Section 3.5

Estimation of Amount of Nitrogen Volatilized and Leached in the Project

In cases where detailed project-specific data is unavailable or when a simplified estimation is preferred, a fraction-based approach is used to calculate emissions from fertilizer use. This method relies on default fractions for nitrogen volatilization and leaching, as outlined in the IPCC guidelines (Volume 4, Chapter 11). Specifically, it assumes that a set percentage of the applied nitrogen is volatilized or leached, with associated emission factors for each pathway. By applying these default fractions to the total nitrogen applied, the emissions from volatilization and leaching can be estimated without the need for detailed field measurements.

The fraction-based estimation method provides a streamlined and efficient way to calculate project emissions, especially in cases where more specific data is not available or when a less granular approach is deemed sufficient for the purpose of carbon crediting. This methodology is consistent with Tier 1 IPCC guidelines for emissions estimation and ensures transparency and comparability across projects.

Amount of Volatilisation

N_v = N_a \times Frac_v

(3.5)

Where $Frac_v$ is the fraction of nitrogen volatilized.

Parameter	Description	(Default) Value	Source
$Frac_v$	Volatilisation compared to synthetic fertiliser applied (t NH₃–N + NOx–N) / (t N applied)	Derive from Table 11.3	IPCC Volume 4, Chapter 11 (2006, updated 2019)

Table 3: Amount of Nitrogen Volatilized in the project

Amount of losses by leaching/runoff

N_l = N_a \times Frac_l

(3.6)

Where $Frac_l$ is the fraction of nitrogen leaching.

Parameter	Description	(Default) Value	Source
$Frac_l$	N losses by leaching/runoff compared to synthetic fertiliser applied (t NH₃–N + NOx–N) / (t N applied)	Derive from Table 11.3	IPCC Volume 4, Chapter 11 (2006, updated 2019)

Table 4: Amount of Nitrogen leached/runoff in the project

Project Emissions Calculation Monitoring Parameters