[Terrapreta] FIeld and Nursery Trials

[Tom Miles]

Jim,

 

You may not have received Richard's reply to you  before you replied.  He
said, "Our charcoal dosage was to bring total carbon (OM + added charcoal )
to something less than 10%. We determined this to be a maximum dose and not
a dose for large scale application." He'll provide the first year report to
the list when it is complete. The plots have been replanted with no
additional charcoal and the test is ongoing for the next 1-3 years. 

 

If you go back through the field trials by the various Cornell and U
Beyreuth researchers you'll find that most applications land in the 1-10
mt/ha range.  U Beyreuth found that most of the Amazonian soils were 3C% or
less. 10% is considered a maximum. See Julie Majors poster on arid soils in
Columbia etc. Most of these are linked on the TP site. They are all listed
and linked on the Cornell and EPRIDA sites.   

 

The question remains of how much charcoal is required in a particular soil
in combination with other nutrients for a marginal gain of a specific
agronomic value such as yield, fertilizer reduction, inoculation/healthy,
etc. General formulas may apply as a baseline but if there is value in terra
preta agronomists will test the variations for centuries to come. 

 

We look forward to seeing what you finally decide to put in the ground. 

 

Tom

 

 

 

 

From: terrapreta-bounces at bioenergylists.org
[mailto:terrapreta-bounces at bioenergylists.org] On Behalf Of Jim Joyner
Sent: Saturday, November 24, 2007 10:04 AM
To: terrapreta at bioenergylists.org
Subject: Re: [Terrapreta] FIeld and Nursery Trials

 

Tom, Let's see, 30 gallons (assuming 231 cu inches per gallon) is about 4 cu
ft or 52 pounds for 85 sq feet, which is about 13 tons an acre. Be
interesting to know how they arrived at that rate. It still looks like there
response was positive. 

Sean, I guess I don't understand why (Cornell) aimed at yield on nitrogen
fixing beans. They didn't explain. Maybe if one doesn't have a history of
soil responses, that is the best one can do. I too would start with legumes
just to try to build up nitrogen, to see what effect there would be on
nitrogen or how much net nitrogen I could generate. But I think it is the
following crops that really count. 

If we can get agriculture to the point we only have to replace the nutrients
in the food we've taken out, that is a very efficient agriculture. The
delusion we live with in modern agriculture is that NPK is all it takes to
grow food, that we are not mining other things out of the soil.

In my experience I've applied as much as 200 tons of compost per acre, not
so much for nutrient but to try to get the carbon and CEC up so it would
hold the nutrient. And, it will, for a while. But then over the years (even
with no-till) the carbon in the soil will literally burns off so that no
matter how much nutrient I put in the soil, it is wasted because the soil
can't hold it. It just washes away. This has been the bane of the organic
farmer particularly in the south.

If, due to charcoal's crystalline structure (or some other magical quality),
it persists, the whole game of agriculture has changed. I'm guessing, of
course, but it might well be something like the paradigm shift as occurred
after WWII with chemical farming.

But I digress.

I suspect, with proper amount of nutrients, one could grow in pure charcoal
-- don't know why anyone would want to, but it could be done. My guess is
that the maximum quantity per acre has more to do with economics than the
soil or even the crop.  

I find it interesting that terra preta can be meters deep. Plants do move
elements around in the soil. By having a loosed subsoil without pans, roots
will take carbon down year after year, but I doubt that accounts for the
pictures of the black soil so deep. (It's just hard to think about a 2
thousand year time horizon.) 

Meters deep charcoal clearly would not be economical. It would not be
harmful, and even though there would be some benefits in having biochar so
deep, those benefits could be accomplished better and cheaper in other ways.
For example, in Guam, after a super typhoon, we buried palm trees in land
that was replanted with fruit trees. In Missouri we buried saw dust up to a
depth of 6 feet (in the sub soil) before planting grapes. Both worked great
for giving the plants a store of moisture and showed clear benefits over
planting without. And the biomass can take decades or longer to go away.

I think, generally, it would be better to put charcoal in the soil in one
shot rather many. First, the expense of doing it, not including the
charcoal, is significant. Second, often such tillage or plowing is two steps
forward and one back as there can be a loss of erosion control and the loss
of soil structure itself. 

BTW, has anyone considered the SARE (Sustainable Agriculture Research and
Education) program? They give out completive grants every year for both
research and education. Their grants can be in the hundreds of thousands $
and for multi-year projects. They even have up to $10,000 grower and
graduate student grants for demonstrations and just good ideas. 

The thing about terra preta research, it wouldn't seem that any one would be
threatened. Until they became trendy we had a terrible time getting funding
for anything "organic" because some private university funders (read
chemical companies) did everything they could to stop them. But , it seems
TP has something for everyone. I mean, even if it lowered the per acre use
of chemicals for conventional farmers, it would still probably make
agriculture as a whole, grow. It might even make up for the loss of the
obscene subsidies large American farmers get (at least I hope they lose
them).

Jim

 

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