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What
is biochar?
How can biochar
help combat climate change?
How
much carbon does biochar contain?
Is
biochar another biofuel?
How
easy is it to make biochar?
If
biochar were to qualify for CER certificates, how
could you be sure that it would not be burnt and
so return carbon to the atmosphere?
Are
we talking about an industrial process or can biochar
be produced on a small scale?
How do
you get the biochar back into the soil?
Doesn’t
the production of charcoal itself cause pollution?
How
does biochar improve the fertility of soil?
How
do you know that it will remain in the soil for hundreds
of years?
If mankind
were to add biochar to the soil wouldn’t that be just
creating a carbon time-bomb for future generations?
If biochar
qualified for carbon credits wouldn’t this mean that
people would cut down standing trees in order to get
them?
Isn’t
this just a scheme to allow developed countries to
go on polluting – surely if global warming is to be
prevented we need to cut emissions?
Does
Carbon Gold have any projects up and running?
How
effective could biochar be in reducing CO₂?
Compost
improves soil humus levels, isn’t it therefore better
to make compost than biochar?
When
you do your calculations do you take account of the
CO₂ that is emitted by transporting biomass to a carbonising
plant, or from using fossil fuels to produce biochar?
It all
sounds too good to be true; there must be some negatives?
What
kinds of biomass can be used?
How
much biochar can be added to the soil?
Can
biochar be added to the soil straight away?
The
Terra Preta were formed thousands of years ago; nobody
can be really sure what the Amazonian Indians did to
create them. Is there any firm scientific evidence
to support the view that biochar will improve soil
fertility when used today?
What
is biochar?
Biochar is a form of form of charcoal that is used to
improve soil fertility. It is made by heating waste biomass
while restricting the oxygen supply. Whereas the kind
of charcoal that people use at home in their barbeques
needs to be in sizeable lumps if it is to burn well,
biochar that is to be mixed into the soil typically is
made up of much smaller pieces and can even be a powder.
Read more…
How
can biochar help combat climate change?
When plants grow they absorb carbon dioxide from the
atmosphere. Under the normal carbon cycle when plants
die they either rot or are burnt and the carbon they
absorbed is returned to the atmosphere. If, instead,
waste biomass is turned into biochar, it can be buried
in the ground, locking in the carbon for hundreds or
even thousands of years.
How
much carbon does biochar contain?
It varies according to production methods, but is typically
between 70 and 90% carbon.
Is
biochar another biofuel?
No. Biofuels are made by a variety of processes but are
mainly derived either from oil bearing plants such as
palm oil or oil-seed rape to produce biodiesel, or, by
the fermentation of crops such as wheat or sugar cane
to produce ethanol. In all cases, the crops from which
biofuels are derived take carbon dioxide out of the atmosphere
while they are growing, but as soon as that biofuels
is used, the carbon is returned to the atmosphere through
the vehicle’s emissions. In contrast biochar locks the
captured carbon into the soil.
How
easy is it to make biochar?
Humans have been making biochar for thousands of years;
the basic production process is not difficult. Carbon
Gold’s technology has been developed to ensure that the
process is as efficient as possible.
If
biochar were to qualify for CER certificates, how could
you be sure that it would not be burnt and so return
carbon to the atmosphere?
Carbon Gold has a methodology for biochar against which
the standard for biochar accreditation can be given.
One way of ensuring that biochar could not subsequently
be burnt is to mix biochar with other soil additives
such as compost; this would ensure that biochar could
not be used as a fuel.
Are
we talking about an industrial process or can biochar
be produced on a small scale?
Biochar can be produced by large plants capable of turning
out 10,000 tonnes per annum or as a cottage process producing
just a handful of biochar each day. Carbon Gold only
operates at the smaller end of this scale.
How
do you get the biochar back into the soil?
Biochar can be simply applied to the surface of the land
or mixed with other organic material as nutrients.
Doesn’t
the production of charcoal itself cause pollution?
Charcoal production can generate pollutants - tars, phenols,
carbon dioxide and nitrous oxides. But it should be remembered
that these are at much lower levels than would be emitted
if the biomass was simply burnt when all the products
of combustion would be released into the atmosphere.
Carbon Gold’s technology minimises pollutants; the bi-products,
such as wood gas which contains methane, which is given
off as part of the carbonisation process can be used
for cooking or heating purposes or used to fire the process.
How
does biochar improve the fertility of soil?
Scientists have known for years that adding biochar could
improve soil fertility. The early Amazonian Indians introduced
biochar to their soil over 3,000 years ago, forming the
Terra Preta, black soil which remains fertile to this
day. It is only recently that the reasons why this happened
have been understood. Biochar is extremely porous; the
surface is like a sponge. According to Johannes Lehmann
of Cornell University, this encourages the growth of
micro-organisms which produce enzymes that release the
mineral ions trapped by the heat stabilized plant resins
in the charcoal and make it available to the root hairs
of the plant as nutrients. Furthermore, the resins within
the charcoal act like an ion exchange resin, absorbing
traces of mineral ions onto the charcoal particle surfaces
from the rain water, and trapping it within the charcoal’s
molecular structure, where it can be held for centuries
- until the soil bacteria associated with a root hair
come along and secrete the enzymes necessary for it to
be released once again. So the trace minerals always
present in rainwater actually act as a fertilizer - providing
the nutrients needed by the crops, year after year.
How
do you know that it will remain in the soil for hundreds
of years?
Carbon is chemically stable; it does not react readily
with water or atmospheric oxygen, so once in the soil
it tends to remain there. The carbon in the Terra Preta
has been subject to some of the highest rainfall on earth
and it is still present after 3000 years so the rate
of break-down is not something with which we need to
be concerned.
If
mankind were to add biochar to the soil wouldn’t that
be just creating a carbon time-bomb for future generations?
No, biochar added to the soil would be like coal reserves
- highly stable. Any breakdown with a return of the carbon
to the atmosphere would be extremely slow and could be
counteracted by continuing biochar production. What we
are proposing is a different agricultural practice that
will do away with harmful slash and burn that can deplete
the soil and add to CO₂ emissions and replace it with
a process that will tie up carbon and improve soil fertility.
If
biochar qualified for carbon credits wouldn’t this
mean that people would cut down standing trees in order
to get them?
In order to qualify for carbon credits, projects need
to be subject to regulation and verification so that
only biomass which is genuine waste is used to create
biochar and qualifies for carbon credits. Where we are
actively restoring neglected coppiced woodlands the products
of coppice rotation management are used to make biochar.
Isn’t
this just a scheme to allow developed countries to
go on polluting – surely if global warming is to be
prevented we need to cut emissions?
Biochar can be an important weapon in the battle against
climate change and can give mankind much needed time
to develop cleaner forms of energy. It cannot be expected
to compensate for increasing emission levels so it is
vital that everybody plays their part in reducing energy
consumption.
Does
Carbon Gold have any projects up and running?
Carbon Gold already has projects underway in Belize
and Sussex We expect others to be up and running by the
end of the year.
How
effective could biochar be in reducing CO₂?
Biochar can be an important part of the solution. It
is not a silver bullet and other measures such as reducing
emissions are essential. It takes 2.12 gigatonnes of
carbon to reduce atmospheric carbon dioxide by 1 part
per million. Johannes Lehman at Cornell University has
calculated that if slash and burn could be changed to
slash and char, it would yield 0.2 gigatonnes of carbon
while forestry residues would yield a further 0.16 gigatonnes,
so already we are up to over a third of a gigatonnes.
Further biomass could be obtained by crop waste; in general
only 5% of plant crops are actually eaten. So creating
a gigatonne of carbon a year from biochar looks possible.
Compost
improves soil humus levels, isn’t it therefore better
to make compost than biochar?
Compost does improve soil quality but the carbon that
is tied up in the humus will break down over a period
of about ten years whereas biochar also improves soil
fertility but the carbon is locked up for hundreds of
years.
When
you do your calculations do you take account of the
CO₂ that is emitted by transporting biomass to a carbonising
plant, or from using fossil fuels to produce biochar?
One of the great benefits of producing biochar is that
it can be done locally keeping transport emissions to
a minimum. Modern biochar plants require very little
energy because they use the gases emitted by the biomass
to fire the process.
It
all sounds too good to be true; there must be some
negatives?
The chief negative is time; if mankind is to avert major
climate change we need to take action now. We also need
to do more research to discover the optimum way that
biochar can produced and the best way that it can be
used to improve soil fertility.
What
kinds of biomass can be used?
Any dry uncontaminated organic material can be used to
create biochar. It is possible to use waste from crops
such corn or sugar cane, wood and sawdust, peanut husks,
or even manure. As one of the advantages of biochar is
that it can be used to improve soil fertility it is important
not to use feed-stocks which may have been contaminated
with heavy metals such as old painted wood which may
contain lead.
How
much biochar can be added to the soil?
Application rates tend to be between 10 and 30 tonnes
per hectaire.
Can
biochar be added to the soil straight away?
Well-made biochar can be applied directly.
The
Terra Preta were formed thousands of years ago; nobody
can be really sure what the Amazonian Indians did to
create them. Is there any firm scientific evidence
to support the view that biochar will improve soil
fertility when used today?
The Department of Crop and Soil Sciences at Cornell University
have studied the use of biochar. They found that it could:
• stop soil degradation and allowing
sustainable crop production with minimal inputs
• reduce pollution of surface and ground water by retention
of phosphorus and nitrogen in soil,
• mitigate climate change by providing a long-term carbon
sink and reducing emissions of greenhouse gases other
than CO₂.
They concluded – “if you consider
adding organic matter to soil, it should be biochar.
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