Build agro-climatic, rainfed-gated fallow allocation weights.

Compute a per-(area, item) weight for distributing reported fallow to crops, from gridded crop placement and a crop x agro-climatic-zone propensity. For each grid cell, rainfed crop area is multiplied by the crop's propensity in the cell's agro-climatic zone (derived from GAEZ length of growing period and thermal climate), then summed to country x item. Dryland cereals/pulses score high in arid/semi-arid zones, rainfed rice high in the humid tropics (rice-fallow); perennials and the irrigated share score ~zero.

Usage

gridded_fallow_weights(gridded_crops, grid_aez = NULL, propensity = NULL)

Arguments

gridded_crops

Tibble keyed by grid cell and item_cbs_code with columns lon, lat, area_code, rainfed_ha.

grid_aez

Tibble of lon, lat, lgp (length of growing period in days), thermal (GAEZ thermal-climate class). If NULL, the packaged grid_aez.csv is used.

propensity

Tibble of item_cbs_code, zone, fallow_propensity. If NULL, the packaged fallow_propensity.csv is used.

Value

A tibble with area_code, item_cbs_code, weight.

Examples

gridded_crops <- tibble::tribble(
  ~lon, ~lat, ~area_code, ~item_cbs_code, ~rainfed_ha,
  0.25, 50.25, 1L, 2511L, 500
)
grid_aez <- tibble::tribble(~lon, ~lat, ~lgp, ~thermal, 0.25, 50.25, 100, 7L)
propensity <- tibble::tribble(
  ~item_cbs_code, ~zone, ~fallow_propensity,
  2511L, "semiarid", 0.8
)
gridded_fallow_weights(gridded_crops, grid_aez, propensity)
#> # A tibble: 1 × 3
#>   area_code item_cbs_code weight
#>       <int>         <int>  <dbl>
#> 1         1          2511    400