Long Arctic Indian Summer

For the moment, I want my readers to totally put all you have been brought to believe about the human impact on global warming completely out of your mind and travel with me on a thought experiment. Let us imagine that humanity is missing. What does the data tell us then?

500 years ago, we had a climate down shift called the Little Ice Age that ended the long lasting Medieval Warm P9eriod that had held sway for over two hundred years. Since then, the climate of the Northern Hemisphere has very slowly warmed back to the previous climate regime. My analysis of the impact of a modest positive warming influence has shown us that this can explain all the current evidence, and that we are about to have a full return to a warmer Northern climate.

The planet Earth has two natural heat sinks at the poles that operate over a yearly cycle due to the tilt of the poles. We like to ignore the Antarctic, but it is the dominant cooling engine, simply because it has a small continent able to collect an ice cap and a huge uninterrupted circumpolar ocean current that shields it from warm water intrusions. This is one mean cooling machine.

The arctic is the complete reverse of this. We have a land ringed deep ocean for most of the ice cap forming 15 degree polar area. There is only one break in this ring and it is fed by a large bounded north equatorial ocean that must pump warm water into the Arctic. Had this been engineered deliberately, I fail to see how it could have been improved on. We may discover, once all the crustal positions are properly worked out, that this is a rarity in global history.

Remember that the ocean rose 300 feet around 12,000 years ago. Prior to that the continental shelf was shaped by ocean currents and land erosion for millions of years. This unusually stable process formed long broad and very shallow coastal plains. This could never have happened if the sea level was shifting radically back and forth.

The indications are though, that left to its own devices, that natural climate balance for the Arctic is a little warmer than what we are experiencing now. The medieval Warm Period lasted a comfortable 200 years if not a great deal longer. The Bronze Age optimum lasted for thousands of years. In between, it is fair to say that it was more often warm than cold.

In fairness, all our information is drawn from proxies that are very prone to local variation. This is particularly a factor with shifting human settlement and disturbance. The only trustworthy information comes from pollen data from the more northerly transition zones and even that will actually lag the changes by a couple of centuries. We are experiencing that today.

The fact remains that a four hundred year climate cycle may simply defy resolution. The only certainty is that the antiquity of human habitation is universal.

The question then, is not why is it not warmer, but what causes it to chill out in the first place. Left to itself, the Arctic climate will moderate with total sea ice destruction every year. A moderate Arctic will mean less extreme winters throughout the Northern Hemisphere and improved growing conditions everywhere.

The good news, is that once the North is at its natural stability point around the complete elimination of summer sea ice, it appears to stay warm for a long time. There is likely enough freezing going on to prevent any cumulative heat retention.

The bad news is that sooner or later, the party is over.

My best theory, is that a surplus of Antarctic cold water is forced into the Benguela Current, strengthening it substantially and for decades lowering the temperature of the Gulf stream sufficient to allow ice accumulation in the Arctic. We are talking of a very small switch in energy transport when compared to the total regime. We do not even know if the atmosphere is a significant factor at this point.

All we really have is plenty of misunderstood and conflicting data of which we need a lot more.

When we see the world from this perspective, the good news is that it is getting warmer. The bad news is that this will end. And what did humanity have to do with any of this?

Sean Barry on the Antiquity of Terra Preta.

Sean Barry gives us this post on the antiquity of Terra preta in Brazil and its living history from the terra preta group.

The people who live in Brazil, the families who have farmed land with Terra Preta soil on it for 500+ years generation after generation, will attest to it, though. Some grow world record productive papaya and mango groves. They do not buy or use industrial fertilizers. They, like the generations of ancestors before them, put back into the soil, those parts of the harvest, which are not eaten. They value the land for its fertility. They guard it closely. There are laws that prohibit "mining" and "selling" TP soil. It is truly valuable land for them because of it productivity. They are not corporate entities, with huge capital assets, and armies of PR people, making things sound so good, that you can hardly believe it. They are truck farmers, peasant farmers. They do what they do and it works for them. That is all the evidence they need.

I grant you that most of these people are not scientists and they could not tell you why the TP soil they live on and grow crops in can do what it does. They just know from experience over their lifetime and the lifetimes of the generations before them that TP soil provides them a bounty for the growth of crops. Some have documented ownership and cultivation for 500+

years.

I, like many, including the people who use TP soil, do not know what the"recipe" is. From what I have read, the cultivation practice that makes most sense to me, for maintaining the soil fertility under continuous cultivation, is that they "return" to the soil all of the plant wastes from the harvest. They compost the food wastes back into the soil, also. My belief is that the charcoal carbon in the soil pays large dividends for their deposits. They give back the plant nutrients that they do not use and the soil/micro-organism ecology in the soil gives it to the plants in their next crop.

I do not know that anyone has come up with a definitive, scientifically arrived at understanding as to how it all works. It is from generations of experience that they "know" that it works. They might not know "why" or "how" it works, but they will protect it as an asset, nonetheless. They do not abandon it because they do not know how it works.

So, I guess I am saying it's anecdotal. This is very like what Dr.A.D. Karve says. He has a hypothesis about why what he is doing works.

He is trying to develop theories as to "why" and "how". He has many village farmers that rely on his methods, practice his methods, and believe that "it works", because it does for them. Maybe, someday, he will be able to show (the damned nit-picking (I'm kidding)) scientists why.

I would say, though (and you have pointed this out yourself recently), there are two camps in here about Terra Preta; 1) those that want it for its enhanced agricultural benefit, and 2) those that want this for carbon sequestration.

I think 1) is possible and hard to know why. I think 2) is obvious and absolutely clear by virtue of the mere existence of 2500+ year old charcoal carbon in the Amazon rainforest. It was put there by people long ago. It is still there. It has been sequestered for 2500+ years ... No doubt about it (not in my mind). This is like 15 times the duration of our entire Industrial Revolution and 15 times the amount of time that it has taken humankind to pump all the 300 million year old fossil fuel carbon into the atmosphere! Clearly, we can sequester carbon by putting charcoal carbon into the soil, don't you think?

Regards,

SKB

Liberating human labor

In yesterday's post I presented a world in which our newly discovered mastery of the art of carbon sequestration allows us to also progressively reclaim the global deserts and wastelands and essentially build out the Garden of Eden as our human homeland. This is the great dream of the romantics.

There is only one remaining brick to put in place. It is the keystone of access to willing human labor. Agriculture needs the use of occasional hand labor and in modern industrial agriculture that has disappeared or minimized unnecessarily. And quite bluntly, illegal immigrants will not be available for much longer. At best we have a generation or two. None of them would be here if a similar job existed at home. And were are all the European immigrants to day?

Yet I grew up on a farm were in my teens there were tasks that I could do to help the farm. A lot of it was incredibly boring, but it provided exercise and consumed surplus time and energy. If an economic model had existed that gave me measurable access to some form of purchasing power, I would have been willing and enthusiastic. I have learned that this is something that every teenager wants and needs.

And I can now say that as an individual reaches an age in which the demands of the work place diminish, that he too would welcome making such a contribution. I recall my father going out every day to tend his garden, simply for the exercise and the sense of well being. How many elders out there would enjoy putting in a four hour stint of hand work in gardens and the like.

Work of this nature becomes a social system rather than solely an economic system.

I contend that we now have the tools for making this to happen properly in hand. The advent of the concrete slab condo tower creates a small footprint system that can be integrated into the agricultural system readily.

For example, if we designate a square mile of farmland as an agro-community, we can use two or three acres for building towers to hold a couple of thousand residents. The soil can readily be redistributed, and services implemented. The title would be strata title with an additional share in the capital of the farm and access to the resources.

All of a sudden it becomes possible to manage the agricultural component on the basis of both individual initiative and shared initiatives. We actually recreate the traditional village environment in a modern setting and we can make it a better social system than ever arose naturally.

That is the way ten billion people can live on earth and prosper.

New Age Global Agriculture

When I started this blog, I had one very important arrow in my quiver. That was the knowledge that it was becoming feasible to produce a small stand alone solar atmospheric water harvesting device capable of daily producing a 100 liters of water per day.

This would be sufficient to support a growing tree in any arid desert were the humidity was high enough. Of course that means all deserts since one would start at the humid rim and slowly advance into the desert effectively bringing the natural humidity with you. This terra forming of the desert would naturally support a cropland fraction and an extensive animal husbandry among the trees and orchards.

We can easily globally double the available land under agricultural management in this way and sequester a huge amount of carbon.

I then extended this approach to current agricultural practice and developed an economic model for bringing agricultural waste land under managed forest practice were atmospheric water harvesting is less important.

An underlying assumption for both approaches was that current practice would not be modified very quickly and that no good solutions for soil improvement were at hand. But we could live with that since we had done so for thousands of years. I was still very uncomfortable though that we were mining the soil for nutrients and that replacement strategies consisted of mining and producing minerals often in a non sustainable manner.

This also meant that desert lands would require long periods of time to reconstitute soils. Trees would be fine because they reach deep into the earth to find nutrients, but the surface would suffer. Again time and careful effort would overcome all this. A thousand years of effort and every hillside and former dry land could be fully timbered and vegetated with modest final water inputs. This is a fine dream and project for humanity to embark upon.

And then I was introduced to Terra preta. This was work that conformed to and confirmed a previous effort that I had put into Zeolites in which a great deal of field work has been done by researchers. I understood immediately the importance to the globe of this discovery. The problem was to figure out how to produce the soil.

This I was able to tentatively solve through the use of an infield carefully constructed corn stover stack kiln that would produce a ton of biochar per acre.

All of a sudden we have a method of swiftly building out soils anywhere in the world.

Let us engage in a thought experiment. Keep in mind that we cannot quite do this yet. We take a square mile of desert fairly close to adjacent agricultural land. We isolate the low lying areas (perhaps a 100 acres) as potential crop land toward which surplus water will flow. We plant tree cover with solar water harvesting devices outside these areas.

As the trees grow out, the soils begin to build up some water retention and this supports an increase in ground water finding its way into the designated crop lands. As soon as feasible we start the first corn crop. Each crop puts a ton of biochar back into the soil and several years of this attention we should have well developed soil. At that point, we continue to produce biochar which is then transported into the woodlands an integrated into those soils accelerating their maturing. If we are already running cattle, we will witness a rapid improvement in available fodder.

If the objective is to create mature soils throughout and to achieve maximum yield throughout, then at the end of fifty years every acre should have several tons of carbon in the form of char and additional living carbon totaling another twenty tons or so. This can all be done in the lifetime of an individual owner.

This is a far cry from the current situation in which we are running fast just to stay even.

Global Corn Culture

I have become progressively more comfortable with the production of biochar using some form of corn stack. As each new issue is addressed, the genius of the Amazonian Indians becomes more apparent and appreciated. The difficulties of providing a mechanical assist also seem readily surmountable.

I am far less comfortable using various oven designs and pressure chamber converters to achieve largely the same end with a marginally better yield, yet with an order of magnitude jump in handling costs. My best design concept of the two lung incinerator, while maximizing yield will also demand to be fed year round in order to be possibly economic. And that also applies to pyrolyzers and the like. This means that a minimal 1000 ton per day operation will require at least a 1000 square miles of supply area and all the trucking that goes with that. Tom Miles is certainly not wrong on this.

My single farm modified container will only operate for around a month during the appropriate season and very little in between. It must be cheap and I do not know if that will actually be achievable. The second lung and its controls could turn out to be commercially crippling, principally because an expensive high grade fire brick must be used.

I keep coming back to the simplicity of carefully field stacking corn stover to produce the biochar. We know that this will yield a mix of char and soil representing a twenty percent yield with only a small increase in handling effort. With equipment we can actually build windrows, even driving on top of them to compact the stack properly before covering with dirt and igniting.

The only drawback, which seems to make some folks hysterical is that we lose the volatiles into the atmosphere. Most of this is CO2, while the rest is in the form of a wide range of organic molecules, similar to that produced from a forest fire or slash and burn agriculture. The heavy end falls back onto the soil, while the lights are typically degraded sooner or later in the upper atmosphere. Methane and probably ethane even end up in the troposphere above our atmospheric circulation system.

Unlike forest fires and their like, this process sequesters a great deal of carbon. Which returns us to the whole point of the exercise. Adding charcoal to the soil appears to vastly improve and stabilize the majority of soils. Right now we do not know were it does not work.

This is because charcoal is a strong acid, yet is insoluble. That allows it to grab nutrients year after year and recycle them back to the plants. A minimum amount of maintenance ensures maximal fertility anywhere once the initial effort is made to create the soils.

I suspect that, while terra preta soil manufacturing was the dominant culture in the Amazon, that there is no reason for it to be a continuously applied system in most soils. After all we know that a season's corn production will generate around a ton of charcoal per acre which is actually a lot already. Fifty tons per acre is likely the maximum that you would ever want in the soil.

Thus doing corn with terra preta in normal field rotation is very plausible everywhere. Europe and North America are the most glaring examples that I am familiar with, and I am very sure that this will be another green revolution in both India and China. Fifty years of effort and all crop lands will be well on the way to be terra preta soils and their permanent fertility will be secure. I can tell you that from a farmers perspective, that this is almost too good to be true. Fertility has been foremost on their thoughts forever.

Even more exciting, this looks like a method to restore fertility in despoiled lands were past practice has destroyed fertility and with it the soil's water holding ability. Mesopotamia particularly leaps to mind. Why should the Garden of Eden be covered with blowing salt ladened dust and treeless hillsides.

I am hopeful that the simple restoration of irrigation, can allow a corn crop to be nursed into full growth. Remember that the root practically lies on the surface, so working the top three inches of soil with biochar should quickly restore these soils. The important question is whether the charcoal will progressively sequester the salts and as a result to gently sweeten the soils. If it does not, there are still practical options because of the soil improvement brought on. They will simply take longer to have effect.

Methane and pottery

In the end concerns over methane production are irrelevant. We have doubled production in the last century and it is all gone. The reason is ultimately very simple. It migrates to the upper atmosphere and is consumed. This is something that is not an option for CO2.

Does the sharp increase in methane reaching the troposphere have any effect whatsoever? The quick answer is nothing that is obvious. It is a little like measuring the effect of the Mississippi on the Atlantic. The practical answer as always is to make as much as you desire and see were it takes you. My guess is nowhere.

That means that methane production concerns regarding all forms of biowaste combustion are misplaced. My real concern would be for well intentioned government regulation been actively imposed forcing a larger industrial price for the use of the method.

The second issue that has attracted comment is the association of pottery shards in the terra preta soils. I naturally postulated that this was partly to do with the disposal of kitchen waste in the corn stover stack kilns as we described in earlier postings in July. I also realized that a large bowl would have to be used to transport hot coals to the top of the stack and perhaps dumped into a prepared chimney.

These bowls are as primitive as you can get and very prone to heat breakage, so the presence of pottery is no surprise. My discomfort came from the fact that they would have normally taken broken pottery away with them for disposal elsewhere. So why not?

The answer came to me this morning. It is natural to take the bowl of coals to the top of the stack and to dump them there in the center and to let the coals slowly burn out a chimney. The problem is that you have to cover these coals with dirt to prevent flame out. The best way to do that is to upend the bowl on top of the coals and to throw dirt on top of that. Otherwise, the coals will end up been smothered by the dirt. The bowl would then migrate slowly to the bottom of the stack. In the process the high heat would cause this low quality pottery to breakup into very small pieces not worth recovering or causing any difficulty for cultivation.

Actually a pretty nifty solution to the problem of controlling the ignition coal mass. While this was progressing, the farmer would stand by to throw dirt on any emerging openings in the stack to prevent a flare up.

Methane fears

We have had a lot of enthusiasm for methane lately for its potential as a so called greenhouse gas.

http://www.physicalgeography.net/fundamentals/7a.html

Methane is a very strong greenhouse gas. Since 1750, methane concentrations in the atmosphere have increased by more than 150%. The primary sources for the additional methane added to the atmosphere (in order of importance) are: rice cultivation; domestic grazing animals; termites; landfills; coal mining; and, oil and gas extraction. Anaerobic conditions associated with rice paddy flooding results in the formation of methane gas. However, an accurate estimate of how much methane is being produced from rice paddies has been difficult to ascertain. More than 60% of all rice paddies are found in India and China where scientific data concerning emission rates are unavailable. Nevertheless, scientists believe that the contribution of rice paddies is large because this form of crop production has more than doubled since 1950. Grazing animals release methane to the environment as a result of herbaceous digestion. Some researchers believe the addition of methane from this source has more than quadrupled over the last century. Termites also release methane through similar processes. Land-use change in the tropics, due to deforestation, ranching, and farming, may be causing termite numbers to expand. If this assumption is correct, the contribution from these insects may be important. Methane is also released from landfills, coal mines, and gas and oil drilling. Landfills produce methane as organic wastes decompose over time. Coal, oil, and natural gas deposits release methane to the atmosphere when these deposits are excavated or drilled.

Table 7a-1: Average composition of the atmosphere up to an altitude of 25 km.

Gas Name	Chemical Formula	Percent Volume
Nitrogen	N2	78.08%
Oxygen	O2	20.95%
*Water	H2O	0 to 4%
Argon	Ar	0.93%
*Carbon Dioxide	CO2	0.0360%
Neon	Ne	0.0018%
Helium	He	0.0005%
*Methane	CH4	0.00017%
Hydrogen	H2	0.00005%
*Nitrous Oxide	N2O	0.00003%
*Ozone	O3	0.000004%

I want you to observe that everything in this list is at its lowest oxygenation level with the sole exception of methane. Also observe that CO2 is 200 times more available. This is true because methane is almost as good a rocket fuel as hydrogen. We usually call it natural gas when we use it to heat our homes. In fact, it is the one gas that has all the cards stacked against its survival.

Even with all the rice paddies, termites and cows hard at work producing methane and all the plants on earth consuming CO2 and nothing consuming methane except oxidizers, CO2 content exceeds CH4 content by a factor of 200.

This entry also makes the claim that since 1750, methane content has increased 150%. Who was measuring? Most certainly this has to be an educated guess linking human population growth and normal related agricultural usage to the current regime. In other words, rubbish has discovered a neat new way to produce methane.

The point is that CH4 is produced in normal biomass combustion and almost as swiftly consumed. This is not true at all for carbon dioxide.

Yesterday we addressed sustainable biochar production. Much concern was expressed over the production of combustibles like CH4 that will escape into the atmosphere. And a natural earthen field kiln will lose a lot of combustibles in this manner and not just methane. My description of the inexpensive modified incinerator design took advantage of that out gassing to fuel a second high temperature oven whose heat was then used to accelerate the carbonization process.

That solution is possibly available to industrialized agriculture. It is certainly not an option for everyone else, and may be suspect even were the equipment is available. Of course even more expensive systems can be deployed for a very small incremental gain.

The point that I want to make is that the primitive earthen kiln and my incinerator are separated only by efficiency. I would reasonably expect perhaps twice as much product to be produced. This cannot be accomplished with a sharp increase in haulage costs. I also point out that the jury is truly out as to the quality of the end product. The kiln promises to produce a more uniform end product but that may not be as advantageous.

In either case, gases are produced once a year for any plot of land and are then swiftly mopped up by the local environment.

The objective after all is to put carbon into the soil for a long time. Both these techniques do just that. The only other technique that convincingly does the same thing is the growth of new forests. Every other agricultural process that we have created is in a constant struggle to just maintain carbon content and related fertility. Terra preta promises to end this ten thousand year struggle forever.

Every subsistence farmer now has the option of either burning all his plant waste out in the open field as he has done forever, or building an earthen kiln and producing a few tons of Biochar as fertilizer for next year’s crop. He does not need a dime from his government to do this nor does he need any special equipment that he does not already have. He had no other choice before and has been the source of monster smoke clouds out of Asia’s rainforests. Now those smoke clouds can become a fraction of what they are today while he mops up the carbon for us and strengthens his farms fertility.

Machinery and Biochar

I posted a draft of this on the Terra Preta and Black Earth news groups.

I cannot help but think that the methods used to produce the black soils must be self sustaining and indigenous to the farm itself. I also fail to see the use of fairly large pieces of charcoal from wood that is difficult to pulverize properly as a very viable source. Remember that grinding has a natural sizing limit, past which a great deal of effort is needed. It would be much better if it came already sized.

Without question the use of corn stover to build natural earthen kilns is a great solution when we are relying on hand labor alone.

We also can conclude that corn stover is the best available source of large volume biochar. It needs to be central to any program simply to ensure 100% coverage of the fields with sufficient biochar. There is little enthusiasm for a system that depletes fifty acres to benefit five.

Is there a way to do this in the field with equipment?

Let us return first to best hand practice. From there we can speculate on how this can be made easier with power equipment.

We do not know how the Indians in the Amazon did this but we certainly know how they grew corn everywhere else.

In North America, they used a ternary system.

That meant that they cleared a seed hill, likely two plus feet across, perhaps slightly raised, in which they planted several corn seeds and also several beans. These hills would have been at least two feet apart. This means that twenty five percent of the land was been cropped in this way. They also planted every few hills with a few pumpkins. This provided ground cover for the seventy five percent of the land that was not been directly cropped.

An interesting modern experiment would be to now grow alfalfa in between the hills in order to fix nitrogen and provide a late fall crop. It unfortunately would likely take too much water. Recall that one of the major draw backs of corn culture is its demand for ample water, usually in the form of precipitation. This Indian methodology gave the corn a moisture bank in the adjacent soil.

This Indian corn culture system is ideal for hand work and for the production of terra preta by hand.

In September, after the corn, beans, and pumpkins are picked, it is time to remove the drying corn stover and bean waste. The pumpkin waste will be trampled into the ground fairly easily by now.

Hand pulling the stalks from one seed hill gives you a nice bundle to carry off the field to where an earthen beehive as described in my July posts is built for the production of Terra preta.

How do we accomplish the same result with the use of equipment is a more difficult question. Using a stone boat or wagon is obvious. A hydraulic grabber of some sort to pull the bunch associated with a hill would be very helpful. Tying the bundles would also be helpful.

This would allow two workers to clear a larger field quite handily.

After the earthen field stack is set up, the rest is fairly simple. A wagon full of biochar is taken to the field and each hill is replenished with biochar before planting. This is still a lot of labor but much easier than the most basic hand only system.

To do this with row agriculture will mean the creation of some fairly complex lifting and baling machinery. One method is to use a row of spikes that can get down into the soil as the machine is advancing and then rotate back up pulling the corn root from its bed. The stalks can be beat in unto a tray and perhaps automatically bundled. A lot like a swather with a root lifting modification and sizing appropriate to corn. It sounds like a bit of a challenge to this old farm boy.

If the machinery is designed to produce tightly packed one ton square bales, then we will make the rest of the handling process much easier. Remember my incinerator design? Otherwise we are still able to contemplate field processing as an option for biochar production.

At least we are on the right track.

I have seen a fair bit of comment regarding the out gassing of open air Biochar manufacture which I will be addressing again in another post.

Mel Landers and Jackie Foo on Field testing Corn Stover Stacks

The following posts from the Black Earth Soils newsgroup (Bionet) are well worth reading since we are addressing the possibility of restarting hand production were it is the only option.

Mel Landers:

arclein wrote: Their principle option was to use corn stover and I show how.

Thank you for sharing this idea. This is very helpful. Having grown Maize for a number of decades now, I can attest to what you have stated about its stacking capacity.

I also know the difficulty in utilizing Maize stumps if you don't burn them. (not that I ever thought to do so) The Amazon Basin can grow an amazing amount of biomass in a short period of time. (I have attached a photo I took four decades ago, when I introduced slash and mulch methods to the Urarina of Peru. It shows the abundance of biomass left on the soil after cutting tropical kudzu.) But, maize is a challenge to grow in that environment. The fact that maize pollen is so common attests value of dark earth soils and their ability to retain nutrients.

It makes sense that, women would long ago have turned to firing their pots in order to increase their strength and longevity. The clays in the upper Amazon Basin are high in sand. The area is one big flood plain with continual deposition of sand. If the same is true in the lower Amazon, their pots likely needed firing. I have also attached a photo of an Urarina woman making a pot. Notice the grey color of the clay. The pot I brought back with me had a very rough texture, due to the sand.

Why not turn to maize stumps to produce a high temperature fire. Place that fire under the soil, in an impromptu dirt oven, and you have maize charcoal. It would be easily powdered and once your soils started improving, it would have been plentiful as well. It is a short step ahead to do the process specifically for soil improvement. If anyone doubts that they might do this, they need to read the information written up by Suzanna Hecht on the practices of the Kayapo.

Here is a type of biomass that is even plentiful in the temperate zone. O.K.....I can hear Bob thinking....But, how can I stack the Maize stumps from a whole section of land. That is where a large scale pyrolysis retort comes in. But, here in Nicaragua and in many other maize growing regions of the world. Stacking by hand makes good sense.

Nicaraguan producers already think I'm crazy for wanting the grass they cut off the fields in preparation for plowing. Now they will think I am totally insane for requesting their maize stumps as well. This should be interesting! Thanks again!

mel

This is an excellent validation of the proposed mechanism

arclein wrote:

Hi I did a post describing a method of producing terra preta soils using only primative stick agriculture. Their principle option was to use corn stover and I show how.

I am hesitant about other feed stocks in general been as forgiving as corn stover, but that has to be shaken out through practice.

I also describe a modified incinerator design to utilize a full range of biomass in later posts.

The astounding revelation is that the Indians sustained continuous agriculture in the Amazon for centuries.

See my post at:

http://globalwarming-arclein.blogspot.com/2007/07/ carbonizing-corn-in-field.html

This has turned out to be my most popular post to date. Enjoy the site.

From Jacky Foo

Hi arclein

I checked your profile at www.blogger.com/profile but found no "real name" and therefore I address you as "arclein".

I have not made charcoal nor charred materials before and therefore I ask you.

Q: have you tested your idea of "carbonizing corn in the field" as described (Wednesday, July 4, 2007) in the link provided above ? or is there a drawing of what you described anywhere ?
>...the Indians in the Amazon likely created windrows that they
>then lightly buried and set afire. Your idea sounds very logical if the Amazonians were making charred materials (from corn stalks with their roots intact). But did they make charred materials to fertilise their soils or was charred materials simply a by-product of their burning away of agricultural wastes (corn stalk and tapioca stems) ? . (your message of Friday, July 6, 2007 "Those amazonian soils" in:

http://globalwarming-arclein.blogspot.com/2007_07_01_archive.html .

Given that we now want to make charred materials and we have corn stalks with their roots intact, the idea of stacking a windrow of two rows of corn stalks with their roots to form the outside walls is a good one.

So let's say I have 5 acres of corn where I could get 50 tons of stover. I have no machinery (nor container to make a kiln), just bare hands of the workers e.g. in Kenya.

How big (length and height) would this single windrow be ? What materials can I use to make the outer wall ? ...etc

regards jacky foo

arclein wrote:

However they began doing this, the rewards were immediate inasmuch as the soil retained fertility that would have completely disappeared in perhaps three years.

The volume of corn stover made this possible over the whole growing area so that there was no lack of biochar even at the very beginning. Most other likely sources would restrict you to treating a fraction of the original cropped area and likely not be very sustainable.

Right now, we are speculating. I would actually try to build a circle with the roots on the outside and see if it is possible to build a beehive shape as an experiment. I would leave a central chimney, probably because I had to, and fill the bottom of it with a well stamped mass of biowaste.

Once the beehive had reached the point of almost been closed off, I would throw a large mass of glowing coals into the chimney and then fill the chimney with corn stover with a dirt capping. Then I would stand by and shovel dirt on any breakthrough for the next few hours.

We can try other methods of stacking once we have a little experience. And no, no one has done this yet and I am keen to see how it goes.

regards

arclein

Tom Miles comments on Biochar production costs

This is from the Terra preta site.


Agreed. Production and use of the charcoal on the farm is
 not trivial. It's at a different scale than commercial
charcoal production but it is done with a purpose. That
purpose is clearly defined in your case. It is not yet
clear in many cases.    

The actual cost may exceed the current returns on the
investment of labor and capital but the value
(cost/benefit) may not be calculated in strictly current
economic terms. That's not uncommon when developing new
technologies or applications, so I jokingly say that it
must be amortized on its entertainment value. The point
is that there must be a purpose, a product and a value.

Serious farm production of biochar in our area will be
regulated in a similar manner as outdoor wood boilers:
systems will have to comply with air, soil and water
quality regulations. The amount of regulation will
depend on the scale of the charcoal production. Let's
look at scale. 

In your plots you have used 30 gallons (4 ft3) or 60 lbs
(4 ft3 x 15 lb/ft3) of charcoal in 85 ft2 plots
(5 x 17ft= 4). 60 lb/85 ft2 = 0.7 lbs/ft2 equal to about
14 tons of charcoal per acre. If your planted area is
50% of the total area you would use 7 tons of charcoal
per acre.

If you used a kiln the size of Robert Flanagan's (1.5
tonnes [1.65 t] biomass per charge) you would produce
about 0.66 tons per day (at two charges/day) or 20 tons
of charcoal in 30 days
 http://terrapreta.bioenergylists.org/flanaganvinegar

So if you ran Flanagan's kiln for 30 days at two charges
per day you could treat about 3 acres per year (20
tons/7 tons per acre). In 15 years you'll cover the
whole 45 acre nursery. 1.65 tons/8 hours with wood
vinegar recovery would exhaust about 3 MMBtuh which is
large enough to be regulated in some states. 

If you treat 5 acres per year that's 35 tons of
charcoal per year representing 175 tons of biomass (35
tons charcoal/20%) per year. If you make your own
charcoal at 5 tons of charcoal per day (175 tons/30
days = 5.8t/day) each kiln charge would be about 25
tons of biomass/24 hours or 1 ton per hour (2 big bales).

Your kiln will be rated at about 12 million Btuh(80%
biomass x 15 MM Btu/ton x 1 ton/hour) if no oil is
recovered, or 5 million Btuh if just the offgas is
burned to drive the process of making oil and char.

Either way you have an system is large enough that it
will be regulated for particulate, CO and NOx emissions. 

A system of this size is likely to be operated as a
stationary production facility operating 250 days per
year (6250 tons biomass or 1250 tpy charcoal). Large
bale combustors of the 1980s (Agrifurnaces, IA) were
rarely moved. Most systems included debalers like the
farm scale straw burning gasifiers and boilers or today. 

A farm scale charcoal system might include the same
amount of equipment as Vidir's Greenhouse Gas
Displacement system which gasifies straw to replace
natural gas for heating heat poultry houses.

http://www.vidir.biz/index-biomass.htm

Vidir's smallest system consumes 500lb/hr (3 Million
Btuh) of wheat straw. If built as a pyrolyzer it would
produce 100 lb charcoal and 1-2 million Btuh heat. The
system cost is $200,000. Annual operating cost with straw
at $10/bale is estimated at $16,000. Labor is figured at
3 hours per day $15/hr. Economics are based on 6 months
operating time (in Manitoba) or 375 tonnes (752 x 500
kg bales/year).

At 20% yield that would produce 82 tons (75 tonnes) of
charcoal which could treat about 12 acres (at 7 tons/
acre). In four years you would produce enough charcoal
for a 40 acre farm. At $200/ton the charcoal would be
worth about $16,400/year whch would just offset the
operating costs but not capital. If you had a use for
the heat (2 million btuh x 70% to hot water = 1.4
MMBtuh, 33.6 MMBtu/day) in 30 days you would recover
more than $12,800 additional revenue to help pay for
the plant. In six months you would recover $16,400 in
charcoal value and $76,800 in heat savings. So the
payback could be 4 years with heat recovery. To a see
a system like that in operation would be entertaining. 

Regards,

Tom             

Getting the job done - Biochar on the modern farm

Getting the job done on the modern farm is a challenge that needs to be confronted on a capital sensitive basis. A good analysis of the problems facing us comes from Tom Miles over at the Terra Preta website in links. I have also posted one of his posts today and the reader can get a taste of the current debate by visiting the Terra preta link.

The rest of the world still relying on traditional agriculture can readily use the corn culture biochar stack that we believe created the Terra preta soils in the first place and have described earlier. This requires no capital investment whatsoever and likely achieves satisfactory results. It would be ironic if it turns out to be the best system which it reasonably could.

For the modern farm, I have proposed the application of a modified incinerator to produce Biochar. My first description came in my June post:

http://globalwarming-arclein.blogspot.com/2007/06/pushing-envelope-on-incineration.html

And you may wish to review that. What is becoming painfully clear, is that the secondary chamber will have to be fabricated inexpensively, eliminating its secondary usefulness as a incinerator and likely eliminating alternative recovery concepts. The machine needs to be basic and cheap because it cannot be operated year round to produce a premium byproduct.

Let us return to the concept of the modified shipping container. The original intent for this design concept was to deliver low impact incineration to a small municipality. This is achieved by the use of a two step burn. The first burn inside of the fire brick lined shipping container is held to just under 600 degrees by controlling the oxygen supply.

The flue gas, containing volatiles and other nasties (municipal waste, remember) is then vented into a separate much smaller chamber. Fresh air is injected, immediately jumping the temperature to 2000 degrees. This technique bypasses the production of intermediary combustion products that will be an emission problem. The high temperature flue gas can then be sent back into the first chamber as needed to increase the heat of its contents.

The system was extremely successful in largely eliminating emission problems surrounding the hospital waste that had driven the original development of this system.

This same system, built around a steel shipping container and perhaps a little simplification, can be used to produce a range of low temperature carbon based products ranging from biochar to possibly fully activated charcoal. The sizing is also right for agricultural use and the implied capital cost should come in at under $50,000 with any level of volume production. I anticipate that a manufacturer will simply supply the second chamber and the control system, while the buyer will acquire and line a shipping container. This will reduce costs even further and avoid shipping damage with the firebricks. A warning though, the second chamber, though comparatively small, must withstand very high temperatures and other stresses. The high performance and engineered municipal model of the secondary high temperature burner was costing out at a lot over $100,000 since it was cylindrical in shape and the bricks were over twice as thick and specially fabricated.

This system can be readily varied under operation in order to achieve the best possible yield of product including the option of not burning anything in the main chamber at all.

A typical charge of biomass will likely be less than ten tons for anything except wood for a twenty foot container. Something like straw could even be blown in.

As we have posted earlier, the one crop that can produce the most biomass per acre is corn. Corn will make ten plus tons of stover, while any grain crop will make at best one plus tons per acre. There is an order of magnitude difference. That also rather obviously implies an order of magnitude difference in haulage costs.

A farm producing enough corn stover to operate the carbonizer for say 40 days is not likely to have produced other types of waste that would need more than several days of additional operation. This means that the facility will be operated in the fall for a little over a month just after harvest. The produced carbon can be readily stored in preparation for been rebroadcast in combination with fertilizer onto the field originally cropped.

Our output is at least a ton of carbon for each acre of corn grown. We can then anticipate that the farm will be able to add a ton of carbon each year to every acre used for corn production. The increased fertility and the improved soil quality will also lead to an increase in corn production accelerating the process.

This new system now calls for a multi year field test aimed at defining costs and operating parameters and should be done soonest under an agricultural extension program. The visible payoff should come in the form of both sharply increased yields and a reduction in chemical inputs. In other words, the economic model is no different than the old traditional manure cycle of a mixed farm. It promises to just be a much better way.

It is clear that we will only achieve capital efficiency if we make the system a biochar only solution and integrate its use into farm operations in a way similar to the manure spreader. We may end up using the manure spreader to distribute the biochar unto the field. That would even clean the damn thing.

Oceanic Heat Transfer

We know that the Ice age ended over 10,000 years ago and we know that it took around three thousand years for the ice to melt to current levels. I discuss the likely reasons for the ending of the Ice Age in my chapter Pleistocene Nonconformity posted earlier.

Amazingly, we also know that the Northern Hemisphere at least experienced a climate warmer than todays for the next 5000 years up to around 3000 years ago. In an earlier post, I posited that this was a reflection of the Antarctic cold water mass reaching its maximum extent.

We now live in a semi stable regime in which temperatures in the Northern Hemisphere attempt to converge on their Bronze Age highs, yet constrained by some mechanism that likely injects surplus cold water into the south Atlantic ultimately chilling the Gulf stream by a degree or two. An engine of this nature easily accounts for the little ice age and the known variations that have been experienced.

Currents are driven in the Atlantic around two Gyres which are induced by the Coriolis force. It is very much like the foot print of an eggbeater with the center flow feeding into the Caribbean. Rather obviously, a major increase of cold Antarctic surface water which is at least 5 degrees colder at the boundary contact even in the southern latitudes, would have a chilling effect on the equatorial waters that ultimately form the Gulf Stream.

At present, each year, the Atlantic equatorial zone receives a quantity of solar energy that we can conveniently name Q. This quantity does not vary. Q is eventually delivered, almost intact into the arctic and is discharged melting winter sea ice. The point that I want to make here is that there is no credible or significant mechanism in the Northern Hemisphere capable of altering this exchange. I question whether it can even be varied significantly by any force at work in the Northern Hemisphere.

Yet a little ice age must have been induced by a reduction in Q delivered to the Arctic. Barring extraordinary variation in Solar output which I think is rubbish, we have only one remaining choice. That is a sharp jump in the amount of cold water injected into the south Atlantic. The temperature differential is so large, that only a moderate shift in flow will be sufficient to achieve our ends.

And we do know that the surface waters around Antarctica can be pulsed by shifts in winds alone. Right now, unfortunately we have little knowledge of the workings of the exchange mechanisms between the South Polar current and the various currents interacting with it. However, learning how to measure the current flow rates of ocean currents (particularly the Benguela Current) is timely, and integrating that information into our models rather wise.

A simple change in the mix of source waters for the Benguela Current could have a huge multiplier effect on Equatorial surface temperatures. Scary thought!

Heat Distribution and Terra Preta soils

As could be expected, we are now seeing a range of tests been done in the creation of terra preta. this is generating discussion on the terra preta web site that you can link to from here. Most of these tests, so far are using some form of commercial charcoal as would be expected.

In earlier posts, I have described the corn stover protocol that I suggest was used as the only practical means available to the populations. What I have not discussed are some of the likely derivative benefits of the approach.

The most important characteristic of corn stover is that it will produce a fine grained product. There will be almost no lumps to breakdown, although there will be remnant roasted plant fiber that will be slowly degraded by bacteria in the soil.

The covering of dirt maintained while the stack is burning is still porus to air. This permits a steady supply of oxygen to the burn but at a low level. We anticipate that the average temperature will be around 380 to 400 degrees. This is hot enough to drive off the volitiles and char most of the carbon. It is not hot enough to do more to the stover than properly carbonize most of it.

However for the stack to reach a general average of 400 degrees, the volitiles must burn at much higher temperatures. That means that we will have a distribution of high temperature carbon products within the stack that will include high temperature activated charcoal. This is one of the benefits of the stack method that is hard to replicate in a carbonizing device were one gets a little too efficient.

I know that the agricultural carbonizer design that I posted on earlier posts separates the volatiles and burns them at 2000 dgrees before throwing the heat back into the fuel to produce more volatiles. More direct combustion within the fuel may well be called for.

I think that we need to sample the production of dirt covered burn stacks and measure not just the carbon output but the distribution of types by size and if possble, activity. then we can use better production methods and blending to match the terra preta profile.

Uniqueness of corn culture

Reading through the posts on the Terra Preta site reinforces one important reality. That is that the knowledge needed to work with plant waste and char has been with us for thousands of years. However using char to cover a field had to wait for the emergence of corn culture. It is the only crop that could be worked this way in sufficient volume to have made a difference.

Wood waste was a non starter, simply because the tools did not exist. Even today we will need to use a chipper to achieve the necessary density in a productive manner.

Crop waste with few exceptions, degrades far too fast and are of such low volume as to be fairly insignificant.

Garden waste is usually combined with household waste on a small fertile patch and is the likely best location for developing a black soil outside of corn culture.

Pollutants from Carbonization

There has been some discussion on the obvious generation of pollutants when plant material is carbonized. As I pointed out, we can sharply curtail that problem with an enclosed tightly managed oven system in the world of modern agriculture.

Where labor is available and near subsistence agriculture is practiced, then we want to apply the stack system that I have already described. This will produce a lot of out gassing of volatiles that then rely on atmospheric dispersion. These are no different than the gases generated by straight open burning with a lot less carbon dioxide.

In fact this system is a general improvement over traditional practices associated with slash and burn, while within the means of the family.

Obviously, no one has actually operated a corn stack for at least 500 years so we do not have the art of it yet. I suspect that it takes a good twelve to fifteen hours to run out of fuel and while that is happening someone is standing by to throw dirt wherever too much smoke is escaping. The next morning you would rake the soil, char and ash into a neat stack for distribution.

It would be fun to build out a number of stacks using a number of different dimensions in order to discern any particular favored style. Right now we must wait for test results!

Human Labor

I often forget that few understand how dominant to the economic model underlying agriculture is the element of human labor. Every shift in effort means the reallocation of that very limited resource.

Thus for an Indian family in the Amazon to put in the extra effort to carbonize corn stalks, they must have realized an immediate benefit. That came about by the ability to reseed the hills in a couple of weeks. Unless someone tells me otherwise, the Indians of the Amazon had a continuous growing season that could readily support three crops per year provided that nutrients could be restored immediately.

Since the likely biochar would contain a mix of soil,ash,charcoal,char and even a little unburned material as well as four months of chared household waste, the nutrient release profile would be sustained over the next growing season.

The whole field would thus require a concerted effort during the planting period, perhaps lasting a week or two with minimal weeding thereafter. That is an incredible return on labor for pre-modern agriculture.

Those amazonian soils

Reviewing again some of the material on Terra Preta soils, now that I have a clear understanding of the method used, is immediately rewarding. The evidence lines up and falls into place. This strengthens my confidence that I have the right of it.

First, pollen analysis shows that the principal crops grown on these soils were corn(a confirmation) and manioc or cassava. The latter also produces a woody waste material which also needed burning.

Second, high population densities existed which this style of food culture obviously calls for. I suspect that we approach the carrying capacity of a family per acre or two that is achieved by potatoes.

Third, a high nutrient content has been built up that includes the all important phosphorus. these nutrients are still intact and are held or adsorbed by the presence of the chacoal. Remember activated charcoal?

Forth, Phosphorus is a natural result of the other great Indian agricultural culture - the raising of Tilapia in small ponds. Since they were not raising ruminants, they needed an alternative source of high quality protein. Tilapia was the foundation of the ditch and bank system that we have been rediscovering throughout the Americas. It is a vegetarian fish that consumes the plant life that would quickly choke a pond.

Fifth, the resulting staple diet would then consist of corn mush and a piece of Tilapia and perhaps something using Manioc. This implies that kitchen waste would contain a steady stream of fish bones and waste which would find its way into the spoil heap.

Sixth, the burning of the stover stack is never perfect. Ash, charcoal and biochar will be produced and be immediately used. However, some uncombusted material will remain and this will be saved as starter fuel for next season's stack. This is a perfect medium in which to throw kitchen waste with all the attendant benefits of odor reduction and preserving fertilizer. A quick turn with a shovel will keep this pile from getting too ripe. And of course, the broken crockery will find its way into the pile.

Seventh, there is reason to believe that this culture was sustained for thousands of years and very likely fell to the ravages of new European pathogens ripping through densely populated villages and towns. A simple flu or two would have done this as has been repeatedly demonstrated among many other formerly isolated communities.

The most important point that I want to make is that this was an incredibly successful life way. The surprise comes in the fact that this protocol was never applied elsewhere like Eastern North America. Perhaps necessity drove it in the tropics and it simply was not critical enough elsewhere to justify the same attention.

Discussion on Terra Preta (pollution impact)

Robert:

I hope we can agree that this is a method of producing charcoal that is more apt to be harmful that helpful for climate change reasons - and therefore should not be encouraged. The ancient Indians who might have produced char in this clever way didn't have the knowledge of how bad the CO, CH4, H2 and other gases are. We should.

Ron AND

Bob (cc terra preta list):

Last night, you responded to my expression of concern about too-serious emissions from in-field carbonization of corn stalks, saying (with responses interspersed):

> Hi Ron
>
> I do not actually agree with that. In ideal controlled
> circumstances which I demonstrated earlier in my blog,
> it is possible to get a completely reduced waste gas
> that is primarily CO2. In the meantime we get a
> maximal yield of either charcoal or lower temperature
> carbonized material.
>

[RWL: Thanks for reminding of your blog (shown below - nice work!). I think you are referring perhaps to a Canadian incinerator two-chamber system you wrote about - the first chamber being for pyrolysis. I like that. My concern is that the "ideal controlled circumstances" you refer to are going to be very difficult to achieve in the field. I don't understand your "meantime" - but guess you believe that the emissions that I feel are almost inevitable in the field (without some controls) are justified by the produced charcoal. I still think that could have been case 1000's of years ago - but not now.

> The method just described will be fairly less
> efficient since temperature cannot be controlled and
> the combustion gases cannot be superburned. This
> produces a lot of carbon monoxide instead.

RWL: Yup - and CH4 etc. - all polluting.
>
> However, a subsistance farmer does not have the type
> of tools we take for granted. And this
> new(ancient)method will produce a yield likely close
> to sixty to seventy percent of the best case.
>

RWL: Granted - but still something to avoid. My first recommendation is that the corn stover (or whatever) is worth bringing to a central location where the CO, CH4, etc can be combusted to serve a practical purpose - cooking being one such - but maybe electrical production, etc.

> And that product, however obtained will sequester
> carbon for decades, if not centuries.

RWL: Agreed - maybe millenia. But I feel we on this list must do all we can to avoid char production that is polluting. I am certain that there will be no carbon credit funds sent when the production is done badly.

>
> The alternative today in most of the world is to burn
> the waste outright and in the tropics to abandon the
> field for years.
>

RWL: There are other alternatives. A great project for many of us is/will be to figure out best charcoaling approaches that are non-polluting, and justify the extra efforts of doing other than "to burn the waste outright and in the tropics to abandon the field for years". Thanks for carrying this idea further on your blog. Sorry to not being in support of any form of in-field charcoaling which is polluting. The work of AD Karve is not in that category - but I still hope we can find ways to productively use those valuable pyrolysis gases.

Ron

I certainly am sympathetic to the desire to minimize the out gassing of combustion products into the environment. The best use of a closed combustion oven with a second high temperature (2000 degrees)chamber to swiftly oxidize the initial combustion gases (at 350 to 600 degrees)is the one way we can do this. This will also end up been the final resolution unless we can figure out how use fusion power to do this.

The challenge is to covert tons of stover into bio char with the least amount of immediate consumption of the stover producing the needed heat.

Burning all of it as a low quality fuel simply releases all the carbon back into the atmosphere.

What those ancient Indians have gifted us with is a well proven protocol for soil enhancement and fertility retention that just happens to sequester hundreds of pounds of carbon per acre every year in perpetuity.

Mike Kiely commentary on soils

This post is responding to my post in April.

Michael Kiely said...

Good to see agriculture getting some attention. A few facts from Australia, which has many advanced 'carbon farmers' sequestering carbon dioxide via native perennial grasses, shrubs and trees: 1. If the world stopped emitting CO2 today there is already enough up there to drive us through the 2°C limit into climate chaos. 2. Only photosynthesis can extract the 'legacy load' of 200 years worth of emissions. 3. It would require 7 planet the size of Earth entirely covered in forests that never died or fell down or burned to do the job. 4. An acre of pasture can hold more carbon than an acre of forest. 5. Soil already holds 1500GT of Carbon vs 750GT held in the Air and 650GT in Vegetation. 6. Farmland (mainly pasture) covers 65% of the landmass of the Earth. 7. A change in land management from conventional farming to carbon farming is easy when farmers can trade the credits for the carbon they store in their soils. 8. Farming techniques that capture and store carbon stimulate soil biology and restore health to soils, waterways, and farmland ecologies. Biodiversity increases. Resistance to pests increases. Soil productivity increases. Reliance on chemical inputs falls. Profits rise. 9. Life's beautiful.

July 5, 2007 12:51 AM

I am personally not convinced that all pasture land holds more carbon than all woodland although that is certainly true in selected cases. Unfortunately, most original grassland has been plowed and a lot of the carbon bank has been released. The most egregious example of this is the area of the buffalo commons in western North America. It would actually be nice to see extensive carbon measurement on soils done on a global scale so as to establish benchmarks.

A quick review of he literature reveals that that is not so easy yet. Which means that there is currently a lot of educated guessing going on.

Woodland has a potential to ultimately store fifty to one hundred tons of carbon for every acre without been clever about carbonization. We are referring to temperate woodlands. Dry land environments are not nearly so cooperative, although the tropics can easily double these figures.

Agricultural soils usually deteriorate down to a layer that is perhaps several inches in thickness for a number of reasons, but mostly to do with the shallow root systems of the annuals used as our primary crops. I grew up with a working six inches of soil were once stood a maple forest that certainly carried a ton of carbon for every tree. This includes the root ball.

In all likelihood the soil itself still contains similar amounts of carbon as the original forest soils although the science is indicating a 35% reduction. What is missing is the tree itself that drew up nutrients from deep down and dumped them every year onto the surface. The elimination of the tree's root system then shrank the soil layer.

One needs to be reminded that the tallest and largest trees(Douglas firs and the like) on the planet grow in the mountains on which soil cover is often negligible. We can have our cake and eat it too by the simple expedient of promoting silviculture on waste and marginal land and employing carbonization to enhance crop lands.

carbonizing corn in the field

I have already commented earlier in how I thought that the Indians in the Amazon likely created windrows that they then lightly buried and set afire. Today I figured out the rest of it.

When a corn stalk is pulled out of the ground, the root ball resembles an eight inch wide disk. This allows the building of a wall of inward pointing corn stalks in which the earthen root ball forms a brick on the outer surface. The stalks will stack and pack very well. Of course, you build a matching wall on the other side of the first stack so that you get a two sided bank protected by the root balls. With any luck the tops of the stalks will compact well and a small space of a several inches can be left between the two halves for fire ignition. The compaction could allow the formation of an arched top to the bank that continues the root ball surface unto the top of the bank.

The ends of the bank can then be sealed off with with either more stalks or more likely a little earth. The same holds true for any gaps in the roof. Building one of these things would even be fun for the community, since pulling the corn is very easy work.

It is then a simple matter to wait for the right time to set this stack afire and you have a natural carbonizing oven. Two days later, you have a nice pile of reduced carbonized corn waste mixed with dirt that can be forked unto seed hills for the next corn crop. It really is that easy and only requires a little bit of additional effort in the stacking.

What I am very conscious of is that is not a lot of work compared to what many other crops require. A family could even do this today on any simple one acre patch, anywhere in the world.