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Check how much arable land the fallow split attributes to fodder crops.

Source: R/arable_permanent_land.R
check_fodder_land_share.Rd

Report, per (year, area_code), the share of the reconciled arable land extension that lands on the FAOSTAT fodder items (commodity-balance items of Cat_1 == "Fodder_green" that are not grass, i.e. 2000-2003).

With fallow_weights = NULL — the default, and the path the land-balance footprint (build_land_balance_footprint()) takes — build_fao_arable_fallow_extension() rescales every arable crop's cropped physical area proportionally up to FAO Arable land. Each crop's share of the output is therefore exactly its share of the input harvested area, so an inflated fodder harvested area is passed straight through into the published per-crop arable land footprint, taking land away from the ordinary crops (whep#356). Fodder harvested area is reconstructed rather than surveyed (dry-matter yield imputation, EU AgriDB splicing, linear filling), so it is the term most likely to be wrong, and in some country-years it alone exceeds the country's whole FAO arable land.

This is a diagnostic, not a correction: nothing is rescaled or dropped. It flags where the attribution is implausible so the fodder reconstruction can be inspected, or agro-climatic fallow_weights (see gridded_fallow_weights()) supplied instead.

Usage

check_fodder_land_share(
  extension,
  threshold = 0.5,
  items_prod_full = whep::items_prod_full
)

Arguments

extension

Tibble of the arable/permanent land extension with columns year, area_code, item_cbs_code and impact_u, as returned by build_fao_arable_fallow_extension().

threshold

Share of arable land above which a (year, area_code) is flagged (default 0.5). Fodder is real land use, so a moderate share is expected; half a country's arable land is not.

items_prod_full

Crosswalk used to classify item_cbs_code as perennial via Herb_Woody. Defaults to items_prod_full.

Value

A tibble with one row per (year, area_code) that has at least one arable row in extension, ordered by descending fodder_share:

  • year, area_code: the country-year.

  • fodder_ha: arable land attributed to fodder items.

  • arable_ha: total arable (non-perennial) land attributed.

  • fodder_share: fodder_ha / arable_ha (NA when arable_ha is zero).

  • flagged: TRUE when fodder_share > threshold.

Examples

extension <- tibble::tribble(
  ~year, ~area_code, ~item_cbs_code, ~impact_u,
  2000L, 10L, 2003L, 700, # fodder mix
  2000L, 10L, 2511L, 300 # wheat
)
check_fodder_land_share(extension)
#> # A tibble: 1 × 6
#>    year area_code fodder_ha arable_ha fodder_share flagged
#>   <int>     <int>     <dbl>     <dbl>        <dbl> <lgl>  
#> 1  2000        10       700      1000          0.7 TRUE