How does the Cool Farm Tool estimate soil carbon change due to management interventions? What parameters are taken into account?

How does the Cool Farm Tool estimate soil carbon change due to management interventions? What parameters are taken into account?

The Cool Farm Tool calculates changes in soil carbon, whether it involves emissions or sequestration, by considering historical changes in land use change, tillage and carbon input. The method employed is based on the IPCC 2019 guidelines. It's important to note that data entries related to practices implemented more than 20 years ago will not impact results, as the tool focuses on changes occurring within a 20-year window.

Here's a breakdown of how the Cool Farm Tool estimates soil carbon changes and the parameters it takes into account: 

1. Management Differences: Soil carbon changes are estimated by examining differences in land management practices. This includes factors such as tillage and carbon input into the soil. 

2. Land Use Change: The tool considers the change of land use from or to a new state, for example grassland to arable land and vice versa, recognizing the significant impact this can have on soil carbon. 

3. Tier 1 Model: The method used aligns with the IPCC 2019 guidelines for land use, management, and change for mineral soils. It is classified as a tier 1 model, indicating a standardized approach to estimate soil carbon changes. 

 4. Simulation Over 20 Years: The approach simulates the increase or decrease of soil carbon within a soil layer of up to 30 cm over a 20-year timeframe. It achieves this by comparing historic changes in land use, management practices, and soil carbon with current conditions. 

 5. Magnitude Determined by Intervention: The magnitude of carbon emissions or removals is influenced by the type of management intervention (e.g., transitioning from tillage to no-till, converting forests to arable land) and the initial soil carbon stock. 

 6. 20 Year Equilibrium assumption: The effect of the change is evenly distributed over the 20-year period, resulting in linear attribution. This assumes that after this period, the soil carbon has reached a new equilibrium and will remain relatively stable. 

 7. Consideration of Historic Changes: Historic management changes dating back up to 80 years ago are accounted for. These changes and their impact on soil organic carbon (SOC) stocks are considered when estimating the SOC stock at the beginning of the most recent change. This historical data forms the basis for estimating annual emissions as the land transitions towards a new equilibrium over the 20-year period.