“Activated” by Biochar: A Boon for Building Soil
Late winter and early spring make one thing clear about agroforestry: it produces lots of sticks!
As the Horn Farm continues to develop agricultural teaching spaces informed by agroforestry–an approach to farming that integrates trees and shrubs to produce abundant and ecologically healthy landscapes–we’re finding that the “yields” go far beyond the berries and nuts. To start this growing season, volunteers and staff coppiced willows, harvested live stakes, and pruned elderberries, all producing one common denominator. Before we knew it, we had imposing pile of “biomass”: dead branches, sticks, and twigs galore!
By thinking like an ecosystem, farmers, gardeners, and land stewards know that a dry pile of branches isn’t the end of the line. Decomposing wood makes for great habitat, either left untouched or assembled into wildlife stacks in woodland areas. Or, with just some biodegradable twine and muscle, surplus wood can be tied into tight brushwood bundles and placed along the edges of streams, capturing sediment and helping to curb erosion in riparian areas. We could even ignite our biomass harvest into a bonfire, enjoy some s’mores, and call it a day!
But there’s another, more direct way to leverage a pile of wood for the continued nourishment of the soil that produced it: biochar.
Earlier this June, we invited longtime horticulturist and friend of the farm Dale Hendricks to provide a public demonstration on producing biochar at a home scale. With juicy mulberries in tow, Dale gave a stirring talk on the history and science of biochar, which has its roots (like many ecological farming practices) in Indigenous land management, from the Amazon to Africa. Producing biochar has helped people across history maintain fertile, abundant landscapes, taking the surplus that the land provides and returning it to the soil in way that concentrates what plants need most to thrive.
Put simply, biochar is made through burning woody biomass in a high-heat, low-oxygen environment. This controlled burning method generates a charcoal-like substance that can be added to soil to:
- Improve water retention,
- Enhance nutrient availability,
- Foster healthy microbes, and
- Keep excess carbon out of the atmosphere by storing it the ground long-term.
There are many ways to produce biochar, with different designs based on scale. Pit and pyre burns are used for larger quantities of biomass, while for the small farm or home garden, Dale demonstrated a low-tech, two-barrel arrangement. This set-up manages the oxygen level while producing a very hot fire, creating the conditions needed to break down tightly-packed biomass into charcoal. Even with passing rain showers during the burn, it took about 40 minutes to transform hundreds of elderberry, willow, and assorted other sticks into readily usable biochar.
Like agroforestry itself, biochar is an empowering example of small-scale solutions to global environmental problems. With 100% local materials and simple methods, farmers, gardeners, and land stewards can use woody surplus to generate a stable form of carbon, improving soils while reducing atmospheric CO2–a major greenhouse gas contributing to climate change.
While students walked away with ideas for producing their own biochar at home, our staff is looking forward to integrating biochar production into our regular rotation of land management. As we continue our agroforestry journey, it’s increasingly clear that we’ll have no shortage of stems and twigs to transform into biochar, offering another way to close loops and create a self-sufficient ecological farm.
But land stewardship is just the first part of the story. Through community classes and programs exploring topics like biochar, we’ll continue to empower folks from across our region with the skills to work with the land in restorative, resourceful, and mutually beneficial ways.
As one student shared after the program: “I’m grateful for opportunities like this to learn and grow, and I’m looking forward to seeing what other workshops will be offered in the future.“
