To estimate or calculate the soil organic carbon formation from organic amendments like manure, compost, or biochar, you can use the following general equation:

(SOCf - SOCi) = Corg - (SOCi x ρbiom) x f

Where:

- SOCf is the final soil organic carbon content after the organic amendment treatment

- SOCi is the initial soil organic carbon content before the organic amendment treatment

- Corg is the total amount of carbon added to the soil through the organic amendment

- ρbiom is the bulk density of the organic amendment

- f is the fraction of the added carbon that remains in the soil after decomposition

We can calculate the initial and final soil organic carbon content (SOC) by conducting soil sampling and analysis. The total amount of carbon added to the soil (Corg) can be determined based on the application rate of the organic amendment. The bulk density of the organic amendment (ρbiom) can be measured in the laboratory. The fraction of the added carbon that remains in the soil after decomposition (f) can also be determined through experimentation or literature values.

By plugging in these values into the equation, you can estimate or calculate the soil organic carbon formation resulting from the organic amendment treatment.

Change in Soil Organic Carbon (ΔSOC) = (Mass of Amendment × Carbon Content × Sequestration Factor) - (Mass of Amendment × Carbon Content × Decomposition Rate)

For example, suppose you apply 1000 kg of biochar with a carbon content of 70% and a sequestration factor of 0.8, and 500 kg of manure with the % carbon content of 40% and a decomposition rate of 0.5. In that case, the change in SOC can be estimated as follows:

ΔSOC = (1000 kg × 0.70 × 0.8) - (500 kg × 0.40 × 0.5)

ΔSOC = (560 kg) - (100 kg)

ΔSOC = 460 kg

This means there is a net increase of 460 kg of SOC.

Estimating soil organic carbon (SOC) formation and loss when using organic amendments like biochar, manure, and compost involves several steps and can be approached through different methods, including field experiments, modeling, and laboratory analysis. Here's a general outline of how you can estimate SOC dynamics with these amendments: 1. Field Experiments and Sampling 2. Modeling SOC Dynamics 3. Laboratory Incubation Studies 4. Isotopic Tracing (if applicable) 5. Data Analysis and Interpretation 6. Long-Term Monitoring ,, Tools and Resources: Case Studies and Literature

• Reviewing case studies and published research where these methods were applied can provide additional insights and specific methodologies relevant to your context. Look for studies on SOC sequestration with biochar, manure, and compost in similar soil types and climates to those you are working with.
• Example Studies:
• Lehmann, J., & Joseph, S. (Eds.). (2015). Biochar for Environmental Management: Science, Technology and Implementation. Earthscan.
• Lal, R. (2004). Soil Carbon Sequestration Impacts on Global Climate Change and Food Security. Science, 304(5677), 1623-1627.

These steps will help you estimate how much SOC is formed or lost due to the application of organic amendments, and allow you to assess the long-term sustainability and carbon sequestration potential of these practices.