When you first hear about “biochar”, it is because someone around you most likely said something about it. And when you gave them that look that you didn’t understand what they were talking about, they launched into a diatribe on biochar and how it can save the world.
But wait, you scream. WHAT IS BIOCHAR? Where does it come from? How is it made? And why is it such a good thing? And explain these things to me as if you were speaking to your 9 year old nephew! They consider what you said for a while, and then they reply.
Biochar is made by heating organic matter (wood, manure, lawn debris, cornstalks) in a closed container in the absence of oxygen, a process called pyrolysis. Instead of burning, which leaves mostly ash, the material “thermally decomposes” into charcoal. As it does, the organic feedstock—say, wood—gives off gases that can be captured and turned into biofuel.
“BioChar” is a new word from the 1990’s. It is a combination of “biomass” and “charcoal”.
BIOMASS … is matter usually thought of as garbage. Some of it is just stuff lying around — dead trees, tree branches, yard clippings, left-over crops, wood chips, and bark and sawdust from lumber mills. It can even include used tires and livestock manure.
CHARCOAL … is a light black residue consisting of carbon, and any remaining ash, obtained by removing water and other volatile constituents from animal and vegetation substances
Biochar is just charcoal, produced by burning organic matter such as wood, grasses, crop residues and manure, under conditions of low oxygen (pyrolysis).
But the process and concept of “biochar” didn’t start in the 90’s. It started thousands of years ago, when farmers would roast 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 then buried in fields where crops were grown.
As colonization occurred, these fields were forgotten about. 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 man-made.
Why is this soil special? This 2,000 year-old practice of adding biochar to the soil, converts agricultural waste into a soil enhancer that can hold carbon, boost food security, and increase soil biodiversity, and discourage deforestation. The process creates a fine-grained, highly porous charcoal that helps soils retain nutrients and water.
“But, didn’t you just describe compost? That pile of rotting grass leaves, manure and other yard waste in the back of the house?”
No. Compost is the natural decaying of organic matter for use as a fertilizer only. Biochar is the controlled and smothered burn of waste that can be used as a fertilizer as well as other types of energy.
Compost doesn’t have charcoal: Biochar is pulverised charcoal made from any organic material (not just wood) and, when mixed with soil, it enhances its fertility. It locks carbon into the soil and increases the yield of crops. To many, this appears the closest thing to a miracle.
Biochar has been shown to increase the yields of rice (by 70%), tomatoes (over 150%). sugar cane (over 75%), Peanuts (over 50%) and Onions (over 50%).