The more I discuss and pull apart the concept of the corn stover bio char production system, the more that I come to admire the achievement of these so called primitives. As my readers know, large areas of Brazil's tropical soils were made continuously fertile by the addition of many tons of low temperature charcoal or biochar per acre. This is carbon sequestration by any other name and is called terra preta.
I recognized that the only crop that lent itself easily to the charing process was corn. It produced ten tons of dry unusable waste for every acre which could produce at least a ton of char per acre. This is more than enough to visibly impact fertility. On top of that, the crop husbandry system was all about hills, so that the char was delivered directly to the hill and not to the 75% of the field kept fallow between the hills. It sounds like a basket full to me.
A review of the literature revealed that corn pollen and cassava pollen were in fact the principle crops. Cassava also produces a great deal of biomass and would nicely augment any Biochar production protocol, although I have never emphasized it.
I then recognized, from personal experience that corn had one unique characteristic that hugely accommodated the production of Biochar. Corn produces a horizontal root pad that is easily pulled out of the soil. This brick like root ball is a natural brick that permits the building of an earthen shell that could form the near vertical walls of an earthen kiln. This is hugely important, because it eliminates the need to dig a huge pit or to build a large soil bank. It can also be built anywhere and sized to the most efficient design possible.
Any piece of jungle can be burned out and with a first corn crop, terra preta can be established. Constant repetition will easily build up the carbon content to the 15% charcoal level inside a couple of generations, while preserving soil fertility.
There is also very little additional labor required, an awfully important consideration in a ulture that had no draft animals.
Once the stack is built in whatever shape works best through experience and discussed earlier, It is necessary to throw a layer of dirt on the flat top of the stack, to effect final closure. We end up with a complete dirt shell surrounding tightly packed corn stalks with a packing ratio of at least 70%.
Now comes the problem of ignition. My conjecture is that they opened a chimney in the center of the pile by pushing the dirt aside. They then dumped in a large charge of glowing coals from a wood fire held in a earthenware platter, which was then tipped over and used to cap the coals and prevent flaming. This was then covered with the displaced dirt.
And this is were the genius of the Indians really comes in. As the coal mass ate its way down through the bio mass, it drew a steady controlled stream of air in through the earthen walls and sustaining the burn. But as the burn progressed, the plate forced the process gases initially away from the chimney in back through the smoldering wall of the chimney before it finally exits through the chimney. A constant supply of fresh dirt to cover any breakouts should maintain a steady burn.
Without field trials, we seem to have a method that produces biochar by burning the process gas very completely and getting the maximum heat.
I am convinced that with a little practice, any family can produce biochar at a very high level of efficiency. This method will end slash and burn agricultural as still practiced in the tropics.
The modern farmer will want to use a closed incinerator with a double lung design to capture the maximum heat and to produce the cleanest exhaust gas. This is very capital intensive if done properly even if using the shipping container system previously aired.
I wonder what we will learn when field tests are done to compare the two systems?
All I am sure about is that the elimination of slash and burn with an annual earthen kiln system on perhaps 20% of the arable land in the tropics is a vast improvement over what passes for current practice. It will also increase the amount of continuously cropped land by orders of magnitude. To say absolutely nothing about fertility enhancement on established fields.
Traditional agriculture has beggered millions for generations. This can now change completely.
I recognized that the only crop that lent itself easily to the charing process was corn. It produced ten tons of dry unusable waste for every acre which could produce at least a ton of char per acre. This is more than enough to visibly impact fertility. On top of that, the crop husbandry system was all about hills, so that the char was delivered directly to the hill and not to the 75% of the field kept fallow between the hills. It sounds like a basket full to me.
A review of the literature revealed that corn pollen and cassava pollen were in fact the principle crops. Cassava also produces a great deal of biomass and would nicely augment any Biochar production protocol, although I have never emphasized it.
I then recognized, from personal experience that corn had one unique characteristic that hugely accommodated the production of Biochar. Corn produces a horizontal root pad that is easily pulled out of the soil. This brick like root ball is a natural brick that permits the building of an earthen shell that could form the near vertical walls of an earthen kiln. This is hugely important, because it eliminates the need to dig a huge pit or to build a large soil bank. It can also be built anywhere and sized to the most efficient design possible.
Any piece of jungle can be burned out and with a first corn crop, terra preta can be established. Constant repetition will easily build up the carbon content to the 15% charcoal level inside a couple of generations, while preserving soil fertility.
There is also very little additional labor required, an awfully important consideration in a ulture that had no draft animals.
Once the stack is built in whatever shape works best through experience and discussed earlier, It is necessary to throw a layer of dirt on the flat top of the stack, to effect final closure. We end up with a complete dirt shell surrounding tightly packed corn stalks with a packing ratio of at least 70%.
Now comes the problem of ignition. My conjecture is that they opened a chimney in the center of the pile by pushing the dirt aside. They then dumped in a large charge of glowing coals from a wood fire held in a earthenware platter, which was then tipped over and used to cap the coals and prevent flaming. This was then covered with the displaced dirt.
And this is were the genius of the Indians really comes in. As the coal mass ate its way down through the bio mass, it drew a steady controlled stream of air in through the earthen walls and sustaining the burn. But as the burn progressed, the plate forced the process gases initially away from the chimney in back through the smoldering wall of the chimney before it finally exits through the chimney. A constant supply of fresh dirt to cover any breakouts should maintain a steady burn.
Without field trials, we seem to have a method that produces biochar by burning the process gas very completely and getting the maximum heat.
I am convinced that with a little practice, any family can produce biochar at a very high level of efficiency. This method will end slash and burn agricultural as still practiced in the tropics.
The modern farmer will want to use a closed incinerator with a double lung design to capture the maximum heat and to produce the cleanest exhaust gas. This is very capital intensive if done properly even if using the shipping container system previously aired.
I wonder what we will learn when field tests are done to compare the two systems?
All I am sure about is that the elimination of slash and burn with an annual earthen kiln system on perhaps 20% of the arable land in the tropics is a vast improvement over what passes for current practice. It will also increase the amount of continuously cropped land by orders of magnitude. To say absolutely nothing about fertility enhancement on established fields.
Traditional agriculture has beggered millions for generations. This can now change completely.
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