% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-horizons-wrb.R
\name{umbric_horizon}
\alias{umbric_horizon}
\title{Umbric horizon (WRB 2022)}
\usage{
umbric_horizon(
  pedon,
  min_thickness = 20,
  min_oc = 0.6,
  max_bs = 50,
  surface_top_cm = 5
)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}

\item{min_thickness}{Minimum thickness (cm; default 20).}

\item{min_oc}{Minimum SOC \% (default 0.6).}

\item{max_bs}{Maximum base saturation \% (default 50; profile must
be BELOW this).}

\item{surface_top_cm}{Maximum top_cm for surface-related layers
(default 5).}
}
\value{
A \code{\link{DiagnosticResult}}.
}
\description{
Tests for the umbric horizon -- a thick, dark, organic-rich surface
horizon like mollic, but with low base saturation (< 50\%).
Diagnostic of Umbrisols.
}
\details{
Implementation reuses every mollic sub-test except the BS test,
which is inverted via \code{\link{test_bs_below}}.
}
\references{
IUSS Working Group WRB (2022), Chapter 3, Umbric horizon.
}
