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Calculate daily enteric methane emissions

Source: R/core_model_emissions_enteric.R
calc_ch4_enteric.Rd

Calculates daily enteric methane emissions (kg CH4/head/day) based on gross energy intake, methane conversion factor (ym), and dry matter intake.

Usage

calc_ch4_enteric(
  species_short,
  ch4_conversion_factor_ym,
  ch4_mitigation_factor,
  ration_gross_energy,
  ration_intake
)

Arguments

species_short

Character. Code identifying the livestock species. Supported values include:

  • PGS: pigs

  • CML: camels

  • CTL: cattle

  • BFL: buffalo

  • SHP: sheep

  • GTS: goats

ch4_conversion_factor_ym

Numeric. Methane (CH4) conversion factor (ym), representing the percentage of gross energy of the feed ration that is converted to CH4 (percentage).

ch4_mitigation_factor

Numeric. Optional. Multiplicative mitigation factor applied to baseline enteric methane (CH4) emissions (dimensionless). If not provided, a default value of 1 (no mitigation) is used. Values lower than 1 represent proportional reductions (e.g., 0.90 = 10% reduction). This factor can represent mitigation measures with a direct effect on enteric methane emissions, such as the use of feed additives or methane inhibitors.

ration_gross_energy

Numeric. Average gross energy content of the diet (MJ/kg DM).

ration_intake

Numeric. Average daily dry matter intake of feed (kg DM/head/day).

Value

Numeric. Average daily enteric methane (CH4) emissions (kg CH4/head/day).

Details

The formula used to estimate daily enteric methane emissions is:

$$CH_4 = \frac{ration\_gross\_energy \times ration\_intake \times ch4\_conversion\_factor\_ym}{55.65 \times 100}$$

where 55.65 MJ/kg is the energy content of methane.

ration_gross_energy and ration_intake can be calculated with calc_ration_gross_energy and calc_ration_intake ( see also run_ration_quality_module and run_metabolic_energy_req_module).

This function is part of the run_emissions_enteric_module().

References

IPCC. (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Chapter 10: Emissions from Livestock and Manure Management, Equation 10.21.

IPCC. (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Chapter 10: Emissions from Livestock and Manure Management, Equation 10.21.

See also

run_emissions_enteric_module, calc_ration_gross_energy, calc_ration_intake, run_ration_quality_module run_metabolic_energy_req_module