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Estimate livestock nitrogen, carbon and volatile-solids excretion.

Source: R/excretion.R
estimate_n_excretion.Rd

Converts realised feed intake (the output of redistribute_feed()) into excreted nitrogen, carbon and volatile solids per year x territory x sub_territory x livestock_category. All excretion methods share one canonical nitrogen intake, n_intake = sum(intake_dm_t * feed_n_content), so the methods are directly comparable.

Usage

estimate_n_excretion(intake, options = list())

Arguments

intake

A tibble of realised feed intake with at least year, territory, sub_territory, livestock_category, item_cbs_code, feed_quality and intake_dm_t (the redistribute_feed() result). territory is a stringified area_code (as.character(area_code), what redistribute_feed() emits and what the whole manure chain carries through to the nitrogen inputs); an iso3c literal is still resolved there but is deprecated, since it can only answer with an aggregation bucket and so loses the territory for 62 of the 257 codes it knows.

options

A named list of method options:

  • method: "intake_minus_retention" (default, n_intake * (1 - n_retention_frac)) or "intake_minus_product_n" (n_intake - product_n).

  • method_vs: "intake_digestibility" (default, intake_dm_t * (1 - digestibility) * (1 - ash)).

  • product_n: a tibble (year, territory, sub_territory, livestock_category, product_n) required by "intake_minus_product_n".

Value

A tibble with one row per year x territory x sub_territory x livestock_category and columns n_intake, n_excretion, c_excretion, vs_excretion, method_n_excretion and method_vs.

Examples

intake <- tibble::tribble(
  ~year, ~territory, ~sub_territory, ~livestock_category,
  ~item_cbs_code, ~feed_quality, ~intake_dm_t,
  2020L, "203", NA, "Cattle_milk", 2513L, "high_quality", 100,
  2020L, "203", NA, "Cattle_milk", NA, "grass", 500
)
estimate_n_excretion(intake)
#> # A tibble: 1 × 10
#>    year territory sub_territory livestock_category n_intake n_excretion
#>   <int> <chr>     <lgl>         <chr>                 <dbl>       <dbl>
#> 1  2020 203       NA            Cattle_milk            11.9        9.49
#> # ℹ 4 more variables: c_excretion <dbl>, vs_excretion <dbl>,
#> #   method_n_excretion <chr>, method_vs <chr>