The Growing Benefits of Soil Carbon

Businesses are seeking paid contracts with landowners to provide offsets and routes to reaching net zero. But for these benefits to be realized they need to be measurable and reliable.

The Growing Benefits of Soil Carbon
The following article was written in the Summer of 2022 for the Scottish Land and Estates’ Land Business Magazine
Front cover of Summer 2022’s LandBusiness Magazine

Restoring soil organic carbon through regenerative land use and farming practices establishes a vital foundation for the future of soil health, fertility, and productivity of the land.

Today, interest in soil carbon has intensified because of tantalizing new opportunities to monetize the benefits. A growing host of businesses are seeking paid contracts with farmers and landowners to provide carbon supply-chain certificates, offsets, and other environmental services.

Soils hold about 80% of the carbon in the terrestrial ecosystem and over three times more carbon than the atmosphere. Scottish soils are believed to hold around 3 billion tonnes of carbon: three-quarters of the total UK soil carbon stock.

However, the activities of man have stripped billions of tonnes of carbon from our soils, with drastic consequences for our climate and food system security. Regenerative farming and nature-friendly land uses like rewilding and habitat restoration can reverse this destructive cycle, slowly removing CO2 from the atmosphere and replenishing organic carbon in the soil.

Nature-based solutions for CO2 removal – including soil carbon restoration – offer highly attractive routes to reaching net zero.

Food and beverage companies particularly value the opportunity for soil carbon sequestration to reduce the carbon footprint of their supply chain in a way that shores up future health and resilience, improving soil fertility and resistance to drought and flood.

Across a 200-hectare farm, soil carbon sequestration could represent an annual carbon value of around £6,000 at a £30/tonne price and significantly more as carbon prices increase over coming years.

But for any of these benefits to be realized and, importantly, to drive real value back to the farmer or landowner, they need to be measurable and reliable.

Herein lies a major challenge.

“Anyone working the land will know that soil is highly variable. The texture, type and characteristics can change markedly within the boundaries of a single field”

Annie Leeson
A field operator using our CarbonForce to extract a soil core in a field in Perth and Kinross, Scotland.

Anyone working the land will know that soil is highly variable. The texture, type, and characteristics can change markedly within the boundaries of a single field. To reliably quantify soil carbon stock – total tonnes of carbon in the soil – it must be measured at multiple locations and depths to account for this variability.

To compound the issue, soil carbon restoration occurs slowly; small increases are difficult to detect without highly accurate measurement from high numbers of samples. Historically, this has been prohibitively expensive and difficult, limiting the potential to commercialize soil carbon restoration as a type of carbon offset.

Today, the climate crisis is demanding new solutions. A raft of farm carbon retail companies has sprung into being, including Ruumi, Sub51, Agreena, Sward, and Trinity Ag. They will all need a considerable foundation of ground truth data – real soil samples tested using recognized scientific analysis – to demonstrate that soil carbon gains are real and have been accurately quantified.

To qualify for genuine carbon offsets, a robust soil carbon baseline assessment must be carried out before any land use or practice changes take place, with further validation exercises at least every five years.

Typically, this demands intensive soil sample collection followed by laboratory tests specifically for detecting organic carbon and bulk density measurements to quantify the tonnes of carbon in a field. Due to the variability of soil, this must be carried out across the entire project area. The challenge is reaching sufficient sample numbers before the exercise becomes too costly: this is where Agricarbon specialises.

Having developed industrial machinery to process and analyse soil samples at very high throughput, Agricarbon provides a thorough and reliable audit of soil carbon stock for a fraction of the conventional cost. The service includes sampling strategy design, collection of soil cores down to one metre, using specialist equipment, and processing and analysis of samples to calculate soil carbon stock for individual fields, farms, and estates. The methods used are the same, best-in-class analyses used by labs – Dumas dry combustion for organic carbon and bulk density measured for each individual sample – but the mechanised approach improves the consistency of data across projects. The audits are designed to comply with current and in-development carbon offset standards, which mandate a directly sampled soil carbon baseline before any farming practice or land use changes take place and retesting with direct measurement at least every five years. Agricarbon’s low per-sample cost allows for sufficient sample numbers to confidently detect small changes in carbon against the natural backdrop of high variability of UK soils.

With more than 25,000 acres of UK farmland already baselined and a growing database exceeding 75,000 samples (as of summer 2022), Agricarbon is in a unique position to support the development of soil carbon market opportunities for landowners. Some of the world’s largest offset buyers have already recognised Agricarbon’s methods as an essential foundation to underpin confidence in soil carbon projects.

Over time, the data will yield essential insights into the way farming and land use restores soil carbon and correlates with other important aspects of soil health. For farmers and food companies wishing to include soil carbon gains in carbon footprinting and reporting, whether, for net zero or carbon offsets, a reliable, intensively sampled baseline is an essential first step.

About the Author – Annie Leeson

Annie is the Co-Founder and CEO of Agricarbon, providing a cost-effective, direct measurement of soil carbon stock: a vital foundation for net zero farming and carbon markets. With a background in biochemistry, Unilever marketing and strategy, and innovation consultancy, Annie spent several years working on Decarbonisation Strategies with big corporates and cities. Her concerns about the reliance on Nature Based Solutions, and lack of viable, reliable options, drove her to innovate. Annie saw the fundamental lack of ‘ground-truth’ data, to quantify soil carbon sequestration, as a major barrier to deploying soil as a carbon sink, and co-founded Agricarbon to address the gap.


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