Apply the NFert balance to every plot of a farm

Reads a vector layer (GeoJSON, Shapefile, GeoPackage, or an in-memory sf object) in which each feature is an agronomic plot, runs N_balance on every feature using the attributes as arguments, and returns an enriched sf object with the field-scale target N* (N_target, kg N ha\(^{-1}\)), the crop- specific MAS cap, a compliance flag and the total N (kg) required by each plot (N_total_kg = N_target * area_ha). The enriched layer can be written back to disk as GeoJSON or any other OGR format.

Usage

farm_balance(
  x,
  p_balance = FALSE,
  k_balance = FALSE,
  output = NULL,
  quiet = TRUE
)

Arguments

x: Either a path to a file readable by st_read (GeoJSON, Shapefile, GeoPackage, ...) or a pre-loaded sf object.
p_balance: Logical. If TRUE also run P_balance per plot, using the columns olsen_value (ppm) and olsen_unit (default "P2O5"). Adds P2O5_target and P2O5_total_kg.
k_balance: Logical. Same for K_balance, with columns k_value (ppm) and k_unit (default "K2O").
output: Optional path where to write the enriched layer (the extension determines the driver used by st_write; .geojson is a common choice).
quiet: Logical, passed to st_read and st_write.

Value

The enriched sf object. If output is given, the file is also written to disk (existing files are overwritten).

Expected attribute columns

Every feature must carry at least:

Column	Example	Notes
`crop`	"Mais da insilato (classe 700)"	DPI 2026 name
`expected_yield_tons_ha`	60	target yield
`ccp`	"Spring-summer crop 100-130 days"	climate period
`sand`, `clay`	50, 35	pct of texture
`Ntot`, `SOM`, `CN`	1.2, 1.2, 9.5	soil analysis
`oxygen_availability`	"Normal" / "Low" / "High"
`winter_rain`, `start_spring_rain`	160, 40	mm
`prev_crop`	"Winter cereals straw removal"
`source`	"Cattle slurry" or "None"/NA	organic source
`fertorg_frequency`	"every year"
`location`	"Plain adjacent to urbanized areas"
`forg_quantity`	100	kg N ha\(^{-1}\) from organic
`area_ha`	5.2	used to derive `N_total_kg`

Italian aliases (Frumento tenero, Liquame bovino, Cereali vernini - paglia asportata, ...) are accepted because the underlying NFert functions carry the translation layer.

Output columns added to the layer

N_target: Net mineral N to apply (kg N ha\(^{-1}\)).
MAS_cap: Crop-specific maximum allowed dose.
MAS_ok: Logical - N_target <= MAS_cap.
N_total_kg: N_target * area_ha (kg N for the plot).
balance_error: NA on success, error message otherwise (rows that fail are not dropped).

Examples

if (FALSE) { # \dontrun{
ex <- system.file("extdata/example_farm.geojson", package = "NFert")
farm <- farm_balance(ex)
print(farm[, c("plot_id", "crop", "area_ha",
                "N_target", "MAS_cap", "N_total_kg")])

# Write the enriched layer for GIS use:
farm_balance(ex, output = "my_farm_with_Ntargets.geojson")
} # }