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.