calc_emissions_manure: Calculate manure management emissions (Tier 1 & Tier 2)

In cowfootR: Dairy Farm Carbon Footprint Assessment

Calculate manure management emissions (Tier 1 & Tier 2)

Description

Estimates CH4 and N2O emissions from manure management using IPCC Tier 1 or Tier 2 methodology with practical settings for dairy systems.

Usage

calc_emissions_manure(
  n_cows,
  manure_system = "pasture",
  tier = 1L,
  ef_ch4 = NULL,
  n_excreted = 100,
  ef_n2o_direct = 0.02,
  include_indirect = FALSE,
  climate = "temperate",
  avg_body_weight = 600,
  diet_digestibility = 0.65,
  protein_intake_kg = NULL,
  retention_days = NULL,
  system_temperature = NULL,
  gwp_ch4 = 27.2,
  gwp_n2o = 273,
  boundaries = NULL
)

Arguments

n_cows	Numeric scalar > 0. Number of dairy cows.
manure_system	Character. One of "pasture", "solid_storage", "liquid_storage", "anaerobic_digester". Default = "pasture".
tier	Integer. IPCC tier (1 or 2). Default = 1.
ef_ch4	Numeric. CH4 EF (kg CH4/cow/year). If NULL, system-specific defaults are used (Tier 1 only).
n_excreted	Numeric. N excreted per cow per year (kg N). Default = 100. In Tier 2 it may be recalculated if protein intake is provided.
ef_n2o_direct	Numeric. Direct N2O-N EF (kg N2O-N per kg N). Default = 0.02.
include_indirect	Logical. Include indirect N2O (volatilization + leaching)? Default = FALSE.
climate	Character. One of "cold", "temperate", "warm". Default = "temperate" (Tier 2).
avg_body_weight	Numeric. Average live weight (kg). Default = 600 (Tier 2).
diet_digestibility	Numeric in (0, 1]. Apparent digestibility. Default = 0.65 (Tier 2).
protein_intake_kg	Numeric. Daily protein intake (kg/day). If provided, Tier 2 can refine N excretion.
retention_days	Numeric. Days manure remains in system (Tier 2 adjustment).
system_temperature	Numeric. Average system temperature (Tier 2 adjustment).
gwp_ch4	Numeric. GWP for CH4 (AR6). Default = 27.2.
gwp_n2o	Numeric. GWP for N2O (AR6). Default = 273.
boundaries	Optional list from set_system_boundaries().

Value

A list with CH4 (kg), N2O (kg), CO2eq (kg), metadata, and per-cow metrics. The returned object includes a co2eq_kg field compatible with calc_total_emissions(). Absolute emissions are annual farm-level emissions (kg CO2eq yr-1) within the defined system boundaries.

Examples

# Tier 1, liquid storage
calc_emissions_manure(n_cows = 120, manure_system = "liquid_storage")

# Tier 1 with indirect N2O
calc_emissions_manure(n_cows = 120, manure_system = "solid_storage", include_indirect = TRUE)

# Tier 2 (VS_B0_MCF approach) with refinements
calc_emissions_manure(
  n_cows = 100, manure_system = "liquid_storage", tier = 2,
  avg_body_weight = 580, diet_digestibility = 0.68, climate = "temperate",
  protein_intake_kg = 3.2, include_indirect = TRUE
)

cowfootR documentation built on Jan. 13, 2026, 5:07 p.m.