Improved Soil Management

This Protocol provides the requirements and procedures for the calculation of net carbon dioxide equivalent (CO₂e) removal from the atmosphere via improvements to soil organic carbon (SOC) stocks. In the context of this Protocol, we define SOC enhancement as the intentional adoption or intensification of land management practices that increase the accumulation of organic carbon within the soil profile, providing additional net carbon storage against a counterfactual baseline.

Soils represent the largest terrestrial carbon pool on Earth, storing an estimated 3,000 Pg of organic carbon¹. The potential for agricultural soils alone to contribute to climate mitigation is substantial: recent estimates suggest that improved cropland and grassland management could sequester between 0.28 and 0.43 Gt CO₂e yr⁻¹ globally², placing SOC enhancement among the most scalable nature-based climate solutions available. In addition to climate mitigation, improvements to SOC can provide a wide range of environmental and social co-benefits, including enhanced soil water retention and drought resilience, improved crop yields and long-term agricultural productivity, reduced fertilizer dependency, support for above- and below-ground biodiversity, and mitigation of erosion and nutrient runoff into waterways^3,4. Despite these potential benefits, adoption of SOC-enhancing practices is frequently constrained by upfront implementation costs, limited access to agronomic expertise, and the absence of reliable financial incentives for farmers^5,6. Carbon finance presents a meaningful opportunity to address these barriers, enabling the climate mitigation potential of improved soil management to be realized alongside tangible co-benefits for land managers and local communities.

This Protocol applies to a wide range of land management practices capable of demonstrably increasing SOC stocks within agricultural and grassland systems and other landscapes. This Protocol is process-agnostic, focusing on verified outcomes rather than prescribed methods. Eligible Project activities encompass any practice that results in a net, sustained increase in SOC stocks against a counterfactual baseline.

This Protocol and its eligibility requirements are designed to ensure that all Project activities support the goal of durable climate mitigation and associated co-benefits, while excluding practices that may produce short-term apparent SOC gains without genuine long-term carbon storage.

This Protocol accounts for the quantification of the gross amount of CO₂ removed via net increases in SOC stocks, as well as all cradle-to-grave life-cycle Greenhouse Gas (GHG) emissions associated with project activities (excluding continuation of pre-project activity emissions - see Section 8.1). This Protocol is developed to adhere to the requirements of ISO 14064-2: 2019 – Greenhouse Gases – Part 2: Specification with guidance at the project level for quantification, monitoring, and reporting of greenhouse gas emission reductions or removal enhancements.

The Protocol ensures:

• Consistent, accurate procedures are used to measure and monitor SOC stocks across the project area, utilizing direct soil sampling combined with validated modeling approaches to enable accurate accounting of net CO₂e removals;
• Consistent system boundaries and calculations are utilized to quantify net CO₂e removal, incorporating all material GHG sources and sinks within the project boundary;
• All net CO₂e removal claims are verified by an accredited third party;
• Project activities avoid harm to local ecosystems or biodiversity;
• Leakage impacts are quantified and appropriately addressed;
• Agreements with smallholder landowners and farmers, where applicable, are the result of a thorough engagement process and the terms help to support and advance local livelihoods;
• Removals are additional through the use of baseline approaches that integrate data on changing conditions and other guardrails set forth in the Isometric Standard;
• Comprehensive guidance on project design, soil sampling protocols, and monitoring mechanisms to confirm Durability and protect against Reversals, ensuring transparent Credit delivery.

This Protocol and all standardized approaches therein, including but not limited to the baseline, removal quantification, and the treatment of non-permanence risk, are informed by the best available scientific knowledge and have undergone external review by subject matter experts and relevant stakeholders. All comments received during consultation are publicly addressed, with revisions incorporated as appropriate, to ensure the certified version of the Protocol will yield high-quality Carbon Credits via rigorous, conservative, and appropriate methodologies.

Throughout this Protocol, the use of "must" indicates a requirement, whereas "should" indicates a recommendation.

This Protocol relies on and is intended to be compliant with the following standards and protocols:

• The Isometric Standard
• ISO 14064-2: 2019 - Greenhouse Gases - Part 2: Specification with guidance at the project level for quantification, monitoring, and reporting of greenhouse gas emission reductions or removal enhancements

Additional reference standards that inform the requirements and overall practices incorporated in this Protocol include:

• ISO 14064-3: 2019 - Greenhouse Gases - Part 3: Specification with Guidance for the verification and validation of greenhouse gas statements
• ISO 14040: 2006 - Environmental Management - Lifecycle Assessment - Principles & Framework
• ISO 14044: 2006 - Environmental Management - Lifecycle Assessment - Requirements & Guidelines

Additional principles that were considered in the development of this Protocol and aligned with, where feasible, include:

• The Core Carbon Principles of The Integrity Council for the Voluntary Carbon Market, v1.1, ICVCM, 2024
• Criteria for High-Quality Carbon Dioxide Removal, Carbon Direct & Microsoft, 2025
• Challenges and Opportunities in Soil Carbon Credits, Carbon Direct, 2025

Protocols and Methodologies that were assessed as part of a literature review during the development of this Protocol include:

• VM0042 Improved Agricultural Land Management, v2.2, Verra, 2025
• VMD0053 Model Calibration, Validation, and Uncertainty Guidance for Biogeochemical Modeling for Agricultural Land Management Projects, v2.1, Verra, 2025
• VT0014 Estimating organic carbon stocks using digital soil mapping, version 1.0, Verra, 2025
• US Soil Enrichment Protocol v1.1, Climate Action Reserve, 2022

This Protocol was developed based on the current state of the art, publicly available science regarding soil organic carbon improvement activities and MRV of improved soil management projects. This Protocol aims to be scientifically stringent and robust. We recognize that some requirements may exceed the status quo in the market and that there are numerous opportunities to improve the rigor of this Protocol. Key future improvements to the Protocol are outlined in Appendix A.

Additionally, this Protocol will be reviewed when there is an update to published scientific literature, government policies, or legal requirements which would affect net CO₂e removal quantification or the monitoring guidelines outlined in this Protocol, or at a minimum of every 2 years.

This Protocol sets forth universal requirements for all Improved Soil Management Projects. All Projects are also subject to additional requirements tailored to the implementation practice(s) and setting of the Project Proponent’s soil management activities,

This Protocol applies across the full temporal (see Section 5.0) and spatial scope of the Project. The Project Boundary is set at the time of project initiation and may be modified during the Crediting Period in the following circumstances:

• Addition of new units. New units may be added to the Project Boundary during the Crediting Period, subject to the eligibility, baseline, and additionality requirements set out in this Protocol. Added areas enter The Project at the time of their addition and are subject to a Project Timeline reflecting that initiation date.
• Removal of units. Units may be removed from the Project Boundary during the Crediting Period. Removed areas are treated in accordance with the unenrollment provisions of this Protocol, including the default assumption of a full reversal where ongoing monitoring is not maintained.
• Correction of boundary errors. Project Proponents may correct errors in unit boundaries (for example, where owner-submitted boundaries require revision based on subsequent data review) without these corrections being treated as additions or removals, provided that: (i) the correction reflects a data-quality refinement rather than a substantive change to the enrolled area; (ii) the cumulative net effect of boundary corrections in any Reporting Period does not exceed 5% of the total enrolled area; and (iii) all corrections are documented, justified, and reported at verification.

The Project must not harm biodiversity or existing ecological function, and should aim to improve ecosystem function and biodiversity where possible.

The Project must not harm Indigenous Peoples and local, underserved, or marginalized communities, in compliance with the Social Impacts Section of the Isometric Standard and Section 6 of this Protocol. Where project activities occur on land owned, occupied, or customarily used by Indigenous Peoples, or where project activities have the potential to directly or indirectly affect the territories, resources, or livelihoods of Indigenous Peoples, Project Proponents must enact a Stakeholder Engagement Plan consistent with the principles of Free, Prior, and Informed Consent (FPIC) as outlined by the United Nations Declaration on the Rights of Indigenous Peoples. Project Proponents must document the impact assessment underlying their determination. Geographic proximity alone, in the absence of a plausible impact pathway, does not trigger this requirement.

The unit of enrollment, eligibility assessment, baseline determination, and quantification under this Protocol is defined as a contiguous area under a single management regime. Project Proponents may enroll individual units within a landowner's or operator's holdings without requiring enrollment of all units under common ownership, lease, or operational control. Across different settings and intervention Modules, further details may be provided to more explicitly define this. References to "farm," "property," or "landowner" elsewhere in this Protocol should be interpreted at the unit level unless the context expressly requires otherwise (for example, where legal tenure or contractual obligations are inherently held at the entity or parcel level).

A unit's Enrollment Date precedes or coincides with its Project Initiation. Project Establishment activities undertaken after the Enrollment Date but before SOC-enhancing operations begin (e.g., capital deployment into infrastructure during a ramp-up phase), form part of the Project and do not constitute prior adoption.

Additionally, projects under this Protocol must meet all of the following project conditions:

• The Project must provide a net-negative CO₂e impact (net CO₂e removal) as calculated in the GHG Statement, in compliance with Section 9.
• The Project must be considered additional, in accordance with the requirements of Section 7.4.  
• The Project must meet the transparency requirements of this Protocol, outlined in Section 7.6.

• Baseline design, particularly the establishment of a pre-intervention soil organic carbon baseline
• Sampling plan design, particularly the stratification and quantification of in-field heterogeneity across soil types, land-use histories, and management zones
• Sample depth and the basis of stock calculation (fixed depth or equivalent soil mass)
• Bulk density measurement
• Sample compositing and pooling practices
• Laboratory analytical methods, including the treatment of soil inorganic carbon
• Model calibration and validation, where modeling is relied upon
• Any other major deviations from the current Protocol requirements

Projects started prior to the publication of this Protocol are subject to the same uncertainty and statistical significance requirements throughout this Protocol. Where a deviation from this Protocol precludes a robust determination of net CO₂e removal, that Project is not applicable under this clause. At a minimum, all Projects must:

• Have taken physical soil samples within the project area;

Crediting under this clause remains subject to the additionality and Prior Adoption requirements of Section 7.4, and to the Crediting Period Start Date limit in corresponding section of the Isometric Standard; removals occurring before the Crediting Period Start Date are not eligible for crediting.

Projects that are credited under this clause may be subject to additional tests and checks that are not explicitly required in this Protocol, as these Projects often use methods and techniques that differ from those given within this Protocol. The purpose of these checks is to evaluate the validity of such methods and ensure that there is sufficient confidence for credit issuance. The specific checks required will depend on the Project and the deviations from this Protocol.

• Participation in any other carbon program by The Project, or a legal predecessor, within the preceding 5 years, and the reasons for transition or withdrawal
• Validation and Verification audit reports from the two most recent processes under any previous program
• Evidence that Credits previously issued for the same removals, or for any overlapping period, have been cancelled, retired, or permanently de-registered
• The baseline, additionality determination, and quantification approach relied upon under the previous program, and their consistency with Sections 7.4, 8.0, and 9.0 of this Protocol
• Any other major deviations from the current Protocol requirements

Baselines, additionality determinations, and quantification accepted under another program are not automatically valid under this Protocol and will be assessed by Isometric on a case-by-case basis. The Crediting Period start date under this Protocol must not predate the end of the last period for which Credits issued by another program remain live.

As with pre-existing deployments, Projects credited following a transition may be subject to additional tests and checks that are not explicitly required in this Protocol, to evaluate the validity of methods used under the previous program and ensure sufficient confidence for credit issuance.

The Project Commitment Period consists of the Crediting Period and any Ongoing Monitoring Period which is required by the Module under which The Project is crediting.

The Crediting Period is the interval between project initiation (e.g., first implementation of the project intervention) and the end of the last Reporting Period. The Crediting Period is made up of successive Reporting Periods.

The Ongoing Monitoring period encompasses a period following the Crediting Period during which carbon stocks are monitored for potential reversals. Requirements for inclusion of an Ongoing Monitoring Period as part of the Project Commitment Period, as well as monitoring requirements, are covered at the Module level.

The Project Enrollment Date is the date a field is formally added to The Project, evidenced by the landowner's or operator's signatory consent and documented land tenure recorded in the PDD. This is an administrative milestone only: it does not start the Crediting Period and does not, by itself, authorize any project-activity grazing-management change. 

The Project Initiation / Project Start Date is the date the first project-activity grazing-management change is implemented. This date triggers the start of the Crediting Period and is the anchor for the additionality prior-adoption lookback. The installation of infrastructure and the conduct of baseline measurement during the Enablement Window do not, of themselves, constitute Project Initiation.

Credit issuances occur throughout the Crediting Period and are issued upon verification of a Reporting Period. Under the cumulative accounting framework, Credits issued at each verification event represent the cumulative net CO₂e removal from project initiation to the end of the current Reporting Period, less all Credits previously issued under the Project and other discounts (e.g., leakage discount), in accordance with Section 9.0.

Abandonment of The Project or failure to perform the land management activities required to maintain SOC stocks at any point during the Crediting Period may result in project failure. In the event of project failure, all Credits issued under The Project may be canceled.

The duration of the Crediting Period, Reporting Period and Ongoing Monitoring Period, and Durability are defined at the Module level.

Tenure and contractual arrangements with individual landowners or operators are not required to extend to the full Project Commitment Period. Where they do not, the Project Proponent's project-level monitoring and reversal-compensation obligations continue to apply across the full Project Commitment Period as set out in Section 5.1 and Section 10, and an additional buffer pool contribution applies in accordance with Section 10.4.1.

• The Project Proponent and/or landowner(s) must provide documentation to verify their tenure, which could be demonstrated via legal agreements/contracts, tax records, notarized statements, and/or government records.

• Government or commons. In cases where all land is held by the government or in commons, or in cases where the land will be returned to the government during the Project Commitment Period, the Project Proponent must provide legal documents attesting to such land ownership structure and a legal agreement from the relevant authorities that project activities can be carried out for the length of the Crediting Period, and access will be granted during any Ongoing Monitoring Period.
• Land held in trust. For land held in trust, the governing body must provide signatory consent for carbon credit enrollment.
• Multiple owners. For land with multiple owners, all parties must give their signatory consent. Where extensive co-ownership structures (e.g., heirship land, undivided family interests, or analogous arrangements under local law) render universal signatory consent impracticable, the Project Proponent may instead demonstrate all of the following:
  • The operator enrolling the land holds documented, legally enforceable rights of use through ownership, lease, usufruct, or equivalent sufficient to direct land management activities for the duration of the Crediting Period applicable to that area;
  • Reasonable efforts have been made to identify and engage non-signing co-owners or rights-holders, including documented notification of project activities and a documented opportunity for them to raise objections, in accordance with Section 6.6.1; and
  • Any objections received from non-signing co-owners or rights-holders have been documented and addressed.
  • For areas with customary land tenure systems, Project Proponents may submit documentation or statements from local authorities or leaders.
  • The reversal risk arising from co-ownership fragmentation is addressed through the buffer pool framework in Section 10.4.
• The same alternative pathway set out above applies where land is enrolled by an operator under a leasehold or analogous tenure arrangement and signatory consent from the landowner is impracticable due to fragmented landownership, absent or unreachable landowners, or analogous circumstances. In such cases, the operator must demonstrate documented, legally enforceable rights of use sufficient to direct land management activities for the duration of the applicable Crediting Period, and must satisfy the engagement and objection-handling requirements set out above with respect to the landowner(s).
• In the event of land ownership transfer, including inheritance, sale, or other forms of succession, the Project Proponent should - subject to local, national, and regional laws - make every effort to ensure that the new owner(s) or heir(s) uphold the commitments outlined in the land agreement. This includes maintaining the system carbon stocks in accordance with the requirements of this Protocol and applicable Modules, and upholding any other project requirements for the duration of the Project Commitment Period. If land area is unenrolled as a result of transfer of ownership, then the requirement for ongoing monitoring in Section 5.1.1.1 must be upheld.

• Revenue or subsistence benefits from commodity production occurring within the project system; and/or
• Investing a portion of revenue into a trust which shifts payments over the full Project Commitment Period.

Following the Isometric Standard, Credits issued under this Protocol are contingent on the implementation, transparent reporting, and independent Verification of comprehensive safeguards. These safeguards encompass a wide range of considerations, including environmental protection, social equity, community engagement, and respect for cultural values. The process mandates that safeguard plans be incorporated into all major project phases, with detailed reports made accessible to stakeholders. Adherence to and verification of environmental and social safeguards is a condition for all Crediting Projects.

An environmental and social risk assessment, in compliance with the Environmental and Social Impacts Section of the Isometric Standard, must be completed to identify potential risks, followed by the development of tailored mitigation plans. These plans must encompass specific actions to avoid, minimize or rectify identified impacts. Effective implementation of these measures must also be accompanied by a robust monitoring plan to detect adverse effects and pause project activities if necessary, using the principles of adaptive management described below.

Environmental and social risk identification, assessment, avoidance, and mitigation planning will be unique to the technical, environmental, and social contexts of The Project. To accommodate this variation, the requirements outlined in this section serve as minimum safeguards to which the Project Proponent and Isometric can add to on a case by case basis, to be included in the PDD, if applicable.

Project Proponents must comply with all national and local laws, regulations and policies, and receive any necessary permits for project activities, if applicable. Where relevant, projects must comply with international conventions and standards governing human rights and uses of the environment.

1. Document any activities that trigger environmental permitting requirements, and demonstrate that any product has regulatory approval or is registered with the relevant regulatory authority where required by national legislation.
2. Demonstrate that use of the product in The Project context has no adverse effect on soil, plant, human, or animal health or the surrounding environment, both after application to the soil and during storage and handling.
3. Where the product is relied upon as an SOC-enhancement intervention for the purposes of crediting, Project Proponents must provide evidence, appropriate to the product's novelty and the project context, of a credible and durable mechanism by which the product produces net SOC stock gains, and that those gains can be reliably attributed to the product. a. Acceptable evidence includes: (i) peer-reviewed studies quantifying the product's effect on measured SOC stocks (not solely biomass, yield, or microbial proxies) in comparable soil, climate, and cropping contexts; (ii) controlled field trials with untreated controls demonstrating a statistically significant, attributable SOC response; and/or (iii) systematic reviews or meta-analyses characterizing the magnitude and persistence of that response. b. The level of evidence required is proportionate to the product's deployment history: products without an established, well-characterized SOC mechanism must be supported by site-specific or closely analogous trial evidence. c. This requirement does not apply where the product is deployed for agronomic purposes (such as crop stress tolerance, pest management, or nutrient cycling) and any contribution to SOC is incidental to its primary use.

• A mitigation plan that covers risks that are relevant for the Project Area
• The measured or observed outcome that will trigger the mitigation plan
• Plan for information sharing
• Emergency response plan, if applicable

The Project should not hinder the ability of the community or local ecosystem to adapt to climate change as a result of the CDR activity.

Projects must maintain and should enhance the biodiversity of existing ecosystems while optimizing carbon storage outcomes, regardless of whether the project interventions involve a change in land use. Some projects under this Protocol may be established in working landscapes where existing species assemblages, soil communities, and ecological processes are already present. The primary biodiversity objective for these projects is to ensure that land management practice changes designed to enhance soil carbon sequestration and storage do not compromise the ecological integrity of these established land uses, and where possible, enhance biodiversity through improved soil health, vegetation diversity, and habitat complexity.

SOC-enhancing practices can provide significant opportunities to enhance biodiversity by improving soil biological diversity, increasing vegetation cover, supporting pollinator habitat, and reducing agrochemical inputs. However, these same practices must be carefully designed to avoid unintended consequences such as introduction of invasive species, disruption of existing soil communities, or habitat degradation arising from changes in water management or agrochemical use.

• The species do not have the potential to become invasive, evidenced through peer-reviewed literature or observational studies from the same region or regions with similar climates, geographies, and ecologies; and
• The species will serve a functional role consistent with the ecological context of the project area (e.g., as a nitrogen-fixing cover crop or pollinator resource), and that its introduction is not expected to materially disrupt nutrient cycling regimes, pollinator resource availability, soil microbial communities, or other ecological functions of the project area or surrounding landscape, beyond the effects intended as part of the project intervention.
• The level of evidence required is proportionate to the species and context: species with extensive regional deployment history and well-characterized ecological behavior may rely on existing peer-reviewed literature and observational evidence, while species without such deployment history must be supported by site-specific or analogous evidence sufficient to characterize the relevant ecological risks.

The definition of 'invasive species' in this Protocol is consistent with the Convention on Biological Diversity's definition of Invasive Alien Species, being a "species whose introduction and/or spread threatens biological diversity”⁸.

• Ecosystem services vital to the ecology and population stability of the species in the project area;
• How The Project will maintain or enhance these ecosystem services throughout the Project Commitment Period; and
• A population monitoring plan where project activities pose an identified risk to the species.

Reporting of chemical amendment use is required as follows:

• At enrollment: Project Proponents must report in the PDD the chemical amendments planned for use within the Project Area, their intended purpose, and any predicted increase in use induced by project interventions relative to the baseline, and must identify the applicable BMPs, laws, and regulations and describe how The Project will conform.

The emissions associated with any induced increase in the use of synthetic herbicides, fertilizers, and pesticides must be accounted for in line with the emissions accounting requirements of Section 9.6.

In accordance with the Stakeholder Input Process Section of the Isometric Standard, Project Proponents must demonstrate active stakeholder engagement throughout project planning and operation, ensuring that all risk mitigation strategies contribute to sustainable project outcomes. Local stakeholders may contribute an in-depth understanding of the project area and operations, and provide invaluable insights and recommendations on potential risks, necessary safeguards, and specific monitoring needs. Engaging local stakeholders creates community buy-in, providing long-term commitment and investment in the success of nature-based projects^{9, 10}. Furthermore, lack of community support, stakeholder engagement, and perceived community benefits has been identified as a primary source of project failure in previous nature-based projects¹¹.

• Project activities that occur on land or territories that are owned, occupied, or utilized by Indigenous Peoples, regardless of whether that claim is recognized by the local governing body or held by rights to self-determination, as recognized by the United Nations;
• Project activities that will affect natural resources necessary for the livelihoods or cultural rights of Indigenous Peoples.

This assessment must incorporate analysis of reputable, independent data by a subject matter expert, who may be a third party. The results of this assessment must be included in the PDD. If the assessment identifies potential impacts to Indigenous Peoples, the additional requirements in Section 6.6.2 apply.

Where the assessment does not identify potential impacts on Indigenous Peoples, Project Proponents are encouraged, but not required, to complete a Stakeholder Engagement Plan consistent with FPIC principles for other relevant stakeholders who rely on land or resources located within the project area. This encouragement is without prejudice to Section 6.6.3: where FPIC is required for enrolled Operators or Subsistence smallholders under that Section, it applies regardless of any finding on Indigenous impact.

• Due diligence that the stakeholder engagement processes were carried out (e.g., meeting recordings or copies of information shared with stakeholders);
• The structure of revenue-sharing arrangements, as set out in Section 6.6.3.6.

Absolute revenue figures, individual transaction values, and buyer-specific pricing are not required to be made publicly available under this Protocol. Where the Isometric Standard or this Protocol requires Project Proponents to report financial information to Isometric for verification or oversight purposes, that information may be submitted in confidence and is not subject to public disclosure unless expressly required elsewhere in this Protocol.

FPIC is a governance mechanism, not an informational disclosure process. The requirements of this Section are intended to ensure that affected Indigenous Peoples have a substantive role in shaping project design and the genuine ability to grant, condition, or withhold consent — not merely to receive information about decisions already made.

The FPIC principles are as follows:

• Free: Stakeholders are not subject to intimidation, coercion, or manipulation during the decision-making process.

• Prior: Engagement is sought in the early stages of project development, before commencement of project activities. Consent must be sought as part of project development, regardless of local requirements. The timeline for the decision-making and deliberation periods is set in consultation with all stakeholder groups and is informed by customary, local, and/or traditional practices. The stakeholder engagement process must be enacted early in the project development process, prior to the initiation of Project activities. The stakeholder engagement schedule must be circulated prior to project initiation, with enough notice to engage stakeholders in the planning process. In some instances, Project Proponents that initiated project activities prior to engaging with Isometric, and did not engage Indigenous Peoples stakeholders under the principles of FPIC, may still be eligible for crediting under this Protocol, in consultation with Isometric, by demonstrating how stakeholder engagement will be incorporated into future project planning.

• Informed: Information is presented in a manner that is accessible to all stakeholder groups. Accessible content may differ across stakeholder groups. The Project Proponent must consider the language and medium of communication in the information-sharing process. For example, if information is presented electronically, stakeholders must have access to and familiarity with the necessary technology to review it; if information is presented during in-person meetings, the meetings must be held at a time and in a location conducive to stakeholder attendance. Information presented to stakeholders must be objective and present trade-offs fairly and accurately, and must be provided on an ongoing basis. The following due diligence is strongly recommended to ensure stakeholder groups are well informed of project development and outcomes:

  • Stakeholders should be made aware of the value of the Credits and the anticipated revenue of The Project at large. The Project's anticipated growth and issuance should be modeled, and simulations describing the value of Credits at current market prices should be made clear.
  • Stakeholders should have full access to The Project's finances, budget, and forecasted returns.
  • Stakeholders should be aware of alternative land-use / land-management scenarios.
  • Stakeholders should be aware of how changes in management practices might affect expected yields within existing productive areas.
  • Stakeholders should have a clear understanding of the breakdown of project income and expenditure, and of the precise percentage of revenue to which they are entitled.

  Where a stakeholder is also an enrolled party under Section 6.6.3, the disclosures in Section 6.6.3.5 are mandatory rather than recommended, and govern to the extent of any overlap.

• Consent: Must be freely given and may be withdrawn. Consent may be conditional upon milestones in project development or the emergence of new information. Stakeholder consent is not guaranteed as a result of the Stakeholder Input Process.

The Project Proponent is encouraged to prepare alternatives for the withdrawal or denial of consent to project activities by stakeholder groups.

The following may serve as burdens of proof that the Stakeholder Input Process conforms with the principles of FPIC. The Project Proponent must indicate how these steps were or will be carried out during the project lifetime. Multiple rounds of stakeholder engagement may take place during a project lifetime, as needed. The Project Proponent may identify other burdens of proof demonstrating that the principles of FPIC have been observed and submit them in the PDD, in addition to or instead of those below, in consultation with Isometric.

• The manner in which information was presented to stakeholders, including the medium and language.
• How stakeholder input was obtained, including the medium and language.
• How stakeholder input was incorporated into the project design.

The VVB may conduct random surveys or interviews with stakeholder groups, and/or witness some or all of the processes described above.

Additional requirements apply to any Project which operates via partnerships with enrolled parties via a collection of separate agreements held directly with those who hold rights to, operate, or work the enrolled land. There is no standard definition of the term "smallholder," and the land area, asset value, livelihood dependence, and bargaining power of enrolled parties vary considerably across the globe and across Project types. Treating all such parties as a single class risks both under-protecting those with limited bargaining power and applying protections designed for vulnerable parties to sophisticated commercial counterparties for whom they are not appropriate.

This Section sets out the safeguarding objectives that every such Project must meet, together with a set of categories to help Project Proponents identify which objectives apply to which parties. It is intended to be applied in a Project-specific context: the categories and mechanisms described below are a framework and a set of worked examples, not a rigid or exhaustive checklist. A Project Proponent may adopt classifications, instruments, and engagement approaches suited to the legal, cultural, and operational context of its Project, provided the underlying safeguarding objective of each applicable category is met and the approach is documented and justified in the PDD.

• develop and follow a Stakeholder Engagement Plan covering those parties, in accordance with Section 6.6.1;
• apply the environmental and biodiversity safeguards of Section 6 to all enrolled land;
• apply the contractual carbon-stock maintenance obligations of Section 5.1.1 to all enrolled land; and
• make the monitoring and public data-sharing disclosures identified in Section 6.6.3.5.

These are the minimum obligations. The categories in Section 6.6.3.2 add further, more protective requirements where relevant; FPIC, consultation, informed approval, and the revenue-share floor attach through those categories rather than through this baseline.

Landowner. A party that holds property rights to enrolled land, for example a government entity, corporation, investment vehicle, or private individual or family. Objective: the landowner gives informed approval to The Project, and receives the minimum revenue-share floor of Section 6.6.3.6. The appropriate approval mechanism will depend on the landowner's relationship to the land, for example, a Land Use Agreement (LUA) may be suitable for an absentee or institutional landowner, and a collaboration agreement for a hands-on landowner but a Project Proponent may use whatever instrument achieves genuine informed approval in its context.

Operator. A party that holds the right to operate the enrolled land, whether or not it also holds property rights to it. Objective: engagement is conducted consistent with the principles of FPIC set out in Section 6.6.2.

Worker. A party involved in the day-to-day operations on the enrolled land, whether or not it holds any property or operating rights. Objective: meaningful consultation appropriate to its involvement.

Subsistence smallholder. A rights holder to a small land area under legal or customary rights who depends on that land primarily for their own subsistence and who plays a primary role in the management activities occurring on the land. Because these parties are the most exposed, this category carries the full set of protections: engagement consistent with the principles of FPIC (Section 6.6.2), the complete disclosure obligations of Section 6.6.3.5, the minimum revenue-share floor of Section 6.6.3.6, and the landowner-privacy data restrictions of Section 7.6. A Project Proponent retains flexibility in how these protections are implemented but may not waive or dilute them for a party that meets this description.

Because the categories are additive, a Project Proponent builds the safeguarding approach for each enrolled party out of the applicable objectives. For example:

• A subsistence rights holder who owns and personally works their own plot occupies the Landowner, Operator, Worker, and Subsistence smallholder categories simultaneously, and receives the full combined set of protections.
• A government entity that leases out land it neither operates nor works occupies only the Landowner category; its obligations are informed approval and the revenue-share floor, on top of the baseline.
• A family or owner-operator holding a larger, non-subsistence holding that they manage directly occupies the Landowner and Operator categories (and the Worker category where they carry out operations themselves), and so is owed informed approval, the revenue-share floor, and FPIC-consistent engagement.

Where a Project's circumstances are not well captured by these examples, the Project Proponent should apply the categories purposively asking which safeguarding objectives the party's actual position calls for and document the reasoning in the PDD.

A Project that operates via separate agreements with any party in the Subsistence smallholder category is considered to be operating via a smallholder arrangement and is subject to the requirements of this Section in full. The means by which a Project meets those requirements may be tailored to context, but the protections owed to subsistence smallholders represent a floor rather than a starting point for negotiation.

The disclosures in this Section apply in two tiers. Where a party is also covered by the recommended "Informed" due diligence in Section 6.6.2, these obligations are mandatory and govern to the extent of any overlap.

• Monitoring: that their land may be monitored via satellite imagery as required by this Protocol and related Modules, and that this data as well as geospatial information related to their land will be anonymized and shared with the public through the Isometric Registry. Geospatial information and other data that must be publicly shared includes remote-sensing maps and imagery documenting The Project's carbon stocks, structure, and ecological benefits.
• Data-sharing practices: what data will be shared with which parties (e.g., Isometric, the public, government bodies), how data collected from their land will be used, the Project Proponent's data-security procedures, and data ownership.

• Financials: the revenue-sharing arrangement between The Project and the enrolled party, the anticipated value of the carbon Credits, and the anticipated earnings of The Project.
• Carbon markets: the volatility of the carbon market and that the sale of carbon Credits is not guaranteed, where the party's compensation varies with carbon-credit pricing.
• Project crediting: the concept of counterfactuals and the unpredictability of carbon storage and loss over time; Credits may be fewer than anticipated under ex-ante projections.

Eligible forms of revenue sharing include:

• Direct payments (which may include lease payments for land access by The Project);
• Planting materials (e.g., seedlings, fertilizer);
• Equipment and/or infrastructure;
• Training (the cost of conducting the training).

The Project Proponent must identify and develop processes for the protection and promotion of community well-being in the PDD, as follows:

• Protection of human rights:
  • Policies and practices upholding anti-discrimination on the basis of gender, sexual orientation, etc.
• Grievances, feedback, and complaints:
  • The process by which the Project Proponent accepts grievances, feedback, and complaints. Project Proponents must provide details on how adjudication and oversight will be supported with third parties. The grievance redress process must be outlined in the PDD.
  • Mediation and resolution process for grievances and complaints.
• Employment Opportunities:
  • Hiring practices and policies, including the number of short-, medium-, and long-term employment opportunities that were directly created (or expected to be created) via project activities. The Project Proponent must also report how many of these employment opportunities were/will be recruited for in the local community.

As previously mentioned, community buy-in is critical to the success of improved soil management projects. Community buy-in may be established when stakeholders are properly informed about the benefits they can expect from The Project. Equally important in maintaining buy-in is for the positive impacts resulting from The Project to match the (perception of) potential benefits presented to community stakeholders at the project onset. A mismatch in benefits expected and benefits realized may similarly hinder project success.

While this Protocol will not prescribe requirements for community impacts, the Project Proponent is strongly encouraged to consider establishing the following programs and activities:

• Employment opportunity programs favoring local community members, especially in the creation of long-term jobs;
• Establishment of community benefit-sharing arrangements;
• Construction of infrastructure, such as roads, that are accessible to the community;
• Establishment of programs to support training in sustainable land management practices;
• Development of site specific mitigation plans for potential negative community impacts.

Positive impacts should be felt by all stakeholder groups identified in Section 6.6.1. Project Proponents should consider which groups may face the brunt of negative community impacts, and how positive community benefits may be shared equitably with these and other marginalized groups.

It is recommended that the Project Proponent provide support to the local communities and ecosystems to establish locally-relevant mitigation strategies to adapt to changing climates.

The following topics are covered briefly in this Protocol due to their inclusion in the Isometric Standard, which governs all Isometric Protocols. See in-text references to the Isometric Standard for further guidance.

For each specific Project to be evaluated under this Protocol, the Project Proponent must document project characteristics in a Project Design Document (PDD) as outlined in the Documentation Section of the Isometric Standard. The PDD will form the basis for project validation and evaluation in accordance with this Protocol.

Projects must be validated and net CO₂e removals verified by an independent third party, consistent with the requirements described in this Protocol and the Module(s) under which The Project is crediting, as well as in the Validation and Verification Requirements Section of the Isometric Standard.

The Validation and Verification Body (VVB) must consider the following requisite components:

• Verify that The Project meets the Applicability conditions described in Section 4
• Verify that the Environmental & Social Safeguards outlined in Section 6 are met
• Verify that the System Boundary & Leakage assessment adheres to the requirements of Section 8
• Verify that the quantification approach and monitoring plan adheres to requirements of Section 9
• Verify that the conditions for ensuring durability and monitoring for Reversals in Section 10 are met
• Verify that The Project is compliant with requirements outlined in the Isometric Standard

As part of this evaluation, the VVB must also review the characterization and quantification of all individual uncertainty sources within the listed components that contribute to the calculation of net CO₂e removal.

The threshold for Materiality, considering the totality of all omissions, errors and misstatements, is 5%, in accordance with the Materiality Threshold Section of the Isometric Standard.

Verifiers should also verify the documentation of uncertainty of the GHG Statement as required by the Uncertainty in Removals and Reductions Section of the Isometric Standard. Qualitative Materiality issues may also be identified and documented, such as:

• Control issues that erode the verifier’s confidence in the reported data;
• Poor management documented information;
• Difficulty in locating requested information; and
• Noncompliance with regulations indirectly related to GHG emissions, removals or storage.

Project Validation and Verification must incorporate site visits to Project facilities, namely in situ field plots, in accordance with the requirements of ISO 14064-3, 6.1.4.2. This is to include, at a minimum, site visits during the first Validation or Verification of a Project, to the project site(s). Validators should, whenever possible, observe project operation to ensure full documentation of process inputs and outputs through visual observation and validation of instrumentation, measurements, and required data quality measures.

A site visit must occur at least once during each Project Validation. Additional site visits may be required if there are substantial changes to operations over the course of a Project's Validation period, or if deemed necessary by Isometric or the VVB. Site visit plans are to be determined according to the VVB's internal assessment, in consultation with Isometric.

Verifiers and Validators must comply with the requirements defined in the Validation and Verification Requirements Section of the Isometric Standard. In addition, verification teams must maintain and demonstrate expertise associated with land management practices and soil science, including both field measurements processing and analysis and model-based analysis. Verification teams must also demonstrate competence in assessing stakeholder engagement processes.

CDR via soil sequestration is a result of a multi-step process (e.g., site preparation, land management activities, system maintenance, monitoring), with activities in each step potentially managed by a different operator, company, or owner. Further, improved soil management projects can also often involve a coalition of smallholder landowners. A single Project Proponent must be specified contractually as the sole owner of the Credits when there are multiple parties involved in the process, and to avoid Double Counting of net CO₂e removals. Contracts must comply with all requirements defined in the Ownership Section of the Isometric Standard.

The Project Proponent must be able to demonstrate additionality through compliance with the Additionality Section of the Isometric Standard. The Baseline scenario and Counterfactual utilized to assess additionality must be project-specific and comply with Section 9.4.

Projects must not occur in regions where significant rates of the project interventions are driven by market demand, local and/or national incentives, or policies that would lead to similar land management practices without Carbon Finance.

Government subsidies or civil contractual obligations for specific land management practices, such as organization bylaws, inhibit additionality and fall under the Regulatory criteria in the Additionality section of the Isometric Standard. Additionality is assessed each Reporting Period using the counterfactual assessment described in Section 9.4.

All projects must demonstrate the necessity of Carbon Finance for project viability following the Additionality Section of the Isometric Standard. If any revenue will be produced from commodity production within the project area or sources other than Removals, additional requirements for demonstrating financial additionality are described in Financial Additionality Considerations Section of the Isometric Standard.

• Default: 5 consecutive years of non-adoption for the relevant project activities immediately preceding the Enrollment Date.

Demonstration of financial additionality for each enrolled project participant (e.g., grower) is impractical for purposes of successfully implementing this program and given the complexity of farming operations and diffuse costs. Alternatively, evaluating financial additionality for the Project Proponent whose enterprise may be entirely or mostly focused on revenue from the voluntary carbon market is not appropriate as it does not speak to the additionality or lack of of a given project enrollee.

Projects must meet either one of the criteria in Table 1.

Table 1. Documentation requirements for financial additionality

For purposes of demonstrating financial additionality, incentive payments include practice-linked payments meaning any payment, cost-share, rental payment, easement payment, or in-kind support from a public authority that is conditional upon the adoption, maintenance, or outcome of a specific land-management practice or set of practices.

This does not include any public payment in respect of the Project Area that is not conditional upon the adoption of a specific land-management practice, including without limitation price-support payments, revenue-insurance indemnities, premium subsidies, ad hoc disaster relief, and area-based income support. 

For Project Areas measured in hectares or other units, the threshold must be converted to the equivalent value per local unit of area at the prevailing exchange rate at the start of the relevant Reporting Period.

The Per-Acre Materiality Threshold is set at USD $5.00 per acre per year, derived from the United States case study and set near the low end of incentive levels historically offered under formal practice-adoption programs in the United States. While empirical evidence on the inducement effect of payments at this level is mixed, retaining the nominal value of USD $5.00 (without inflation indexation) is conservative for the purposes of this Section.

Table 2. Conventions for NPV parameters

For the net cost calculation, cash flows fall into two cost buckets and one benefit bucket:

•  Fixed / start-up costs, assessed at t = 0: equipment or modifications, planning, soil testing, establishment, etc.
• Ongoing annual costs: added inputs (e.g., cover crop seed and termination), labour, additional field passes, and monitoring. t= the year in which the costs are incurred. 
• Ongoing annual benefits, excluding yield: reduced inputs, reduced fuel (e.g. reduced diesel for no-till), and/or reduced machinery wear.

All cost and benefit cash flows are converted to present-value units. The net present value of the practice cost is the sum, across every year of the horizon, of cost minus benefit, each discounted to the present:

$$NPV_{cost} = \sum\frac{C_t - B_t}{(1+r)^t}$$

(Equation 1)

Where:

• $C_t$ are all costs incurred in year t
• $B_t$ are all non-yield benefits (i.e., reduced costs) realized in year t
• $r$ is the interest/discount rate, default is 7%
• $t$ indexes years
• The summation is over all years

Non-carbon incentives, for example NRCS EQIP or CSP payments, state cost-share, or buyer premiums, are converted to present value in exactly the same way. Each incentive payment is placed in the year it is received and discounted at the same rate over the same horizon:

$$NPV_{incentives} = \sum\frac{I_t}{(1+r)^t}$$

(Equation 2)

Financial Additionality must be reconsidered at Crediting Period renewal, in accordance with the requirements in this section. Projects must select one of the following options to meet ongoing Financial Additionality:

1. Continued validity of existing Financial Additionality demonstration
2. Reassessment of Financial Additionality

If a review indicates The Project has become non-additional, The Project will be ineligible for future Credits. Current or past Crediting Periods will not be affected.

Where a Project’s existing Financial Additionality demonstration was conducted over a defined investment horizon, the existing Financial Additionality determination remains valid up to the end of that investment horizon, provided The Project can demonstrate that key economic and operational assumptions used in the original demonstration remain materially unchanged. Projects which continue under an existing Financial Additionality determination in this way may only do so until the end of the investment horizon considered in the original determination, and must reassess Financial Additionality at the first verification event following the end of the existing investment horizon period.

Reassessment of Financial Additionality is required if any of the following conditions apply:

1. The renewal date occurs after the originally defined investment horizon;
2. A new investment or continuation decision is necessary to continue project crediting activities; and/or
3. Material changes to market conditions, regulatory requirements or project operations have occurred such that the original assumptions are no longer valid.

Where reassessment is required in accordance with the above requirements, the Project Proponent must demonstrate that continued Carbon Finance remains necessary to continue project crediting activities, by conducting a full Financial Additionality assessment against the updated Project and baseline scenarios.

1. Define the project activity (e.g., no tillage). Any components of the definition which serve to narrow the scope of the activity must be material to soil carbon dynamics.
2. Identify the applicable geographic area, as described in the Common Practice Analysis Section of the Isometric Standard.
3. Identify a similar class of adopters or landowners (e.g., smallholder farmers, community-held land, private concessions).
4. Identify and explain any essential distinctions between the proposed Project and similar activities, as described in the Common Practice Analysis Section of the Isometric Standard.
5. Assess the market penetration rate using either a) a survey-based approach, or b) relevant data from existing literature, as follows:

a) Survey-based approach:

• Survey a representative sample of similar landowners from within the relevant geographic domain within five years of the project start date. The sampling design and method must be documented, including how the comparable land owners were identified, how the sample was drawn, the methods used for contacting the selected landowners, a copy of the questions that were asked, and the response rates. The documentation must be submitted for VVB review at validation. A minimum of 30 responses is recommended, but Project Proponents should aim to collect as many responses as is practical.
• Calculate the cumulative market penetration rate (as an area percentage) of the project activity by landowners who have not received Carbon Finance revenue (e.g., are neither part of a registered Isometric Project, nor registered under other GHG programs) in the sample of adopters.

b) Data from existing literature: Statistics on land management activities derived from data collected within five years of the project start date may be used for this demonstration, provided they are relevant to the project area, do not distinguish between activities incentivized by and not incentivized by Carbon Finance (thus are conservative), and are publicly available as:

• agricultural census, survey or other government data;
• peer-reviewed scientific literature; or
• independent research or reports, with full and transparent methods and documentation of results.

In regions where there is established government data on practice adoption rates (e.g., the United States) the official data must be used for assessing market penetration rates (e.g., USDA Census of Agriculture).

For proprietary technologies, land management activities may be derived from first-party data collected from customer data to establish rates of practice adoption.

In accordance with the Common Practice Analysis Section of the Isometric Standard, the proposed Project activity must demonstrate Common Practice additionality.

Table 3. Common Practice criteria and documentation

These rates must be reflective of overall adoption rates across agricultural systems in the project’s geographic area by default (e.g., “Cropland planted to a cover crop (excluding CRP)” in USDA Census of Agriculture), however more granular data for adoption rates for specific farm practices that match project conditions (e.g., similar cropping rotations and irrigation infrastructures) as available may be used for purposes of identifying market penetration rates subject to Isometric review.

The adoption rate for a practice should control for adoption funded or motivated by other incentives or programs. The following acre categories should be subtracted from adoption rate in the geographic area according to procedures above to yield the net adoption rate:

• Acres enrolled in any private-market carbon credit program for the relevant practice.
• Acres under any per-acre incentive program paying > $5/acre for the relevant practice.
• Acres under USDA EQIP/CSP contracts (or equivalent government conservation programs) that specifically name the relevant practice.

For example, if in a geographic area where there has been modest growth in cover crop planting (Test 1 above) and the gross adoption rate is 35%, but 20% of that adoption is due to enrollment in alternative carbon credit programs, and a USDA conservation program, the net adoption rate is 15% and The Project is deemed additional from a common practice standpoint, all else equal.

The uncertainty in the overall estimate of the net CO₂e removal and reductions as a result of The Project must be accounted for. The total net increase in CO₂e removed for a specific Reporting Period, CO₂e_Removal,RP, and the total net decrease in CO₂e reduced for a specific Reporting Period, CO₂e_Reduction,RP , must be conservatively determined in accordance with the requirements outlined in the Uncertainty in Removals and Reductions Section of the Isometric Standard.

Projects must report a list of all key variables used in the net CO₂e removal and reduction calculation and their individual uncertainties, as well as a description of the uncertainty analysis approach, including:

• field measurements used for the net CO₂e removal calculation
• parameters that impact the estimation of the soil organic carbon content, such as bulk density, etc.
• emission factors utilized, as published in public and other databases used
• models used for the net CO₂e removal calculation

For each variable that contributes to the uncertainty of the net CO₂e removal estimate, the Project Proponent must report the variable's central estimate, its assumed probability distribution, and the parameters defining that distribution (for example, minimum and maximum values for a uniform distribution, or mean and standard deviation for a normal distribution), together with a brief justification of the chosen distribution and its parameters. Where project-specific data are not available, published literature values, peer-reviewed default distributions, or values from established databases may be used, provided the source is cited and its applicability to the project context is justified. More detailed uncertainty characterization should be provided where available, as outlined in the corresponding section of the Isometric Standard. Variables that are demonstrably non-material to total uncertainty may be omitted in accordance with the sensitivity analysis outcomes below.

A sensitivity analysis that demonstrates the impact of each input parameter’s uncertainty on the final net CO₂e uncertainty must be provided. Variables may be omitted from the sensitivity analysis if they are already being included in the uncertainty analysis. Details of the sensitivity analysis method must be provided such that a third party can reproduce the results. Input variables may be omitted from an uncertainty analysis if they contribute to a < 1% change in the net CO₂e removal. For all other parameters, information about uncertainty must be specified.

In accordance with the Isometric Standard, all evidence and data related to the underlying quantification of CO₂e removal and environmental and social safeguards monitoring will be available to the public through the Isometric platform. That includes:

• Project Design Document
• GHG Statement
• Measurements taken, with supporting documentation (e.g., calibration certificates)
• Emission factors used
• Scientific literature used
• Proof of approval for necessary permits
• Remote sensing and/or field plot data collected by The Project
• All data and methodological details used for the baseline calculation
• Model specifications and output

The Project Proponent can request certain information to be restricted (only available to authorized Buyers, the Registry, and VVB) where it is subject to confidentiality. This includes emission factors, specific data, and/or proprietary models from licensed databases. Restrictions can also be requested when working with smallholder landowners when it is necessary for protecting landowner privacy. However, all other numerical data produced or used as part of the quantification of net CO₂e removal will be made available.

The scope of this Protocol includes GHG sources, sinks and reservoirs (SSRs) associated with an improved soil management project.

A cradle-to-grave GHG Statement must be prepared encompassing the GHG emissions and removals relating to the activities outlined within the system boundary.

GHG emissions and removals associated with the Project may be direct emissions from a process, or indirect emissions from combustion of fuels, electricity generation, or other sources. Emissions must include all GHG SSRs within the system boundary, from the establishment of amended land management practices and associated inputs, through to the end of the Project Commitment Period. This includes embodied emissions of all equipment, amendments, and consumables used in the project. The Project Proponent must identify all sources of emissions directly or indirectly related to project activities.

Any emissions from sub-processes or process changes that would not have taken place without the CDR Project must be fully considered in the system boundary. Any activity that ultimately leads to the issuance of Credits must be included in the system boundary.

Where projects are implemented on land under active production prior to the project start date, emissions associated with continuation of pre-project productivity are excluded from the calculation (see Section 9.6).

The system boundary must include all relevant GHG SSRs controlled and related to The Project, including but not limited to the SSRs set out in Table 4. Values for all SSRs outlined in Table 4 must be strictly positive. Any emissions reductions will not count to offset positive emissions for purposes of calculating CO2e_Removals. See Section 8.2.1.1 for further details.

If any GHG SSRs within Table 4 are deemed not appropriate to include in the system boundary, they may be excluded provided that robust justification and appropriate evidence is provided in the PDD. Furthermore, if any SSR is expected to be negligible, they may be excluded in line with Section 5 of the GHG Accounting Module.

Table 4. Scope of activities and GHG SSRs to be included in the system boundary.

Emissions associated with The Project's impact on activities that fall outside of the system boundary of The Project must also be considered. This is covered under Leakage in Section 9.5.4.

Miscellaneous GHG emissions are those that cannot be categorized by the GHG SSR categories provided in Table 4. The Project Proponent must identify all sources of emissions directly or indirectly related to project activities and must report any outside of the SSR categories identified as miscellaneous emissions.

In line with the GHG Accounting Module v1.1, The Project must:

• Consider all GHGs associated with SSRs, in alignment with the United States Environmental Protection Agency’s definition of GHGs which includes: carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂0) and fluorinated gasses such as hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulfur hexafluoride (SF₆) and nitrogen trifluoride (NF₃). For CO₂ stored, only CO₂ must be included as part of the quantification. For all other activities all GHGs must be considered. For example, the release of CO₂, CH₄, and N₂O is expected during diesel consumption;
• Quantify emissions in tonnes CO₂ equivalent (t CO₂e) using the 100-year Global Warming Potential (GWP) for the GHG of interest, based on the most recent volume of the IPCC Assessment Report (currently the Sixth Assessment Report); and
• Consider Materiality of SSRs in line with Isometric requirements.

The Baseline scenario for improved soil management assumes that the activities associated with The Project do not take place and that any infrastructure associated with The Project is not built.

The Counterfactual is the CO₂ stored that would have occurred under business as usual management practices over the Crediting Period in the absence of The Project. This is detailed in Section 9.4.

Improved soil management interventions may involve reductions in activities that result in emissions. A limited set of emissions reductions - specifically reduced CO₂, N₂O, and CH₄ from diesel use in tractors corresponding to fewer passes in no- and reduced-tilling intervention and avoided N₂O emissions from less fertilizer inputs into soils - are scoped in the Agricultural Practices Reduction Module. The Agricultural Practices Reduction Module scopes the eligibility criteria for evaluating these sources, as well as the accounting approach.

In order for a Project to claim emissions reductions Credits, The Project must engage in interventions to increase SOC; A Project cannot generate stand-alone emissions reductions Credits.

The permissible emissions reductions scoped in the Agricultural Practices Reductions Module are not expected to have any positive emissions associated with them that are not also related to the intervention to generate removals. All emissions with The Project must be assigned to the term CO₂e_Emissions,RP for purposes of estimating CO2e_{Removals, RP} as outlined in Section 9. Any leakage emissions corresponding to yield reductions associated with The Project must be allocated CO2e_{Removals, RP} .

Additionally, emissions reductions do not inflate removals by counting against CO₂e_Emissions,RP and are credited separately in the Agricultural Practices Reductions Module.

If Reductions are generated, they must be submitted together with Removals as part of a GHG Entry for every Reporting Period:

$$GHG_{Entry} = CO₂e_{Removals} + CO₂e_{Reductions}$$

(Equation 3)

Where:

• CO₂e_Removals are the net removals, quantified in accordance with the Improved Soil Management Protocol. CO₂e_Removals must be greater than zero.
• CO₂e_Reductions are net reductions, quantified in accordance with the Agricultural Practices Reductions Module, where applicable. CO₂e_Reductions may be zero.

See the specific Agricultural Practices Reductions Module for specific details on emissions reductions eligible under this Protocol.

The Reporting Period for improved soil management projects represents the interval of time over which removals are calculated and reported for Verification. The minimum duration of a Reporting Period is one year and the maximum duration is five years, unless otherwise specified within the selected intervention Module.

The increase in total net CO₂e removal is calculated for at Reporting Period and is referred to hereafter as CO₂e_Removal,RP. The net CO₂e removal must be conservatively determined, such that there is high confidence that, at a minimum, the credited quantity of CO₂e was removed and stored in the assessed pools.

GHG emission calculations must include all emissions associated with project activities occurring within the Reporting Period. This includes:

• Emissions associated with project establishment, allocated to the Reporting Period on a pro-rata basis;
• Operations emissions occurring within the Reporting Period, including those arising from changes to tillage, fertilizer application, cover cropping, or other soil management practices;
• Any end-of-life or reversal-risk emissions allocated to the Reporting Period; and
• Market and activity-shifting leakage emissions occurring outside the system boundary that are attributable to the Reporting Period.

Changes in carbon stocks within eligible pools must be estimated following the requirements within the intervention Module under which The Project is crediting.

In line with the Isometric Standard, this Protocol requires that Removal Credits are issued ex-post. Credits may only be issued once an increase in the relevant carbon pools has been documented and verified within the project boundary, and after accounting for all associated emissions and uncertainty discounts.

This Protocol adopts a cumulative accounting approach. At each Verification, the net CO₂e removal to which The Project is entitled is assessed on a cumulative basis, as the total net removal achieved from project initiation (t=0) to the end of the current Reporting Period. Uncertainty and conservativeness discounts are applied to this cumulative quantity. The quantity issued for the current Reporting Period is then the discounted cumulative net removal to date, less all Credits already issued in prior Reporting Periods. Because uncertainty is assessed against the cumulative quantity, which is anchored to the measured stock at the current time point and at t=0, rather than against each Reporting Period's increment in isolation, measurement uncertainty is not propagated or accumulated across successive Reporting Periods.

Net CO₂e removal is assessed on a cumulative basis. The cumulative net CO₂e removal achieved by The Project from initiation ($t=0$) to the end of the most recent Reporting Period ($RP_n$) is calculated as:

$$CO_2e_{Removal,cum,n} = CO_2e_{Stored,cum,n} - CO_2e_{Counterfactual,cum,n} - CO_2e_{Emissions,cum,n}$$

(Equation 4)

Where:

• $CO_2e_{Removal,cum,n}$ is the cumulative net carbon removal from $t=0$ to the end of the most recent Reporting Period, before application of uncertainty and conservativeness discounts, in tonnes CO₂e
• $CO_2e_{Stored,cum,n}$ is the cumulative change in carbon removed from the atmosphere and stored within the project boundary from $t=0$ to the end of the most recent Reporting Period, calculated in accordance with Section 9.3, in tonnes CO₂e
• $CO_2e_{Counterfactual,cum,n}$ is the cumulative change in counterfactual carbon that would have been stored within the project area in the absence of project activities from $t=0$ to the end of the most recent Reporting Period, calculated in accordance with Section 9.4, in tonnes CO₂e
• $CO_2e_{Emissions,cum,n}$ is the cumulative GHG emissions associated with project activities from $t=0$ to the end of the most recent Reporting Period, including all sources within the system boundary set out in Table 4 and calculated in accordance with Section 9.6, in tonnes CO₂e

The cumulative net removal must be adjusted for uncertainty in accordance with the uncertainty and conservativeness requirements of this Protocol and the applicable intervention Module. The uncertainty assessment must be performed on the cumulative net removal quantity, $CO_2e_{Removal,cum,n}$, not on individual Reporting Period increments. The resulting uncertainty-adjusted cumulative quantity is denoted $CO_2e_{Removal,cum,n}^{*}$.

The net CO₂e removal for the current Reporting Period is the uncertainty-adjusted cumulative net removal to date, less all net removal already credited in prior Reporting Periods:

$$CO_2e_{Removal,RP_n} = CO_2e_{Removal,cum,n}^{*} - \sum_{i=1}^{n-1}CO_2e_{Removal,RP_i}$$

(Equation 5)

Where:

• $CO_2e_{Removal,RP_n}$ is the net CO₂e removal for the current Reporting Period, in tonnes CO₂e. This is the quantity of new net removal attributable to the Reporting Period.
• $\sum_{i=1}^{n-1}CO_2e_{Removal,RP_i}$ is the sum of net CO₂e removal already credited to The Project for all prior Reporting Periods. These values are those determined at the time of each prior Verification and are treated as fixed; they are not recalculated using currently available data.

The cumulative increase in the amount of CO₂e stored for an improved soil management project from project initiation to the end of the most recent Reporting Period ($RP\_n$) is calculated directly from the point-in-time stock defined in Equation 7:

$$CO_2e_{Stored,cum,n} = CO_2e_{Stored,t=n} - CO_2e_{Stored,t=0}$$

(Equation 6)

Where:

• $CO_2e_{Stored,cum,n}$ is the cumulative increase in organic carbon storage from project activities from $t=0$ to the end of the most recent Reporting Period, in tonnes CO₂e. This is the cumulative stored quantity used in Equation 4.
• $CO_2e_{Stored,t=n}$ is the total carbon storage within the project area at time $t=n$, the end of the most recent Reporting Period, evaluated using Equation 7, in tonnes CO₂e
• $CO_2e_{Stored,t=0}$ is the total carbon storage within the project area at time $t=0$, the time of project initiation, evaluated using Equation 7, in tonnes CO₂e

Uncertainty in stored carbon must be characterised on this cumulative change, $CO_2e_{Stored,cum,n}$, and carried through to the uncertainty assessment on the cumulative net removal in Section 9.2.

At any given time point, the carbon storage within the Project Area is calculated as:

$$CO_2e_{Stored,t} = CO_2e_{SOC,t} + CO_2e_{AGB,t} + CO_2e_{BGB,t}$$

(Equation 7)

Where:

• $CO_2e_{Stored,t}$ is the total CO₂e stored across all eligible organic carbon pools at time $t$, in tonnes CO₂e
• $CO_2e_{SOC,t}$ is the total carbon stored as soil organic carbon at time $t$, calculated in accordance with the appropriate methods under the intervention Module, in tonnes CO₂e; this term is mandatory for all projects under this Protocol
• $CO_2e_{AGB,t}$ is the total carbon stored in aboveground woody biomass at time $t$ in tonnes CO₂e. This term is optional and its inclusion is subject to requirements within the intervention Module The Project is crediting under
• $CO_2e_{BGB,t}$ is the total carbon stored in belowground woody biomass at time $t$ in tonnes CO₂e. This term is optional and its inclusion is subject to requirements within the intervention Module The Project is crediting under

Calculation of $CO_2e_{Stored,t}$ , including the which pools are included, must follow the requirements within the relevant intervention Module. The mandatory carbon pool under this Protocol is soil organic carbon ($CO_2e_{SOC,t}$), since it represents the primary storage reservoir for all project types within scope. The eligibility of inclusion of aboveground and belowground woody biomass pools is subject to requirements within the intervention Module under which The Project is crediting. All quantification of storage pools must follow the methodological and reporting requirements within the intervention Module under which The Project is crediting.

Deadwood, litter, and non-woody herbaceous biomass carbon pools are excluded from the calculation of $CO_2e_{Stored,RP}$ under this Protocol as these pools are considered transient.

The value of $CO_2e_{Counterfactual}$ represents the storage of carbon that would have happened in absence of the project interventions and act as a reference from which to assess the additionality of the project interventions. The Project Proponent is responsible for generating a conservative estimate of $CO_2e_{Counterfactual}$ following the requirements within the Module under which The Project is crediting.

$CO_2e_{Counterfactual,cum,n}$ is assessed as the cumulative change in counterfactual carbon storage from project initiation to the end of the most recent Reporting Period ($RP_n$):

$$CO_2e_{Counterfactual,cum,n} = CO_2e_{Counterfactual,t=n} - CO_2e_{Counterfactual,t=0}$$

(Equation 8)

Where:

$CO_2e_{Counterfactual,cum,n}$ is the cumulative change in counterfactual carbon storage from $t=0$ to the end of the most recent Reporting Period, in tonnes CO₂e. This is the cumulative counterfactual quantity used in Equation 4.

$CO_2e_{Counterfactual,t=n}$ is the total carbon storage within the counterfactual scenario at time $t=n$, the end of the most recent Reporting Period, in tonnes CO₂e

$CO_2e_{Counterfactual,t=0}$ is the total carbon storage within the counterfactual scenario at time $t=0$, the time of project initiation, in tonnes CO₂e

Uncertainty in the counterfactual must be characterized on this cumulative change and carried through to the uncertainty assessment in Section 9.2.

The methods and requirements for calculating $CO_2e_{Counterfactual,t}$ are specified within the intervention Module under which The Project is crediting.

The total GHG emissions associated with a Reporting Period, RP can be calculated as:

$$CO_2e_{Emissions,RP}=CO_2e_{Establishment,RP}+CO_2e_{Operations,RP }+CO_2e_{EndOfLife,RP}+CO_2e_{Leakage,RP}$$

(Equation 9)

Where:

• $CO_2e_{Emissions,RP}$ represents the total GHG emissions for a Reporting Period, in tonnes of CO₂e.
• $CO_2e_{Establishment,RP}$ represents the GHG emissions associated with project establishment, represented for the RP, in tonnes of CO₂e, see Section 9.5.1.
• $CO_2e_{Operations,RP}$ represents the total GHG emissions associated with operational processes for a RP, in tonnes of CO2e, see Section 9.5.2.
• $CO_2e_{EndOfLife,RP}$ represents GHG emissions that occur after the RP and are allocated to a RP, in tonnes of CO2e, see Section 9.5.3.
• $CO_2e_{Leakage,RP}$ represents GHG emissions associated with the impact of the Project on activities that fall outside of the system boundary of the Project, over a given RP, in tonnes of CO₂e, see Section 9.5.4.

The following sections set out specific quantification requirements for each term in Equation 9. Note that the emissions term in Equation 4 is the cumulative value over all Reporting Periods up to the current time.

GHG emissions associated with project establishment should include all historic emissions incurred as a result of project establishment, including but not limited to the SSRs set out in Table 4, such as biomass removal, irrigation installation, etc.

Project establishment emissions occur from the point of project inception to the moment before the first removal activity takes place. GHG emissions associated with project establishment may be amortized following the requirements for amortization as outlined in Section 7 of the GHG Accounting Module.

GHG emissions associated with CO₂e_{Operations,RP} should include all emissions associated with operational activities, including but not limited to the SSRs set out in Table 4.

For improved soil management projects, the Reporting Period covers a set period of time (e.g., one year), during which soil organic carbon accumulates. CO₂e_{Operations,RP} emissions must be attributed to the Reporting Period in which they occur. This includes any emissions associated with management of the soil system or harvesting/processing of commodities for which production was established by The Project. The emissions from these activities must be calculated as explained in Section 9.6. Allocation outside of the current Reporting Period may be permitted in certain instances, on a case-by-case basis in agreement with Isometric.

CO₂e_EndOfLife,RP includes all emissions associated with activities that are anticipated to occur after the Crediting Period until the end of the Project Commitment Period. This includes activities related to ongoing monitoring for Reversals.

CO₂e_EndOfLife,RP must be estimated upfront and allocated in the same way as set out for calculation of CO₂e_{Establishment,RP}.

Given the uncertain nature of CO₂e_EndOfLife,RP emissions, assumptions must be revisited at each Reporting Period and any necessary adjustments made. Furthermore, if there are unexpected CO₂e_EndOfLife,RP emissions that occur after The Project has ended, then the Reversal process described in the Reversals and Buffer Pools Section of the Isometric Standard will be triggered to compensate for any emissions not accounted for.

CO₂e_Leakage,RP includes emissions associated with a Project's impact on activities that fall outside of the system boundary of The Project. It includes increases in GHG emissions as a result of The Project displacing emissions or causing a secondary effect that increases emissions elsewhere.

For Projects engaging in interventions to increase SOC the primary risk of leakage comes from reduced agricultural productivity on the project sites leading to supply shortfalls and price-induced market leakage emissions. This could present through reduced agricultural yields or reduced livestock productivity corresponding to the intervention. Market leakage could also result from retention of agricultural residues for SOC improvements that historically went to market for alternative productive use.

Specifics of leakage considerations and calculation approaches can be found in appropriate Modules under this Protocol.

GHG emissions accounting must be undertaken in alignment with the GHG Accounting Module v1.1, which ensures a consistently rigorous standard in how GHG emissions are quantified and reported between different CDR Projects and approaches. This includes:

• Requirements for data quality, including a detailed data quality hierarchy for activity data and emission factors;
• Consideration of materiality in emissions accounting;
• Emissions amortization requirements;
• Co-product and by-product allocation requirements. For improved soil management projects, this will apply to the production of co-products such as co-products from a cover- or rotational-crop for which the oil or grain is harvested for productive use;
• Waste input accounting relating to inputs to the process that are wastes, for example manure as a fertilizer amendment if it is demonstrated to be in excess.

The Energy Use Accounting Module 1.3 provides requirements on how energy-related emissions must be calculated for The Project so that they can be subtracted in the net CO₂e removal calculation. It sets out the calculation approach to be followed for intensive facilities and non-intensive facilities and acceptable emission factors.

Energy emissions are those related to electricity or fuel usage. They may include, but are not limited to:

• Emissions associated with operating mobile farm equipment (e.g., diesel use in tractors)
• Emissions associated with operating stationary farm equipment (e.g., electricity for pumps)

The GHG Accounting Module v1.1 provides requirements on how transportation and energy-related emissions must be calculated for The Project so that they can be subtracted in the net CO₂e removal calculation.

Embodied emissions are those related to the life cycle impact of equipment and consumables. They may include, but are not limited to:

• Embodied emissions associated with any new equipment required for executing the project intervention(s)
• Embodied emissions associated new seeds or seedlings that are applied as part of The Project
• Embodied emissions associated with any soil additives (e.g., biostimulants, fertilizer)

Transportation emissions are those related to transportation of products and equipment. They may include, but are not limited to:

• Emissions associated with the transportation of any new seeds or seedlings
• Emissions associated with the collection, processing, and transport of any new products resulting from the intervention (e.g., from a new rotational crop)
• Emissions associated with the transportation of any additional agricultural inputs (e.g., fertilizer, pesticides, herbicides)

The storage reservoirs of the CO₂ removed through soil management interventions are soil organic carbon and optionally live aboveground woody biomass and belowground woody biomass depending on the intervention Module. The durability of a CDR process refers to the length of time for which CO₂ is removed from the Earth’s atmosphere and cannot contribute to further climate change.

For requirements associated with durability, reversal risk, risk assessment and management and buffer pool, please refer to the intervention Module under which The Project is crediting.

The durability of awarded Credits are defined by the Module under which The Project is crediting.

The durability must not exceed any of the following:

• This Project Proponent–level obligation persists regardless of the contract length of any individual enrolled landowner. Where individual contracts are shorter than the Project Commitment Period, the Project Proponent must demonstrate how monitoring and reversal liability will be maintained across the full Project Commitment Period, including through the Ongoing Monitoring Period set out in Section 5.1 where applicable.
• Project financial plan duration. Project Proponents must demonstrate continued payments and/or financial incentive to maintain carbon stocks during The Project.
• Soil carbon maintenance activities. Project Proponents must continue soil carbon management and risk mitigation practices to maintain carbon stocks throughout the Project Commitment Period.

Reversal risks which may threaten the durability of project system carbon and project-level risk assessment and mitigation requirements are discussed in Section 10.2 and Section 10.3, respectively.

A improved soil management-wide Buffer Pool managed by Isometric is used to insure Credits against Reversals. Throughout any Ongoing Monitoring Period, project carbon stocks must be monitored for Reversals to ensure Credits achieve their stated durability. Upon detection and quantification of carbon losses, Credits issued to the Buffer Pool will be canceled in equal proportion to the loss (see Section 10.4 and Section 10.5).

• Ongoing project financial sustainability after the Project Commitment Period, such as through alternative income streams from commodity production within the project system or process improvements which encourage continued maintenance;
• Establishing a plan to attain legal protection beyond the Project Commitment Period; and
• Building technical capacity or employment to facilitate long-term carbon stock management.

Reversals are defined as reductions in stored carbon within applicable pools that may result in emissions of CO₂ to the atmosphere. Reversal risk is quantified by assessing the likelihood of a disturbance event occurring over a period of time and estimating the severity of the disturbance in terms of carbon loss. Disturbance events may be natural or anthropogenic, such as fire, drought/heat, insect and disease, changes in management practices, and land use conversion. A disturbance event which results in a reduction in soil carbon and/or other covered pools is considered a loss event. The duration of disturbance events may be over multiple years (e.g., drought) or for a very limited duration (e.g., flood).

The likelihood and severity of disturbances are influenced by external and project-related factors.

External factors:

• Climate change effects
• Changes in areas adjacent to the project area(s) (e.g., land ownership, land use, farming practices, industrial activities, upstream water stress, ecosystem change)
• Suitability of landscape for supporting project activities
• Regulatory changes
• Historic disturbances in and around the project area(s)
• Changes in economics and/or market incentives

Project-related factors:

• Project plan (e.g., climate resilient interventions, management practices)
• Project governance (e.g., operations and financial structure, community ownership, local training)
• Risk mitigation safeguards
• Changes in land use, management, or ownership of the project area(s)
• Participation of enrolled landowners

Furthermore, the risk profile of The Project may change over the Project Commitment Period due to:

• Temporal variation in the risk profile of the project system due to age or characteristics
• Temporal variation in the risk profile of natural risks (e.g., wildfires, drought) and anthropogenic risks (e.g., land use changes)
• Length of the Project Commitment Period

Projects must complete the Risk Assessment(s) of the Improved Soil Management intervention Module(s) The Project is crediting against, the results of which are independently evaluated by a third-party VVB.

The Risk Assessment is used to determine the risk profile of The Project, including risks to Credit delivery and storage. Aspects of The Project which have higher risk exposure should be accompanied by an appropriate risk mitigation plan. To safeguard against high risk projects, the Project must score below the thresholds indicated within the corresponding intervention Module to be eligible for crediting under this Protocol.

The Risk Assessment(s) must be updated each Reporting Period by the Project Proponent and increased risk scores will result in additional mitigation activities.

• Site The Project appropriately to reduce disturbance risk from neighboring activities.
• Reduce risk of unintended fires through a fire management plan (e.g., removing fuel, fire breaks or fire towers, fire-fighting equipment and training).
• Reduce risk of drought through a water management plan (e.g., securing water supply, water infrastructure, drought resilience measures). If The Project has been identified to present other risks to local water resources, additional measures must be included that describe how the Project will mitigate risks and safeguard water resources.
• Reduce risks of flooding and erosion through land and water management practices.
• Identify and reduce risks unique to The Project, e.g., regionally pervasive pests.

As outlined in the Buffer Pools Section of the Isometric Standard, the Buffer Pool is a mechanism used to insure against risks of Reversals that may be observable and attributable to The Project through monitoring.

Currently, there is insufficient published scientific evidence to quantitatively account for climate change, management activities, or project age and translate this into a highly accurate Buffer Pool contribution. As a result, we apply either a flat contribution requirement on The Project or a model to translate the Risk Assessment for the intervention Module into a Buffer Pool contribution. As actuarial data improve and more research is published, Protocol requirements will be updated accordingly.

• Contribute 20% of Credits generated in a Reporting Period to the Buffer Pool; or
• Opt-in to the method outlined in the intervention Module(s) The Project is crediting against. This project-specific method permits changes to the contribution for each Reporting Period as the risk profiles of the Project Proponent and project system change over time. The Buffer Pool contribution determined from this approach cannot be less than 10% of the Credits generated in any Reporting Period.

The intervention Module's project-specific Risk Assessment does not account for contract-tenure or non-renewal risk; that risk is addressed solely by the Contract Coverage Buffer below. The Contract Coverage Buffer is therefore additive to the base contribution and does not duplicate any charge within it, whichever base method The Project uses.

The Contract Coverage Buffer applies an additional Buffer Pool contribution scaled to the share of The Project exposed to contract non-renewal over the remaining Project Commitment Period, weighted by each enrolled field's contribution to the Project's net removals and by the share of the coverage horizon left uncontracted. A Project that lacks the data to run this calculation may instead elect the flat ceiling rate of 5%; this choice is fixed at the first verification of the Project. Credits contributed under this section are held in the improved soil management-wide Buffer Pool (Section 10.4.2).

The base contribution under Section 10.4.1 applies to physical carbon reversal, including the treatment of lost land access as a Reversal under Section 5.1.1.1. The Contract Coverage Buffer applies to contractual continuity only and does not apply to physical reversal.

For each enrolled field, the share of the required coverage horizon left uncontracted is determined and aggregated across The Project, weighted by carbon contribution, to give a single Project-level exposure figure:

$$E = \frac{\sum_{i} A_i \times \max\!\left(0,\ \dfrac{T_{req} - C_i}{T_{req}}\right)}{\sum_{i} A_i}$$

(Equation 10)

Where:

• $E$ is the project-level, carbon-weighted share of The Project not under contract for the full remaining coverage horizon, dimensionless, in the range 0–1.
• $i$ indexes the enrolled fields, being the unit of enrollment defined in Section 4.2, or the smallest enrolled unit holding its own contract term.
• $T_{req}$ is the required coverage horizon, equal to the remaining length of the Project Commitment Period measured from the Verification date, in years. Where $T_{req} \le 0$ at a Verification, $E$ is set to 0 and no Contract Coverage Buffer applies for that Reporting Period.
• $C_i$ is the remaining executed contract term for enrolled field $i$, measured from the same Verification date, capped at $T_{req}$ and floored at 0 (that is, $C_i = \min(\text{remaining contract term},\ T_{req})$, with $C_i = 0$ where the term is zero or negative), in years. Contracts must be signed and on record at the Verification event; any unsigned or anticipated renewal, and any expired contract, is treated as $C_i = 0$.
• $A_i$ is the carbon weight of enrolled field $i$, equal to its share of the net CO₂e removal ($CO_2e_{Removal,RP}$) generated in the Reporting Period, in tonnes CO₂e, floored at 0. Where carbon-weighting is waived with justification accepted by Isometric, or where $\sum_i A_i \le 0$, enrolled area (ha) is used in place of carbon weight.

$$CCB_{base} = B_{max} \times E$$

(Equation 11)

Where:

• $CCB_{base}$ is the base Contract Coverage Buffer rate before mitigation, expressed as a percentage of Credits generated in the Reporting Period, in the range 0–$B_{max}$.
• $B_{max}$ is the maximum (ceiling) Contract Coverage Buffer rate, fixed at 5%.
• $E$ is the exposure from Equation 10.

Rates expressed as percentages enter the products in Equations 10 and 11 as decimals ($B_{max} = 5\% = 0.05$); $E$ and $M$ are dimensionless in the range 0–1.

$$M = \max\!\left(M_{floor},\ 1 - d_{rev} - d_{eng} - d_{ret}\right)$$

(Equation 12)

Where:

• $M$ is the mitigation multiplier applied to the base rate, dimensionless, in the range $M_{floor}$–1.
• $M_{floor}$ is the floor on the multiplier, fixed at 0.5.
• $d_{rev}$ is the revenue-share discount, applied where The Project contractually commits to disburse a revenue share to enrolled landowners above the 20% minimum required under Section 6.6.3.6:

$$d_{rev} = \begin{cases} 0.15 & \text{if } RS > 20\% \\ 0 & \text{if } RS \le 20\% \end{cases}$$

(Equation 13)

Where:

• $RS$ is the contractually committed revenue share to enrolled landowners.
• $d_{eng}$ is the stakeholder-engagement discount, up to 0.15, equal to the sum of 0.05 for each of the following demonstrated with evidence accepted at the Verification event, capped at 0.15: (i) a documented, ongoing stakeholder-engagement process meeting Section 6.6.1; (ii) delivered, verifiable community co-benefits; and (iii) a functioning grievance and dispute-resolution mechanism with a record of use.
• $d_{ret}$ is the retention discount, up to 0.20, applied where observed contract non-renewal over the elapsed period is below the expected rate. This discount is not available at the first Verification. It is determined as:

$$d_{ret} = 0.20 \times \operatorname{clamp}\!\left(\frac{D_{exp} - D_{obs}}{D_{exp}},\ 0,\ 1\right)$$

(Equation 14)

Where:

• $\operatorname{clamp}(x, 0, 1)$ returns 0 if $x < 0$, 1 if $x > 1$, and $x$ otherwise
• $D_{obs}$ is the observed cumulative non-renewal, the share of originally enrolled units, weighted on their enrolment-baseline carbon (or enrolled area where carbon-weighting is waived), whose contracts have lapsed without renewal or that have otherwise exited enrolment by this Verification

$D_{exp}$ is the expected cumulative non-renewal over the elapsed period:

$$D_{exp} = 1 - (1 - a)^{\,t}$$

(Equation 15)

Where:

• $t$ is the elapsed years of The Project at the Verification event
• $a$ is the assumed annual contract non-renewal (enrollment-exit) rate

Where $D_{exp} = 0$, $d_{ret}$ is set to 0.

$a$ is set to 0.05/year, reflecting the central rate of annual attrition observed in comparable working-land conservation practices (net cover-crop and no-till disadoption of roughly 3–6%/year). A Project-specific value may be substituted only on the basis of evidence accepted by Isometric.

Each discount is 0 where its condition is not met.

$$CCB_{final} = B_{max} \times E \times M$$

(Equation 16)

Where:

• $CCB_{final}$ is the final Contract Coverage Buffer rate for the Reporting Period, expressed as a percentage of Credits generated in the Reporting Period, in the range 0–$B_{max}$.
• $B_{max}$ is the ceiling rate from Equation 11.
• $E$ is the exposure from Equation 10.
• $M$ is the mitigation multiplier from Equation 12.

The resulting Credits are contributed to the improved soil management-wide Buffer Pool (Section 10.4.2) and reported as a distinct line, in addition to the base contribution under Section 10.4.1 and in place of the flat contract-coverage 5% within it.

A Project that does not have the data required to determine exposure or mitigation under Steps 1–4, in particular, the field-level contract terms or the carbon (or area) weighting needed for Equation 11, may instead elect to contribute the flat ceiling rate of $CCB_{final} = B_{max} = 5\%$, equivalent to setting $E = 1$ and $M = 1$ in Equation 16. A Project may elect the flat rate without acceptance by Isometric. This election replaces, and is not additional to, the flat contract-coverage 5% within Section 10.4.1.

The choice between the calculated method (Steps 1–4) and the flat-rate election must be made at the first Verification and is fixed for the remainder of the Project Commitment Period. A Project may not switch between the two methods at any subsequent Verification. A Project that elects the flat rate contributes 5% of the Credits generated in each Reporting Period to the improved soil management-wide Buffer Pool (Section 10.4.2) under this section, in addition to its base contribution.

For a Project on the calculated method (Steps 1–4), the Contract Coverage Buffer rate must be recomputed at every Verification event. At each Verification, both $T_{req}$ and each $C_i$ are re-measured as the term remaining from the Verification date.

Recalculation applies only to Credits not yet issued. Credits already contributed to the Buffer Pool remain in the Pool and are non-returnable, consistent with the Buffer Pool Compensation Process (Section 10.4.3) and the Reversals and Buffer Pools Section of the Isometric Standard.

A Project on the flat-rate election performs no recalculation under this Step and contributes the 5% ceiling in every Reporting Period.

The Buffer Pool contribution will be held in an improved soil management-wide Buffer Pool managed by Isometric. Pooling of a diversified portfolio of improved soil management projects across geographic regions, project types, spatial scales and temporal scales can reduce the exposure to systemic risks stemming from nature-based projects constrained to a geographic area or ecological type^12,13,14. The improved soil management-wide Buffer Pool composition will be transparently reported on the Isometric Registry.

The Buffer Pool Compensation Process is governed by the Isometric Standard. The following procedures apply upon detection and quantification of a loss event.

• Within the Crediting Period. For Reversals that occur during the Crediting Period (e.g., widespread disturbance), loss of soil carbon is incorporated into the quantification at each Verification. If the net CO₂e storage change in a Reporting Period is found to be negative (soil carbon stock at t < soil carbon stock at t-1), Buffer Pool Credits are canceled equal to the net emissions from the Reporting Period.
• Within any Ongoing Monitoring Period after the end of the Crediting Period. Reversals that occur after the Crediting Period must be quantified following the requirements within the intervention Module that The Project is crediting under and fully compensated by the Buffer Pool within one year of the loss event.
• Procedure for Avoidable Reversals. Isometric cancels Credits in the Buffer Pool equal to the Reversal.
  • During the Crediting Period: Project Proponents must replenish the canceled Credits in the Buffer Pool using Credits generated in the next Reporting Period before additional Credits are issued.
  • Within any Ongoing Monitoring Period after the end of the Crediting Period: Project Proponents must replenish the canceled Credits in the Buffer Pool using Credits generated from other projects under operation by the Project Proponent, or using Credit generated from another project, deemed of equivalent quality by Isometric, at the Project Proponent's expense.
• Procedure for Unavoidable Reversals. Isometric cancels Credits in the Buffer Pool equal to the Reversal.
• Buffer Pool Depletion. If the Reversal has depleted The Project's share of the Buffer Pool, the Project will be in a deficit, and must make up the loss within the next Reporting Period, or within one year of the loss event if the loss occurs during an Ongoing Monitoring Period. If the Project Proponent does not replenish the canceled Credits in the Buffer Pool in the amount equal to the Reversal, then The Project fails and is ineligible for future crediting. All Credits are canceled.

For more details on Reversals, refer to Isometric Standard sections covering risk of reversal and buffer pools.

Monitoring, reporting, and quantification of reversals must follow the requirements set within the Improved Soil Management intervention Module(s) The Project is crediting under.

Isometric would like to thank the following external contributors to this Protocol:

• Nuala Fitton PhD
• Benjamin Dube PhD
• Matthew Gammans PhD

Buffer Pool Contribution

• Isometric will review and adapt third-party tools and datasets, such as buffer pool density maps, as they become publicly available to enable project- and site-specific determination. Buffer Pools will be reassessed and scaled as appropriate to account for risk amplification or mitigation due to management activities and climate change.

Geospatial Dynamic Baselines

• The current baseline approach is designed to incorporate dynamic variables which evolve over the course of The Project. As techniques improve for remote sensing of soil carbon relevant variables, Isometric will consider opportunities to incorporate dynamic baseline approaches which utilize remotely sensed data between project areas and control areas in the broader region to assess additionality.

Fractionation of Soil Carbon Pools

• It is known that different fractions of soil carbon (i.e., particulate organic matter vs mineral-associated organic matter) have different durabilities. However, measurement cost and complexity makes it challenging to implement characterization in the context of the voluntary carbon market. Advances in measurement and opportunities for implementation in the context of carbon projects will be monitored and considered for implementation in future versions.

Insurance

• Insurance providers can provide a third party risk assessment, are financially incentivized to correctly price risk, and have a fiduciary responsibility to pay out in the event of a Reversal. Presently, insurance cannot be used for the purpose of reducing Buffer Pool allocation size. This is due to limitations in the transparency in risk calculations, lack of data to substantiate risk models, and lack of supply of high quality Carbon Credits. As this area develops, insurance will be considered for inclusion in future versions of the Protocol. At minimum, insurance solutions must provide coverage for the entirety of the Project Commitment Period, either through a policy which extends for the full Project Commitment Period (e.g., 100 year policy) or an insurance contract extending for the full Project Commitment Period (e.g., 1 year policy with contract for 100 years).

Quantification Methods

• The Protocol currently uses quantification via ex situ sampling and model-based as the primary approaches. As technological advances continue via other approaches (e.g., in situ measurements, remote sensing, digital soil mapping) additional options may be explicitly incorporated into the Protocol.

Stakeholder Engagement

• More detailed guidance on stakeholder identification and differentiation will be considered for future versions of the Protocol.
• Additional guidance on due diligence required to demonstrate that stakeholder rights are upheld will be considered for future versions of the Protocol.
• Further requirements on requirements for projects with non-smallholder designs may be considered for future version of the Protocol.

Uncertainty

• Project Proponents are expected to quantify and justify the uncertainty associated with each parameter in the carbon removal calculation.
• Additional guidance on model validation metrics will be considered for future improvements.
• Isometric will consider providing a case study of uncertainty propagation for carbon stock quantification.

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7. Di Sacco, A., Hardwick, K. A., Blakesley, D., Brancalion, P. H., Breman, E., Cecilio Rebola, L., ... & Antonelli, A. (2021). Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits. \*Global Change Biology\*, \*27\*(7), 1328-1348. ↩

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10. Di Sacco, A., Hardwick, K. A., Blakesley, D., Brancalion, P. H., Breman, E., Cecilio Rebola, L., ... & Antonelli, A. (2021). Ten golden rules for reforestation to optimize carbon sequestration, biodiversity recovery and livelihood benefits. \*Global Change Biology\*, \*27\*(7), 1328-1348. ↩

11. United Nations General Assembly. (2007). United Nations declaration on the rights of indigenous peoples (A/RES/61/295). Retrieved from [https://www.un.org/development/desa/indigenouspeoples/wp-content/uploads/sites/19/2018/11/UNDRIP\\\\\\\_E\\\\\\\_web.pdf\](https://www.un.org/development/desa/indigenouspeoples/wp-content/uploads/sites/19/2018/11/UNDRIP\_E\_web.pdf) ↩

12. United Nations General Assembly. (2007). United Nations declaration on the rights of indigenous peoples (A/RES/61/295). Retrieved from [https://www.un.org/development/desa/indigenouspeoples/wp-content/uploads/sites/19/2018/11/UNDRIP\\\\\\\_E\\\\\\\_web.pdf\](https://www.un.org/development/desa/indigenouspeoples/wp-content/uploads/sites/19/2018/11/UNDRIP\_E\_web.pdf) ↩ ↩²

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