Pyrogenic Carbon, Soil, and biochar

Aug 31, 2016

Josiah Hunt of Pacific Biochar wrote a nice article soon to appear on the nascent California Biochar Association website: 

 

Pyrogenic Organic Matter in Soil (aka biochar)


As long as fire and plant life have co-existed, charcoal has played a role in the development and fertility of topsoil. With thanks to some scientific sleuthing, we can pin that down to about 400 some odd million years ago, in the Palaeozoic period. (Heike Knicker, 2011, Link to full article: https://www.researchgate.net/profile/Heike_Knicker/publication/232408899_Pyrogenic_organic_matter_in_soil_Its_origin_and_occurrence_its_chemistry_and_survival_in_soil_environments/links/02e7e529090d0535b8000000.pdf

 

“The presence of [soil organic matter] SOM is regarded as being critical for soil function and soil quality.[2]”, it says on the Wikipedia description of Soil Organic Matter, citing Beare et al. 1994. On that same page two mentions of charcoal can be found:

In mentioning sources of Soil Organic Matter:

- “Additional sources of soil organic matter include plant root exudates[9] and charcoal.[10]

In describing Plant Residues:

- “Charcoal is elemental carbon derived from incomplete combustion of organic matter. Charcoal is resistant to decomposition.”

Using Wikipedia as a proxy for general awareness, it appears that there is at least an acknowledgment of charcoal as a piece of the soil organic matter puzzle, and that the SOM puzzle is “critical for soil function and soil quality”. While seafood does fill some of our diet, the rest of our food ultimately comes from soil. It doesn't seem too far of a stretch to say that soil organic matter is critical to humanity's food supply. Yet common farming and gardening practice in modern America is seemingly devoid of intentional use of charcoal in managing soil organic matter.

Into this gap came the word biochar. Biochar fills the void between the general lack of intentional use of charcoal and soil life's affinity for it (and some interesting climate change implications too). And apparently that void must have had quite a vacuum to it, since the term biochar popped onto the scene several years ago, there has been an explosion of research and literary work devoted to it. Some 4,000 research articles to date.

It could have been called the California Pyrogenic Organic Matter for Soil Association, or the California Charcoal for Soil Association, but it is not. We are the California Biochar Association. It is just a made up word – biochar – but it is pretty useful. Pyrogenic organic matter is quite a mouthful. Charcoal usually brings to mind a BBQ. Agri-char was an interesting option for a while, but according to an unconfirmed mention, that word was already a registered trademark, but “biochar” was still open.

I hope you will enjoy the wide range of information we present here for an incredibly old material with a relatively new name.

Thank you for taking part.

- Josiah Hunt


Bibliography:

1.) Pyrogenic organic matter in soil: Its origin and occurrence, its chemistry and survival in soil environments
Heike Knicker,
Instituto de Recursos Naturales y Agrobiología, CSIC, Avda. Reina Mercedes, 10, P.O. Box 1052, E-41080 Sevilla, Spain

Available online 12 March 2011

https://www.researchgate.net/profile/Heike_Knicker/publication/232408899_Pyrogenic_organic_matter_in_soil_Its_origin_and_occurrence_its_chemistry_and_survival_in_soil_environments/links/02e7e529090d0535b8000000.pdf

 

2.) Beare, M. H.; Hendrix, P. F.; Cabrera, M. L.; Coleman, D. C. (1994). "Aggregate-Protected and Unprotected Organic Matter Pools in Conventional- and No-Tillage Soils" (PDF). Soil Science Society of America Journal. Free PDF download. 58 (3): 787. doi:10.2136/sssaj1994.03615995005800030021x. Retrieved 13 July 2016.


By Milton E McGiffen
Author - CE Specialist and Plant Physiologist