By James MacPhail, a biochar consultant for Positive BioCarbon

The UK government’s recently published Carbon Budget Delivery Plan highlights the need for farmers to keep reducing agricultural carbon emissions to help the country meet the goal of creating a net-zero emission economy by 2050.

With this pressure to reduce carbon emissions in mind, farmers are now beginning to use biochar, an easily accessible and usable product that can capture carbon and re-fertilise poor, low-quality soil for crop growth. High-quality, high-carbon biochar uses consistent feedstock with low PAH levels, giving farmers proven benefits such as carbon capture, soil remediation and water conservation.

What is Biochar and how does it work?

Biochar is a charcoal-like substance obtained through the heating of biomass (wood-derived material) at high temperatures and without oxygen. This is a controlled process called pyrolysis that converts organic biomass waste into stable soil carbon, concentrating the carbon in a form which is very resistant to biological decomposition.

Biochar can be used for agricultural or industrial purposes, to enhance the quality of soils or for removing pollutants from wastewater. The physical, chemical, and biological properties of biochar make it a very versatile material which can be used in a variety of applications. Biochar is also a powerful tool for removing carbon dioxide from the atmosphere and has many social and environmental benefits, too, including soil remediation.

For every tonne of biochar, approximately three tonnes of atmospheric CO₂ are captured, and carbon is permanently stored when sequestered in soils or building materials. Biochar effectively stores carbon for hundreds of years in the ground, and today is one of the most promising near-term commercially viable carbon removal approaches.

There are several critical influences presenting challenges for farmers and the rural sector, most notably rising input costs, climate change and significant shifts in agricultural policy as Governments tackle the issues. The potential to make land more productive for growing grass, crops and trees through the use of biochar can help farmers to address some of the concerns, increasing the rate at which they remove CO2 from the air during the process.

Why is biochar useful in soil remediation?

 Biochar has been used to great effect for years on remediating soils that are contaminated with heavy metals such as cadmium, lead and zinc, dangerous chemicals such as arsenic, pesticides and organic pollutants.

There have been a vast number of international scientific studies into the effect biochar has on contaminated soils. Crucially, once the sponge-like structure of the biochar absorbs the pollutants, these aren’t released again. The immobilisation of the contaminants through biochar can lock up 500 times more than soil alone, due to its high surface area, high cation exchange capacity, and the 97% permanent residence time in the soil.

Biochar doesn’t reduce the total levels of heavy metals in soils; it reduces the bioavailability of plants and mobility in soils. Phytoremediation consists of growing plants that can actively take up heavy metals.

These can be harvested to reduce the level of contaminants in the soil — therefore, a combination of biochar addition and phytoremediation is a good option for any polluted soils.

What’s so special about biochar?

Industry and academia have been adapting and formatting biochar to be applied to a huge variety of soils, crops, agroforestry and substrates applications for years. As such, biochar is most generally viewed as a soil improvement tool which can both sequester carbon and improve soil health by retaining nutrients and water.

More recently, however, the properties of biochar that give it such versatility is allowing the development of new products for green infrastructure, water quality and construction materials (specifically concrete and asphalt), and a variety of other useful applications.

The use of biochar as a Nature Based Solution has been fully international for many years. Individuals, businesses and research organisations have been busy developing biochar products to meet the demands of agriculture, horticulture, reforestation and, importantly, the carbon markets.

A Collaborative Approach

Lancashire County Council is already working in partnership with Positive BioCarbon and using its high-quality biochar at two separate sites in the North-West of England: Chisnall Hall, near Chorley, and Midgeland Farm, near Blackpool. A total of six hectares of farmland is being used throughout the pilot programme.

Nik Bruce, Principal Nature Recovery Officer for Lancashire County Council, has described the project as a “ground-breaking way to lock CO₂ into the ground for thousands of years.”  He says with this approach, Lancashire County Council, in just 10-13 years, could lock as much CO₂ into the ground as a broadleaf woodland of the same size could in 50 years.

Lancashire County Council is one of the first in the UK to use biochar and is doing so in conjunction with a range of other measures to create a cleaner, greener environment in the region. This includes the use of compost created from garden waste to help establish new woodlands. 

County Councillor and Cabinet Member for the Environment & Climate Change, Cllr Shaun Turner, said the idea behind the programme is that while people are using the land, carbon will be held in the ground beneath their feet. As part of the programme, the Council has also incorporated a sustainable solution to trees felled due to Ash Die-Back, by turning them into biochar so the carbon contained within the trees is not lost back into the atmosphere.

Positive BioCarbon’s collaborative approach provides a sustainable and effective solution to the issue and supports farmers and local authorities in their bids to meet net zero targets with a collective method. We firmly agree with the view that Government needs to work together with businesses and households to be able to affect real change, and by working with local authorities, it is offering a practical and tangible way to achieve that.

There are many ways biochar can help improve farmland. For example; we know salts, heavy oils and other pollutants from roads kill street trees, but this can be affect can be reduce by using biochar in the soils.

Is biochar a solution to climate change?

As a stable form of carbon, biochar sequestration provides an additional route for terrestrial carbon storage. The research paper, ‘Negative Emissions Technologies and Reliable Sequestration (2019) stated, “To achieve goals for climate and economic growth, negative emissions technologies (NETs) that remove and sequester carbon dioxide from the air will need to play a significant role in mitigating climate change.”

The paper goes on to explain, “Storing the carbon dioxide from NETs has the same impact on the atmosphere and climate as simultaneously preventing an equal amount of carbon dioxide from being emitted”. It highlights recent analyses found that deploying NETs “may be less expensive and less disruptive than reducing some emissions, such as a substantial portion of agricultural and land-use emissions and some transportation emissions”.

Biochar is a viable solution as it addresses 12 of the 17 United Nations’ Sustainable Development Goals (SDGs), and the demand for the CO2 Removal Certificates (CORCS) has already outstripped global supply.

Every farming business has carbon reduction targets to meet — what we’re seeing through the active projects we’re working on is that pyrolysis biochar can be a powerful tool in climate action to achieve these goals.