Farmer John: With biochar, looking at past practices for better soil today


SIGMA — Imagine being in the paradise state, inside a condo on a beautiful day. I was there, in Hawaii, back when I was blond-haired. Now I still have three or four blond hairs left.

My dermatologist told me that, as a blue eyed, blond, fair-skinned person, I had a quota of sunshine hours in my life, and I had used most of them already. Taking his advice, I would come in during the middle of the day for several hours. 

One fateful day, I returned inside, turned on the TV and caught a BBC documentary, Unnatural Histories: Amazon, which discusses terra preta, a soil-building method used in the Amazon. Being a soil geek, I instantly knew this would be good. By the end of the show, I was standing, mouth open, pointing at the tube. I was hooked on the topic. I had no idea then how important it really was.

The great secret hiding in plain sight is called biochar, a term that refers to converted biomass used to improve soil. Wider knowledge of biochar was just beginning take off then. Many others have also become hooked. 

Bio refers to life, char to burned wood. Rediscovered by aerial photography, archaeology and soil science, its value became apparent. Terra preta, or dark earth, has been made for at least 8,000 years by indigenous people, according to a new book called Sacred Soil: Biochar and the Regeneration of the Earth.

Authors Robert Tindall, Frederique Apffel-Marglin and David Shearer use research to show how these soils are more fertile for longer periods than anything we do today. The use of biochar has also been found in other continents – also made by people long gone.

Fast forward to the present. Virginia Tech has done research on biochar in a controlled greenhouse setting. Dr. Ron Morse found as much as 40 percent increase in size and health in tomato plants. And Dr. Doris Hammil, a researcher from NASA Langley, was tasked with finding the most useful carbon sequestering process available today. Her answer, biochar, had no equal. I had the pleasure of seeing a presentation about her results at an event on the farm. The soil implications are vast.

The char part is made by a process called pyrolisis, or burning wood without oxygen. It ‘carbonises,’  becoming pure carbon, which can last for thousands of years. 

It also becomes microscopically porous, which is important because it becomes the permanent home to those all-important microbes which make soil healthy and productive. 

Microbes do the heavy lifting in soil development and nutrient cycling. This process may sound technical, but it is scalable to any farming or gardening situation. I make it at home using two barrels. After it is carbonized, I add it to an almost-finished compost pile where it absorbs the microbes.

It could and should be a part of a citywide management plan for dead and downed limbs and construction debris. Like composting, this would keep refuse out of the landfill while creating something of great value. 

Other benefits can be added to a scaled up version as well. Electricity can be made, water  heated or even buildings heated, to name a few.

The Amazon peoples were decimated by the European diseases left behind after the first voyage from Spanish explorers. So we can’t know every detail, but research being done suggests that they had a strong ethic of giving back to Mother Earth.

Those of you who are in a healthy relationship know this from your union: it is a 100 percent effort from both, not 50-50. Their own efforts or making new soil continuously rewarded them with a very prosperous civilization which lasted a long time. Terra preta soils remain healthy to this day.

I use a little biochar on every garden I build and every farm I work on, and I keep some on hand for sale as well.

With results pulled from ancient sites, NASA research facilities, Virginia Tech researchers and many other sources added all the time, I think its time to employ this remarkable soil restoration technique.

Wilson, a farmer and consultant who lives in Sigma, writes about sustainable agriculture for The Independent News. Reach him via

© 2017 Pungo Publishing Co., LLC

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