Biochar Blog #3: Biosolids, Fertilisers and Local Feedstocks – A warm welcome to our gap-filling research projects
The Biochar Demonstrator is pleased to announce the first round of Flexible Fund Early Career Researcher (ECR) projects. ECRs from UKCEH, Bangor University and Aberystwyth University have been awarded up to £40,000 each for gap-filling research projects.
Emily Cooledge, Bangor University will be working on ‘An assessment of biosolids as a viable feedstock for pyrolysis and quantification of its impact on soil quality, carbon cycling and forage production’.
The UK produces ~3.5 million tonnes of biosolids (anaerobically digested sewage sludge) annually, which is commonly used as an agricultural soil conditioner and fertiliser. However, biosolids contains a wide range of chemically complex organic and inorganic contaminants, which may have a detrimental effect on the soils’ delivery of a wide range of ecosystem services. Biochar is now considered to have great potential to stabilise and sequester carbon on a timescale of centuries to millennia. A co-benefit of pyrolysis is the degradation of organic pollutants and pathogenic organisms. Thus, pyrolysis of biosolids may be a cost effective and efficient method of reducing the risk of environmental contamination. However, to date, little work has focused on the effect of applying pyrolyzed biosolids to agricultural land, particularly regarding soil carbon dynamics and effects on soil health, nutrient dynamics and ability to support crop production. This project will assess the short-term environmental and agronomic implications of using pyrolyzed biosolids as a soil amendment using a mesocosm-scale experiment comparing the application of pyrolyzed biosolids and non-pyrolyzed biosolids, a positive control of wood derived biochar, and a control. Measurements will include the carbon (soil organic carbon and greenhouses gas fluxes) and nutrient dynamics of soil, the fate of common organic (microplastics and PAHs) and inorganic (heavy metal) pollutants, as well as grass yield and quality. Results will improve our understanding of the potential viability of biosolids as a sustainable, low-cost and high-volume feedstock for biochar production and use in agriculture, particularly in a UK context.
Ben Roberts, Aberystwyth University’s project is ‘Understanding the soil conditioning potential of biochar in upland grasslands and forestry using locally derived feedstocks’.
Changes in support mechanisms and other economic pressures have led to a considerable increase in cover dominant plant species, notably bracken, rushes and purple moorgrass across many upland areas. This has resulted in agricultural productivity declining, and in many cases has also led to decreases in biodiversity and an inhibition of ecosystem functionality. As a result, an increasingly commonplace management practice by both farmers and conservationists has been the mechanical cutting of this vegetation. Given the volume of the material cut, the carbon sequestration potential is considerable, however the vast majority is currently left discarded on site. Currently, most biochar produced in the UK is derived from wood biomass, with little focus so far given to material created as a by-product of land management activities. The study will investigate the soil conditioning potential of biochar in upland grasslands and forestry using locally derived feedstocks, notably rushes, bracken, purple moorgrass and heather. This project will test the economic and environmental viability of a circular economy approach whereby locally derived feedstock, that is charred using a mobile pyrolysis rig on farm, would be used to produce biochar applied as a soil amendment on-site or on nearby farms. Aside from the carbon sequestration benefit of using biochar, further GHG reductions would be made by reducing the use of imported soil conditioners, and also completing all processes in the same locality and therefore reducing transport costs of having to move the feedstock and the subsequent biochar produced.
Ashley Taylor, UKCEH will be ‘Investigating soil nutrient interactions between biochar and fertiliser in agricultural systems’.
Biochar is a soil additive made mainly from plant material which has been heated to high temperatures in the absence of oxygen, leaving behind a charcoal like material. Besides containing carbon dioxide once converted by plants into woody material, biochar is also very porous, has a high surface area, and attracts chemicals from the soil to its surface. While biochar is great at protecting the carbon dioxide stored within its structure, thus keeping it out of the atmosphere, its chemistry mean it interacts with important nutrients in the soil which plants and soil microbes need to grow.
This project aims to investigate how the nutrients provided by different types of fertilisers interact with biochar, as the chemical makeup of fertilisers can vary greatly. This is important as land managers need to know how much of each fertiliser to apply to maximise their yield and save money, what effects adding biochar will have on their crops, and whether biochar can help them reduce the greenhouse gas emissions from their land.
This will be done by working with two ongoing research projects: PBC4GGR (https://pbc4ggr.org.uk/) and The Biochar Network (www.blackbullbiochar.com), who are already taking many measurements of biochar’s effects on nutrients and greenhouse gases. Our work will add to these projects and combine forces to create a bigger picture and answer remaining questions, while further testing the effectiveness of biochar across different land uses and in different situations to inform future work.
A big congratulations go to our ECR awardees, and a huge thank you to all our applicants. We will be launching the second and final round of funding later in 2023.
- Biochar Blog #3: Biosolids, Fertilisers and Local Feedstocks – A warm welcome to our gap-filling research projects
- Biochar Blog #2 – Critical Understanding of Biochar: Sequestration potential and economic performance
- Research Update – Summer 2022
- Research Update – Biochar in Bangor
- In the Media – Listen by the Lake