Does soil biochar ‘lock in’ carbon or does it ultimately release it into the atmosphere?


A carbon source is an activity or material that ends up pumping carbon into the air we breathe .e.g. fossil fuels.

A carbon sink on the other hand is an activity that instead ‘locks up’ carbon out of the air we breathe .e.g. planting of trees which is a climate change mitigation strategy.

In considering how to categorize biochar, what are the knowns and unknowns?

In this case, we’ll consider some unknowns which we’ll call ‘somewhat unknowns’…


Though there are many lingering unknowns on biochar use in soil, three come to mind.


Though biochar’s porosity is known to improve soil microbial life, what types of microorganisms thrive in this situation?

What type of gases do they release?

What is the long term effect on the overall microbial balance in the soil?

Because these microbes don’t easily breakdown biochar, what do they use as an alternative energy source?

Could there be microorganisms that break down and use biochar as an energy source?

Such questions should trigger the research community to not only measure growth of microbial communities but also understand what types of communities thrive and the soil emissions that go with it.

But beyond adjusting the microbial life balance, incorporation of biochar into the soil comes with it’s fair share of inconveniences.


Biochar is mainly incorporated into the soil as small particles for good mixture.

What is the fate of this dust once it is disturbed and displaced from the soil?

What contribution does it make to atmospheric particulates and what implications does this have on air quality?

What are some better methods of incorporating soil biochar to reduce air char dust?

But lastly, though biochar is produced from many types of farm wastes, some international advocates seem to promote the use of wood from trees as a viable source.


Since trees do sequester atmospheric carbon into organic matter, they are a sure way to reduce the atmospheric effects of greenhouse gases.

But using these same trees to make biochar is a whole different ball game because of two reasons.

First, perhaps the best way to refer to biochar is biochars because of it’s multiple sources one of which is wood.

How would we know the best type of wood to produce the best biochar for a specific type of soil?

More research therefore needs to be done on the effects of different types of biochar to different soils over the long haul.

But secondly, biochar production from trees would promote deforestation in many areas who’s adverse effects are known.


Biochar use as soil amendment provides us with a unique opportunity not only to research on it’s benefit to agriculture but on it’s environmental impact over the long haul.

It’s not necessarily an opportunity waiting for the lab based researcher but that experimental land owner willing to improve productivity sustainably.