What is Biochar? Uses, Benefits, and How to Make Biochar

Biochar is a charcoal-like substance rich in carbon, made by heating organic materials (usually biomass waste) through a process called pyrolysis. These materials are heated under high temperatures (300-500°C) involving little to no oxygen. 

Under those conditions, the biomass is converted into a stable form of carbon and, thus, sequesters those carbons that otherwise would be released into the atmosphere if the biomass decomposes. 

In this article, we will dive deep into everything that is biochar, from its origins, physical properties, uses and benefits, and how you can take advantage of this powerful material.

How Does It Differ with Other Forms of Charcoal?

Biochar looks like common charcoal. However, it is highly porous and has a large surface area — which is very beneficial for soil applications and chemical adsorptions.

Moreover, in terms of chemical composition, 70% of its composition is carbon. Other chemical properties will differ according to the type and quality of biomass used as feedstock, as well as the methods used to produce biochar. For instance, WasteX’s rice husk biochar has 74.5% C-organic, while the corn cob biochar has 43.5%.

Biochar made from palm kernel

Almost any type of biomass can be made into biochar, such as rice husks, wood chips, cocoa pod husks, and corn cobs. As such, any agricultural producer can convert their biomass waste and produce biochar instead of simply burning or throwing them away.

Origins of Biochar

Nowadays, biochar is mainly known for its capabilities in sequestering carbon dioxide. However, biochar has its origins in ancient practices of soil management and agriculture. 

One notable example is a practice known as "terra preta" or "dark earth" by indigenous people in the Amazon. These dark, highly fertile soils contain a significant amount of biochar, created through a combination of deliberate charcoal production and the addition of charcoal to agricultural fields.

Terra preta still exists in the Amazon basin and consists of 70 times more black carbon than the surrounding soils, according to a 2014 study, resulting in much more fertile soils and creating a stable carbon sink.

Similar practices of using charred organic matter in agriculture have been found in other parts of the world, including ancient China, where the use of "black earth" was documented. These historical practices demonstrate the early recognition of the positive effects of biochar on soil productivity.

Uses and Benefits of Biochar

Biochar offers a range of environmental benefits that make it an attractive solution for sustainable land management. 

1. Mitigating Climate Change

One significant advantage of biochar is its capacity to sequester carbon in the soil. Adding biochar to soil locks away carbon, reducing greenhouse gas emissions and mitigating climate change.

Moreover, the byproduct of pyrolysis can be used as a source of clean energy. The heat and syngas can be captured and further processed which can replace fossil fuels. 

Here are other ways how biochar can be beneficial for the environment:

• Adsorb heavy metals and other pollution from groundwater

• Reduce biomass waste

• Reduce soil erosion by increasing its water-holding capacity and improving its stability.

  
  

2. Improving Soil Health

Various studies have shown that applications of biochar to the soil can increase soil health due to its porous structure. 

These tiny pores are capable of adsorbing and retaining essential nutrients as well as holding water. This greatly improves the soil’s water retention capacity, helping farmers endure challenges like droughts and rising fertilizer costs.

Biochar’s porous structure also provides a habitat for the growth of beneficial microbes that contribute to nutrient cycling, organic matter decomposition, and disease suppression. All of this will eventually lead to improved crop yields and ensure food security.

3. Lowering Input Costs

Beyond just holding nutrients and water, biochar can also release them gradually as needed by plants. This property is known as cation exchange capacity (CEC)—the higher the CEC, the more effectively the soil can supply nutrients over time.

Thanks to this CEC, biochar-treated soils typically require less chemical fertilizer, reducing input costs for farmers. In turn, lower fertilizer use leads to decreased greenhouse gas emissions, making agriculture more sustainable and climate-friendly.

4. Neutralizing and Stabilizing Soil pH

Biochar is often alkaline, meaning it has a high pH. When added to acidic soils, it can help neutralize the acidity, making the soil more favorable for plant growth.

Biochar can also act as a buffer, helping to stabilize soil pH. This means it can resist changes in pH, preventing the soil from becoming too acidic or too alkaline.

5. Improving Livestock and Poultry Health 

Meanwhile, when applied to livestock and poultry farms, biochar can be used as follows:

1. Manure management. Biochar can be used as a bedding material in animal housing or added to manure storage facilities to improve odor control and absorb moisture, reducing the release of ammonia and other volatile compounds.

2. Pathogen control. The pores in biochar can absorb and immobilize pathogens, reducing their availability for transmission. This can contribute to improved biosecurity and animal health.

3. Feed additive potential. There is ongoing research on using biochar as a feed additive in livestock and poultry diets. Adding biochar to animal feed can potentially improve nutrient utilization, digestion, and overall gut health. It may also reduce the negative impact of toxins and mycotoxins in the digestive system.

6. Restoring Mine Sites

Biochar is also used in mine-site restoration, where landscapes have often been stripped of nutrients and contaminated with heavy metals or toxic residues.

The porous structure and chemical properties of biochar allow it to adsorb and immobilize these harmful substances, reducing their mobility and bioavailability in the soil. This helps to contain pollution and initiate the slow process of ecological recovery.

How Biochar is Produced

The biochar production involves the following steps:

1. Feedstock Preparation

As mentioned above, any organic materials can be converted into biochar. Ideally, it must be high in lignin which contributes to producing a more stable, carbon-rich, and structurally robust biochar.

The most sustainable way is to use waste near you. That way, we eliminate the additional carbon footprint from long-distance transportation.

The feedstock also needs to be clean and uncontaminated. Using polluted materials can introduce heavy metals and other harmful compounds into the soil. Common contaminants to avoid:

• Plastics

• Painted or treated wood

• Industrial waste

• Household garbage

  
  

After that, dry the waste to achieve efficient pyrolysis. Ideally, the waste should have a maximum of 15% moisture content. Too much moisture can reduce energy efficiency and slow the pyrolysis process.

2. Pyrolysis

There are many methods to produce biochar, from traditional equipment like TLUD or Kontiki to industrial machines. In this article, we will explain how to make biochar using biochar equipment by WasteX.

WasteX's biochar machine v2.3

The process begins by igniting the fuel to heat the combustion chamber. Once the temperature reaches 300°C, the operator can activate automatic mode, which enables the machine to auto-feed biomass into the combustion chamber. This continues until the temperature reaches approximately 500°C.

Meanwhile, in a separate pyrolysis chamber, the biomass is indirectly heated by the heat generated from the combustion chamber. As a result, the biomass undergoes thermal decomposition, stabilizing the carbon and transforming it into biochar.

Once the pyrolysis process is complete, the machine automatically discharges the finished biochar into a storage barrel. The biochar should then be allowed to cool before handling or application.

How to Use Biochar

Biochar can be used either raw or charged, depending on your goal.

If you want to use biochar to filter water or remediate contaminated soils, it’s best to use it raw as it will absorb the pollutants.

However, if you want to use it as a soil amendment, it’s recommended that you charge it first. Essentially, charging is filling biochar with beneficial microorganisms and nutrients. Charged biochar will bring immediate benefits to your plants.

You can charge biochar using fertilizers, compost, and manure, among other things. You can read more about charging biochar in our article.

It's important to note that the effectiveness of biochar application can vary depending on soil type, climate, biochar properties, and management practices. 

Proper assessment of soil conditions and appropriate application rates are necessary for maximizing the benefits of biochar. WasteX can help you and your farm if you want further information on properly producing and applying biochar to maximize yield.

Real-Life Examples of Biochar Usage

1. Coffee Farming by Nestle

Nespresso, a brand under Nestle, launched a series of pilots to test biochar’s potential on AAA Nespresso coffee supplier farms. The aim is to evaluate biochar’s capacity to boost productivity, lower coffee production's carbon footprint, and deliver tangible benefits to farmers.

2. Green Bridge Construction and Water Filtration, UK

A trial by the UK’s National Highways will use biochar in the construction of what will be the UK's largest green bridge, replacing synthetic gels typically used for moisture retention. Biochar will also be incorporated into drainage systems to capture microplastics from road runoff, thereby protecting local ecosystems.

3. Soil Amendments and Carbon Capture, USA

Wilbourne Farm in Virginia, USA, is testing different combinations of biochar, basalt, compost, and other materials on their land to increase carbon content and sequestration. 

Conclusion

In conclusion, biochar is a valuable resource made from organic materials and has distinct properties that set it apart from traditional charcoal.

Biochar offers advantages such as carbon sequestration, improved soil fertility, reduced greenhouse gas emissions, and increased yields. By incorporating biochar into agricultural practices and utilizing its potential as a soil amendment, we can enhance soil health, promote sustainable land management, and contribute to a greener future.