% Generated by roxygen2: do not edit by hand
% Please edit documentation in R/diagnostics-conditions-usda.R
\name{aquic_conditions_usda}
\alias{aquic_conditions_usda}
\title{Aquic conditions (USDA Soil Taxonomy, 13th edition)}
\usage{
aquic_conditions_usda(
  pedon,
  max_top_cm = 100,
  min_redox_pct = 5,
  max_chroma = 2
)
}
\arguments{
\item{pedon}{A \code{\link{PedonRecord}}.}

\item{max_top_cm}{Maximum depth at which saturation must occur
(default 100 -- typical for Suborder keys; 200 for some).}

\item{min_redox_pct}{Threshold for redoximorphic features
(default 5 percent).}

\item{max_chroma}{Maximum chroma indicating reduction
(default 2).}
}
\value{
A \code{\link{DiagnosticResult}} with
        \code{evidence$saturation_type} = "endo" / "epi" / NA.
}
\description{
"Soils with aquic conditions are those that currently undergo
continuous or periodic saturation and reduction. The presence of
these conditions is indicated by redoximorphic features, except
in Histosols and Histels."  -- KST 13ed, Ch 3, p 41.
}
\details{
Three types of saturation are defined:
\itemize{
  \item \strong{Endosaturation}: saturated in all layers from the
        upper boundary of saturation to >=200 cm.
  \item \strong{Episaturation}: saturated in one or more layers
        within 200 cm with unsaturated layer(s) below.
  \item \strong{Anthric saturation}: cultivated/flood-irrigated.
}

Implementation (v0.8.x):
\itemize{
  \item Saturation is inferred from the presence of redoximorphic
        features (\code{redoximorphic_features_pct >= 5}) and/or a
        glei horizon (designation containing 'g').
  \item Reduction is inferred when chroma <= 2 in the matrix.
  \item Artificial drainage is treated as positive aquic when
        \code{site$artificially_drained == TRUE} (deferred -- not
        in current schema).
}
}
\references{
Soil Survey Staff (2022), KST 13ed, Ch. 3, pp 41-44.
}
