Carbon – How valuable is it for your soil?


Carbon – How valuable is it for your soil?

Back in July 2016 I posted an article on chemicals in horse manure and the damaging effects it had on that man’s garden. Literally that same week I had a customer come by to pick up some more Compots and she told me she had the exact same problem in her garden when she added horse manure. She managed to resolve the problem by adding Activated Carbon to the soil.

So this sent me on a mission to find out about Carbon and Activated Carbon because I sell what I call ‘Old Forest Carbon’, which is essentially old forest tree bark that has been slowly composting away for hundreds of years beneath a river bed that was dug up for sand mining. I wanted to know if this Old Forest Carbon was of any value to your soil and how it differed from Activated Carbon.

So with Bob’s help and hours and hours of research on Carbon, Soil Organic Carbon (SOC), agricultural importance of carbon and soil fertility, this is what I came up with.

The Carbon Cycle

As we all know all soil has a mixture of nutrients as does the air above it, both of which are constantly changing. Carbon (C) being one of those nutrients is mainly tied up with Oxygen to form Carbon Dioxide (CO2) in the air, and exists in the ground as a component of Soil Organic Matter (SOM).

It is constantly being taken up by plants, processed and released back into the atmosphere and soil as the plant grows and dies.
The Carbon Cycle.

Soil Flora, (Bacteria and Fungi) which live in the ground, also use CO2 to make soil material, eg Fungi Mycelium. These are the fine white threads you see in a rich or composted soil that has a lot of Fungi growing in it. Eg. Mushrooms – the fruiting visible part of the Fungi Mycelium.

All living material has Carbon in the form of Carbohydrates (Carbon, Hydrogen & Oxygen – ie. Sugar, Starch or plant fibre).

When a plant or animal dies the breakdown Bacteria and Fungi attack it and reduce it to Organic Matter that we call Compost.

Compost is a rich source of AVAILABLE nutrients which includes Carbon and can therefore be used to increase the Carbon content of your soil which aids plant growth along with all the other necessary nutrients.

Layers of Compost

Most soils used for agriculture over a long period of time will be lacking in Carbon (˂ 1%). Destroyed by frequent cultivation, stubble burning, overgrazing and fallowing that destroys the soil’s structure.

Farming methods need to change in order to maintain carbon levels or measures need to be taken to increase the carbon level by adding a Carbon rich supplement.

This can be done with a product rich in Carbon or by making your own Compost. Plus(for farmers)following more recent farming practices of not tilling the soil, not burning the stubble, reducing grazing, crops rotation, and green manures and composting.

The same can be done in your garden on a smaller scale or by adding a Carbon supplements as well as Compost. But remember to make your Compost from a variety of sources or you are likely to end up lacking a nutrient in your Compost that you won’t know is lacking until you grow some plants.

Farmers also now try to sequester (capture) Carbon to improve their land and plant quality. And to reduce the problems associated with increased Carbon in the Atmosphere from the burning of fossil fuels that is creating much of the green house problems we have today from putting excess carbon into the atmosphere.

Charcoal consists of Carbon and the left over ash that remains after water and volatile gases have been removed from such things as animal and vegetable material.

It is made by slowly heating wood in the absence of oxygen. Charcoal sticks used in Art are simply Charcoal bound together with a binding agent.


Activated Charcoal on the other hand is Carbon material that has been put through a high pressure hot steam system to remove matter from within its structure thereby increasing its capacity to absorb new material and thus ‘activate’ it (ready to absorb matter).

When it absorbs water and nutrients it allows plant roots to access and use these nutrients for growth, but it is also used to absorb harmful chemicals and poisons, and is used in many other applications such as water filters and mask filters.

Biochar is a form of Activated Charcoal used to promote soil health due to its very porous nature as it retains both water & water–soluble nutrients (remember that plants can obtain nutrients ONLY in solution)

Biochar also:-

  • Reduces leaching of E. coli through sandy soils (Some forms of E.coli act as Organic Matter decomposers)
  • Improves soil quality
  • Reduces soil vaporisation of green house gasses. Eg reduces Nitrous oxide by up to 80% & wipes out Methane both of which are more potent as greenhouse gasses than Carbon Dioxide
  • Reduces nutrient leaching
  • e. Reduces soil acidity and need for extra nutrient supplements, but due to its high absorption capacity it can reduce efficiency of soil applied pesticides. But if you don’t use pesticides then it doesn’t matter.

So where does that leave the Old Forrest Carbon?  From my research it’s a slow release carbon supplement (much like Biochar) but formed naturally beneath the river bed.  And like charcoal can aid in soil fertility management of nutrients, water and organic matter retention but this Old Forest Carbon contains 27% Carbon.
Click this link to see the carbon test results
Check out the Terra preta soils found in the Amazon that mostly were built from carbon. See below.

“The charcoal is very stable and remains in the soil for thousands of years, binding and retaining minerals and nutrients”


Today’s Did You Know…?

Amazonian people inadvertently produced amazing soil known today as Terra Preta whose black characteristic come from its weathered charcoal content, bone, and manure mixed in with the relatively infertile Amazonian soil.

The charcoal was produce by a slash-and-char method of agriculture rather than a slash-and-burn system that has in the past helped cause much of the degradation of soil on farming lands today.

“The processes responsible for the formation of terra preta soils are:

  • Incorporation of wood charcoal
  • Incorporation of organic matter and of nutrients
  • Role of micro-organisms and animals in the soil”