Biochar as a redox dance floor for Mn

[Philip Small]

“We all should fall upon our knees and sing out praise for manganese” Richmond Bartlett 1995, at the introduction of his piece on Mn in Environmental Soil Chemistry, edited by Don Sparks.

 

I spent 5 hours in deep discussion with Mark and Kim, 2 fellow biochar nuts, last Saturday. Kim is a follower of Bahá'u'lláh, so no beer (dang). Like me Mark is a waste-use soil scientist, Kim is a wastewater engineer. They work together and wanted to run Kim's latest theory about biochar by me, and I admit to be quite taken by the concept.

 

Thanks to Bartlett, the three of us have share an appreciation for the importance of Mn in soil redox. What other cation can dance so easily between energy states like Mn++, +++, ++++? And this dance happens at higher Mv than will bring behemouth Fe++,+++ out onto the dance floor. That means Mn dances in the range that the living soil community is happiest at. Agility and grace, the three of us share this view. But Kim took us to the next level on Saturday.

 

If you can conceive a 3D redox topography map, with equi-millivolt contours, soluble Mn+++ will disperse itself along the contour until it hits enough Mv difference that it precipitates. And it will tend to concentrate where the contour lines bunch up. Because redox currents are like varied breezes passing through the soil, thus these Mn party spots don't stay in one place very long. If you are a microbe and a party spot happens on your corner, life is good because redox based processes (respiration) are easier: on the one hand its easier to get rid of those excess electrons generated by respiration and on the other hand reduced ions, a source of energy, are also handy. For those that didn't understand that, its like a kegger with no lines at the keg or at the bathroom. Mn++ is the keg, ++++ is the toilet, and Mn+++ is there to make sure everybody is having a good time. If you are a microbe, Mn parties are tops.

 

Mark kicks in at this point. The limit to microbial respiration in soil is commonly understood to be the supply of oxygen. Oxygen resupply works by diffusion more than actual volumetric gas exchange, and responds to gradients. CO2 diffuses out, O2 diffuses in. But these movements are in response to the underlying redox demand gradients. Mn++ seems to be a bit better at calling in the Oxygen than other reduced entities, somehow making a more intense oxygen demanding hole in the redox gradient than its peers. Mark equates increased char to increased soil lung capacity. I find that a weak analogy for my use, but biochar has demonstrated behavior along these lines. grok on.

 

Still with me. Sorry but it gets even more boggling.

 

As a sailboat can progress upwind, Mn can change state against the redox current. It takes a keel, and an able hand at the tiller to complete the picture. I can conceive a living organism providing the keel and the hand on the tiller. Kim, a Gaia enthusist, can see Mn self organizing but that is a bridge too far for me just yet. So Mn has way more moves on the dance floor than anybody can imagine. Except maybe Kim, Sparks and Bartlett.

 

Charcoal is a weak conducter of electricity with a vast surface area for redox gradients to play across. A party landscape for Mn. What is important here is not the quantity of Mn but the rapidity that Mn can cycle between states.

 

One of the puzzling features of terra preta is that the microbial biomass is larger than the soil respiration rate would lead you to expect. It's like the little fellas are all on siesta. But with char easing delivery of the energy goods and making it easier to get rid of the trash electrons generated, why work hard? Life is good.

 

Despite the continued efforts of both Bartlett and Sparks, the world has largely failed to appreciate the tremendous contribution of Mn to soil. Evidence is that all soils have some charcoal in it. With soil Mn, I suspect charcoal is tops.

[Turtle]

...Charcoal is a weak conducter of electricity with a vast surface area for redox gradients to play across. A party landscape for Mn. What is important here is not the quantity of Mn but the rapidity that Mn can cycle between states.

...

 

May I cut in? While you say charcoal is a weak conductor, it is the fact that it is an additional or unique conductor in the mix that you are on about, oui/no?

 

Mmmmm....anybody experimetning with applying electric currents to soils to stimulate plant growth? :singer:

[freeztar]

Mmmmm....anybody experimetning with applying electric currents to soils to stimulate plant growth?

 

It's a bit off-topic, but an interesting thought nonetheless.

 

The research workers, K. S. Rathore and A. Goldsworthy of the college's department of pure and applied biology, applied direct current of about a millionth of an ampere to cells of tobacco plants growing in laboratory flasks. The specimens were growing as aggregations of cells called callus rather than as complete plants.

 

The influence of electric current on these cell cultures first became noticeable after about 10 days and was dramatically obvious by 22 days.

 

''The effect was dependent on the direction of the current,'' the scientists reported. ''When the callus was made negative, the growth rate was stimulated by about 70 percent, whereas current in the reverse direction was slightly inhibitory.''

ELECTRICITY MAY PLAY ROLE IN PLANT GROWTH - New York Times

[Philip Small]

May I cut in? While you say charcoal is a weak conductor, it is the fact that it is an additional or unique conductor in the mix that you are on about, oui/no?

 

Charcoal is fairly unigue as a soil resident conductor. While soil solution is an excellent conductor, especially if salty, few solid materials in soil conduct as well as charcoal. But charcoal is really a semiconductor - the current is carried along the surface only. Its a pretty good conductor if the surfaces are lined up, like in a carbon fiber hiking pole, yet not so reliable in the view of some (example).

 

....anybody experimetning with applying electric currents to soils to stimulate plant growth?

Yes. It's called electroculture and its got quite a history, sometime using some pretty impressive voltage, right up there with electric worm harvesting.:hyper:

 

Toaldo proved that plants grew better near a lightning rod.

 

Wonder if Toaldo's lightning rod was grounded in charcoal.? Benjamin Franklin promoted charcoal grounding, and it is still accepted practice, so maybe electroculture isn't so off topic as one might suspect. :singer:

[Turtle]

Charcoal is fairly unigue as a soil resident conductor. While soil solution is an excellent conductor, especially if salty, few solid materials in soil conduct as well as charcoal. But charcoal is really a semiconductor - the current is carried along the surface only. Its a pretty good conductor if the surfaces are lined up, like in a carbon fiber hiking pole, yet not so reliable in the view of some (example).

As in they say flat out there at your link that charcoal is not a conductor? :D Shall we all agree then that at least carbon is a conditional conductor? :eek2: :doh:

 

Yes. It's called electroculture and its got quite a history, sometime using some pretty impressive voltage, right up there with electric worm harvesting.:hihi:

My pop was an electrical engineer and had a little hand-cranked generator they used for something at work, but he used it at home to zap up some worms before we went fishing. :hihi: I ran across a term years ago while reading an encyclopedia for sport, electro-something-or-other, that described how fish swimming in a tank would align their swimming to a low current passed between two electrodes in the water. :eek2:

 

Toaldo proved that plants grew better near a lightning rod.

 

:singer: Wonder if Toaldo's lightning rod was grounded in charcoal.? Benjamin Franklin promoted charcoal grounding, and it is still accepted practice, so maybe electroculture isn't so off topic as one might suspect.

 

Ben Franklin is never off-topic. :D Thnx for the links & I'll be reading them all soon. :hyper: :eek:

[Essay]

“We all should fall upon our knees and sing out praise for manganese” Richmond Bartlett 1995, at the introduction of his piece on Mn in Environmental Soil Chemistry, edited by Don Sparks.

Hey! I'm ready and quivering....

 

I spent 5 hours in deep discussion with Mark and Kim, 2 fellow biochar nuts, last Saturday. Kim is a follower of Bahá'u'lláh, so no beer (dang). Like me Mark is a waste-use soil scientist, Kim is a wastewater engineer. They work together and wanted to run Kim's latest theory about biochar by me, and I admit to be quite taken by the concept.

...and I'm jealous!

 

Thanks to Bartlett, the three of us have share an appreciation for the importance of Mn in soil redox. What other cation can dance so easily between energy states like Mn++, +++, ++++? And this dance happens at higher Mv than will bring behemouth Fe++,+++ out onto the dance floor. That means Mn dances in the range that the living soil community is happiest at. Agility and grace, the three of us share this view. But Kim took us to the next level on Saturday.

...and I'm inspired by this quest newly before me.

 

If you can conceive a 3D redox topography map, with equi-millivolt contours, ...like varied breezes passing through the soil,... life is good because ...(respirations) are easier: ... and on the other hand reduced ions, a source of energy, are also handy.

...Wow....

 

For those that didn't understand that, its like a kegger with no lines at the keg or at the bathroom. Mn++ is the keg, ++++ is the toilet, and Mn+++ is there to make sure everybody is having a good time. If you are a microbe, Mn parties are tops.

...and also very helpful, if not quirkily appropriate.

 

Mark kicks in at this point. The limit to microbial respiration in soil is commonly understood to be the supply of oxygen. Oxygen resupply works by diffusion more than actual volumetric gas exchange, and responds to gradients. CO2 diffuses out, O2 diffuses in. But these movements are in response to the underlying redox demand gradients. Mn++ seems to be a bit better at calling in the Oxygen than other reduced entities, somehow making a more intense oxygen demanding hole in the redox gradient than its peers. Mark equates increased char to increased soil lung capacity.

Yes! Exactly!! [said intuitively; ...but there's so much to learn]

 

So Mn has way more moves on the dance floor than anybody can imagine. Except maybe Kim, Sparks and Bartlett.

...someday ...something to dream for

 

Charcoal is a weak conducter of electricity with a vast surface area for redox gradients to play across. A party landscape for Mn. What is important here is not the quantity of Mn but the rapidity that Mn can cycle between states.

...hmmmm.

 

One of the puzzling features of terra preta is that the microbial biomass is larger than the soil respiration rate would lead you to expect. It's like the little fellas are all on siesta. But with char easing delivery of the energy goods and making it easier to get rid of the trash electrons generated, why work hard? Life is good.

Life is good.

 

Despite the continued efforts of both Bartlett and Sparks, the world has largely failed to appreciate the tremendous contribution of Mn to soil. Evidence is that all soils have some charcoal in it. With soil Mn, I suspect charcoal is tops.

Maybe it's only noticable with natural, very rich soils; and not with disturbed, artificially stimulated and/or leached soils.

 

Thanks Phillip, just what I need--something more to occupy my time.

...don't know when I'll get to this... or back, but thanks for this fascinating insight.

===

 

And about the conductivity....

 

Differing levels of hydration (and biofilm) may account for the variability of conductance along the surface. I think pure dry char would be fairly insulating, but in soil char should be like a plinko machine--bouncing the charge along the surface.

 

Conductance (via char) needs to consider hydration, and bio-load and/or bio-film. ...imho

 

Thanks again!

~

[erich]

The Mn dance seems a perfect example of char's ability to overcome the limitations to growth of the soil food web.

 

Michael Antal at U. of H. is working with biocarbon's electrical properties in Carbon Fuel Cells;

 

http://docs.google.com/gview?a=v&attid=0.6&thid=11f23a5350753ea4&mt=application%2Fpdf

 

Also he is investigating biocarbons for an important bridging technology, the scrubbing of Hg from Coal fired power plant emissions. This would allow for economic CO2 scrubbing.

This application could speed development of pyrolysis infrastructure now, and later, after coal's eventual demise, the biocarbon production could be redirected to the soil.

 

Erich

[freeztar]

http://docs.google.com/gview?a=v&attid=0.6&thid=11f23a5350753ea4&mt=application%2Fpdf

 

The link does not work unfortunately.

[erich]

Sorry .........I forget that GooGle docs links work when I check them, but don't work for others, My computer incompetence overwhelms me.

 

Electrical_properties (iecr03).pdf

270K View Download

 

When I down load them , I can't find them , or if I can find them, I can't load them to this forum.