The mathamatics of terra preta.(sums)

[Michaelangelica]

As most of you on hypography know I am a maths retard.

But there are important "sums" to be made about TP..

 

How long does charcoal stay in soils?

 

Is it useful all this time?

 

Is the energy used in making TP (and/or charcoal) efficient?

 

How much charcoal in soil will make a significant difference to GHGs?

 

And a dozen other questions I can't think of at the moment

[Philip Small]

As most of you on hypography know I am a maths retard.

But there are important "sums" to be made about TP.

 

I know some work has been done in this area by Johannes Lehman.

 

How long does charcoal stay in soils?

From thousands to hundreds of thousands of years. How long depends on the source, and the reactivity of the soil. Desert soil - v. long. Amazonian oxisol, not so much. Johannes Lehman says char doesn't last forever in soils or it would be the dominant soil organic C constituent on very old surfaces. Very difficult number to establish through direct measurement since early degradation rate is far higher than long term rate. Like a lot of stuff relating to soil, mind bogglingly recalcitrant yet reactive on large time scale stuff. Like silica glass. Insoluble in the short term, yet soluble enough to move and form cemented pans in soil on a mere 1000s year scale. But I digress!

 

Is it useful all this time?

 

This is a yes. I'ld like to see some numbers too. The part bleeding off as the won't-last-forever portion does good, supporting biological processes. The structure on the residual portion is beneficial for the residence life of the charcoal. Further study needed.

 

My understanding is that it is more useful in its more reactive state, and charcoal with more reactive compounds is more useful. But activated charcoal is still useful for structure.

 

Is the energy used in making TP (and/or charcoal) efficient?

 

Good question, thought about it myself. Important how the question is defined. definite No (<100%) on a simple pyrolysis yield basis. and Maybe if one considers biomass management inputs. Critical that charcoal production be convenient, with a minimum of transportation and incorporation costs involved. and hopefully Yes Yes Yes (>>>100%) if one factors in higher capture of solar radiation (and C) through enhanced biomass function over the full residence time of the charcoal.

 

How much charcoal in soil will make a significant difference to GHGs?

 

Some one else has the quantified answer to this. Significant to me means a measurable affect on observed atmospheric CO2 levels/trends. Right?

 

And a dozen other questions I can't think of at the moment

 

Thanks for the delightful opportunity to respond. Apologize for not coming up with numbers.

[Essay]

Some one else has the quantified answer to this. Significant to me means a measurable affect on observed atmospheric CO2 levels/trends. Right?

Right!

Why does the media only talk about cutting emissions, when information such as this below has been around for years now!

…and these folks aren’t even talking about amending the soil with agri-char or garba-char.

 

...fyi: 1 Gigatonne Carbon Sequestered = 1 ppm drop in atmospheric CO2 levels, I think, roughly.

 

...from

Storing Carbon in Agricultural Soils:

Climatic Change, Vol.51, no.1, 2001

 

In its Second Assessment Report the IPCC, 1996 estimated that it might be possible, over the next 50 to 100 years, to sequester 40-80 Gt of C in cropland soils (Cole et al., 1996; Paustian et al., 1998; Rosenberg et al., 1998).

 

.... if this is so, agricultural soils alone could capture enough Carbon to offset any further increase in the atmospheric inventory for a period lasting between 12 and 24 years. These calculations are still crude and cannot be taken as certain, but they do suggest a potential to offset significant amounts of CO2 emissions by sequestering Carbon in the soils of lands currently in agricultural production. Of course, there is additional Carbon sequestration potential in the soils of managed forests and grasslands, but these opportunities will not be addressed here. And, ...there is also a very large potential for Carbon storage in the soils of degraded and desertified lands.

 

40-80 Gigatonnes!

:eek:

[freeztar]

I posted some char math in another thread, but I'll copy it here.

 

For every 1 gallon of gasoline, there is about 5.5 lbs. of carbon.

So every time I fill up (~15 gallon tank), I should be sequestering about 82.5 lbs. of carbon! :eek: :lol:

 

Numbers from here: How can 6 pounds of gasoline create 19 pounds of Carbon dioxide?

[Michaelangelica]

How much carbon is in each kilo of charcoal?

Does it matter what the charcoal is made of (hardwood, softwood, paper, poo)

how long does SOM (organic carbon) from fertilisers green crops etc stay in the soil.

 

How come multinationals are buying up farm land all over Oz at the moment? Do they know something we don't?

or are looking to make money sequestering carbon when a carbon trading system comes in?

(Next year, after the Democrats are in the White House? or the year after?)

 

Good question, thought about it myself. Important how the question is defined. definite No (<100%) on a simple pyrolysis yield basis. and Maybe if one considers biomass management inputs. Critical that charcoal production be convenient, with a minimum of transportation and incorporation costs involved. and hopefully Yes Yes Yes (>>>100%) if one factors in higher capture of solar radiation (and C) through enhanced biomass function over the full residence time of the charcoal

.

Pyrolosis at least harvests the energy in the biomass. BUt you have to build a pyrolosis plant and keep feeding it with raw biomas and doing something with the charcoal output.

Collecting and delivering and feeding bio-mass to the plant.

Transporting, distributing it to farms, markets nurseries, fertiliser companies spreading charcoal on the soil etc.

Perhaps if you use your own energy doing this?

What about down-time, repairs supply hiccups, maintenance etc?

[Michaelangelica]

A relevant Blog

The carbon numbers II

The carbon numbers

Folke Günther´s blog

If you can't stand numbers, stop reading here.

I batted on to the second paragraph, then gave up.

 

Kind, monosylabic, English explanations will be accepted gratefully:)

[Essay]

A relevant Blog

 

Folke Günther´s blog

 

I batted on to the second paragraph, then gave up.

 

Kind, monosylabic, English explanations will be accepted gratefully:)

 

Okay, I think I follow what this guy is thinking. He has made some wild assumptions and missed some important points; as well as mixed apples and oranges to reach his conclusion.

 

But his answer sounds possibly reasonable (except for the 300 years part):

“That amount would add about 95 kg char per hectare agricultural land globally. 38 bags of barbecue char. Not very much. But with the above efforts, 2 Gt p.a., it would take more than three hundred years to reach that point.” [p.a.(?); …per annum?]

 

Most importantly, I think, is that he is equating the “carbon sequestered” with the actual charcoal; thus a pound of charcoal mixed into the soil means a pound of carbon buried.

 

Not!

I think he misses the concept that the charcoal provides a habitat for microbes; the bodies of which constitute the sequestered carbon.

The value of Charcoal is not as an end product of already sequestered carbon, but as a multiplier for soil sequestration of carbon.

Dry charcoal absorbs over 10% of its weight in water just from sitting around in the air (just a fun fact).

In moist soil, I think charcoal holds 4 to 8 times its weight in microbes (50% of which would be carbon).

i.e. 1 lb. charcoal =3 lb. microbes =1.5 lb. carbon =4.5 lb. CO2 sequestered.

 

…and then there’s the increased microbial activity in the other 75% of the soil leading to …much more sequestration (Gt's/year globally).

[erich]

Great points Essay;

 

Add to this , the recalsatrent Glomalin production, increased CO2 scrubbing via plants increased growth and not least, the N2O & CH4 soil emission reductions .................so GHG equivalents must be added to the tally of carbon C sequestered.

 

 

 

 

Here is a strait forward conversion of the impact of building soil organic material (SOM) on ppm of GHGs using just marginal land.

 

Restoring soil carbon can reverse global warming, desertification and biodiversity loss

 

 

Tony Lovell of Soil Carbon P/L in Australia estimates that by actively supporting regrowth of vegetation in damaged ecosystems, billions of tons of carbon dioxide can be sequestered from the atmosphere.

 

 

"Determining how much carbon dioxide (CO2) can physically be consumed from the atmosphere?

 

 

 

As the planet has 7.8 billion tonnes of carbon dioxide in circulation for each 1 ppm of atmospheric CO2, and there are 5 billion hectares of inappropriately managed or unmanaged, desertifying savannahs on the Earth (which on empirical evidence we contend to be the case), the question that should sensibly be asked is: How much carbon dioxide would be absorbed if policies were put in place (in Australia and elsewhere) that caused the focus of on-ground management to be deliberately directed towards the widespread consumption of cyclical GHGs within the currently under-utilised savannah lands?

 

Consumption of CO2 per hectare

One hectare is 10,000 sq. metres. If a hectare of soil 33.5 cm deep, with a bulk density of 1.4 tonnes per cubic metre is considered, there is a soil mass per hectare of about 4,700 tonnes.

If appropriate management practices were adopted and these practices achieved and sustained a 1% increase in soil organic matter (SOM)6, then 47 tonnes of SOM per hectare will be added to organic matter stocks held below the soil surface

This 47 tonnes of SOM will contain approximately 27 tonnes of Soil Carbon (ie 47 tonnes at 58% Carbon) per hectare

In the absence of other inputs this Carbon may only be derived from the atmosphere via the natural function known as the photo-synthetic process. To place approximately 27 tonnes of Soil Carbon per hectare into the soil, approximately 100 tonnes of carbon dioxide must be consumed out of the atmosphere by photosynthesis

A 1% change in soil organic matter across 5 billion hectares will sequester 500 billion tonnes of physical CO2

Converting global Soil Carbon capacity to ppm of atmospheric GHGs

Every 1% increase in retained SOM within the topmost 33.5 cm of the soil must capture and hold approximately 100 tonnes per hectare of atmospheric carbon dioxide (the variability in the equation being due only to the soil bulk density). We submit that under determined, appropriate management, that this is readily achievable within a very few years

For each 1% increase in SOM achieved on the 5 billion hectares there will be removed 64 ppm of carbon dioxide from atmospheric circulation (500,000,000,000 tonnes CO2 / 7,800,000,000 tonnes per ppm = 64 ppm).

Soil Organic Matter is the plant material released into the soil during the natural phases of plant growth. It includes root material sloughed off below the soil surface and plant litter carried into the soil by microbes, insects and rainfall

Soil Carbon is the elemental carbon contained within Soil Organic Matter (SOM).

One tonne of CO2 contains 12/44 units of carbon (ie 0.27 tonnes of carbon per tonne of CO2.). Therefore 27 tonnes of carbon sequesters 27/0.27 = 100 tonnes CO2 (rounded). NB Carbon atomic weight 12, oxygen atomic weight 16 ie CO2 = 12+(16+16) = 44

The global opportunity and numbers

 

 

 

It appears that the pre-industrial level of atmospheric carbon dioxide was 280ppm, and that globally we are now at 455ppm, and heading towards 550ppm. To get from 550ppm back to 280ppm, 270ppm must be removed. Globally, a 4.2% increase in SOM would potentially reverse the expected situation. In any case, any form of determined management will substantially reduce the now crippling legacy loadings in the atmosphere.

 

Erich

[Michaelangelica]

OK Essay

Could you please attack the above article with your wonderful maths deciphering technology and give it to me in words of three syllables, preferably less?

[Essay]

Thanks Erich!

This is a great, comprehensive set of conversions, relating the carbon in the soil to the atmospheric CO2.

...and more accurate than my guestimated figures; thanks! Where'd you get that 7.8Gt/ppmCO2 figure? I was within an order of magnitude, at least (...I was off by 2x just because I forgot how high the current CO2 levels are).

 

Also, I sure enjoyed googling Glomalin (my something new for the day!). See:

SpringerLink - Journal Article

Glomalin--Soil's Superglue

ARS "soil scientist Sara E. Wright has discovered a unique fungal protein that may be the primary glue that holds soils together."

...and see wiki....

 

...other memorable numbers from above (#8):

"Every 1% increase in retained SOM within the topmost 33.5 cm of the soil must capture and hold approximately 100 tonnes per hectare of atmospheric carbon dioxide (the variability in the equation being due only to the soil bulk density). We submit that under determined, appropriate management, that this is readily achievable within a very few years."

 

I've seen other research on SOM. If their assumptions are supportable, then these numbers look right and are consistent with the stuff I've seen. It took me about 25 minutes of pondering the conversions and various aspects presented above (#8) to easily see the conclusion: Are there particular conversions or jumps from one "carbon state" to another that seem unclear (or cut 'n pasted)?

[Turtle]

...

Pyrolosis at least harvests the energy in the biomass. BUt you have to build a pyrolosis plant and keep feeding it with raw biomas and doing something with the charcoal output.

Collecting and delivering and feeding bio-mass to the plant.

Transporting, distributing it to farms, markets nurseries, fertiliser companies spreading charcoal on the soil etc.

Perhaps if you use your own energy doing this?

What about down-time, repairs supply hiccups, maintenance etc?

 

I propose traveling charcoal retorts that drive (on wood gas no less) to whatever site has wastewood, charcoalizes it, leaves it there for burial, and then moves on to the next job. i saw a piece on TV where in Europe a guy was doing this with a still and turning farmers' fruit into liquor.

 

I think it is a good entrepreneurial opportunity as well, both for folks making the pyrolyzers as well as those using them. Win, win, win! ? ...:)

[Michaelangelica]

I propose traveling charcoal retorts that drive (on wood gas no less) to whatever site has wastewood, charcoalizes it, leaves it there for burial, and then moves on to the next job. i saw a piece on TV where in Europe a guy was doing this with a still and turning farmers' fruit into liquor.

I want the first one you make

 

Some sums from

Restoring soil carbon can reverse global warming, desertification and biodiversity loss

Consumption of CO2 per hectare

 

* One hectare is 10,000 sq. metres. If a hectare of soil 33.5 cm deep, with a bulk density of 1.4 tonnes per cubic metre is considered, there is a soil mass per hectare of about 4,700 tonnes.

* If appropriate management practices were adopted and these practices achieved and sustained a 1% increase in soil organic matter (SOM)6, then 47 tonnes of SOM per hectare will be added to organic matter stocks held below the soil surface

* This 47 tonnes of SOM will contain approximately 27 tonnes of Soil Carbon (ie 47 tonnes at 58% Carbon) per hectare

* In the absence of other inputs this Carbon may only be derived from the atmosphere via the natural function known as the photo-synthetic process. To place approximately 27 tonnes of Soil Carbon per hectare into the soil, approximately 100 tonnes of carbon dioxide must be consumed out of the atmosphere by photosynthesis

* A 1% change in soil organic matter across 5 billion hectares will sequester 500 billion tonnes of physical CO2

 

Converting global Soil Carbon capacity to ppm of atmospheric GHGs

 

1. Every 1% increase in retained SOM within the topmost 33.5 cm of the soil must capture and hold approximately 100 tonnes per hectare of atmospheric carbon dioxide (the variability in the equation being due only to the soil bulk density). We submit that under determined, appropriate management, that this is readily achievable within a very few years

2. For each 1% increase in SOM achieved on the 5 billion hectares there will be removed 64 ppm of carbon dioxide from atmospheric circulation (500,000,000,000 tonnes CO2 / 7,800,000,000 tonnes per ppm = 64 ppm).

3. Soil Organic Matter is the plant material released into the soil during the natural phases of plant growth. It includes root material sloughed off below the soil surface and plant litter carried into the soil by microbes, insects and rainfall

4. Soil Carbon is the elemental carbon contained within Soil Organic Matter (SOM).

5. One tonne of CO2 contains 12/44 units of carbon (ie 0.27 tonnes of carbon per tonne of CO2.). Therefore 27 tonnes of carbon sequesters 27/0.27 = 100 tonnes CO2 (rounded). NB Carbon atomic weight 12, oxygen atomic weight 16 ie CO2 = 12+(16+16) = 44

 

 

TOP: This cattle ranch in Sonora, Mexico, is typical of hundreds of millions of hectares of grazing land in arid and seasonally dry areas worldwide. BOTTOM: This is the neighboring ranch, La Inmaculada. The ranch is in the same area; has the same rainfall, same soils, and same plant species. The pictures were taken on the same day and La Inmaculada actually has more cattle than the drier ranch. The only difference between the two is management

The global opportunity and numbers

It appears that the pre-industrial level of atmospheric carbon dioxide was 280ppm, and that globally we are now at 455ppm, and heading towards 550ppm. To get from 550ppm back to 280ppm, 270ppm must be removed.

Globally, a 4.2% increase in SOM would potentially reverse the expected situation.

In any case, any form of determined management will substantially reduce the now crippling legacy loadings in the atmosphere.

 

Lehmann et al.

(2006) estimated that a total of 9.5 billion tons of

carbon could potentially be stored in soils by the year

2100 using a wide variety of biochar application

programs. Once equipped with a better understanding

of this potential synergism and the mechanisms that

drive it, we could utilize biochar/mycorrhizae interactions

for sequestration of carbon in soils to

contribute to climate change mitigation. This interaction

could also be harnessed for the restoration of

disturbed ecosystems, the reclamation of sites contaminated

by industrial pollution and mine wastes,

increasing fertilizer use efficiencies (with all associated

economic and environmental benefits) and the

development of methods for attaining increased crop

yields from sustainable agricultural activities.

http://www.css.cornell.edu/faculty/lehmann/publ/PlantSoil%20300,%209-20,%202007,%20Warnock.pdf

The uncertainties and areas requiring further research are outlined below:

• A maximum of 1 PgCyr-1 biochar might be produced from agricultural residues (if all current global agricultural residues were converted to biochar).

In practice, this figure will be constrained by cost, suitability of different residues, requirements to incorporate residues into the soil, and other competing demands.

How much biochar might be produced from agricultural residues once such

constraints have been taken into account is a matter for further research.

 

• Estimates of how much biomass might be produced by dedicated cropping

remains a highly debated question. At the low end, figures from Sims et al (2006) suggest that between 0.06 - 0.7 PgC yr-1 might be realistically achievable by 2025.

 

At the high end, figures from Smeets et al (2007) suggest that up to

46 PgC yr-1 might be achievable if we were to transform the planet into a large factory farm. More detailed studies at the local level will be required to ascertain the true potential for dedicated production of biomass.

http://orgprints.org/13268/01/Biochar_as_a_soil_amendment_-_a_review.pdf

 

??????? It is all Gre3k to me

[Folke Günther]

Carbon dioxide has the molecular weight of 44, carbon is 12,. Roughly, you can say that gasoline is CH2, i.e. mw of 14. Thus, burning 1 kg of gasoline emits 44/14=3.14 kg of CO2

FG

[Folke Günther]

 

It appears that the pre-industrial level of atmospheric carbon dioxide was 280ppm, and that globally we are now at 455ppm, and heading towards 550ppm. To get from 550ppm back to 280ppm, 270ppm must be removed. Globally, a 4.2% increase in SOM would potentially reverse the expected situation. In any case, any form of determined management will substantially reduce the now crippling legacy loadings in the atmosphere.

 

Erich

 

I agree with you that an increase in SOM would sequester a lagre amount of atmospheric carbon. However, since the SOM content of a soil is a steady state (degrading with an estimated half-tome of at best 30-40 years, must constantly be replenished), an increased SOM content must be associated with a globally accomplished radical change in agricultural practice, especially of the degraded soils you are talking about. This is not a small task. However, I certainly wish it would be accomplished.

 

Simultaneously, of course, you could encourage the incorporation of charcoal into the soils, as the char has a half-time of 6000-7000 years depending, this would be a much more stable type of sequestration, not needing a simultaneous change in peoples basic behavour, althogh it may lead to that too.

 

Assuming a global agricultural land of 5E8 (500 million, FAO) hectares, an annual addition of 4 tonnes of charcoal per hectare would mean a global sequestration of 2 Gt carbon. The mentioned increase in biomass is significant, but ephemeral. It shold be regarded as a bonus.

 

However, since the current CO2-level is about 385 ppm and increasing 2-3 ppm annually (8 Gt C), the above reduction of 2 Gt C is far fom enough, even to change the increase to a reduction. Since it is in the same dimension as the global forest industry (FAO), 5-10% of the global gross biomass production, it is hard to assume a larger charring rate.

 

Therefore, to make a change, the charring sequestration must be combined with a simultaneous reduction of emissions, with, say, 90% i.e. from the current 8 Gt C to 1 Gt.

That would imply a net sequstration rate 1 Gt annually (2Gt down,1Gt up). Carrying on with that policy for 70 years would reduce the current, very risky (see 'tipping points, Tim Lenton') level of 385 ppm to a level of 350 ppm, which is considered reasonably safe by Jim Hansen & al.

[Folke Günther]

I propose traveling charcoal retorts that drive (on wood gas no less) to whatever site has wastewood, charcoalizes it, leaves it there for burial, and then moves on to the next job.

 

I think it is a good entrepreneurial opportunity as well, both for folks making the pyrolyzers as well as those using them. Win, win, win! ? ...:unsure:

 

We, a group of people at Uppsala University under the leadership of ***.prof Lars Hylander are working on precisely that. We have got grants from the Swedish MISTRA to make a prototype.

[Michaelangelica]

We, a group of people at Uppsala University under the leadership of ***.prof Lars Hylander are working on precisely that. We have got grants from the Swedish MISTRA to make a prototype.

 

 

:xparty:

Hooray!!

:unsure:

 

Let us know the results please.

[Essay]

I'm hoping to get into the numbers (and chemistry) a bit more, later; but I just ran across this:

neat info....

ScienceDirect - Geoderma : Stabilization of organic carbon in chemically separated pools in no-till and meadow soils in Northern Appalachia

Stabilization of organic carbon in chemically separated pools in no-till and meadow soils in Northern Appalachia

doi:10.1016/j.geoderma.2006.08.010

Geoderma

Volume 137, Issues 1-2, 31 December 2006, Pages 205-211

 

Abstract

Land use and soil management affects soil organic carbon (SOC) pools, chemical composition of stabilized SOC fractions, and the depth distribution. No-till production of corn (Zea mays L.) is a recommended management practice that reduces soil losses and increases SOC concentration, but the scientific knowledge of the mechanisms of C sequestration and protection is scanty. Therefore, the objective of this research was to compare the SOC pool, C pool in fine roots, and chemically separated C fractions with depth in three pedons from the same soil series: (i) meadow converted from no-till corn in 1988 (Meadow), (ii) continuous no-till corn since 1970 (NT); and (iii) continuous no-till corn with beef cattle manure since 1964 (NTm) at the North Appalachian Experimental Watershed near Coshocton, Ohio. The SOC pool (Mg ha− 1) from 0–69 cm was the highest in NTm (76.2) and progressively smaller in NT (49.3) and Meadow (46.6) pedons. The SOC concentrations and pool sharply decreased with depth, but were always more in NTm than NT soil. Fine root C pool (Mg ha− 1) was much larger in the pedon with perennial vegetation (Meadow, 1.28) than in those under corn (NT, 0.21; NTm, 0.09). The pool of chemically separated C fractions and their depth distribution varied depending on the separation technique. The amounts of C preferentially bound to soil minerals in 0–69 cm depth were comparable among pedons, as indicated by treatment with HF to release mineral-bound SOC. The NTm pedon had a larger pool of recalcitrant non-hydrolyzable C (58.4 Mg ha− 1), as indicated by HCl treatment. The Meadow pedon stored the smallest pool (3.4 Mg ha− 1) of oxidisable C, as was indicated by treatment with disodium peroxodisulfate (Na2S2O8). The relationship between chemically separated C fractions and turnover time of SOC at depth, however, warrants further studies. Nevertheless, the results indicate that no-till corn with added manure has a high potential for C sequestration by increasing the size of the SOC pool in the subsurface horizons.

 

Keywords: Carbon sequestration; Land-use and soil management; Soil C depth distribution; Chemically separated C fractions

 

Article Outline

1. Introduction

2. Material and methods

2.1. Sites and soils

2.2. Soil and fine root sampling

2.3. Chemical separation

2.4. Carbon and nitrogen determinations

2.5. Statistical analysis

3. Results and discussion

3.1. Carbon and nitrogen in pedons and fine roots

3.2. Chemically separated soil organic carbon fractions

4. Conclusions

References

 

"...but the scientific knowledge of the mechanisms of C sequestration and protection is scanty."

...in December 2006!!

 

These guys would undertand more, and know what to study, if they'd read some of the threads here at Hypography.

 

~ :hyper:

 

p.s. (Mg ha-1) is Mega grams per hectare ...or (conveniently) Tons per hectare.

...or Tons per 2.5 acres.