Chapter 1: The Basics of Carbon Sequestration

How does soil extract carbon from the atmosphere? Essentially, plants act as carbon pumps, drawing in CO2 and channeling it into the soil, where it becomes sequestered by microbes.

In light of rising fears regarding severe climate change, carbon sequestration has gained significant attention. This process involves removing carbon from the atmosphere and storing it in natural reservoirs, such as soil. Interestingly, soil contributes to around 46% of terrestrial carbon sequestration. But how does this process unfold?

Paying Farmers to Combat Climate Change?

Soil health is finally gaining recognition, and many ecological farmers and soil scientists are pleased to see increased public interest in the vital ground beneath us. However, general knowledge about soil remains limited. Many enthusiastically support the notion of compensating farmers for their role in combating climate change, which is a central tenet of both regenerative and climate farming practices.

The Biden Administration has introduced carbon credits for farmers to incentivize reduced emissions and enhanced carbon sequestration on agricultural lands. Unfortunately, scientists have yet to develop a consistent method for measuring soil carbon sequestration across large areas. Consider the challenge of detecting carbon across vast fields with deeply layered soil.

Furthermore, it is often overlooked that many farms, particularly those practicing industrial corn and soybean monoculture, would need to make substantial changes in their farming approaches to balance their carbon emissions, let alone achieve carbon drawdown. This is especially pressing given that much of the soil in the U.S. has been degraded to the point where it can no longer sequester carbon.

Soil vs. Dirt

At its essence, soil is a vibrant ecosystem akin to a tropical rainforest, yet even more diverse and intricate. It teems with life, hosting both macroscopic creatures, such as earthworms and groundhogs, and microscopic organisms invisible to the naked eye. Regrettably, vast quantities of soil are being converted to dirt—an expression used to describe lifeless, degraded soil that lacks the ability to support a thriving ecosystem.

Dirt fails to provide essential soil ecosystem services, such as nutrient creation, water filtration and storage, erosion prevention, and carbon sequestration. Modern agricultural practices have employed various synthetic herbicides, pesticides, and heavy machinery to damage soil health, leading to a reliance on chemicals and fertilizers to cultivate crops in lifeless dirt.

Healthy soil, in contrast, is rich in beneficial microorganisms. While dirt contains few microorganisms, healthy soil holds billions of beneficial or neutral microbes in just a small sample. These organisms are crucial for enabling carbon sequestration.

Microorganisms: The Carbon-Based Lifeforms

Microorganisms, including bacteria and fungi, are carbon-based, just like all living entities on Earth. While bacteria play a minor role in the soil carbon cycle, fungi are the heavy lifters, possessing extensive and carbon-rich networks.

Fungi can maintain a carbon-to-nitrogen ratio of 1000:1, compared to bacteria's 5:1, making them integral to the carbon sequestration process.

Plants and Their Role

Plants utilize photosynthesis to create carbohydrates and sugars from sunlight, water, and carbon dioxide. Surprisingly, they also transfer a significant portion of their carbon-rich sugars to the soil, sharing up to 40% of their energy with their microbial community in the rhizosphere.

As soil microbiologist Dr. Elaine Ingham notes, plants essentially deliver "cakes and cookies" to their microbial companions. These sugars, known as root exudates, facilitate the transformation of atmospheric CO2 into stable carbon within the soil.

For a more in-depth explanation, watch this video:

The Symbiotic Relationship

Why do plants give away such a large portion of their carbohydrates? The answer lies in the symbiotic relationships they form with microorganisms. Contrary to mainstream perceptions of microbes as harmful agents, both plants and microorganisms benefit from these partnerships.

Plants communicate their nutrient needs to the microbes, which in turn supply essential minerals and water. This collaboration extends the root zone and acts like an on-demand nutrient delivery service. Soil microorganisms have been naturally mining minerals and nutrients from rocks and organic matter for millennia, long before synthetic fertilizers were developed.

Fungi, in particular, are essential for storing carbon, utilizing the carbon from root exudates to strengthen their hyphae. These mycelial networks, formed by thread-like structures, play a pivotal role in carbon sequestration.

The Carbon Pump Analogy

To simplify the concept, envision soil carbon sequestration as a carbon pump. Plants draw carbon from the atmosphere and transfer it to the soil, where it can be securely stored for extensive periods, thanks to fungal networks. This highlights why the protection and restoration of forests, which are rich in fungi, is crucial in the fight against climate change.

The Potential for Soil Carbon Storage

Currently, atmospheric carbon levels are around 410 ppm, the highest in the past 450,000 years. The UN considers a "safe" level to be 350 ppm, indicating that we need to remove approximately 60 ppm, equivalent to 450 billion tons of CO2, from the atmosphere. Can soil achieve this?

The answer remains uncertain. As mentioned earlier, precise measurement techniques for soil carbon sequestration are still being developed due to the dynamic nature of soil ecosystems.

A 2019 report from the Intergovernmental Panel on Climate Change suggests that global croplands and grasslands could potentially capture and store up to 8.6 gigatons of CO2 annually. Dr. David Johnson from New Mexico State University has demonstrated that using biological farming methods could result in the sequestration of 20 tons of carbon per hectare each year with fungal-rich compost.

Dr. Elaine Ingham's Soil Food Web, Inc. claims that we could reverse climate change through soil carbon sequestration within 15 years if regenerative soil practices are widely adopted.

The Impact of Tillage and Chemicals

Understanding how soil can help mitigate climate change leads to an important question: Can farmers who employ tillage or agricultural chemicals sequester carbon? The answer is a resounding "NO."

Only living soil can sequester carbon; dead dirt cannot. Tillage disrupts soil structure, releasing CO2 emissions into the atmosphere. It churns organic matter, releasing the carbon that had been previously sequestered by microbes. Over time, excessive tillage transforms soil into lifeless dirt incapable of carbon capture.

Synthetic herbicides, pesticides, and fertilizers similarly harm soil microorganisms. Regular use of these chemicals decimates microbial life, making it clear that drawing down carbon is impossible with degraded soil.

Embracing Nature's Approach

As you consider the concept of carbon farming credits or regenerative farming practices, remember that no-till and organic methods are the only true paths to regenerating soil and harnessing the carbon storage capabilities of fungi.

Dr. Elaine Ingham and Soil Food Web, Inc. are at the forefront of this movement, sharing valuable knowledge about soil microbiology. Ultimately, we must acknowledge that nature has been cycling carbon for billions of years, and our understanding of this process is still evolving.

The responsibility lies with us to address the climate crisis and ecological degradation through regenerative farming and biological soil management strategies.

Key Points to Remember:

• Plants absorb atmospheric carbon through photosynthesis, using it to create carbohydrates.
• They share a significant portion of their energy with soil microorganisms.
• Fungal networks play a crucial role in storing carbon within the soil.
• Degraded soils, often referred to as dirt, cannot sequester carbon effectively.
• Current agricultural practices that involve tillage and synthetic chemicals hinder carbon sequestration.
• Regenerative and organic methods are essential for restoring soil health and enabling carbon capture.

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