Sometimes referred to as ‘black gold’, biochar stores carbon for thousands of years as well as provides a host of soil health and environmental benefits.
How does biochar benefit soil?
High Porosity
- Biochar acts like a sponge, absorbing and retaining moisture and nutrients, and reducing run-off
Large Surface Area
- Makes biochar an excellent medium for mycorrhizal fungi which strengthens plant roots and increases healthy growth
Stable Carbon Capture
- Means biochar can lock carbon in the soil for hundreds of years, mitigating climate change
Preloaded With Nutrients
- When mixed with compost or fertiliser the biochar can deliver nutrients more sustainably than direct application
How is biochar made?
Biochar is made through a process called pyrolysis. Here's a step-by-step explanation of how it works:
1. Biomass Collection
- The first step involves gathering organic material, known as biomass. This can include wood, agricultural residues, manure, or other organic waste.
2. Preparation of Biochar
- The collected biomass is often processed to achieve uniformity in size and reduce moisture content. This preparation ensures more efficient pyrolysis.
3. Pyrolysis
- The prepared biomass is then subjected to pyrolysis. This involves heating the material to high temperatures (typically between 300°C and 700°C) in a chamber with little to no oxygen. The lack of oxygen is crucial as it prevents the biomass from burning completely.
4. Chemical Transformation
- Under these high-temperature and low-oxygen conditions, the biomass undergoes a chemical transformation. Instead of burning, it decomposes into several different substances, one of which is biochar.
5. Cooling & Final Processing
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After pyrolysis, the biochar is cooled and can then be processed further if required, such as being ground into smaller particles.
History of Biochar
Terra preta, or Amazonian dark earth, enriches poor soils using biochar, bone, manure, and plant residues, creating nutrient-rich, moisture-retentive soil that promotes plant growth.
Central to its effectiveness, biochar improves soil health, supports a vibrant microbial ecosystem, and increases agricultural yields while sequestering carbon.
This ancient method, which offers a sustainable solution to modern agricultural challenges, inspires contemporary biochar products aimed at soil rejuvenation, crop productivity enhancement, and climate change mitigation, leveraging the wisdom of ancient soil enrichment practices.