26 Feb Charcoal to Improve Soil: What do you Think?
I was reading recently in Mother Earth News about an ancient technique of using charcoal for soil improvement. Author Barbara Pleasant says that the technique is 3,000 years old and involves digging a ditch and burning the weeds (with woody matter) after weeds have gone to seed. They call it biochar.
According to Wikipedia, “Biochar is charcoal created by pyrolysis of biomass. The resulting charcoal-like material can be used as a soil improver to create terra preta, and is a form of carbon capture and storage. Charcoal is a stable solid and rich in carbon content, and thus, can be used to lock carbon in the soil. Biochar is of increasing interest because of concerns about climate change caused by emissions of carbon dioxide and other greenhouse gases.”
Barbara says that the idea originated from the Amazonian rain forests of Brazil. Apparently the tribes there grew crops in soil made from compost, mulch and smoldered plant matter. The Amazonian “dark earths” hold many plant nutrients including nitrogen, phosphorous, calcium and magnesium. “Many scientists are working around the world to beter understand how biochar works,” she says.
Barbara outlines the steps to making biochar in Mother Earth News.
- Pile up woody debris in a shallow pit in garden bed.
- Burn the brush until the smoke thins and then damp-down the fire by covering it with about an inch of soil.
- Let it smolder until the brush is charred, then put the fire out.
See this month’s Mother Earth to learn more on this amazing technique and the benefits to your gardening.