USDA Soil Taxonomy <-> WRB Reference Soil Group correlation table

Returns the single most-common WRB RSG for a given USDA Order + optional Suborder. Based on IUSS WRB (2022) Annex 6.

Usage

usda_to_wrb_rsg(usda_order, usda_suborder = NULL)

Arguments

usda_order: Character vector of USDA Order names. Case- insensitive; trailing 's' stripped (e.g.\ both "Mollisols" and "Mollisol" accepted).
usda_suborder: Optional character vector of USDA Suborder names (case-insensitive) used to refine the mapping. Same length as usda_order or recycled.

Value

Character vector of WRB Reference Soil Group names (singular, no plural 's'). NA for unrecognised inputs.

Caveat

This is a "best-guess" cross-walk for benchmark validation only. Real-world correlation requires per-pedon evaluation of WRB diagnostic horizons. Use this function to derive a reasonable expected WRB classification from a USDA-classified pedon (e.g.\ from KSSL/NASIS) so that classify_wrb2022() can be validated against an external taxonomy on the same profiles.

References

IUSS Working Group WRB (2022). World Reference Base for Soil Resources, 4th edition, Annex 6. International Union of Soil Sciences, Vienna.

Examples

usda_to_wrb_rsg("Mollisols")
#> [1] "Phaeozem"
#> "Phaeozem"
usda_to_wrb_rsg("Aridisols", "Salids")
#> [1] "Solonchak"
#> "Solonchak"
usda_to_wrb_rsg(c("Spodosols", "Oxisols", "Vertisols"))
#> [1] "Podzol"    "Ferralsol" "Vertisol" 
#> c("Podzol", "Ferralsol", "Vertisol")