As concerns about climate change and food security continue to grow, soil carbon sequestration has become a major focus. Soil health practitioners, agronomists, and environmental researchers are increasingly exploring whether soil can help mitigate land degradation and climate change. The answer? It can do so by serving as a natural carbon sink.
However, a soil can only retain carbon if it's healthy. And this is dependent on whether its biological systems remain intact and its structure remains stable. If soil is disturbed, the ecological conditions that support microbial interactions and a stable structure break down, making it difficult to retain carbon.
This guide looks at why disturbed soil struggles to retain carbon and how regenerative agriculture can help.
How healthy soil stores carbon
Healthy soil is a dynamic system that continuously cycles organic matter and draws carbon from the environment. Here's how:
Soil is a living ecosystem
Healthy soil is far from an inert growing medium. It's a living system with plant life and microorganisms that support carbon storage. As little as one gram of soil can contain up to 10 billion microorganisms spanning different species, including fungi, bacteria, insects, and protists. Here's how the living ecosystem promotes carbon retention:
- Plants start the process during photosynthesis — they absorb carbon dioxide from the atmosphere.
- They use some of the carbon to produce glucose (essential for growth) and transfer whatever's left into the soil as exudates (food for microbes) through the roots.
- Soil microbes process the carbon, breaking some of it down into stable forms of carbon-rich soil organic matter, such as humus.
In healthy soils, this process is continuous. Plants capture carbon, and then microorganisms transform and stabilize it.
The role of soil structure in carbon retention
A soil's structure (the arrangement of particles, organic matter, and pore spaces) directly impacts its ability to retain carbon. Soils with stable structures protect carbon from rapid decomposition through aggregation. In healthy soils, mineral particles bind with organic matter to form clumps. The clumps act as protective barriers that shield stored carbon from oxygen and decomposing organisms.
Well-structured soils also improve carbon retention by regulating water and oxygen levels. By maintaining a proper balance of these components, the soils reduce the decomposition of organic matter, which can slow down carbon loss.
Good soil structure also improves aeration and drainage, creating favorable conditions for plant growth. This translates to more carbon entering the soil.
What happens when soil is disturbed?
Soil disturbance and carbon loss are directly related. Disturbance disrupts the natural structure of soil, which in turn increases the release of stored carbon.
Tillage accelerates carbon loss
In undisturbed soils, organic matter binds together to form aggregates. The aggregates then shield carbon from excessive oxygen and microbial decay.
Tillage disrupts these aggregates, exposing soil organic matter to aerobic (oxygen-rich) conditions. This increases microbial decomposition, which accelerates carbon release through heterotrophic respiration. How? Well, microbes consume carbon as they break down organic matter and then release much of it into the atmosphere. According to a 2025 Soil Use and Management report on tillage and soil carbon, increased microbial activity resulting from tillage can lead to carbon emissions of up to 6100 kg CO2e/ha/year.
Disturbance harms soil biology
Undisturbed soils typically have strong fungal structures that build carbon-rich matter. Mycorrhizal fungi are especially important for carbon retention, with researchers estimating that they channel 4-20% of plant-fixed carbon into the soil.
Disturbances, such as tillage and chemical use, disrupt this process. They kill the fungi responsible for building carbon-rich structures and destroy their aggregates, causing soils to release trapped carbon back into the environment.
Disturbances also replace fungi and microbes with fast-growing bacteria that quickly consume organic matter. The process increases microbial respiration, which converts soil carbon into carbon dioxide and releases it into the atmosphere.
Bare soil interrupts the carbon cycle
The carbon cycle relies on a delicate balance of processes: plants capture carbon dioxide through photosynthesis and release it into the soil as root exudates, while fungi trap carbon in the soil. Getting rid of living plants disrupts this system.
Without plants, the transfer of carbon to the soil comes to a stop. However, microbial respiration doesn't. Microbes continue to consume organic matter to survive, during which they release carbon dioxide into the atmosphere. The result is soil emitting more carbon than it absorbs.
Bare soil also exposes carbon-rich decayed organic matter (peat) to the atmosphere. This causes oxidation, releasing carbon dioxide to the atmosphere.
Why soil biology matters for long-term carbon storage
Soil biology is the engine that powers carbon storage. Microbes and biodiversity are especially crucial in this system. Below is a look at how they promote carbon retention:
Microbes help stabilize carbon
According to a 2026 LSCE study, soils with higher microbial growth rates tend to retain more carbon. Here's a quick breakdown of how that comes to be:
- Plants exude carbon through their roots during photosynthesis.
- Microbes then feed on the exudates. They release some of the carbon in the exudates into the atmosphere as carbon dioxide and absorb part of it to fuel their growth. That means that microbes themselves house carbon.
- When the microbes die, their carbon-rich bodies (microbial necromass) bind to soil minerals to form soil organic carbon. This form of carbon doesn't undergo further microbial breakdown, so it can survive for a long time.
Biodiversity improves soil resilience
Plant diversity promotes long-term carbon storage by nurturing a strong microbial community. According to a 2024 study on plant diversity, diverse plant communities release unique root exudates and litter. This provides a broader range of nutrient resources in the rhizosphere, creating favorable conditions for a wide range of microbes to thrive.
High microbial diversity, in turn, enhances carbon use efficiency (CUE)—diverse communities use more carbon for growth than respiration. This could be explained by a couple of reasons. One, diverse communities can break down a broader range of organic compounds and convert them into microbial biomass to support carbon stabilization. And two, diversity creates functional redundancy, which reduces the risk of carbon-stabilization collapse if stressors (such as drought and chemicals) remove one or a few species from the ecosystem.
How regenerative agriculture supports carbon retention
Regenerative agriculture promotes carbon retention by helping maintain proper soil structure, reducing erosion, and increasing biodiversity:
Minimizing soil disturbance
One of the core principles of regenerative agriculture is to minimize physical, chemical, or biological alterations to soil structure. Practices such as tilling and chemical use disrupt soil structure, weakening soils' ability to store carbon. When a soil is disturbed, aggregates break down, exposing carbon-rich organic matter to oxygen. This accelerates microbial decomposition and increases the amount of carbon dioxide released into the atmosphere.
Regenerative agriculture lessens such disruptions by abandoning conventional tillage and advocating for reduced tillage or no-till farming. Reduced-tillage and no-till systems maintain soil structure by minimizing disturbance. Instead of plowing entire fields during planting, you can create narrow strips or furrows where you want to plant and leave the rest of your fields undisturbed. This preserves the physical barriers that store soil carbon and protects the fungal networks that continually build carbon-rich matter.
Keeping living roots in the ground
During photosynthesis, plants capture carbon dioxide, use some of it to produce the glucose needed for above-ground growth, and then transfer the rest underground through their roots. That makes roots among the most valuable assets for soil carbon sequestration.
Living roots continuously release carbon-rich exudates into the soil. These exudates then serve as food for microbes such as mycorrhizal fungi, enabling them to continue the biological functions that help retain carbon in the soil. For example, mycorrhizal fungi can continuously form carbon-rich, thread-like networks that bind to soil minerals (after death) to create a stable carbon pool.
To keep living roots in the ground, regenerative agriculture calls for practices such as cover cropping and perennial planting. These practices provide year-round soil cover, which can reduce soil erosion and, consequently, soil carbon exposure. They also provide a continuous supply of exudates, which can facilitate a thriving microbial ecosystem.
Supporting ecosystem function
Regenerative agriculture focuses on natural physical and biological processes that can strengthen soil health and carbon retention. Some ecosystem functions that are especially valuable for carbon sequestration include:
- Managed grazing: Controlled grazing promotes plant growth through natural soil fertilization. It also transfers organic matter to the soil through plant litter trampling. These processes support root exudation and microbial growth, which help stabilize carbon compounds in the soil.
- Water cycle regulation: Practices such as mulching and cover cropping help sustain soil moisture. The moisture promotes healthy plant growth, which can increase carbon capture during photosynthesis. Moisture also facilitates the binding of minerals and organic carbon, which can slow microbial decomposition, allowing soils to retain carbon for longer periods.
- Biodiversity: Soil health practices, such as maintaining diverse plant life, foster resilient ecosystems that contribute to carbon cycling. For example, diverse plant life releases unique root exudates, which in turn foster assorted microbial communities that transfer carbon into the soil.
Minimize soil disturbance with regenerative agriculture
Soil disturbance practices such as tillage are strongly linked to soil carbon loss. These practices disrupt soil structure and biological activity, reducing the soil's ability to sequester and retain carbon over time.
Regenerative agriculture seeks to improve long-term carbon storage in the soil by promoting practices that restore soil health and ecosystem function. These practices include reducing tillage, implementing rotational grazing, maintaining living roots year-round, and promoting biodiversity.
If you’ve been wondering whether transitioning to regenerative practices is good for our soil and our planet, all the science and evidence confirm that it is.
And if you are a regenerative agriculture brand looking to communicate complex ideas in a way that feels clear, useful, and human — so you can connect more deeply with your target audience and drive greater adoption and revenue — we would love to help. Reach out today, and let us discuss how we can help.
