[Terrapreta] Anthropogenic casue for Global Warming

[Jim Joyner]

From: Sean K. Barry <sean.barry at juno.com>

Farmers are not egghead intellectuals . . .

Not being a farmer myself, I just wondered if that 
diatribe was directed at people like me?


If I were being cynical I might say, "if the shoe fits . . .", but nah, I don't think so. I was trying to make a point about soil improvement, but I can't see that you really disagree. In fact, I don't think we really disagree about much . . . maybe some theoretical stuff, maybe even some political stuff not discussed. But none of those are very important to actually accomplishing something and I think we agree on what must be accomplished..

After being involved in sustainable ag for almost two decades I suppose I'm a
little overly sensitive to people who do not seem to understand a
farmer's plight or role. That may be my hang up.

Not sure I think your numbers are good -- yet. 

The costs I estimated were based on purchasing the charcoal, but if the farmer can somehow manufacture (if that is the word) his/her own charcoal (as you suggest), the economics might be considerably better because many of the costs may already be borne by the farmer. 

For example, I'm re-designing an outdoor masonry stove that heats my house in the winter so as to provide charcoal too. The burn is quite fast, reducing pollution over conventional stoves; the stove runs about 90-95% efficient, so I use about half the wood as most wood stoves. The heat is stored in the mass of the stove and transferred to the house via hot water. I think I can heat my house with about the same amount of wood as a conventional wood stove but 1/2 to 2/3 of the wood will be converted to charcoal. The only thing that is more is my personal labor (chopping wood, I can't get my wife to do
 it).

By doing this I save what would be my heating bill; cuts my cost of providing the charcoal. Of course, it is limited to the amount of heat I can actually use: probably enough to infuse our rather large garden. I'm guessing, but I suspect that if a farmer could find a way to capture/use the resulting heat of making charcoal, it could made economical, hands down, without having a large scale process. 
 

As for the cost of putting charcoal on agricultural fields?  I think 
ag waste should be charred and put onto the fields they came from. [I'm doubtful about use of  field "waste". Any more, most of that gets
left in the field as biomass or for erosion control. Converting that to
charcoal probably wouldn't make sense in most crops; might create other
problems like erosion.] This 
will eliminate any transportation costs for feedstock of charcoal. [Yes, agreed] I think 
total biochar applications to a field could be heavy, like 100+ tons/acre.  
But, the application rate would be much slower.  Charcoal yields on 
pyrolyzing biomass are like 25% = 100 x (weight of char)/(dry weight of 
feedstock). [My calcs are closer to 50 tons per acre, about 2 lbs per sq. foot. But that will vary depending on soil and climate type. I mean, a sandy soil will need much, much more. A clay soil will need less. A muck soil won't need any at all. In the humid south and southeast, one will need a great deal more than in a dryer northern clime. These figures are likely to come with time and experience. Basically, what you are trying for is an optimal CEC.]



So, if you have 10 tons of dry feedstock per acre on a field, you could 
apply 2-3 tons of charcoal per acre per year (eggheads are going to call 
that "kg acre-1 yr-1") [Where will the 10 tons come from?
Surely not from the crops grown on that acre! In a really good year I
might get 4 tons of dry hay per acre. this year I got half that. If I were growing a seed or a
grain, I would get even less. Also, I have an aversion to tilling the
soil, especially every year. You may gain something but you use a
lose a lot in terms of soil structure. I do no-till. Ripping
up a field every year with tiller or plow is not good practice.
Amazonians didn't have tillers or even plows. They were probably more
like your modern day perma-culturist.].  So, take 40 years at 2500 kg acre-1 yr-1 to 
put 100 tons acre-1 yr-1 on a field.  Charcoal can improve soil friability, 
hold water, and hold nutrients, too. [I don't have any doubts about this last statement]

Thanks for the the thoughts and comments. These have forced me to do some serious pencil work. I don't think your numbers will work, but neither will mine.-- yet.

Jim


 







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