Carbon farming: how organic fertiliser helps store carbon in the soil
Agriculture is increasingly recognised as both a contributor to, and a potential solution for, climate change. Carbon farming (the practice of managing land to maximise the amount of carbon stored in soil and vegetation) is gaining serious attention from policymakers, environmental organisations and forward-thinking farmers. Organic fertiliser has a significant role to play.
What is carbon farming?
Carbon farming encompasses a range of practices designed to remove carbon dioxide from the atmosphere and store it in the soil as organic carbon. It is not a single technique but a philosophy of land management that prioritises building soil carbon alongside productive agriculture.
Key carbon farming practices include:
- Adding organic matter: Through organic fertilisers, composts, manures and crop residues.
- Reducing tillage: Minimising soil disturbance to preserve existing carbon stores.
- Cover cropping: Growing plants between cash crops to maintain living roots and add biomass.
- Diverse rotations: Including a mix of crops and grassland to build soil biology.
- Agroforestry: Integrating trees into farming systems for above and below-ground carbon storage.
The potential is substantial. UK agricultural soils contain approximately 10 billion tonnes of carbon. Even modest increases in soil carbon levels across farmed land could make a meaningful contribution to national emissions reduction targets.
Soil as a carbon sink
Healthy soils are the largest terrestrial carbon store on earth, holding more carbon than the atmosphere and all vegetation combined. When soil organic matter increases, carbon is being sequestered. When it decreases (through intensive cultivation, erosion or neglect) that carbon is released back into the atmosphere as CO2.
The relationship is straightforward: soil organic matter is approximately 58% carbon. Every percentage point increase in soil organic matter across the top 30cm of one hectare represents roughly 90 tonnes of carbon stored.
UK arable soils have lost significant organic matter over the past 50–70 years of intensive farming. Reversing this trend is both an environmental opportunity and an agronomic one, since higher organic matter means better soil function, improved yields and greater resilience.
How organic fertiliser contributes to carbon storage
1. Direct carbon addition
Every tonne of SoilWorx organic fertiliser applied to land adds organic carbon directly to the soil. With 75%+ organic matter content (approximately 43% carbon by weight), a typical arable application of 750 kg/ha adds meaningful quantities of carbon with every season.
Not all of this carbon remains permanently, some is mineralised by soil microbes to release nutrients, which is part of the product’s value as a fertiliser. However, a proportion is stabilised into longer-term soil organic matter fractions, contributing to a gradual increase in soil carbon stocks over time.
2. Stimulating biological carbon cycling
Perhaps more importantly, organic fertiliser feeds the soil food web. Active microbial populations process organic matter into stable humus compounds that persist in the soil for decades. They also produce glomalin and other binding substances that physically protect carbon within soil aggregates.
SoilWorx trials at Rothamsted Research (with whom SoilWorx has a research partnership) have shown a 461% increase in organic carbon when applying SoilWorx Dynamo to the ground. Long-term evidence of using organic-based products to build soil carbon shows a 5-10 year timeline, such as the AHDB DC Agri project 2015.
The circular economy connection
SoilWorx organic fertilisers are produced from waste streams that would otherwise contribute to environmental problems. Poultry manure, feather meal and bone meal are by-products of the food industry. By processing these materials into high-quality fertiliser, SoilWorx closes the nutrient loop:
- Organic waste is collected from food production.
- It’s heat-treated, sterilised and pelletised at our plant.
- The finished fertiliser is applied to farmland, returning nutrients and carbon to the soil.
- Crops grow, food is produced, and the cycle continues.
This circular model avoids the carbon-intensive manufacture of synthetic fertilisers (which relies heavily on natural gas for nitrogen production) and puts waste materials to productive use. It’s carbon farming in practice, not just in theory. By closing this loop with high-quality crop nutrition, SoilWorx makes sustainable agriculture measurably achievable.
Practical steps for farmers
If you are interested in carbon farming, here are practical steps to get started:
- Baseline your soil carbon: Test soil organic matter percentage now so you can measure progress. Standard soil analysis from any agricultural lab will provide this.
- Switch to or incorporate organic fertiliser: Replace some or all synthetic inputs with SoilWorx products to begin building organic matter with every application.
- Reduce tillage where possible: Consider minimum tillage or direct drilling to preserve existing soil carbon.
- Introduce cover crops: Keep living roots in the soil for as much of the year as possible.
- Monitor and record: Track soil OM levels over time. Document your practices for potential carbon credit schemes.
- Explore incentives: Check eligibility for SFI soil health actions, carbon credit programmes and environmental stewardship payments that reward soil carbon building.
Building soil carbon is good business
Carbon farming is not just about environmental responsibility. Higher soil carbon means better soil structure, improved water management, better nutrient cycling and greater crop resilience. These translate directly into reduced input costs, more consistent yields and lower risk.
SoilWorx organic fertilisers make carbon farming practical, affordable and measurable. Every tonne applied is an investment in your soil’s long-term productivity and the planet’s future.
Start your carbon farming journey
Explore our agricultural range or talk to our team about building a soil health programme.