Biochar Soil Amendment

biochar seedling

Along with bags of potting soil, mulch, and compost, you can now see our bags of Organic Biochar for sale - with our product being the only BioGro certified Biochar available in New Zealand.  


To explain what Biochar is, we need to return to the Amazon basin circa 450 a.d. Indigenous people didn’t practice slash-and-burn farming as they do now. They practiced slash-and-char agriculture, roasting wood and leafy greens in “smothered” fires, in which lower temperatures and oxygen levels resulted in the production of charcoal instead of ash. The charcoal was buried in fields where crops were grown.

But then, with the arrival of Europeans and their diseases, the Amazon civilizations (including El Dorado), some with cities of more than 100,000 people, collapsed. Slash-and-char agriculture was forgotten, as were the fields of buried charcoal. But they weren’t gone. In the 20th century, huge expanses of black soil were rediscovered, although at first no one knew what they were. Then, in the 1990s, scientists determined that these soils were manmade. They were dubbed terra preta (“dark earth” in Portuguese). And they were extensive. Some estimates put the total acreage covered by the charcoal-enriched soil at twice the size of Great Britain.

Most amazingly, the soils extended up to 6 feet deep in many places. Scientists have theorized that terra preta soils are self-propagating and have grown in depth since they were first made. The charcoal, acting a lot like humus, had been colonized by myriad microbes, fungi, earthworms, and other creatures; these soil organisms produced carbon-based molecules that stuck to the charcoal, gradually increasing the soil’s carbon content. Carbon in decomposing plants, which would otherwise escape into the air as greenhouse gases, was sequestered by the biologically active charcoal in the soil. Scientists theorize that the charcoal was originally laid down in thin layers and that earthworms chewed through the layers and mixed them deeply into the soil. BioGeoChemical Cycle Plus CP Pyrolysis

That is just the beginning of the benefits of this strange soil. It appears that the carbon will be sequestered for a thousand—possibly thousands—of years, unable to contribute to global warming in the form of greenhouse gases. Green charcoal, or biochar made from agricultural residues or renewable biomass, appears to hold the most promise as a carbon sink. Every ton of this biochar in the soil is capable of capturing and holding at least 3 tons of carbon.


According to scientists studying the soils, microbial growth of all kinds is substantially improved. And so is the soil’s ability to hold nutrients until plants need them, then dole them out at the optimum rate for plant health. Crops have been shown to grow 45 percent greater biomass.

Research on biochar is under way at universities around the world (including Massey University in NZ), and agribusiness is beginning to show interest. 

Biochar: The oldest new thing you never heard of

Biochar Tedx      Wae Nelson at TEDx (Click on image)

Please take a moment and click on the video link (left) so watch an amazing video on the history and future benefits of Biochar in our environment. 

Biochar is ... plant biomass derived materials contained within the black carbon (BC) continuum. Like most charcoal, biochar is created by pyrolysis of biomass. Biochar is under investigation as an approach to carbon sequestration to produce negative carbon dioxide emissions.  Biochar thus has the potential to help mitigate climate change, via carbon sequestration. Biochar is carbon negative. Independently, biochar can increase soil fertility of acidic soils (low pH soils), increase agricultural productivity, and provide protection against some foliar and soil-borne diseases.  Furthermore, biochar reduces pressure on forests.  Biochar is a stable solid, rich in carbon, and can endure in soil for thousands of years.  (Abstract from Wikipedia).