On 07/12/13 09:00, David Murphy wrote:
Greetings Biochar/Gasifier people !
Everybody & his dog seems to have something to say about
charcoal/biochar/biochar-compost mix and so on. Well, here's
another dog to bark his piece !
Biochar is often seen as the great agricultural panacea, but _it is
not_.Biochar is a name given to plain ordinary charcoal to indicate
that it is destined for use in soil improvement, but basically it is
still plain ordinary charcoal, just crushed into smaller particles. In
some circumstances it is a very beneficial tool but it is not magical
as some proponents seem to think. Just remember, all charcoal has a
bio-origin - wood.
In some Ag. trials in Australiait significantly improved crop volume
(treble in one case) but in other instances, nothing worth writing
home about.It depends on what the soil is like to start with.
Charcoal is stable.That means it does not take part in any composting
system (which is one primarily of bacterial digestion) and it is
indigestible so that when offered as a dietary supplement (in poultry
food for example) it passes through the digestive system physically
unchanged but will adsorb a high proportion of the gases and some
toxins produced in the process of digestion, because that is what
charcoal does. For this reason, it's adsorption capability, poultry
will generally do better on a little charcoal.
Quite a few pages could be filled on the beneficial services provided
by charcoal as it travels through the digestive system, but it does it
as charcoal only and as nothing else. By all means use a little in
the feed, you can only benefit.
The only physical way to change the nature of charcoal is to burn
it. That is why it lasts in soil (or wherever it is) for thousands
of years.
It has an incredibly high surface area of 360 m^2 (varies) and is a
mass of minute tunnels which in turn means a very high volume and
gases become trapped in these tunnels.It does not _ab_sorb, it
_ad_sorbs and traps only.The difference between absorb and adsorb is
the same as the difference in liquids of suspension and solution.Clay
particles will be in suspension, sugar and salt go into solution.
Charcoal is useful in an aerobic composting system because again of
the entrapment of air in the tunnels.A composting system goes well if
there is enough oxygen bearing air available to the bacteria which are
a significant part of the system.The more air, the higher the
population of bacteria (other factors being OK). The charcoal itself
is inoperative, and doesn't change, nor is it a catalyst, it simply
provides a service. It will only provide a haven for soil benevolent
bacteria if there is something trapped in the tunnels which the
bacteria can eat.
Charcoal is a good adsorber of gas and liquid simply because that is
what it does.Zeolite on the other hand, can have an even higher
surface are per gram and has a propensity to entrap gases, most
particularly nitrogen in it's various forms -- as gas -- ammonium for
example -- and in liquids as a salt of NO_3 .It actually draws them in
(like a magnet attracts ferric objects) where charcoal just takes it
as it comes. It is easy to see also why charcoal is so effective as
a filter, but if you have a solution rich in nitrogen, run it through
Zeolite and the N will be removed. Add some to the litterin poultry
grower sheds, there will be fewer mortalities because the ammonia
which sometimes will asphixiate small birds will be absorbed.
Zeolite will take N out of solution, charcoal will not. There's 40
natural forms of Zeolite and more than another 150 can be synthesised,
so choose carefully for the one most appropriate to your problem.
Zeolite can perform an amazing range of actions. Once used and
applied as fertiliser, Zeolite subsequently will release the Nslowly
and remain in the soil as a balancer of N. Too much, it will take it
in (so that the soil pH is not lowered) and release it as required.
Charcoal's great stuff though, it's easy to make and holds answers to
a lot of problems - but not all !
David Murphy.
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BioChar is not "ordinary charcoal".
Charcoal is usually made at temperatures above 1000C and all volatiles
are removed.
Bio-char is made a lower temperatures, 400~600C just above spontaneous
combustion temperature of organic material (wet or dry). It contains
tars and a different structure withing the hollows than `ordinary
charcoal`. It is the structure and the tars that make a good home for
soil micro organisms. It also holds water and minerals better than
charcoal.
See http://www.biochar-international.org/ for more detailed information
and projects.
Local Australian groups:
http://biocharproject.org/
http://www.bioenergyaustralia.org/
--
Paul Judd B.App.Sc. Secondary Metallurgy, Dip Electrotechnology Renewable
Energy, Dip Sustainability
Trainer and Sustainability Advisor
PAJeco Sustainable Education
Sustainability: Learning to live today but leaving enough to live tomorrow
http://www.pajeco.com.au
[email protected]
+61415518134
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