Making Biochar

It has been very encouraging to watch the expansion of interest in the subject of biochar over the past eighteen months. When I first tripped over the subject in June 2007, the primary forum on the subject went the odd day without a post. I introduced the material to Jerry Pournelle’s site at www.pournelle.com that month and the forum immediately got very active. It also helped attract the first readers to my blog for which I am grateful.

I now receive thirty to forty postings from the forum every day and I have an unbelievable 6000 such postings that I have not found the time to read in my terra preta archive to say nothing of the thousand or so that I have read. It is obvious now that folks are working with the concepts everywhere today on every continent and in every likely environment. Real farmers and real household gardeners are trying out the ideas in their own back yards.

Some very important questions have been answered. It is possible to tackle alkaline and saline soils with this protocol successfully. I thought it likely a year ago but we are getting confirmation. It is not simple but it appears that the conditioning of the soil with char allows the soil to become fertile inside of about two years. It apparently takes a growing season for the soil to be reformed after which you have what you need.

I also pointed out the utility of using seed hills in the early implementation of the biochar protocol. This allows effort to be concentrated on twenty five percent or less of the land in the early stages.

There is little apparent dispute that the working mechanism is that the carbon binds soluble nutrients in place until a root or other biological agent arrives to acquire them. This hugely lowers the need to fertilize the soils as the current massive wastage into the groundwater is hugely reduced if not almost eliminated. This is, by the way, a huge breakthrough in soil husbandry and will be rapidly accepted once it is presented this way.

The other big issue is how to make the stuff. I have introduced ideas on how the originators did it and have investigated a number of more modern systems. The interesting question is how a home gardener or an experimenter can produce a good quality biochar.

The first issue that must be tackled is the feedstock. The whole charcoal industry has predisposed thinking toward using wood. This turns out to be a bad idea. The finer the end product the better, and all wood will give is a coarse product that will be in your soil for generations. Some minor wood will not be harmful, but the majority of the feedstock needs to be non woody plant waste, well dried. Charring will reduce the weight by about eighty percent or less depending on your ability to manage air flow.

Obviously some form of commercial charcoaler will give you a better yield and perhaps a more consistent product. If you do not mind a little work, make a collar out of sheet metal in the form of a ring like a drum that can be set out in the middle of your garden or field. To allow some air flow in through the bottom, place thin branches under the edges. This will need to be experimented with. Load this ring which may be two or three feet high and perhaps four feet across, with a well packed charge of feed stock. Corn stover is certainly the most convenient and I am certain is the original feedstock in Brazil. But any available material will do, particularly for an experiment.

It then needs to be capped. A layer of soil is probably the best option, since it can be topped up whenever a breakthrough occurs. Also it is easy to leave an initial opening in the center to place the fire charge. Once the fire charge is set on top of the load, it can be capped of with a metal garbage can lid.

After all that, it is left to practice and experience to get the best result. It will take hours to completely burn through the whole load and it is likely some of the charge will not be charred at all. No harm however, as it is expedient once the fire is out the next day or so to lift off the ring and blend the biochar and capping soil and any unburnt feedstock into a homogenous product.

This should give any gardener ample material to work with particularly if he employs hills formed with a shovel full of this blend.

If you are really keen, you can review my posts from last year on the making of a corn stover earthen kiln. That is for a field of corn and a few willing backs and I believe is how the Indios made the large fields in the first place after it was first discovered as a result of backyard midden piles.

Anyway, this is as minimalist as I can make it, although an earthen wall and a stove pipe to allow air into the bottom may work well also. That can be a pit with the same stove pipe at work and that emulates some rough charcoal making where efficiency does not matter much, since they lacked the stove pipe.

I would not recommend at this time applying this method in large operations simply because the smoke and unburned gases would likely be huge. Practice may prove otherwise and assuming that a closed modern system is obviously better may well be wrong.

This should help anyone anywhere experiment with biochar, particularly where subsistence farming is practiced and the only tools available are usually strong backs.

African Bio Char

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?

Kind regards,

Bakary Jatta

Bwiam village, WR

The Gambia

Eliminating global hunger and poverty with terra preta

When all is said or done, it is reasonable to say that on average that we are burning approximately one ton of geological carbon for each human on earth each year. That finally scopes out the real human scale of our problem. If every human being becomes responsible for sequestering one ton of carbon, then the globe becomes carbon neutral. It is easy to piece together the economic models from that core idea.

What I think we have also accomplished is to show that this is very feasible. Imagine 2,000,000,000 subsistence farmers annually sequestering three tons per head while producing terra preta soil and hugely upgrading the fertility of their land and generating a crop of corn to feed their family also.

It we subsidized this process at only $20.00 per ton of carbon, we will augment family and farm income also. The total global budget would be as little then as $120 billion dollars. If we are generous and take this figure to $50.00 per acre we end up with a trillion dollar annual budget. This is all within the operating parameters of the carbon credit system.

This is likely the cheapest way available to eliminate the carbon problem and certainly the best way since we simultaneously are creating new capital in the form of fertile lands and well fed and healthy families. Such a program can eliminate global hunger and global poverty, and we have a wonderful check and balance in the need to produce enhanced soil. A simple assay can prove out performance as needed.

The truth is is that these farmers will not need these credits at all to justify the creation of terra preta once they know that it is possible. However, the money is certainly there already and it will sharply kick start the whole process. Knowing that switching to corn on some of his acreage and making biochar will double his family's income will motivate them all. And once the benefits are throughly understood there will be no going back.

You may want to reread my many posts on using corn stover to make an earthen biochar kiln without any outside tools found in this blog.