Section 3.4

    Project Emissions Calculation

    This section outlines the methodology for calculating project emissions, which are based on the reduced or alternative fertilizer use in the project compared to baseline levels. The same formula used for baseline emissions is applied, but with adjustments to reflect the actual amount of synthetic fertilizers used in the project, or alternative fertilizers. The methodology follows a tiered approach based on IPCC guidelines.

    • Tier 1 Approach: Tier 1 calculations rely on IPCC default values, such as global averages or standard emission factors for synthetic fertilizers.
    • Refined Approaches (Tier 2 or 3): When possible, project-specific measurements or species-specific values from peer-reviewed literature should be applied. For example, studies on utilizing nitrogen-fixing rhizobia may provide more accurate data on N₂O reduction.

    The description of the parameters is given in Table 2.

    Eproject=∑n=i(Nproj,a,i×EFproj,d,i+Nproj,v,i×EFproj,v,i+Nproj,l,i×EFproj,l,i)×N to N2O×N2O to CO2E_{project} = \sum_{n=i} \left( N_{proj,a,i} \times EF_{proj,d,i} + N_{proj,v,i} \times EF_{proj,v,i} + N_{proj,l,i} \times EF_{proj,l,i} \right) \times \text{N to N}_2\text{O} \times \text{N}_2\text{O to CO}_2
    (3.4)

    Where ii is the type of synthetic fertilizer.

    ParameterDescription(Default) ValueSource
    Nproj,a,iN_{proj,a,i}Amount of synthetic fertilizer applied in the project year (t N/ha)Variable (project-specific)Farm records, receipts
    EFproj,d,iEF_{proj,d,i}Direct emission factor for synthetic fertilizers in the projectDerive from Table 11.1Tier 1: IPCC Volume 4, Chapter 11 (2006, updated 2019). Tier 2: Field-specific emission studies.
    Nproj,v,iN_{proj,v,i}Amount of nitrogen volatilized in the project (fraction of applied nitrogen)Variable (project-specific)Tier 1: IPCC Volume 4, Chapter 11 (2006, updated 2019). Tier 2: Region-specific measurements or models.
    EFproj,v,iEF_{proj,v,i}Emission factor for volatilized nitrogen in the projectDerive from Table 11.3 (0.01 t N₂O-N per t N volatilized)Tier 1: IPCC Volume 4, Chapter 11 (2006, updated 2019). Tier 2: Context-specific emission factors (e.g., biologically enhanced nitrogen cycling).
    Nproj,l,iN_{proj,l,i}Amount of nitrogen leached/runoff in the project (fraction of applied nitrogen)Variable (project-specific)Tier 1: IPCC Volume 4, Chapter 11 (2006, updated 2019). Tier 2: Measured local leaching data and context-specific emission factors.
    EFproj,l,iEF_{proj,l,i}Emission factor for leached nitrogen in the project0.0075 t N₂O-N per t N leachedTier 1: IPCC Volume 4, Chapter 11 (2006, updated 2019). Tier 2: Site-specific leaching studies.
    N to N₂OMolecular weight ratio to convert N₂O-N to N₂O1.57IPCC Volume 4, Chapter 11 (2006)
    N₂O to CO₂N₂O to CO₂ conversion factor310IPCC Volume 4, Chapter 11 (2006)
    Table 2: Parameters for Project Emissions Calculation
    Baseline Emissions CalculationEstimation of Amount of Nitrogen Volatilized and Leached in the Project