% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/usda-wrb-crosswalk.R
\name{usda_to_wrb_rsg}
\alias{usda_to_wrb_rsg}
\title{USDA Soil Taxonomy <-> WRB Reference Soil Group correlation table}
\usage{
usda_to_wrb_rsg(usda_order, usda_suborder = NULL)
}
\arguments{
\item{usda_order}{Character vector of USDA Order names. Case-
insensitive; trailing 's' stripped (e.g.\ both "Mollisols"
and "Mollisol" accepted).}

\item{usda_suborder}{Optional character vector of USDA Suborder
names (case-insensitive) used to refine the mapping.
Same length as \code{usda_order} or recycled.}
}
\value{
Character vector of WRB Reference Soil Group names
  (singular, no plural 's'). \code{NA} for unrecognised inputs.
}
\description{
Returns the single most-common WRB RSG for a given USDA Order +
optional Suborder. Based on IUSS WRB (2022) Annex 6.
}
\section{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
\emph{expected} WRB classification from a USDA-classified pedon
(e.g.\ from KSSL/NASIS) so that \code{classify_wrb2022()} can be
validated against an external taxonomy on the same profiles.
}

\section{References}{

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

\examples{
usda_to_wrb_rsg("Mollisols")
#> "Phaeozem"
usda_to_wrb_rsg("Aridisols", "Salids")
#> "Solonchak"
usda_to_wrb_rsg(c("Spodosols", "Oxisols", "Vertisols"))
#> c("Podzol", "Ferralsol", "Vertisol")

}
