Increasing Carbon Capture Through Cropping
Agriculture has a vital role to play in meeting the United Kingdom’s Net Zero targets. Increasing carbon capture through cropping is not only about reducing emissions, but about building healthier soils, strengthening farm resilience and creating viable, long term value chains for growers.
The Centre for High Carbon Capture, CHCx3, is a four year, 22 partner project that began in 2023. It investigates how arable and forage cropping systems can be diversified to increase carbon sequestration while also improving productivity and economic sustainability. Funded by Defra under the Farming Futures R&D Fund: Climate Smart Farming, the project forms part of Defra’s Farming Innovation Programme delivered in partnership with Innovate UK.
The project structure brings together expertise in crop improvement, soil carbon measurement and life cycle analysis, alongside the development of value chains that can support adoption at scale. Partners include NIAB, Rothamsted Research, University of York, the National Farmers Union of England & Wales and the British Hemp Alliance, alongside a wide range of crop specialists, seed developers and biomass experts.
Cropping Options Under Investigation
The project focuses on four key cropping options.
Cover crops are being assessed for their ability to improve soil structure, increase soil organic matter and reduce nutrient losses. When integrated into rotations, they can enhance soil carbon stocks and contribute to improved resilience during extreme weather conditions.
Annual fibre crops, including industrial hemp and flax, are being evaluated for both above and below ground biomass production. These crops produce substantial root systems and rapid biomass accumulation, offering strong potential for carbon capture while also supporting developing fibre and construction markets.
Perennial food, forage and feed systems, including herbal leys, are being investigated for their capacity to maintain living roots in the soil for longer periods. This can enhance soil biology, improve nutrient cycling and increase long term carbon storage.
Perennial biomass crops such as miscanthus and willow or poplar are also part of the research. These systems provide long term carbon sequestration and renewable biomass feedstocks, contributing to both climate mitigation and diversified farm income.
Soil Sampling and Analysis
A rigorous soil sampling methodology underpins the research. Samples are collected using a gouge auger at depths of 0 to 30 centimetres, 30 to 60 centimetres and 60 to 90 centimetres. This enables a detailed assessment of how carbon and nutrients are distributed through the soil profile.
The samples are analysed for particle size to determine soil texture, soil organic carbon content and carbon calculated through Loss on Ignition. Additional assessments include pH, nitrogen, phosphorus, potassium, magnesium, calcium and sulphur levels, total mineralisable nitrogen, carbon dioxide respiration burst to assess microbial activity and the carbon to nitrogen ratio.
This comprehensive approach allows researchers to understand not only how much carbon is present, but how actively the soil ecosystem is functioning.
Root Biomass Trials
To investigate carbon capture potential in fibre systems, hemp and flax are being grown across six trial sites ranging from York to Kent. Both above ground and below ground biomass are measured to quantify total carbon capture.
Hemp varieties in trial include Fedora 17, Fibror 79, Felina 32, Futura 75, Futura 83 and Finola. Flax varieties include Avian, Delta, Tango, WPB Celeste, WPB Eloise and WPB Felice. By comparing different varieties across multiple locations, the project aims to identify which genetics and management systems deliver the strongest carbon outcomes under UK growing conditions.
Building the Value Chain
Carbon capture alone is not sufficient. For these systems to be adopted at scale, they must be supported by viable markets and supply chains. The project therefore integrates life cycle analysis and value chain development to ensure that environmental benefits align with economic opportunity.
The next stages of the project focus on understanding the needs of growers and farmers, sharing primary research findings through events and knowledge exchange, and strengthening the value chains surrounding the four cropping pathways.
Increasing carbon capture through cropping represents a practical and science led route towards climate smart farming. By combining robust soil measurement, crop innovation and market development, this work supports a transition to farming systems that are productive, resilient and aligned with the UK’s climate ambitions.
