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Decompose livestock manure management losses into herd, feed, excretion, and management-loss drivers

Source: R/decomposition_analysis.R
decompose_manure_losses.Rd

Decomposes the year-on-year change in nitrogen (N) lost from livestock housing and manure storage (before any manure reaches land) into four multiplicative drivers, computed at the national level: herd size, feed N intake per livestock unit, excreted fraction of feed N (1 - feed nitrogen use efficiency), and the management-loss fraction of excreted N.

This is a simplified, national-only view with no species breakdown (no species-mix factor); decompose_specialization_cov() still uses the full per-species detail for its livestock_species series. Only livestock categories with a livestock-unit (LU) coefficient in livestock_units are included in the underlying herd/feed/excretion totals (currently Cattle_milk, Cattle_meat, Sheep, Goats, Horses, Donkeys_mules, Pigs, Poultry, Rabbits); categories present in intake_ygiac/n_excretion_ygs but absent from livestock_units (e.g. "Fur animals", "Other", "Other_birds") are dropped.

n_prov_destiny records manure already applied to land without retaining which species it came from, so the management-loss fraction has always been computed nationally, not per species.

Usage

decompose_manure_losses(
  n_prov_destiny = NULL,
  intake_ygiac = NULL,
  n_excretion_ygs = NULL,
  stock_prod_ygps = NULL,
  livestock_units = NULL,
  by_period = FALSE,
  example = FALSE
)

Arguments

n_prov_destiny

Nitrogen flows tibble from create_n_prov_destiny(). If NULL, loaded automatically.

intake_ygiac

Feed intake tibble from whep_read_file("intake_ygiac"). If NULL, loaded automatically.

n_excretion_ygs

Livestock excretion tibble from whep_read_file("n_excretion_ygs"). If NULL, loaded automatically.

stock_prod_ygps

Livestock stock tibble from whep_read_file("stock_prod_ygps"). If NULL, loaded automatically.

livestock_units

Livestock unit coefficients tibble from whep_read_file("livestock_units"). If NULL, loaded automatically.

by_period

If TRUE, compares each reference period (each averaged across its ten years) against the immediately preceding one — 1860-1870 -> 1920-1930 -> 1960-1970 -> 2010-2020 — plus one extra transition spanning the full analysis window, 1860-1870 straight to 2010-2020 (the total change) — instead of chaining year on year.

example

If TRUE, return a small hardcoded output without downloading remote data. Default is FALSE.

Value

A tibble from calculate_lmdi() with columns period, period_years, factor_label, component_type, additive, multiplicative, and multiplicative_log.

Examples

decompose_manure_losses(example = TRUE)
#> # A tibble: 10 × 7
#>    period    period_years factor_label    component_type additive multiplicative
#>    <chr>            <dbl> <chr>           <chr>             <dbl>          <dbl>
#>  1 1860-1861            1 Herd size       factor             0             1    
#>  2 1860-1861            1 Feed intensity  factor             1.78          1    
#>  3 1860-1861            1 Excreted feed … factor            16.7           1.00 
#>  4 1860-1861            1 Management los… factor            56.3           1.00 
#>  5 1860-1861            1 Manure managem… target            74.8           1.00 
#>  6 1861-1862            1 Herd size       factor             0             1    
#>  7 1861-1862            1 Feed intensity  factor            80.1           1.00 
#>  8 1861-1862            1 Excreted feed … factor           -25.0           1.000
#>  9 1861-1862            1 Management los… factor          -126.            0.998
#> 10 1861-1862            1 Manure managem… target           -71.2           0.999
#> # ℹ 1 more variable: multiplicative_log <dbl>