This is another excellent letter from Bakary Jetta to the terra preta group. Again I cannot emphasize the importance of creating terra preta or bio char using the most primitive methods as was done originally in the Amazon.
The use of a drum is informative. He can feed the volatiles back into to fire with a pipe. I assume the CO2 leaks out everywhere.
The limitation is the small supply of plant waste, but that suits the type of burner and the way the bio char is used. By putting the material into the holes dug for the seeds along with any nutrients, he can stretch the usage over his field.
As I have argued earlier, larger scale application of terra preta soils demands integration with corn culture where a couple of tons of bio char per acre is possible.
I expect the earthen kiln technique (see earlier postings) to be less productive than his drum at forty percent. On the other hand, the modern double chamber metal kiln should match this handily.
I would like to recruit volunteers with access to a convenient corn field to this project. I emphasize corn simply because of the huge supply of corn stover that must be disposed of anyway. Perhaps several acres need to be set aside, depending on the available backs of course. Building several kilns will be backbreaking effort. It may turn out that small is best but we need to check each option out.
Otherwise, folks will chatter forever rather than make it happen. And it is not something an old farm boy can hope to quite do on his own. Even Bakary with his drum will need strong hands to make his drum really productive.
Dear list members,
At great cost of telephone bills and ISP charges I tried to keep up with the postings, hoping to find something practical beyond what I am doing myself right now.
Unfortunately I see long repetitions of previous posts and stuff that does not edify matters in the least, but rather confused what appeared to be a straight forward thing.
My retort is in my back yard. It is a drum with a fairly tight lid and a piece of pipe letting volatile gasses take over the initial firing in the firebox underneath. The drum is enclosed in a rock and soil and lime plaster wall. For a quick start I surrounded the drum with small branches or crop waste before covering the top with a scrap iron sheet with a gap for smoke to escape in the beginning. The drum costs money, the rest is labor.
The biomass is crop waste and or tree trimmings. Some material is up to 50 mm thick and still chars all through. Like was stated on the list, the char appears to be about 40 %. After initial smoke, the volatiles take over and burn with a roaring sound. Sorry, no analysis of the off gasses, but I trust I am not a polluter beyond the normal CO2. With adequate investment the excess gas or heat can be utilized, not likely an easy option for most third world farmers.
Where does all the biomass come from? Plant it! People still get rid of lots of it to clear roadsides and farms here. OTOH, I am planting more biomass every year and my soil is improving in the process. My mini climate is improving too as many of the trees retain their leaves during the dry season . Jatropha curcass is a soil improver and wind break. Not useful for char, but it makes great fuel oil for lamps and soap making. The oil cake makes good methane gas for cooking. The digester effluent is mixed with the bio char before it put in the planting holes on the field. A soil improver,energy and soil micro-organism inoculant.
Is it economic? What is the meaning of that? Maybe, when I get a good harvest, which depends on many other factors, like rain, etc. After all, food prices are going up because of increasing scarcity. Maybe some people think they can eat their economic gain in the form of money. During the last world war money could not buy food that was not there! You think the government is going to regulate food production to assure economic gain and sustainability? Or the market place will be regulating the climate in a timely fashion so that harvests will be reliable. My conclusion is that the real value is the food and other resources provided by the life of the plant springing from the soil.
Why am I doing this? I think it is a usefull thing to do. There was a quotation that I recognized as true: 'The Spritual precedes the material'
The economic consideration will not bring a solution. It has in fact been the cause of the problem!
So, considering economic criteria, maybe no present value seen yet, but the net value will be having a future worth having at all. It is a choice and it better be a collective choice. If it does not do all as expected, do we lose anything?
Bwiam village, WR