Biochar, Solution to Soil Conservation
Green San Miguel
By Rachel Kastner
A soil amendment first used by the ancient Amazonians, biochar has been rediscovered by scientists looking to combat the impact of climate change. Although biochar has been around since ancient times, few people today know what it is, or that it can be used to supercharge compost, increase soil fertility, sequester carbon, and raise soil’s water retention ability.
In the 20th century scientists uncovered some of the most fertile soil in the world in the depths of the Amazon basin. They were astounded to discover that this incredibly rich soil, which is known as Terra Preta, or “black earth,” was created by the ancient Amazonians using techniques that helped the soil to maintain long-term fertility for hundreds of years. Researchers found that the secret to Terra Preta’s long-term fertility lies in the diversity of microbial life and organic material the Amazonians were able to integrate into their soil. Indigenous communities pioneered these techniques over 2,000 years ago, burning plant residues, animal manure, bone and other organic waste in a low oxygen environment, they created a unique form of charcoal. This charcoal, which is known today as biochar, was reintegrated into the soil, improving soil biodiversity, and producing the legendary fertility of the Terra Preta found in the Amazon basin.
Today, biochar is making a comeback as scientists have discovered that in addition to improving soil quality, it also has an incredible capacity to sequester carbon. The physical structure of biochar, which is created by burning organic materials in the absence of oxygen (a process known as pyrolysis), makes it a desirable soil amendment for a number of reasons. For example, biochar has a very porous structure with tiny cavities along its surface. The additional surface area serves as an excellent host site for beneficial bacteria and fungi. These microorganisms process organic material into nutrients for plants, and help to continually regenerate soil, thus creating long-term fertility. Using biochar and other regenerative organic farming methods creates soils that produce their own nutrients and allows farmers to grow more nutrient-rich food with less input, such as the damaging petrochemical fertilizers that dominate industrial agriculture today. Another benefit of biochar in today’s uncertain climate is its ability also increase soil’s water-holding capacity and overall structure. The proper use of biochar in agriculture has been proven to increase yields, improve soil`s water retention, reduce plant disease and restore life to biologically barren soils.
The methods used to create biochar do not contribute additional CO2 to the atmosphere, as it is created by slowly heating biomass in a low-oxygen environment, such as a kiln, until everything but the carbon is burned off, and then put back into the ground. When this biochar is incorporated into the soil it is able to hold this carbon underground for hundreds or even thousands of years. Today’s agricultural lands have lost an average of 50 percent of their carbon content due to intensive tillage and other human activities. Instead of releasing this carbon into the atmosphere with conventional farming methods, carbon in the form of biochar can be returned to the soil, providing its benefits to the soil as well as sequestering carbon.
With the assistance of local biochar expert, Rob Lerner, and biochar experts in the US, Via Organica is running a series of trials using biochar at our Ecological Ranch to explore its potential uses on a local level. We are using biochar in our compost production, in cultivation areas, with livestock, and in dry composting toilets. Vía Orgánica is also working to fabricate a locally made stove that will allow people to create biochar and sequester carbon on a household scale. Another local organization, CATIS, is doing experiments to see how biochar can be used to filter fluoride from drinking water. To learn more about the work being done at the Via Organica Ecological Ranch, or see the benefits of biochar first hand, book a tour at viaorganica.org/tours.