The Three Pathways to Soil Carbon

There are three major methods to build carbon in your soil:

1. Liquid Carbon Pathway

   • Coined by Dr Christine Jones

   • Up to 46% efficiency in converting atmospheric carbon into stable SOC

   • Involves feeding mycorrhizal fungi through root exudates (sugars, lipids, proteins), from which they product humus.

2. Decomposition Pathway

   • Comes from breaking down plant litter and organic matter

   • Efficiency around 8.3%

   • Important for early biological stimulation and nutrient cycling

3. Biochar Application

   • Biochar itself is stable for hundreds of years

   • Offers 41% carbon retention, but not active carbon cycling

   • Better used as a delivery mechanism for nutrients and microbes

Each has a role. The goal is not to pick one, but to use them in combination depending on your system’s stage and needs.

Step-by-Step Framework for Building Soil Carbon

We recommend a staged approach inspired by John Kempf’s framework.

Step 1: Stimulate Soil Biology with Decomposition and Nutrition

• Use soil primers like fish hydrolysate, molasses, humic acid, and trace minerals or composts to supply nutrition to stimulate bacteria growth and activity.

• Focus on feeding bacteria, which kickstart microbial activity and plant-microbe interactions. This includes many bacterial processes like solubilising nutrients and fixing nitrogen but also increasing the number of bacteria for the rhizophagy cycle.

• Consider inoculants or compost extracts to jumpstart the system.

This primes the soil, unlocks tied-up nutrients, and activates the Rhizophagy cycle which then supplies the plant with high quality forms of nitrogen and minerals.

Optional: Integrate Biochar To Deliver Nutrition and Microbes

• Use inoculated biochar as a tool for delivering biology and nutrients.

• Charge biochar with:

  • Molasses or compost teas

  • Essential minerals, especially minerals for photosynthesis (N, Mg, Fe, Mn, P)

  • Microbial inoculants like worm castings

This prevents nutrient leaching and helps create microbial hotspots in the soil.

Step 2: Boost Plant Health and Photosynthesis For Increased Lipid Production

• The increase in bacteria will provide the plant with higher quality forms of nitrogen which allows the plant to save energy when converting nitrogen into amino acids and proteins. The gives the plant more energy for lipid production.

• Apply targeted nutrition (e.g. foliar sprays, seed treatments) can further improve plant health.

• A healthy plant photosynthesises better, producing more root exudates.

• This feeds the soil food web, especially mycorrhizal fungi, which build aggregates and store stable carbon in humus.

Lipids are the key exudates here – they’re high-energy, preferred by fungi, and essential for aggregate formation and carbon stability.

Why Focus on the Liquid Carbon Pathway?

Out of all methods, liquid carbon is the most scalable and efficient:

• Can be done through cover crops, relay cropping, and living roots

• Builds soil structure, water-holding capacity, and microbial symbiosis

• Drives the conversion of carbon into humified, stable organic matter

• Builds soil carbon to depth as soil carbon can be deposited as deep as the roots can grow.

You still need decomposition to get things moving, but your end goal should be a functioning liquid carbon system.

Quick Notes on the Fungal:Bacterial Ratio

Although the Fungal to Bacteria ratio is useful, don’t obsess over perfect ratios in degraded soils. Instead:

• Focus on raising both fungi and bacteria populations first

• Once biology is booming, then refine your balance based on your crop type and goals

Conclusion

To build soil carbon in a truly regenerative way:

• Start with decomposition and soil primers

• Boost photosynthesis with proper plant nutrition

• Build towards the liquid carbon pathway through diversity and biology

• Use biochar strategically as a tool, not the end goal