk about using biochar in different ways.   Joining me will be folks from America Sequesters, Biomass Controls, Green Light Plants, Acorn Biochar, RIT’s Golisano Institute for Sustainability and more! 

Many thanks to our host, the Boathouse Beer Garden (6128 State Route 89, Romulus, NY 14541), a lovely spot off the West side of Cayuga Lake.  The good folks from the Ithaca chapter of the Citizens Climate Lobby have been helping to get the policy folks to the event as well. The event will kick off at 10am and run until 4pm on Saturday May 20th.  Lunch and a local beverage (e.g. beer, wine or non-alcoholic) are included and a portion of the proceeds will be used to purchase organic produce from local farmers for the local Food Pantry.  Free biochar samples will be available to those interested in collaborating on small scale biochar trials.

If you’d like to join the fun, register now here or contact me if you would like to help sponsor or provide a demonstration at the event.

One big benefit of adding biochar to livestock feed: healthier milk

While doing some research recently a collaborator asked if biochar fed to dairy cows impacts the quality of milk.  Given that the purpose of adding biochar to livestock feed is to bind toxins and other nasties, it seemed logical but as I sought an answer to the question, the research on this particular question seemed scarce.  However I did find a few tantalizing bits of research which showed how much healthier goat and dairy milk was when goats and cows were fed charcoal.  But before I get to the good news, let me tell you about a not so fun guy (or fungi) that can often be found lurking in different animal products.

Aflatoxins: not a word that is commonly bandied about outside of academia, but aflatoxins can have a major impact on crops and critters, including us!  Aflatoxins are naturally occurring products brought to us by fungi.  They can be generated in soils or silos when too much water is left on crops. They are most commonly found on corn and cottonseed, but may also be found on soybean and distillers grain.  When eaten by livestock a certain amount of it can carry over into eggs, milk and meat.  When consumed by humans, high or long term exposure can lead to all sorts of health issues from convulsions to cancer.  In the US alone, the economic impact of aflatoxins on the dairy industry is estimated to exceed $200M per year!

And now to the good news. The goat research out of India showed that supplementing charcoal in the daily diet of dairy goats (1% DM), significantly reduced the amount of aflatoxins that showed up in their milk without any reduction in milk quantity or nutrient quality – with the exception of Zinc which increased. The two charts in the above graphic show just how much aflatoxin levels can be reduced (T1 is control; T2 is sodium bentonite and T3 is charcoal). The control milk had nearly five times as much aflatoxin as compared to the milk from the char chomping goats! The dairy research done in Italy showed that certain types of activated charcoal could reduce aflatoxin carry over in milk by up to 50%, an improvement of other common binders which topped out at 36%.

Unfortunately in the U.S. the use of plant derived charcoal is not currently permitted as a feed additive for livestock that are expected to enter the human food chain (i.e. its ok for cats but not cows!). In 2012 the Association of Animal Feed Control removed charcoal from their approved list of feed additives citing concerns of possible chemical or heavy metal contamination.  Thankfully researchers and biochar producers are working closely with the Food & Drug Administration to demonstrate that feeding biochar to livestock is not only safe, but highly beneficial.   Researchers and producers in Germany have also been working with regulators quite successfully to demonstrate the multiple health and economic benefits of feeding char to hogs, hens and Holsteins!

 

Acidic Soils & Biochar

I suspect that many people don’t yet realize it, but acidic soils are a growing problem (so to speak!) around the world, already impacting more than 50% of soils used or suitable for agriculture.  Humans are both the cause and the casualty of soil acidification, though other biota are also impacted. We humans have come up with various solutions to combat low soil pH each with their own pros and cons some of which are outlined in a recent paper on this topic by Dai et all (see my summary infographic above).

In attempting to parse the biochar qualities that are relevant to increasing soil pH, the authors highlight feedstock and production temperature as being critical to designing or selecting the right biochar for this particular task.  They note that higher temps tend to increase fixed and total C, pH, ash, total exchangeable and soluable base cations and surface area.  At the same time however higher temps tend to lower yield, volatile matter, total O and CEC.  Generally speaking though if a ‘soil toiler’ wants to increase pH using biochar, so far the best advice points to using relatively high temperature chars (e.g. ~600C) from manure biomass or using a blend of biochars made from different feedstocks.

The discussion on mechanisms or how biochar reduces acidity, gets deep into the weeds of agronomy, but these are the general takeaways from my perspective:

  • Soil acidity: alkaline biochars help acid soils but not alkaline soils – pretty logical!
  • Certain biochars reduce Aluminum (Al) bioavailability & thereby its toxicity to plants; high surface area chars may provide more adsorption sites for Al and other metals
  • Nutrient Availability – research is all over the map at this stage with one of the only consistent findings being that manure chars have more nutrients than chars from plant or woody feedstock.  This is widely acknowledged in the literature.
  • Soil nitrification impacts – also seemingly inconclusive at this stage with much more research recommended.

Lots more work to be done on this subject, especially on long-term impacts of biochar and other soil amendments on soil pH, but overall it was a hopeful read!