In this series, we’ll explore the concept of biochar
The term biochar dates to a 2,000-year-old practice by the ancient Indigenous civilizations of the Amazon, who created rich and fertile soil called terra preta, meaning “dark earth.” Soil gets its biochar deposits through natural events such as forest and grassland fires, but with the release of carbon into the atmosphere. Biochar is charcoal ash produced by burning organic biomass (agricultural and forestry wastes) in a low-oxygen environment in a controlled process with no release of carbon into the atmosphere. When biochar is buried or added to soils, most of the free carbon in the environment gets drawn into biochar and can remain in the soil for decades to centuries; given the right conditions, this process is called carbon sequestration. The natural decomposition of trees/forests and agricultural wastes contributes to a large amount of carbon released into the atmosphere. However, the presence of biochar can store/sequestrate this carbon in soil and channelize the carbon removal/uptake with additional benefits and improvement to soil properties as below.
Benefits:
- Improved Soil quality: Biochar can help restore degraded soils, improve agricultural productivity, and helps soils retain water.
- Energy production: Burning biomass to produce biochar produces energy, which can be used for heat or electricity.
- Sustainable feedstock: The feedstock for producing biochar includes agricultural and forestry residue, animal manures, sewage sludge, and sustainable purpose-grown crops.
- Mitigate climate change: Biochar stores carbon sequestered by plants and can reduce greenhouse gas emissions from soils.
- To sustain soil: Biochar formulations applied to soil can increase crop yields, immobilize heavy metals, and reduce nutrient leaching, irrigation, and fertilizer inputs.
Longevity of Biochar:
The longevity of biochar, a carbon-based porous material, provides higher crop yields, improves soil health, retains nutrients in the soil, and prevents their leaching into the groundwater for over 500 years. This is because biochar has:
- Strong ability to retain hydrocarbons and other organic compounds
- High Cation Exchange Capacity (CEC)
- High physical adsorption capacity within the macropores (up to 10 microns) to micropores (sub-nanometer)
- Surface area correlation numbers of approximately 500 m2/g dry
- The ability to maintain the structure as a stable lattice network
- High carbon content
- High organic content
- The ability to improve soil water retention
- The capacity to provide viable environments for beneficial microbes to grow and positively impact plant growth as well as remove harmful organics