% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-epipedons-usda.R
\name{mollic_epipedon_usda}
\alias{mollic_epipedon_usda}
\title{Mollic epipedon (USDA Soil Taxonomy, 13th edition)}
\usage{
mollic_epipedon_usda(pedon, min_bs = 50, min_oc_pct = 0.6)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}

\item{min_bs}{Default 50 percent.}

\item{min_oc_pct}{Default 0.6 percent.}
}
\value{
A \code{\link{DiagnosticResult}}.
}
\description{
A thick, dark-colored, base-rich mineral surface horizon. The
principal diagnostic horizon of the Mollisols order; also
qualifies many subgroups of other orders as "Mollic" or
"Pachic".
}
\details{
KST 13ed required characteristics (Ch. 3, pp 15-17):
\itemize{
  \item Color: dominant color value <= 3 (moist) AND <= 5 (dry)
        AND chroma <= 3 (moist), with adjustments for CaCO3
        content (deferred to v0.9);
  \item Base saturation (NH4OAc, pH 7) >= 50 percent throughout;
  \item Organic carbon >= 0.6 percent (or 2.5 percent if value
        is 4-5 moist; or 0.6 absolute > C horizon);
  \item Thickness: 18 cm general, 25 cm if texture is loamy fine
        sand or coarser, 10 cm if directly above lithic/densic/
        paralithic contact (\code{thin_lithic_overlay} branch);
  \item Structure: peds <= 30 cm OR rupture-resistance <=
        moderately hard;
  \item Some part moist 90+ days when soil temp at 50 cm is
        >= 5 C (deferred -- requires climatic data).
}

Implementation notes (v0.8.x):
\itemize{
  \item Thickness rule is computed dynamically based on texture
        and presence of underlying lithic/paralithic contact.
  \item N value < 0.7 / fluidity nonfluid is assumed (laboratory
        tests rarely available);
  \item 90-day moisture condition is deferred to v0.9.
}
}
\references{
Soil Survey Staff (2022), KST 13ed, Ch. 3, pp 15-17.
}
