What is Biochar?

Currently, inorganic fertilizer prices have tripled since early 2020 and remain volatile, putting a stable supply of fertilizer out of reach of many farmers.

The increase in human population pressure has decreased the availability of arable land. The shrinking land area has led to a decline in soil quality, which have in turn led to a constant increase in inorganic fertilizer applications from year to year to maintain agricultural productivity.

However, the highly productive fertilizer technologies introduced over the past decades may be reaching a point of diminishing returns.

Assessments have shown that nutrient losses are only partially compensated by natural and man-made inputs, thus the nutrient balance for the total of Sub-Saharan Africa is negative, being currently minus 26 kg Nitrogen, 3 kg Phosphorus, and 19 kg Potassium per hectare.

Maintaining an appropriate level of soil organic matter and ensuring the efficient biological cycling of nutrients is crucial to the success of soil management and agricultural productivity. Soil organic matter is any material produced originally by living organisms (plant or animal) that is returned to the soil and goes through the decomposition process. 

Unfortunately, more than 50% of soil organic matter has been lost from various ecosystems around the globe. 

What is Biochar?

1 gram of biochar has a surface area of about 330m² and can hold 5 times its weight in water.

Biochar is a vital tool in soil health management that increases total soil carbon and various soil functions. Particularly for eroded or otherwise degraded soils, biochar can improve soil health, crop yield, and crop resilience.

Biochar is a natural soil enhancer made from the carbonization of organic materials. Adding biochar to the soil is one of the best practices to overcome any organic stress in the soil and to increase agricultural productivity. Biochar is a long-term solution persisting in the soil even under warm conditions, allowing the soil to retain nutrients and water. The small pores of the biochar act as sponges, holding nutrients and water and creating an ideal microclimate for the beneficial soil microorganisms.

Biochar is the solid product remaining after feedstocks are heated to temperatures typically between 500°C and 700°C under oxygen-deprived conditions, in a process known as “pyrolysis”.

Biochar can be produced from many types of feedstocks including encroacher bush, alien invasive plants and trees, agricultural wastes, paper products, animal manures, and even urban green waste. 

Unlike compost, biochar does not decompose, and its benefits can last hundreds of years.

And although it looks a lot like charcoal, it’s not the same. Charcoal usually refers to carbonized biomass (wood) used for cooking, whereas biochar has many beneficial applications, especially in agriculture. 

The pyrolysis process is what gives biochar superior qualities over charcoal when being used as a soil amendment. The second difference is that biochar can be made from a wide variety of different substances, from wood to grains, bones, chaff, or manure. Charcoal is more commonly made from wood. And thirdly, the traditional charcoal production process releases quite a bit of CO2 back into the atmosphere, whereas the biochar process has been designed to ensure an absolute minimal CO2 release for a cleaner environment.

We produce our biochar by using flame-curtain Kon-Tiki Kilns as they deliver the best balance between cost, operability, robustness, scalability, and environmental impact in African conditions.

The Kon-Tiki flame curtain kiln re-connects biochar making to the ancient wisdom and craft of fire making and combines it with a smart design based on modern thermodynamics to produce high-quality char with low emissions.

Another important benefit of using labour-intensive biochar production methods like the Kon-tiki kilns, is the increased number of employment opportunities for the rural communities. And this enables them to alter current practices and adopt alternative livelihoods, leading to a reduction of the stress on land and having the ability to build climate resilience.

By using the Kon-Tiki kilns, we also are specifically addressing the United Nations Sustainable Development Goals number 1, 2, 5, and 8. 

Kon-Tiki kilns substitute dependence on very expensive automated systems not suitable for our African conditions by the application of important scientific principles resulting in an elegantly simple form of manual operation, nevertheless capable of generating very high-quality biochar. The kiln comprises a trough steel kiln, pivoted to facilitate tipping out the biochar after its production. A trough shield surrounds the kiln during operation, channeling airflow to aid clean pyrolysis operations, by creating inward rolling vortices that ensure volatiles are fully combusted not emitted, and providing a safety barrier to the operator.  

The steel walls reflect the pyrolysis and combustion heat back into the kiln, resulting in a more uniform temperature distribution and thus ensuring more homogeneous charring conditions and resulting biochar quality.

Once the kiln reaches its working temperature of 650°- 700°C, hardly any smoke is visible. The combustion air rolls in over the metal edge of the outer wall and into the kiln. But at the same time, the burning gases must escape upwards and so, similar to a clockwork, a counter-rotating vortex is established in the center of the kiln. Thanks to the establishment of this horizontal vortex, the air supply to the fire zone is stabilized. The wood gas, which is heavier than air, is kept in the vortex until it is completely burned.

Our own analysis of the biochar produced showed that highly stable, porous, and surface-active biochar can be consistently produced.  Emissions are also very low.  Biochar produced in this way meets the most stringent quality criteria set by Carbon Standards International.