% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-spodosols-usda.R
\name{fragipan_usda}
\alias{fragipan_usda}
\title{Fragipan (USDA, KST 13ed Ch 3, p 38)}
\usage{
fragipan_usda(pedon, max_top_cm = 100)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}

\item{max_top_cm}{Default 100.}
}
\value{
A \code{\link{DiagnosticResult}}.
}
\description{
Pass when a horizon has fragic soil properties:
\itemize{
  \item rupture_resistance class >= "firm" (firm, very firm,
        extremely firm); OR
  \item NASIS pediagfeatures has a "Fragipan" entry (v0.9.31:
        the surveyor's field-identified fragipan -- direct evidence,
        used as a tie-breaker when rupture_resistance is missing
        from the lab data); AND
  \item thickness >= 15 cm.
}
KSSL pedons rarely carry rupture_resistance; NASIS pediagfeatures
carries 13 500 entries including "Fragipan" tags from surveyors.
v0.9.31 adds the NASIS path so fragipan can be detected on KSSL+
NASIS pedons (closing the Fragiudults / Fragiudalfs / Fragiaqualfs
confusion documented in the v0.9.25 Great Group analysis).
}
