% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/qualifiers-wrb2022-v0963.R
\name{qual_gibbsic}
\alias{qual_gibbsic}
\title{Gibbsic qualifier (gi): high gibbsite (>= 25\%) in fine earth}
\usage{
qual_gibbsic(pedon)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}
}
\description{
WRB 2022 Ch 5 (Plinthosols / Ferralsols): "Containing layers with
>= 25\% gibbsite by mass averaged over a depth of 100 cm".
}
\details{
soilKey schema does not currently carry direct gibbsite percent.
The closest proxy is \code{al_ox_pct} (oxalate-extractable Al, \%),
but gibbsite is poorly extracted by oxalate. The sulfuric attack
\code{al2o3_sulfuric_pct} captures crystalline Al-oxides (gibbsite
+ boehmite + diaspore + Al-substitution in goethite). This
implementation uses Al2O3 by sulfuric attack >= 25\% as a proxy
(slight over-estimate, since not all crystalline Al is gibbsite).
}
