Calculate indirect Nitrous Oxide (N2O) emissions from manure leaching and runoff

Calculates daily indirect nitrous oxide (N2O) emissions resulting from nitrogen leaching and runoff from manure management systems and separates emissions from manure deposited on pasture, manure burned for fuel, and all other manure management systems.

Usage

calc_n2o_manure_leaching(ratio_N2ON_to_N2O = 44/28, nitrogen_excretion, ...)

Arguments

ratio_N2ON_to_N2O

Numeric. Conversion factor from kg N2O–N to kg N2O, based on molecular weights. Defaults to 44/28.

nitrogen_excretion

Numeric. Daily nitrogen excretion (kg N/head/day).

...

A variable number of manure management system (MMS) arguments. Each MMS must be provided as a named numeric vector with exactly the following fields:

manure_management_system_fraction: Numeric. Fraction of total manure excreted by animals in a given herd and cohort that is handled in a specific manure management system. Values ranges from 0 to 1. The sum of all fractions for each herd_id must equal 1.
n2o_ef5: Numeric. Emission factor for indirect nitrous oxide (N2O) emissions resulting from nitrogen leaching and runoff, expressed as kilograms of N2O–N per kilogram of nitrogen leached or lost through runoff (kg N2O–N / kg N). Default values can be selected from Table 11.3 in IPCC Guidelines (IPCC 2006, 2019).
nitrogen_fracleach: Numeric. Fraction of manure nitrogen excreted by a given livestock category that is lost through leaching and runoff from a specific manure management system. This parameter is highly uncertain and is used to estimate indirect N2O emissions from nitrogen that enters the surrounding environment of the storage facility. It is expressed as a dimensionless fraction (0–1). Default values are provided in Table 10.22 of IPCC Guidelines (IPCC 2006, 2019).

Two MMS names are treated explicitly when present:

mms_pasture: Manure deposited on pasture.
mms_burned: Manure burned for fuel.

All remaining MMS arguments are grouped and treated as other manure management systems.

Value

A named list with the following elements

n2o_manure_pasture_leach: Numeric. Indirect nitrous oxide (N2O) emissions resulting from leaching and runoff of manure nitrogen from manure deposited on pasture (kg N2O/head/day).
n2o_manure_burned_leach: Numeric. Indirect nitrous oxide (N2O) emissions resulting from leaching and runoff of manure nitrogen from manure burned for fuel (kg N2O/head/day).
n2o_manure_other_leach: Numeric. Indirect nitrous oxide (N2O) emissions resulting from leaching and runoff of manure nitrogen from manure management systems, excluding losses from manure deposited on pasture and manure burned for fuel (kg N2O/head/day).
n2o_manure_all_noburn_leach: Numeric. Indirect nitrous oxide (N2O) emissions resulting from leaching and runoff of manure nitrogen from manure management systems, excluding losses from manure burned for fuel (kg N2O/head/day).

Details

This calculation follows the Tier 2 methodology for indirect N2O emissions from manure management as defined in Equations 10.28 (IPCC, 2006), 10.27 (IPCC, 2019), and 10.29 (IPCC, 2006, 2019).

In the IPCC formulation, indirect emissions associated with nitrogen leaching and runoff are calculated as:

$$ N2O_{L(mm)} = \frac{44}{28} \sum_{S} \left( N \times AWMS_S \times FracLeach_{S} \times EF5 \right) $$

where:

$N2O_L(mm)$: Indirect N2O emissions due to leaching and runoff from Manure Management.
$44/28$: Conversion factor from N2O–N to N2O.
$N$: Nitrogen excreted (kg N).
$AWMS_S$: Fraction of excreted nitrogen managed in manure management system $S$.
$FracLeach_{S}$: Fraction of nitrogen lost through leaching and runoff in manure management system $S$.
$EF5$: Emission factor for indirect N2O emissions from leaching and runoff (kg N2O–N per kg N leached or lost through runoff).

In this implementation, calculations are performed at daily, per-head resolution using nitrogen_excretion (kg N/head/day):

$$ \begin{aligned} N_2O &= nitrogen\_excretion \times ratio\_N2ON\_to\_N2O \times \\ & \sum_{S} \left( manure\_management\_system\_fraction \times nitrogen\_fracleach \times n2o\_ef5 \right) \end{aligned} $$

This function is part of the run_emissions_manure_module().

References

IPCC. (2019). 2019 Refinement to the 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Chapter 10: Emissions from Livestock and Manure Management. Equations 10.27; 10.29.

IPCC. (2006). 2006 IPCC Guidelines for National Greenhouse Gas Inventories, Volume 4, Chapter 10: Emissions from Livestock and Manure Management. Equations 10.28; 10.29.

Examples

calc_n2o_manure_leaching(
  ratio_N2ON_to_N2O = 44 / 28,
  nitrogen_excretion = 0.9,
  mms_burned = c(
    manure_management_system_fraction = 0.020,
    n2o_ef5 = 0.011,
    nitrogen_fracleach = 0
  ),
  mms_drylot = c(
    manure_management_system_fraction = 0.264,
    n2o_ef5 = 0.011,
    nitrogen_fracleach = 0.035
  ),
  mms_pasture = c(
    manure_management_system_fraction = 0.310,
    n2o_ef5 = 0.011,
    nitrogen_fracleach = 0.24
  ),
  mms_solid = c(
    manure_management_system_fraction = 0.406,
    n2o_ef5 = 0.011,
    nitrogen_fracleach = 0.02
  )
)
#> $n2o_manure_pasture_leach
#> [1] 0.001157451
#> 
#> $n2o_manure_burned_leach
#> [1] 0
#> 
#> $n2o_manure_other_leach
#> [1] 0.000270072
#> 
#> $n2o_manure_all_noburn_leach
#> [1] 0.001427523
#>