Agricultural Practices Reductions Module

Improved soil management (ISM) practices that sequester carbon in agricultural soils frequently deliver concurrent reductions in greenhouse gas (GHG) emissions. Changes to tillage regime, fertilizer application, and cover cropping alter the flux of nitrous oxide (N₂O), carbon dioxide (CO₂), and methane (CH₄) from agricultural land, producing emission reductions that are mechanistically distinct but operationally inseparable from carbon removals via the soil organic carbon (SOC) targeted by the Improved Soil Management Protocol.

Agriculture is a significant source of direct GHG emissions globally. Synthetic nitrogen fertilizer application is the dominant anthropogenic driver of N₂O emissions, a greenhouse gas with a 100-year global warming potential (GWP) of 273¹. Fossil fuel combustion during field operations, principally diesel use in tillage, contributes direct CO₂, N₂O, and CH₄ emissions. These emission sources are causally linked to identifiable management practices that can be modified to reduce emissions while simultaneously supporting SOC accumulation.

This Module establishes the requirements for quantifying, reporting, and verifying emission reductions achieved through agricultural practice changes that are implemented as part of a project generating carbon dioxide removals under the Improved Soil Management Protocol. It provides a framework for crediting reductions that are conservatively quantified. Reductions credited under this Module must be submitted alongside corresponding removals for the same Reporting Period; they are not eligible to be credited independently of removals.

This Module is designed to be conservative in scope. Only emission reduction categories that meet three essential criteria are eligible for crediting: (1) the emissions are causally linked to specific, identifiable management practices; (2) the management practices can be altered to reduce emissions and are not already widely adopted in the relevant crop, geography, and production context; and (3) pre- and post-intervention physical data can be collected to support estimates of realized emissions and counterfactual emissions.

The quantification of soil organic carbon removals is governed separately by the Improved Soil Management Protocol and the Cropland Management Module.

The combined climate benefit of a project is expressed as a GHG Entry comprising both removals and reductions for a given Reporting Period:

$$GHG \ Entry = CO₂e_{Removals} + CO₂e_{Reduction,Credited}$$

(Equation 1)

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 this Module. CO₂e_Reductions may be zero.

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

• The Isometric Standard
• The Improved Soil Management Protocol
• 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

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

• VM0042 Methodology for Improved Agricultural Land Management, v2.2, Verra, 2025
• VMD0053 Model Calibration, Validation, and Uncertainty Guidance for Biogeochemical Modeling, v2.1, Verra, 2025
• Soil Enrichment Protocol, v1.1, Climate Action Reserve
• 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4, Chapter 11 (N₂O Emissions from Managed Soils)
• 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4, Chapter 10 (Emissions from Livestock and Manure Management)

This version of this Module aims to be scientifically stringent and robust and thus scopes the limited set of agricultural practice emissions reductions sources with approaches that Isometric has confidence in the verifiability and quantification of along with soil carbon interventions scoped in the Improved Soil Management Protocol.

Isometric will continue to evaluate various sources of agricultural practices with emissions reductions. Future versions of this Module will include revised and/or expanded emissions reductions sources eligible for crediting. Revised or additional agricultural practices emissions reductions may relate to existing interventions as scoped in the Improved Soil Management Protocol and may expand as additional interventions are scoped in future versions of the Improved Soil Management Protocol.

To qualify for crediting under this Module, a Project must meet all of the conditions specified in this section, in addition to all requirements of the Improved Soil Management Protocol and the Isometric Standard.

Emission reductions under this Module are only eligible for Projects that are concurrently generating soil organic carbon removals under the Improved Soil Management Protocol. This Module does not support standalone emission reduction projects.

This Module applies to emission reductions arising from the following agricultural practice changes, where the practice change is implemented as part of a project generating removals under the Improved Soil Management Protocol. Each eligible practice must satisfy the three inclusion criteria described in Section 1.

Reductions in synthetic nitrogen fertilizer application directly lower N₂O emissions from managed soils. N₂O is produced through nitrification and denitrification processes in soil, and emissions scale with the quantity of reactive nitrogen applied. Where project activities result in a measurable decrease in synthetic nitrogen application relative to the baseline, the resulting reduction in direct N₂O emissions is eligible for crediting.

Only direct N₂O emissions from the application of synthetic nitrogen to soils are eligible. Embodied emissions associated with the production and transport of fertilizer are excluded from the scope of creditable reductions, consistent with the treatment of avoided upstream emissions across other Isometric Protocols.

Fertilizer reduction carries a material leakage risk through yield reductions. The Cropland Management Module details an approach for assessing leakage impacts from production shortfalls due to yield reductions associated with reductions in fertilizer application.

See Section 8.3 of the Cropland Management Module for a full description of leakage guardrails and estimation.

Where a project activity involves a transition from conventional tillage to reduced or no-tillage, the reduction in on-farm diesel combustion associated with fewer tractor passes is eligible for crediting. Only direct CO₂, N₂O, and CH₄ emissions from diesel combustion are included; upstream emissions from fuel production and supply are excluded.

We introduce this comparative approach as just relying on farm-level historical application rate would introduce adverse selection into crediting (farms that are already looking to reduce anyways enroll in The Project) as well as an incentive to overestimate historical application rates.

Taking the minimum of the farm-level historical application rate and the regional benchmark application rate is conservative; we acknowledge that this "lesser of" requirement limits the reduction potential for fields that have historically applied significantly higher rates of fertilizer. Placing a ceiling on baseline application rates avoids rewarding actors who have historically over-applied fertilizer relative to best practices and in the process penalizing early adopters of more efficient fertilizer regimes.

Isometric retains the right to use historical remote sensing data to confirm that the baseline scenario and historical land use have been accurately described.

All Project Timelines outlined in Section 5 of the Improved Soil Management Protocol apply in full, with one exception.

The Improved Soil Management Protocol provides that in the event of project failure, all Credits issued under The Project will be cancelled. This cancellation provision applies to carbon dioxide removal credits issued under the Project.

Emission reduction credits issued under this Module and verified for a completed Reporting Period prior to the date of project failure are not subject to cancellation. The emission reductions credited under this Module represent permanent, non-reversible atmospheric benefits. Once verified, the avoided emissions cannot be reversed by subsequent changes in land management or project status.

This treatment is consistent with relevant sections of the Isometric Standard, which recognize that some emissions reductions are permanent with no risk of reversal.

In the event of project failure, The Project is immediately ineligible to generate further emission reduction credits under this Module.

All Environmental and Social Safeguarding (ESS) requirements of Section 6 of the Improved Soil Management Protocol and the Isometric Standard apply in full. No additional ESS requirements are introduced by this Module.

All requirements in Section 7 of the Improved Soil Management Protocol apply in full to emission reductions under this Module, including requirements for the PDD, Validation and Verification, Verification Materiality, site visits, verifier qualifications, ownership, and data sharing. The following Module-specific additions and modifications apply.

Where a Project generates both removal and reduction credits, a single PDD is sufficient, provided all requirements of both the Protocol and this Module are met.

In addition to the Validation and Verification Body (VVB) requirements in the Improved Soil Management Protocol, the VVB must:

• Verify that the reduction quantification approach adheres to Section 9;
• Verify the leakage assessment, including the productivity ratio calculation and yield data sources; and
• For aggregated projects, ensure that the site visit plan includes a statistically representative sample of enrolled fields, with the sampling methodology documented.

VVB teams must demonstrate expertise in nitrogen cycling and emission reduction quantification from agricultural practice changes, in addition to the competencies required by the Improved Soil Management Protocol.

All ownership requirements in the Improved Soil Management Protocol and the Isometric Standard apply. In addition, where a Project generates both removal and reduction credits, ownership of both credit types must be assigned to the same Project Proponent. Separate ownership of removal and reduction credits from the same Project is not permitted.

All additionality requirements in the Improved Soil Management Protocol and the Isometric Standard apply.

Because emission reductions under this Module are only creditable as part of a Project concurrently generating removals, the additionality of the reduction activities is assessed in the context of the broader project. The additionality test applies to the bundle of practice changes at the project level, not to individual reduction categories in isolation.

Agricultural practice changes that reduce GHG emissions frequently generate co-benefits that may qualify for separate payments under conservation schemes or other payments for ecosystem services. The stacking disclosure and additionality requirements in Section 7 of the Improved Soil Management Protocol and the Isometric Standard apply.

The Common Practice analysis must be conducted in accordance with the requirements in Section 7.4.3 of the Improved Soil Management Protocol and the Isometric Standard, applied on a practice by practice basis.

All uncertainty requirements in the Improved Soil Management Protocol and the Isometric Standard apply. Module-specific uncertainty discount, applied based on the tier of emission factor and approach to activity data determination, are specified in Section 9.5.

All data sharing requirements in the Improved Soil Management Protocol apply. In addition, the following data specific to this Module must be made available through Isometric's platform:

• Emission factors used for N₂O and diesel quantification
• Activity data (nitrogen application rates, fuel consumption if Approach A is used)
• Model specifications and output (where Method 3 is used)
• Yield data used in the leakage assessment

This Module covers the GHG SSRs relevant to the quantification of emission reductions. SSRs relevant to SOC removals are governed by the Improved Soil Management Protocol. The general system boundary principles and GHG accounting requirements in Section 8.1 of the Improved Soil Management Protocol and the GHG Accounting Module apply.

Table 1: System Boundary for Emission Reductions

• Soil texture (coarse, medium, fine) influences N₂O emissions.
• Soil organic carbon content (low <1%, moderate 1–3%, high >3%).
• Climate zone (Köppen-Geiger classification for multi-zone projects).

The baseline scenario is defined in Section 4.2. Baseline quantification accounts for N₂O emissions from fertilizer (Section 9.2.1) and direct GHGs from diesel combustion during tillage (Section 9.2.2).

The Improved Soil Management Protocol provides general leakage requirements for ISM projects, and the Cropland Management Module details the specific approach assessing productivity declines and quantifying associated leakage emissions. Per Section 8.2.1.1 of the Improved Soil Management Protocol, all leakage emissions occurring as a result of The Project shall be assessed against removals.

$$CO_2e_{Reduction,RP} = CO_2e_{Baseline,RP} - CO_2e_{Project,RP}$$

(Equation 2)

Where:

• $CO_2e_{Reduction,RP}$ is the net CO₂e reduction for the Reporting Period, in tonnes CO₂e. Must be zero or positive. If less than one, emissions must be counted as project emissions per Table 4 of the Improved Soil Management Protocol.
• $CO_2e_{Baseline,RP}$ is the CO₂e emissions that would have occurred absent The Project (Section 9.2), in tonnes CO₂e.
• $CO_2e_{Project,RP}$ is the CO₂e emissions from project activities (Section 9.4), in tonnes CO₂e.

The final credited reduction is:

$$CO_2e_{Reduction,Credited,RP} = CO_2e_{Reduction,RP} \times (1 - D_{uncertainty})$$

(Equation 3)

Where $D_{uncertainty}$ is the total uncertainty discount factor (Section 9.5).

The baseline for a given reporting period $CO_2e_{Baseline,RP}$ is the sum of the respective baselines for N₂O emissions from fertilizer application and the direct CO₂e emissions from tillage:

$$CO_2e_{Baseline,RP} = CO_2e_{BL,N_2O,RP} + CO_2e_{BL,Diesel,RP}$$

(Equation 4)

Where:

• $CO_2e_{BL,N_2O,RP}$ is the baseline for N₂O emissions from fertilizer application, further defined in Section 9.2.1
• $CO_2e_{BL,Diesel,RP}$ is the baseline for direct CO₂e emissions from tillage, further defined in Section 9.2.2

$$CO_2e_{BL,N_2O,RP} = \sum\limits_g \left( Q_{N,BL,g} \times A_g \times EF_{N_2O,g} \times \frac{44}{28} \times 10^{-3} \times GWP_{N_2O} \right)$$

(Equation 5)

Where:

• $Q_{N,BL,g}$ is the baseline synthetic nitrogen application rate for stratum $g$ (kg N/ha/RP), set as the lesser of farm-level historical and regional benchmark per Section 4.2.2.
• $A_g$ is the area of project fields in stratum $g$ (ha).
• $EF_{N_2O,g}$ is the emission factor for direct N₂O from nitrogen inputs (kg N₂O-N/kg N-input), per Section 9.3.1.
• $\frac{44}{28}$ is the molecular weight conversion from N₂O-N to N₂O.
• $10^{-3}$ converts kg to tonnes.
• $GWP_{N_2O}$ is the 100-year GWP of N₂O (currently 273).

$$CO_2e_{BL,Diesel,RP} = \sum\limits_g \left( \sum\limits_p \left( N_{passes,BL,p,g} \times FC_{p,g} \right) \times A_g \times EF_{diesel} \times 10^{-3} \right)$$

(Equation 6)

Where:

• $N_{passes,BL,p,g}$ is the number of passes of tillage operation type $p$ under the baseline regime for stratum $g$.
• $FC_{p,g}$ is the fuel consumption rate (litres diesel/ha/pass), per Section 9.3.2.
• $EF_{diesel}$ is the emission factor for direct diesel combustion, inclusive of CO₂, CH₄, and N₂O (default for 100% fossil diesel: 2.78 kg CO₂e/litre, comprising 2.70 kg CO₂ + 0.01 kg CO₂e from CH₄ + 0.07 kg CO₂e from N₂O, per EPA GHG Emission Factors Hub 2025, using AR6 GWPs). Where biodiesel or renewable diesel was used in baseline operations, a fuel-type-specific emission factor must be applied (see Section 9.3.2).

Method 1: IPCC Tier 1 Default Emission Factors. Default EF of 0.01 kg N₂O-N/kg N-input (IPCC 2019 Refinement, Vol 4, Ch 11, Table 11.1²). Subject to the largest uncertainty discount (Section 9.5).

Method 2: Country-Specific or Regional Emission Factors. Peer-reviewed, published EFs specific to the project country or region, derived from field studies under comparable conditions. Must follow IPCC 2019 Refinement guidance (Ch 11, §11.2.1.1³). Subject to a moderate uncertainty discount.

The emission factor for diesel combustion ($EF_{diesel}$) must be expressed in kg CO₂e per litre, inclusive of direct fossil CO₂, CH₄, and N₂O from combustion. Biogenic CO₂ from the combustion of biofuel components is treated as carbon-neutral, consistent with IPCC GHG inventory conventions. CH₄ and N₂O are included regardless of fuel origin, as these are produced by the combustion process itself.

The emission factor for 100% fossil diesel is 2.78 kg CO₂e per litre (comprising 2.70 kg CO₂ + 0.01 kg CO₂e from CH₄ + 0.07 kg CO₂e from N₂O), based on EPA GHG Emission Factors Hub (2025), Tables 2 and 5, using AR6 GWPs.

$$EF_{blend} = ((1 - x) \times 2.78) + (x \times EF_{bio})$$

(Equation 7)

Where:

• $x$ is the biofuel fraction by volume (e.g., 0.20 for B20).
• $EF_{bio}$ is the CO₂e emission factor for the biofuel component: 0.13 kg CO₂e/L for biodiesel (FAME) or 0.09 kg CO₂e/L for renewable diesel (HVO/HEFA).

The FAME biodiesel emission factor of 0.13 kg CO₂e/L reflects the fossil carbon fraction (~5.3%) originating from methanol used in transesterification, plus residual CH₄ and N₂O from combustion. Renewable diesel (HVO/HEFA) is chemically identical to petroleum-derived hydrocarbons and contains no fossil carbon; its emission factor of 0.09 kg CO₂e/L reflects only CH₄ and N₂O from combustion.

Using a petroleum diesel emission factor when the actual baseline fuel contained biofuel results in overcrediting the baseline emissions are overstated, inflating the credited reduction. To prevent this:

• The petroleum diesel factor (2.78 kg CO₂e/L) may only be used where the Project Proponent provides documented evidence that baseline fuel was 100% petroleum diesel (e.g., off-road dyed diesel purchase records from a supplier confirming no biofuel content).
• Where baseline fuel records are unavailable or the fuel type cannot be determined, a conservative default emission factor of 2.25 kg CO₂e/L must be used. This corresponds to a B20 blend (20% FAME biodiesel, 80% petroleum diesel) and reflects the highest commonly mandated biodiesel blend in US jurisdictions. The B20 default ensures that baseline emissions are not overstated where the actual biofuel content of the fuel supply is unknown.
• Where the project is located in a jurisdiction with an active biodiesel or renewable diesel mandate exceeding B20 during the baseline period, the Project Proponent must use the mandated blend rate (or the documented actual blend, if higher) to determine $EF_{diesel}$.

Approach A: Direct Measurement. On-farm records, fuel gauges, or GPS-linked monitoring. Records should cover five years of baseline operations but must cover at least one year of baseline operations.

Approach B: Equipment-Specific Published Estimates. Published data for the specific equipment type, draft requirement, and soil conditions (e.g., ASABE Standards D497). Must specify implement type, working width, working depth, soil texture, and tractor power class.

Approach C: Default Estimates. Where neither Approach A nor Approach B data are available, the Project Proponent may use the following default fuel consumption values per pass (Table 2). Where multiple peer-reviewed estimates are available for an operation, the most conservative (lowest) value must be used to avoid overstating baseline diesel consumption and the resulting reduction credits.

Table 2: Tillage Diesel Fuel Use Default Estimates

The default values draw from two sources: Filipović et al. (2010), a peer-reviewed four-year instrumented field study on silty loam in a corn-wheat rotation; and Helsel, Grisso, and Grubinger, a US extension publication based on field data for corn production systems. Where the two sources diverge (notably chisel ploughing, disc harrowing, and field cultivation), the lower value is adopted as the conservative default. This reflects the principle that default estimates should not overstate baseline diesel consumption, as overstated baselines would inflate reduction credits.

Values will vary materially by soil type, working depth, tractor power class, and equipment condition. Where local conditions differ from the study conditions, Approach A or B must be used. Approach C is subject to the largest diesel uncertainty discount.

The overall emissions in the project scenario during a given Reporting Period (RP) are calculated as:

$$CO_2e_{Project,RP} = CO_2e_{P,N_2O,RP} + CO_2e_{P,Diesel,RP}$$

(Equation 8)

Where:

• $CO_2e_{Project,RP}$ are the total project emissions associated with the relevant activities under this module for a given reporting period in tonnes CO₂e
• $CO_2e_{P,N2O,RP}$ are the project emissions due to fertilizer application for a given reporting period in tonnes CO₂e
• $CO_2e_{P,Diesel,RP}$ are the project emissions due to tillage for a given reporting period in tonnes CO₂e

The project scenario N₂O emissions for a given Reporting Period are calculated as:

$$CO_2e_{P,N_2O,RP} = \sum\limits_g \left( Q_{N,P,g} \times A_g \times EF_{N_2O,g} \times \frac{44}{28} \times 10^{-3} \times GWP_{N_2O} \right)$$

(Equation 9)

Where:

• $Q_{N,P,g}$ is the project-scenario nitrogen application rate, verified through monitoring (Section 10).

The remaining variables are the same as used for Equation 5 in the determination of the pre-project emissions.

The project scenario emissions from tillage for a given Reporting Period are calculated as:

$$CO_2e_{P,Diesel,RP} = \sum\limits_g \left( \sum\limits_p \left( N_{passes,p,g} \times FC_{p,g} \right) \times A_g \times EF_{diesel} \times 10^{-3} \right)$$

(Equation 10)

Table 3. N₂O Emission Factor Uncertainty Discounts

Table 4. Diesel Activity Uncertainty Discounts

The overall uncertainty is determined by weighting the relative contributions of the two reduction mechanisms:

$$D_{uncertainty} = \frac{D_{N_2O} \times CO_2e_{Red,N_2O,RP} + D_{Diesel} \times CO_2e_{Red,Diesel,RP}}{CO_2e_{Red,N_2O,RP} + CO_2e_{Red,Diesel,RP}}$$

(Equation 11)

Where The Project credits only one practice category, the applicable single-practice discount applies.

All emissions accounting requirements of the Improved Soil Management Protocol, the GHG Accounting Module, and the Energy Use Accounting Module apply to the quantification of reductions under this Module.

Monitoring must be sufficient to enable independent verification of all parameters used in the net reduction calculation (Section 9) and the leakage assessment (Section 4.1.1.1).

Approach A based on direct measurement as detailed in Section 9.3.2 is the preferred approach which produces the lowest discount. On-farm records, data from fuel gauges, or GPS-linked monitoring are viable data sources for the continued monitoring of fuel consumption data. Records must cover at least one full season of baseline operations. Without direct measurement per one of these sources, equipment-specific estimates (Approach B) or literature estimates (Approach C, Table 2) may be used with respectively higher discounts to estimate the diesel fuel consumption.

A 20% biodiesel blend (B20) will be assumed as the default fuel type to minimize the chances of overestimating emissions reductions from more emissions intensive fuel types (e.g., B0, B5). A project may claim reductions of B0 or B5 with sufficient evidence. Acceptable evidence of fuel type includes fuel purchase invoices identifying the product, supplier blend certifications, fuel delivery records, and documentation of applicable state or regional blend mandates during the baseline period.

Where a state or regional mandate requires a minimum biofuel blend and the project area falls within that jurisdiction, the VVB must verify that the declared baseline fuel type is consistent with the applicable mandate. A claim of fossil-only fuel use in a jurisdiction with an active biofuel mandate requires additional evidence demonstrating that the mandate did not apply to The Project's fuel supply (e.g., off-road diesel exemption documentation, direct supplier confirmation of fossil-only product).

1. Forster, P. et al. (2021). The Earth's Energy Budget, Climate Feedbacks, and Climate Sensitivity. In: Climate Change 2021: The Physical Science Basis. IPCC AR6 WGI. Table 7.15. ↩

2. IPCC (2019). 2019 Refinement to the 2006 IPCC Guidelines, Vol 4, Ch 11 Table 11.1. ↩

3. IPCC (2019). 2019 Refinement to the 2006 IPCC Guidelines, Vol 4, Ch 11 Table 11.1 ↩

4. Filipović, D., Košutić, S., and Gospodarić, Z. (2010). Comparison of tillage systems according to fuel consumption. Energy, 35(1), 221–228. https://doi.org/10.1016/j.energy.2009.09.020. Values from Table 3: measured fuel consumption (L ha⁻¹) for individual tillage implements over four experimental years (1996–2000) on Albic Luvisol (silty loam), corn–winter wheat rotation, using a 92 kW four-wheel-drive tractor. ↩

5. McLaughlin, N.B., Drury, C.F., Reynolds, W.D., Yang, X.M., Li, Y.X., Welacky, T.W., and Stewart, G. (2008). Energy inputs for conservation and conventional primary tillage implements in a clay loam soil. Transactions of the ASABE, 51(4), 1153–1163. Mouldboard plough fuel consumption measured at 21.6 L ha⁻¹ on Brookston clay loam over four years (2002–2005). ↩

6. Helsel, Z., Grisso, R., and Grubinger, V. (2019). Reducing Tillage to Save Fuel. Farm Energy, Cooperative Extension. https://farm-energy.extension.org/reducing-tillage-to-save-fuel/ ↩