Soil Organic Carbon: Modeling, Measurement, and Credibly Estimating Outcomes

One of the most important issues facing regenerative agriculture projects is credibly estimating the impacts of practices on the sequestration of carbon in soils. The issue most often comes down to a matter of balancing costs with the accuracy needed to meet the requirements of standards  for carbon credit generation or scope 3 accounting and reporting. Historically, the accepted standard of measuring soil organic carbon stock and its changes has been through soil sampling and laboratory analysis, also referred to as measurement. For projects of 100s or 1000s of acres, the cost of this process can add up. We’ve recently seen the development of multiple biogeochemical models that incorporate relevant input data, including some measurements, to estimate soil organic carbon change through modeling. The ability to estimate outcomes using both modeling and measurement could help to significantly reduce project costs while maintaining the accuracy needed to meet accepted standards. 

Guidance and standards such as the upcoming Land Sector Removals Standard from the Greenhouse Gas Protocol allow for a measurement, modeling, or hybrid measurement/modeling approach for estimating soil organic carbon. Whether using a measurement, modeling, or hybrid approach, a clear methodology for determining how soil sampling measurement will be taken is necessary. Questions such as what fraction of fields should be sampled along with how many samples per field must be answered. Unfortunately, most standards in the scope 3 space are not explicit in how soil sampling should be done outside of providing some broad statistical bounds.

The HabiTerre Project Shed Inventory Approach uses a hybrid approach (measurement + modeling), requiring measurements through soil sampling to initialize and reinitialize the model to generate estimated outcomes. In keeping with our principle of radical transparency, we are publishing our white paper outlining  our specific methodology for soil sampling. This approach allows for program developers to create a program that balances their tolerance for uncertainty in the estimated outcomes with the economics needed to scale the project to meet their GHG emissions and carbon removal goals. This methodology puts the power in the hands of the program developer to create a program that achieves transparent, credible outcomes that are compliant with current scope 3 accounting and reporting standards.

👉 View Soil Sampling Methodology here.