Re: Pit under stack of crop waste - Biochar from maize stalks


Congratulations on the chicken bedding and feed. What a great use for all that manure. Our tests in Africa and Thailand show really promising results with chickens, cows and goats - better health, greater weight gain, more eggs and milk. Your testers will not take our word for it and we would love to get your results, but power to you if you can convince a few big users to try your stuff. With the rising demand for organic, you may have more than a niche. You say that someone else is working on larger-scale char. What can you find out about them and what about scaling up yourself (or bringing in a partner)?


On Tue, Aug 3, 2021 at 8:30 AM Teel, Wayne <teelws@...> wrote:

Stephen and Michael,


Thanks for the information and the long overview article on biochar.  I finds Stephen’s research on practical “chemical” management of biochar very helpful, and Michael’s field work highly valued.  Paul, I think what Stephen means is that the still hot biochar, when quenching with compost, torrifies the organic material in the compost and produces the wood vinegar compounds.  In the process this produces an increase in functional groups on the biochar surface making it more chemically dynamic in soils.  Increased functional groups (carboxyl and hydroxyl) help nutrients stick to the biochar and fungal and plant interactions take advantage of that availability.


Right now the Shenandoah Valley is in a drought situation, not as bad as the western US, but spreading out biochar to cool would be a disaster.  I like my oak and hickory trees.  Context is everything with biochar, so there is no one way to do things, but quenching with clay and compost seems an excellent thing to try.  I will try Stephen’s method with my next batch.  I usually do the kiln burns early in the morning here, which is when the wind is least likely to blow. 


We have a fertile silt loam soil (60% silt) that dominates the valley agriculture, so in many places clay is hard to find, especially the shrink-swell clays with a high CEC that would likely be best in quenching.  Our context is not one with straw or ag waste as a major problem.  People don’t burn here, they mostly feed silage to cows for dairy and the corn grain and soybeans produced is transformed into feed for poultry, of which we have more than the land can handle.  We import over a million tons of grain a year and are a hot spot for nutrient leakage into the Chesapeake Bay.  Phosphorus even shows up in ground water because soils are often saturated.  Poultry litter and dairy manure are our best options for nutrient loading in biochar.  Right now most of my production is ground to a 2mm average diameter and used in the bedding in poultry houses for organic chicken production.  A set of side by side comparisons of impact on nitrogen emissions and bird health is planned for this fall.  The resultant litter enriched with biochar is approved for use on organic farms, so that is our market.  We just have to get the local testing done to encourage the poultry farmers to expand its use.  There are people in the region working on larger scale production of biochar as well.




From: <> On Behalf Of Stephen Joseph
Sent: Monday, August 2, 2021 6:28 PM
Subject: Re: [Biochar] Pit under stack of crop waste - Biochar from maize stalks


CAUTION: This email originated from outside of JMU. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Dear friends 


If you want high yields add clay with you biomass as this will capture some of the volatiles and  provide more consistent heat.  Typical I can get 35-40% yield and because clay is an acid catalyst  we get more of those wonderful oxygen functional groups.


I teach people to quench with either compost, manure or clay or other minerals.  There are different methods of quenching that gives you different results.  In the Kontiki the heat from the charcoal actually  torrefies the biomass and you produce wood vinegar chemicals on the surface of the torrefied biomass.  We have done trials with this in Vietnam with the B4SS project.


There are many ways of increasing yield and efficacy of your biochar.  One of these days I will get time to finish the manual I am writing which puts down my 40 years of experience.  





On Tue, Aug 3, 2021 at 1:23 AM d.michael.shafer@... <d.michael.shafer@...> wrote:



Don't know about you, but finding a windless day where we are is pretty hard, which has discouraging consequences for efficiency!


Regards "quenching," Kelpie suggests pouring out the char on the ground in a thin layer and letting it put itself out. I have not tried this and have no idea how much you might lose to the air.


One thought is to use a moisture meter to calculate the water content of your char. We found a good one on Alibaba for very little. We use it for pricing purposes, but you could use it to back calculate to dry weight.


General question: what are you charging your char with and how good is your soil? In my experience, the better the soil, the more char you need to accomplish anything, no matter how you charge. In the developing world, most of the soil is so bad that 250 grams plus manure, pee and either EM or a handful of forest dirt/litter will come close to doubling the yields of almost anything. (Response varies a lot among species.) Water retention and surface porosity are huge here, too, given clay soils that bake brick hard in the sun and then hold little water when it does penetrate. With climbing temps and more irregular rainfall, biochar is proving to be the poor person's only effective means of mitigating these two big consequences of climate change.




On Mon, Aug 2, 2021 at 7:20 AM Teel, Wayne <teelws@...> wrote:



You are correct on that.  Even in my batch retort I barely get 20% by weight.  I think you can only approach 30% in a continuous feed system where you use the heat from pyrolysis gasses to heat the new material.  I have to light a fire underneath the pyrolysis chamber and count the fuel used for that against my total yield.  On a low wind day, with very dry wood, I likely get above 15% in the Kontiki, but it is hard to measure since I use water to quench, and getting the biochar dry takes an oven since it holds water so well.  I am noticing the effect in my garden this year.  We are very dry this summer, but the biochar beds have a lot less wilt and I don’t have to water as often.




From: <> On Behalf Of d.michael.shafer@...
Sent: Sunday, August 1, 2021 5:56 PM
Subject: Re: [Biochar] Pit under stack of crop waste - Biochar from maize stalks


CAUTION: This email originated from outside of JMU. Do not click links or open attachments unless you recognize the sender and know the content is safe.



I would not complain about 15%. If I am not mistaken, the theoretical max is not much over 30% and both trench and trough pyrolysis are pretty inefficient.


I think that the key thing about Kevin's method is that he achieved his results using literally a hole in the ground. Again, if I am not mistaken, this is reaching way back to the origins of the process in E. Asia where the Japanese used a small pit.


The point is that for Africa, where no one can afford to buy or make a Kontiki, Kevin's method is efficient and effective.




On Sun, Aug 1, 2021 at 4:59 PM Teel, Wayne <teelws@...> wrote:



I have done it with hemp waste after seed harvest.  This was an experimental plot and was not repeated because of Covid.  I used a Kontiki kiln, filled it with stems and before the first addition was completely consumed I added more hemp stems, doing the entire amount I had in a single burn.  I did it alone, using just a shovel to break it down and water to quench.  The yield was good, but I estimate only about 15% of the mass was left.  Most of the biochar went to the raised beds of a local farmer to grow vegetables, and he does not hesitate to take it when I say I have more (mostly from branch wood rather than ag waste).  It is hard to see a large jump in yield on the farmer’s field because he has high quality soil to start with, but it is enough a benefit to be worthwhile.  I am in the Shenandoah Valley in Virginia




From: <> On Behalf Of K McLean
Sent: Sunday, August 1, 2021 4:31 PM
To:; Michael Shafer <d.michael.shafer@...>; Kelpie Wilson <kelpie@...>
Subject: [Biochar] Pit under stack of crop waste - Biochar from maize stalks


CAUTION: This email originated from outside of JMU. Do not click links or open attachments unless you recognize the sender and know the content is safe.

This may be a new way to make biochar from crop waste.  Our early testing with maize stalks has been very successful.


Dig a pit.  In the videos the pit is one meter in diameter and 1/2 meter deep

Stack maize straw above the pit.

Light on top and stir when necessary.


In Africa, when the fire goes out we usually smother the embers with dirt.  In the video, the embers were quenched with water.  Or, the embers could be spread in a thin layer to cool.


It's easy and fast.  Only a shovel is needed.  Smoke is minimal and we get a good amount of biochar.  Much better than open field burning.


Here are videos:


Has anyone done this and can share their experiences?


Can others test this with rice straw and other crop wastes?


Kevin McLean

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