Build the native grassland land extension.

Produce a grassland land extension keyed by (year, area_code, item_cbs_code), replacing the grassland rows that used to come from the external land_fp pin.

Two area sources are available, selected with source:

• "luh2" (default): permanent and temporary grassland area (item_cbs 3000 and 3002, LUH2 pasture and rangeland) taken from build_primary_production(). This shares the gridded LUH2 land-use basis used by the crop land extensions and by livestock spatialisation. Rotational fallow (item_cbs 3003) is excluded because the cropgrids_fallow crop extension already attributes fallow to crops, so counting it here too would double count it.

• "faostat_pasture": FAOSTAT "Permanent meadows and pastures" area (Land Use item 6655), the statistics-based basis comparable to most published footprint studies.

Two metrics are available, selected with grassland_metric:

• "occupation" (default): the full grassland area is charged as occupied land.

• "active_grazing": grassland is capped at the area implied by actual grazing intake (the "grass" feed in get_feed_intake()) divided by a usable grass yield, so ungrazed or marginal rangeland is not charged.

Usage

build_grassland_land_extension(
  source = c("luh2", "faostat_pasture"),
  grassland_metric = c("occupation", "active_grazing"),
  usable_grass_yield_dm_t_ha = 2.06,
  data = list(),
  example = FALSE
)

Arguments

source

Grassland area source, "luh2" (default) or "faostat_pasture".

grassland_metric

Grassland land metric, "occupation" (default) or "active_grazing".

usable_grass_yield_dm_t_ha

Usable grass yield in dry-matter tonnes per hectare, used only by "active_grazing". Defaults to 2.06.

data

Optional named list of pre-loaded inputs to avoid remote reads: primary_prod (for source = "luh2"), landuse (the faostat-landuse pin, for source = "faostat_pasture") and feed_intake (for grassland_metric = "active_grazing"). Each falls back to its reader (get_primary_production(), whep_read_file(), get_feed_intake()) when absent.

example

If TRUE, return a small fixture instead of reading remote data. Defaults to FALSE.

Value

A tibble with columns year, area_code, item_cbs_code, impact_u (grassland area in hectares) and method_grassland (the chosen metric).

Examples

build_grassland_land_extension(example = TRUE)
#> # A tibble: 4 × 5
#>    year area_code item_cbs_code impact_u method_grassland
#>   <int>     <int>         <int>    <dbl> <chr>           
#> 1  1986        10          3000 25000000 occupation      
#> 2  1986       100          3000  8000000 occupation      
#> 3  1987        10          3000 25000000 occupation      
#> 4  1987       100          3000  8100000 occupation