% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-horizons-usda.R
\name{argillic_usda}
\alias{argillic_usda}
\title{Argillic horizon (USDA Soil Taxonomy)}
\usage{
argillic_usda(pedon, ...)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}

\item{...}{Passed to \code{\link{argic}}.}
}
\value{
A \code{\link{DiagnosticResult}}.
}
\description{
v0.2 scaffold delegating to WRB \code{\link{argic}}. The two
diagnostics' clay-increase rules are essentially the same; USDA
argillic additionally requires evidence of clay illuviation (clay
films / clay bridges) on at least 1\% of the surface area, which
v0.8 will enforce against the \code{clay_films_amount} column.
}
\references{
Soil Survey Staff (2014), Keys to Soil Taxonomy,
  Ch. 3 -- argillic horizon.
}
