What is Biochar?

Biochar is an ancient human agricultural practice, largely forgotten until recent decades. Ancient biochar has been discovered in the Amazon basin, where it is known as “Terra Preta.” Fertile soil infused with biochar provided food for millions of Ancient South Americans in a region otherwise challenged by low soil fertility.

“Terra Preta” biochar soil remains rich and fertile to this day. Biochar is the carbon which remains after plant or animal matter is baked or “pyrolized” at low temperatures, in the absence of oxygen. It is a natural process that occurs during forest fires. Carbon is a natural component of healthy living soil. The ancients augmented this naturally occurring soil carbon by producing biochar in a process similar to charcoal-making. Modern biochar pyrolysis is an efficient, tightly engineered process which generates biochar and valuable by-products cleanly, with energy self-sufficiency, and is carbon negative.

How does Biochar work?

1. Production. Biochar, when property produced via pyrolysis, retains the microscopic cell structure of the plant or animal material from which it was made. A handful of biochar contains many square miles of surface area and billions of cellular cavities. Biochar comes out of the pyrolysis process sterile.

2. Inoculation. Sterile biochar is “inoculated” with beneficial biological life. The easiest method is by incorporating biochar into an existing compost operation. Beneficial microorganisms, fungi, and bacteria take up residence in the vast network of biochar cell cavities, where they flourish, reproduce, compete and generate plant-available nutrients. This can take 3-12 weeks.

3. Use as Soil Amendment. Inoculated Biochar compost is introduced into agricultural fields or lawn soil. There, it improves virtuous nutrient cycling, increases water retention, accelerates the building of soil organic matter, and filters out mineral fertilizers and toxins that would normally run off into streams.

Biochar Advantages

• Biochar helps build soil organic matter (SOM), soil organic carbon (SOC) and soil biological activity. Compost alone is a good method to sequester carbon into soil (thus removing it from the atmospheric stock of CO2.) However, compost oxidizes in a few years, returning its carbon into the atmosphere. Biochar is soil carbon which remains stable in soil for hundreds or thousands of years, while also benefiting soil fertility.

• Biochar enhances the rainwater infiltration capacity of soil. Less run-off means reduced nutrient management issues, increased drought tolerance and reduced stormwater management costs.

• Biochar acts as a large-scale “carbon filter,” absorbing surplus mineral fertilizers, pesticides and toxins prior to stormwater carrying them into waterways. • Biochar turns agricultural waste into a valuable farm product. Chicken litter, diseased trees, manure, invasive species biomass, municipal wood chips… All can be pyrolyzed into sterile biochar.

• Biochar production is energy self-sufficient and can generate excess energy for resale into the grid, to heat greenhouses or otherwise displace conventionally-produced energy. • Biochar production is clean, exceeding California emissions standards.

• Biochar production generates valuable by-products. Depending on the feedstock biomass that is being pyrolyzed into biochar, the process can yield valuable quantities of waste heat, syngas, wood vinegar and other high-value products.

• Biochar helps restore essential soil carbon levels and biological biomass levels, which have been depleted by intensive agriculture. Biochar is NOT a waste product, it is carbon mad from organic feedstocks, which augments a natural soil-building process that is millions of years old.

• Biochar is particularly effective in accelerating the conversion of “conventional” agricultural fields, domestic lawns and municipal greenways to organic practices.

 

 

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Richard with biochar that is being blended with his compost.

Richard Jefferies operates Utica Bridge Farms, a chemical-free farmstead which grows 50+ varieties of heirloom vegetables, berries, fruits, nuts and grains, using practices which build healthy biologically-active soil, support biodiversity and produce nutrient-dense food. This work is taken from a presentation he made at a Future Harvest CASA conference.