% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-conditions-usda.R
\name{cryoturbation_usda}
\alias{cryoturbation_usda}
\title{Cryoturbation (USDA Soil Taxonomy, 13th edition)}
\usage{
cryoturbation_usda(pedon)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}
}
\value{
A \code{\link{DiagnosticResult}}.
}
\description{
"Cryoturbation (frost churning) is the mixing of the soil matrix
within the pedon that results in irregular or broken horizons,
involutions, accumulation of organic matter on the permafrost
table, oriented rock fragments, and silt caps on rock fragments."
-- KST 13ed, Ch 3, p 43.
}
\details{
Diagnostic for the Turbels suborder of Gelisols.

Implementation (v0.8.x): Uses heuristics from horizon designations
and morphology data:
\itemize{
  \item Designation contains 'jj' (cryoturbation symbol) per
        KST notation;
  \item OR boundary_topography in \{"irregular", "broken",
        "involuted"\};
  \item OR coarse_fragments_pct varying non-monotonically with
        depth (proxy for "oriented rock fragments");
  \item OR designation contains 'f' (frozen) AND irregular
        boundary_distinctness.
}

Refinement to incorporate explicit \code{cryoturbation_evidence}
column is deferred to v0.9.
}
\references{
Soil Survey Staff (2022), KST 13ed, Ch. 3, p 43.
}
