Human greenhouse gas emissions are the root cause of climate change, affecting the Earth’s natural equilibrium. The effects of climate change are likely to include temperature rise, sea level rise, ocean acidification, and increased frequency and severity of extreme weather events (e.g., drought and flooding), and it is already having a significant impact on society worldwide. Considerable effort is going into reducing greenhouse gas emission, but not all industries can become carbon neutral fast enough. Because of this, we need to remove carbon from the atmosphere and lock it away permanently to meet emissions targets (e.g., UK governments Net Zero by 2050). This is called greenhouse gas removal and one technology that may allow this is biochar.

Biochar is the product of pyrolysis, or the heating of plant and other organic material under low oxygen conditions at between 400 – 1000°C. Pyrolysis transforms plant material into a carbon rich product with increased stability and longevity. In the past, humans have primarily explored biochar as a tool for soil improvement of degraded soils. There’s evidence that it was used for this purpose as early as 450 BCE in the Amazon basin. However, given biochar’s potential to last hundreds (or even thousands) of years in the soil, it’s now being consider as a carbon sequestration approach. As the carbon that is captured throughout the plant’s life is prevented from undergoing natural decomposition, it’s stopped from being released back into the atmosphere as carbon dioxide.

Close-up photograph of biochar
This charcoal-like material is biochar, a carbon-rich material made from plant matter that can be used to store carbon in soils.

One of the main aims of the Biochar Demonstrator is to explore how biochar can be applied to agricultural land, at a large scale, and sequester this carbon in soil. The UK has 17.6 million hectares of agricultural land so applying biochar to these soils could help decarbonise the UK economy, tackle climate change, and potentially improve soil health. Using grassland sites at Bangor University, and arable cropping sites at the University of Nottingham, we are exploring barriers to biochar’s deployment and will identify any additional benefits, such as improved crop productivity.

Our soils provide a wide range of ecosystem services, these are benefits that society gains from the natural environment and healthy ecosystems. For example, supporting the provision of crops, biodiversity, and carbon sequestration. The application of biochar can have physical and chemical effects on soils, which vary between different soils and depend on the type of biochar being used. Biochar may also alter soil texture, water holding capacity, pH and nutrient cycling rates, amongst many other soil characteristics. These impacts may then lead to changes in soil biology. Because of this, the Biochar Demonstrator is taking a holistic approach in understanding how biochar might impact soils and the functions they provide.

Using long term trials, with monitoring for seven years and 200 tonnes of biochar applied over the duration of the project, the demonstrator will explore the impacts of biochar on soil ecosystem functions, as well as exploring the persistence and stability of the biochar itself. We have planned a programme of fieldwork to be undertaken over the duration of the project, which encompasses a broad spectrum of UK soil types and land uses (including forestry, grassland, and arable farmland, as well as railway embankments and contaminated land). The agricultural sites selected will also encompass different farming practices, for example till and no till farms. With this work we will further our understanding of the effect of biochar loading on soil and crop health, potentially paving the way for wider scale adoption and deployment to help the UK reach Net Zero.

This blog post was written by Biochar Demonstrator researchers, Tom Bott (University of Nottingham) and Rob Brown (Bangor University).