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Estimate ammonia-N volatilisation with the MANNER process-based model.

Source: R/manner_model.R
calculate_manner_nh3.Rd

Ports the MANNER (Nicholson et al. 2013) process-based ammonia volatilisation model. Dispatches on fertiliser to one of two independent paths: a synthetic-fertiliser path ("Urea", "AN", "CAN", "AS") driven by soil pH, application rate, rainfall and temperature, and an organic-manure path ("cattle_slurry", "pig_slurry", "FYM", "poultry_manure", "urban") driven by rainfall, temperature, wind speed, application technique, system (arable/grassland) and incorporation delay.

Usage

calculate_manner_nh3(
  n_applied_t = NULL,
  fertiliser = NULL,
  drivers = list(),
  example = FALSE
)

Arguments

n_applied_t

Numeric, nitrogen applied (t).

fertiliser

One of "Urea", "AN", "CAN", "AS" (synthetic path) or "cattle_slurry", "pig_slurry", "FYM", "poultry_manure", "urban" (organic path).

drivers

A named list of driver values. Synthetic path: soil_ph (numeric soil pH), rate_kg_ha (numeric N application rate, kg N/ha), rainfall_mm (numeric period precipitation, mm), irrigated (logical), temp_c (numeric application-period temperature, deg C), temp_c_annual_mean (numeric annual mean temperature, deg C; only used for CAN/AS). Organic path: rainfall_mm, irrigated, windspeed_ms (numeric wind speed, m/s), technique (one of the six manner_params technique keys), system ("Arable" or "Grassland"), temp_c, incorporation_delay_h (numeric hours between surface application and soil incorporation, or Inf/NA for no incorporation), species (optional; one of the eight manure_inorganic_n species, used only to look up inorganic_n_fraction; when omitted it falls back to the manure type's default species, and it is ignored entirely for "urban").

example

If TRUE, return a small fixture instead of computing from drivers. Defaults to FALSE.

Value

A tibble with n_applied_t, ef (realised emission factor), nh3_n_t and method_manner.

Details

The organic path's inorganic_n_fraction lookup (manure_inorganic_n) maps manure_type to its ammoniacal manure_stream ("Liquid" for "cattle_slurry"/"pig_slurry", "Solid" for "FYM"/ "poultry_manure") and reads that stream's fraction for the actual species driver supplied by the caller. This matches Spain_Hist, which maps every species' solid stream to the FYM MANNER class yet looks the inorganic-N fraction up per real species. When species is omitted it falls back to the manure type's default species (Cattle for "cattle_slurry"/"FYM", Pigs for "pig_slurry", Poultry for "poultry_manure"). "urban" bypasses this lookup entirely: it fixes inorganic_n_fraction = 0.5 regardless of species, matching nh3.r:102-104. For the AG availability and incorporation factors, "urban" maps to the FYM manure class (Spain_Hist Manner_ferts row 43), including the 0.4 Org_ef correction.

Examples

calculate_manner_nh3(example = TRUE)
#> # A tibble: 1 × 4
#>   n_applied_t     ef nh3_n_t method_manner        
#>         <dbl>  <dbl>   <dbl> <chr>                
#> 1          10 0.0333   0.333 manner_synthetic_Urea