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Decompose cropland N surplus into size, intensity, and inefficiency drivers

Source: R/decomposition_analysis.R
decompose_cropland_surplus.Rd

Decomposes the year-on-year change in Spain's cropland nitrogen (N) surplus into three multiplicative drivers, following an additive LMDI (logarithmic mean Divisia index) shift-share decomposition computed at the national level:

  • Size: national cropland area.

  • Intensity: N input per hectare of cropland.

  • Inefficiency: surplus fraction of inputs (1 - nitrogen use efficiency).

Contributions are additive and residual-free: they sum exactly to the observed change in cropland N surplus for every year-on-year transition.

This is a simplified, national-only view (no provincial or destiny breakdown); decompose_specialization_cov() still uses the full province x destiny detail for its cropland_province and cropland_destiny series.

Usage

decompose_cropland_surplus(
  n_prov_destiny = NULL,
  npp_ygpit = NULL,
  codes_coefs = NULL,
  by_period = FALSE,
  example = FALSE
)

Arguments

n_prov_destiny

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

npp_ygpit

Land use and area tibble from whep_read_file("npp_ygpit"). If NULL, loaded automatically.

codes_coefs

Item and biomass coefficients tibble from whep_read_file("codes_coefs"). 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_cropland_surplus(example = TRUE)
#> # A tibble: 8 × 7
#>   period    period_years factor_label     component_type additive multiplicative
#>   <chr>            <dbl> <chr>            <chr>             <dbl>          <dbl>
#> 1 1860-1861            1 Size             factor            1004.          1.01 
#> 2 1860-1861            1 Intensity        factor            -171.          0.999
#> 3 1860-1861            1 Inefficiency     factor          -17200.          0.897
#> 4 1860-1861            1 Cropland N surp… target          -16367.          0.902
#> 5 1861-1862            1 Size             factor            1082.          1.01 
#> 6 1861-1862            1 Intensity        factor           13085.          1.08 
#> 7 1861-1862            1 Inefficiency     factor           32979.          1.21 
#> 8 1861-1862            1 Cropland N surp… target           47146           1.31 
#> # ℹ 1 more variable: multiplicative_log <dbl>