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Spill surplus manure to neighbouring cells with spare capacity.

Source: R/manure_transport.R
allocate_manure_transport.Rd

Moves the manure nitrogen that a cell could not place locally (its surplus above the local cropland and grassland caps) to nearby same-polity cells that still have room, on the 0.5-degree grid. Each source offers its surplus to its single-ring (king-move) neighbours in proportion to their remaining room; a sink that is over-subscribed by several sources is filled only to its room and the rejected manure returns to the sources as residual. This is the resolution-robust, mass-conserving analogue of Spain's room-weighted first-ring redistribution (Calc_OA_redistribution); cross-polity transport is not allowed. Carbon and volatile solids ride along with each nitrogen flow at the source cell's bundle ratio.

Usage

allocate_manure_transport(source_cells, sink_cells, options = list())

Arguments

source_cells

A tibble of cells exporting manure, keyed by year, territory and sub_territory (a "lon_lat" cell id), with surplus_n, surplus_c and surplus_vs (t).

sink_cells

A tibble of cells with spare capacity, keyed by year, territory and sub_territory, with room_n (remaining cropland plus grassland N capacity, t).

options

A named list. n_rings (default 1) is the neighbourhood radius in grid steps; only the single-ring kernel is shipped.

Value

A tibble with one row per landing site: year, territory, sub_territory (the sink cell for transported manure, the source cell for residual), applied_n, applied_c, applied_vs, kind ("transported" or "residual") and method_transport. The "residual" rows are the un-transportable surplus handed back for local disposal.

Examples

source_cells <- tibble::tribble(
  ~year, ~territory, ~sub_territory, ~surplus_n, ~surplus_c, ~surplus_vs,
  2020L, "ESP", "1.5_40", 10, 90, 6
)
sink_cells <- tibble::tribble(
  ~year, ~territory, ~sub_territory, ~room_n,
  2020L, "ESP", "1_40", 4,
  2020L, "ESP", "2_40", 6
)
allocate_manure_transport(source_cells, sink_cells)
#> # A tibble: 2 × 8
#>    year territory sub_territory applied_n applied_c applied_vs kind       
#>   <int> <chr>     <chr>             <dbl>     <dbl>      <dbl> <chr>      
#> 1  2020 ESP       1_40                  4        36        2.4 transported
#> 2  2020 ESP       2_40                  6        54        3.6 transported
#> # ℹ 1 more variable: method_transport <chr>