ISOMETRIC-ENHANCED-WEATHERING — Enhanced Weathering in Agriculture

v1.3currentsource

v1.2source

Applicability criteria now permit carbonate feedstocks and non-agricultural settings (Section 4), while system boundary and GHG emission requirements have been updated to align with the GHG Accounting Module (Sections 7.1 and 8.5). Quantification and validation procedures have been refined, including new requirements for soil samples when using porewater-based quantification with ion exchange resin validation (Section 8.3.1), introduction of validation checks where the validation mean must exceed two standard deviations below the quantification mean (Section 8.3.1.1). Ion exchange resin validation now requires detailed procedural descriptions and saturation evaluation (Section 8.3.4). Project design flexibility has increased, allowing smaller control plots for larger projects (Section 10.1) and adding stratification options (Section 10.1.2). Climatic monitoring requirements have been streamlined, with only rainfall now mandatory while temperature, humidity, wind speed, and solar radiation are recommended (Section 10.3). The statistical framework has shifted from demonstrating significant weathering signals to direct confidence interval calculations (Appendix D), and more guidance is provided on the application rate check with detailed pass/fail criteria has been established (Section 10.4.4.3). Additional changes include removal of C and N requirements for biomass loss (Section 10.4.6.6), decrease in the sampling density requirement for soil bulk density (Table 3), integration of the River and Ocean Losses Module (Section 10.5.4), new data reporting requirements for pre-registration and lab accreditation (Section 11), and clarified guidance for projects started prior to this protocol (Section 12). The protocol also adds extensive guidance on uncertainty quantification (Appendix D), metal accumulation risk (Section 5.2), project expansion (Section 6.2), counterfactual calculations (Section 8.4), statistical testing (Section 10.1.1.2), mass change corrections (Section 10.4.6.2), non-carbonic acid weathering methods (Section 10.4.6.7), aqueous flux determination (Section 10.5.1.1.1), suitability checks (Section 10.5.2.3), aqueous measurement uncertainty (Section 10.5.3), and saturation indices for carbonic acid systems (Section 10.5.2.1). Finally, structural improvements include parameter renaming in Equations 4-5, updates to Equation 12 to account for changes in soil mass as a result of feedstock weathering, reorganization of calculation details, and general formatting enhancements.

v1.1source

The changes in V1.1, made in consultation with academic partners and enhanced weathering suppliers, reflect learnings from early deployments, both from a scientific and operational standpoint. These changes are designed to increase flexibility for projects across diverse environments while maintaining a high bar of scientific rigor. Key modifications include: removal of required sampling minima; restructuring of quantification and validation measurements; modifications to requirements for control and treatment plots; and modifications to the requirements for ancillary measurements not directly used in the calculation of carbon removal.

v1.0source

Initial Release.