diff --git a/.gitignore b/.gitignore
index 0d7f03b..265807e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -4,3 +4,4 @@
 .Ruserdata
 docs
 inst/doc
+FIHS.pdf
diff --git a/DESCRIPTION b/DESCRIPTION
index afd94f6..9ec7cd7 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -1,7 +1,7 @@
 Package: hydricsoils
 Type: Package
 Title: Tools for 'Field Indicators of Hydric Soils in the United States' 
-Version: 0.1.1
+Version: 0.1.2
 Author: Andrew G. Brown
 Maintainer: Andrew G. Brown <brown.andrewg@gmail.com>
 Description: The goal of 'hydricsoils' is to provide easy access to definitions, criteria, and area of applicability for 'Field Indicators of Hydric Soils in the United States' and also to provide tools which assist in evaluating associated soil morphology.
@@ -10,7 +10,7 @@ Encoding: UTF-8
 LazyData: false
 Depends: R (>= 4.0.0)
 Roxygen: list(markdown = TRUE)
-RoxygenNote: 7.3.1
+RoxygenNote: 7.3.2
 URL: https://github.com/brownag/hydricsoils/, https://humus.rocks/hydricsoils/
 BugReports: https://github.com/brownag/hydricsoils/issues/
 Imports: 
diff --git a/FIHS.pdf b/FIHS.pdf
deleted file mode 100644
index bdb9d8d..0000000
Binary files a/FIHS.pdf and /dev/null differ
diff --git a/NAMESPACE b/NAMESPACE
index a923e5c..e84df86 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -3,11 +3,13 @@
 export(cache_lrrmlra_geometry)
 export(clear_lrrmlra_geometry)
 export(fihs_match)
+export(hydricsoils_data_dir)
 export(indicator_to_name)
 export(indicator_to_usesym)
 export(lrr_to_lrrname)
 export(lrr_to_mlra)
 export(lrrmlra_geometry)
+export(lrrmlra_geometry_dsn)
 export(lrrmlra_match)
 export(lrrname_to_lrr)
 export(mlra_to_lrr)
diff --git a/NEWS.md b/NEWS.md
index 6f4f5cb..84056e2 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,3 +1,17 @@
+# Changes in version 0.1.2
+
+## Improvements
+
+ - Update `fihs` dataset for Field Indicators of Hydric Soils v9.0
+ 
+   - Adds new "All Soils" indicator: "A18" _Iron Monosulfide_
+
+ - Updated `lrrmlra` geometry source URL
+
+## Additions
+ 
+ - Added `lrrmlra_geometry_dsn()` and `hydricsoils_data_dir()` functions for getting data sources and paths
+ 
 # Changes in version 0.1.1
 
 ## Improvements
diff --git a/R/cache_lrrmlra_geometry.R b/R/cache_lrrmlra_geometry.R
index d8757c0..46306fc 100644
--- a/R/cache_lrrmlra_geometry.R
+++ b/R/cache_lrrmlra_geometry.R
@@ -29,17 +29,16 @@
 #' }
 #'
 cache_lrrmlra_geometry <- function(overwrite = FALSE,
-                                   dsn = "/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022") {
+                                   dsn = lrrmlra_geometry_dsn()) {
 
   if (is.null(dsn)) {
-    dsn <- "/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022"
+    dsn <- lrrmlra_geometry_dsn()
   }
 
-  fp <- file.path(tools::R_user_dir("hydricsoils", which = "data"),
-                  "lrrmlra.gpkg")
+  fp <- file.path(hydricsoils_data_dir(), "lrrmlra.gpkg")
 
   if (!requireNamespace("terra")) {
-    stop("package 'terra' is required to cache the LRR/MLRA spatial dataset")
+    stop("package 'terra' is required to create local MLRA Geographic Database cache")
   }
 
   if (!dir.exists(dirname(fp))) {
@@ -58,21 +57,29 @@ cache_lrrmlra_geometry <- function(overwrite = FALSE,
 #' @rdname lrrmlra-geometry
 #' @return `clear_lrrmlra_geometry()`: logical. Called for the side-effect of removing the MLRA geometry file from the cache. Returns `TRUE` if `"lrrmlra.gpkg"` is successfully removed from user data cache.
 clear_lrrmlra_geometry <- function() {
-  invisible(file.remove(file.path(
-    tools::R_user_dir("hydricsoils", which = "data"),
-    "lrrmlra.gpkg"
-  )))
+  invisible(
+    file.remove(
+      file.path(hydricsoils_data_dir(), "lrrmlra.gpkg")
+    )
+  )
 }
 
 #' @export
 #' @rdname lrrmlra-geometry
 #' @return `lrrmlra_geometry()`: A terra _SpatVector_ object containing `lrrmlra` attributes and geometry.
 lrrmlra_geometry <- function(overwrite = FALSE,
-                             dsn = "/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022") {
+                             dsn = lrrmlra_geometry_dsn()) {
   if (cache_lrrmlra_geometry(overwrite = overwrite, dsn = dsn)) {
-    return(terra::vect(file.path(
-      tools::R_user_dir("hydricsoils", which = "data"),
-      "lrrmlra.gpkg"
-    )))
+    return(terra::vect(
+      file.path(hydricsoils_data_dir(), "lrrmlra.gpkg")
+    ))
   }
 }
+
+#' @export
+#' @rdname lrrmlra-geometry
+#' @return `lrrmlra_geometry_dsn()`: character. Path to MLRA Geographic Database source.
+lrrmlra_geometry_dsn <- function() {
+  # "https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022"
+  "/vsizip//vsicurl/https://s3-fpac-nrcs-dshub-public.s3.us-gov-west-1.amazonaws.com/MLRA_52_2022.zip"
+}
diff --git a/R/hydricsoils-package.R b/R/hydricsoils-package.R
index a65cf64..7400243 100644
--- a/R/hydricsoils-package.R
+++ b/R/hydricsoils-package.R
@@ -4,3 +4,4 @@
 ## usethis namespace: start
 ## usethis namespace: end
 NULL
+
diff --git a/R/hydricsoils.R b/R/hydricsoils.R
index 4c8ab57..4096399 100644
--- a/R/hydricsoils.R
+++ b/R/hydricsoils.R
@@ -15,3 +15,15 @@
 #' @keywords datasets
 #' @references United States Department of Agriculture, Natural Resources Conservation Service. 2022. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture, Agriculture Handbook 296. Available online: <https://www.nrcs.usda.gov/resources/data-and-reports/major-land-resource-area-mlra>
 "lrrmlra"
+
+#' hydricsoils Data Directory
+#' @returns `hydricsoils_data_dir()`: character. Path to hydricsoil package user
+#'   data directory. Default: `tools::R_user_dir("hydricsoils", which = "data")`
+#' @export
+#' @examples
+#'
+#' hydricsoils_data_dir()
+#'
+hydricsoils_data_dir <- function() {
+  tools::R_user_dir("hydricsoils", which = "data")
+}
diff --git a/data-raw/fihs.R b/data-raw/fihs.R
index 0f1d601..87409ba 100644
--- a/data-raw/fihs.R
+++ b/data-raw/fihs.R
@@ -1,5 +1,5 @@
 ## code to prepare `fihs` dataset goes here
-# download.file("https://www.nrcs.usda.gov/sites/default/files/2022-09/Field_Indicators_of_Hydric_Soils.pdf",
+# download.file("https://www.nrcs.usda.gov/sites/default/files/2024-09/Field-Indicators-of-Hydric-Soils.pdf",
 #               destfile = "FIHS.pdf", mode = "wb")
 # system("pdftotext -raw -nodiag FIHS.pdf FIHS.txt")
 
@@ -7,10 +7,16 @@
 x <- readLines("inst/extdata/FIHS.txt", warn = FALSE)
 f <- readLines("inst/extdata/FIGS.txt", warn = FALSE)
 
+# clean FIGS
+cat(trimws(strsplit(paste0(f, collapse = " "), "—")[[1]]), file = "inst/extdata/FIGS.txt", sep = "\n")
+
+f <- readLines("inst/extdata/FIGS.txt", warn = FALSE)
+
+
 ## metadata, added as attributes
-VERSION <- "8.2"
-VERSION_YEAR <- "2018"
-REFERENCE <- "United States Department of Agriculture, Natural Resources Conservation Service. 2018. Field Indicators of Hydric Soils in the United States, Version 8.2. L.M. Vasilas, G.W. Hurt, and J.F. Berkowitz (eds.). USDA, NRCS, in cooperation with the National Technical Committee for Hydric Soils. Available online: <https://www.nrcs.usda.gov/resources/guides-and-instructions/field-indicators-of-hydric-soils>"
+VERSION <- "9.0"
+VERSION_YEAR <- "2024"
+REFERENCE <- "United States Department of Agriculture, Natural Resources Conservation Service. 2024. Field Indicators of Hydric Soils in the United States, Version 9.0. Available online: <https://www.nrcs.usda.gov/resources/guides-and-instructions/field-indicators-of-hydric-soils>"
 
 #
 ##
@@ -22,7 +28,8 @@ REFERENCE <- "United States Department of Agriculture, Natural Resources Conserv
 ##
 ## somehow rebuild suitable text vector from `fd` ...
 ##
-idx <- grep("^All Soils$|^Sandy Soils$|^Loamy and Clayey Soils$|Test Indicators of Hydric Soils$|^\\f\\fAccessibility Statement$", x)
+idx <- grep("^Introduction$|^All Soils$|^Sandy Soils$|^Loamy and Clayey Soils$|Test Indicators of Hydric Soils$|^References$", x)
+idx <- idx[4:8]
 x <- gsub("(for use in all LRRs) or Histel (for", "or Histel. ", x, fixed = TRUE)
 x <- gsub("use in LRRs with permafrost). ", "", x, fixed = TRUE)
 x <- gsub("from12 to18 percent", "from 12 to 18 percent", x)
@@ -34,16 +41,18 @@ x[grep("A1.\u2014", x) + 1]
 sec.idx <- c(idx - 1, length(x))
 sec.len <- diff(c(0, sec.idx))
 sec.lbl <- c("Field Indicators of Hydric Soils",
+             "Front Matter",
              "All Soils", "Sandy Soils", "Loamy and Clayey Soils",
-             "Test Indicators", "All Soils (Test)", "Sandy Soils (Test)",
-             "Loamy and Clayey Soils (Test)", "End Matter")
+             # "Test Indicators",
+             # "All Soils (Test)", "Sandy Soils (Test)", "Loamy and Clayey Soils (Test)",
+             "End Matter")
 page.idx <- grep("^\\f+", x)
 page.len <- diff(c(0, page.idx))
 page.num <- gsub("^\\f+([0-9iv]+).*(Hydric Soils|Field Indicators of)?", "\\1", x[page.idx])
 page.idx <- page.idx - 1
 page.num[1] <- "i"
-page.num[49] <- page.num[48]
-page.num[48] <- "46"
+page.num[40] <- "36"
+page.num[55] <- "52"
 page.num <- gsub("\\f", "", page.num)
 
 # break out page numbers and sections for each line of content
@@ -219,10 +228,12 @@ fihs <- fihs[c("section", "indicator", "indicator_name", "page",
 
 if (interactive())
   View(fihs)
-
+fihs <- fihs[-1,]
+rownames(fihs) <- NULL
 attr(fihs, 'version') <- VERSION
 attr(fihs, 'version_year') <- VERSION_YEAR
 attr(fihs, 'reference') <- REFERENCE
+fihs90 <- fihs
 usethis::use_data(fihs, overwrite = TRUE)
 
 ## TODO: fihs_test dataset; need to confirm where they are being tested
diff --git a/data-raw/fihs_v8.2.R b/data-raw/fihs_v8.2.R
new file mode 100644
index 0000000..0f1d601
--- /dev/null
+++ b/data-raw/fihs_v8.2.R
@@ -0,0 +1,230 @@
+## code to prepare `fihs` dataset goes here
+# download.file("https://www.nrcs.usda.gov/sites/default/files/2022-09/Field_Indicators_of_Hydric_Soils.pdf",
+#               destfile = "FIHS.pdf", mode = "wb")
+# system("pdftotext -raw -nodiag FIHS.pdf FIHS.txt")
+
+# # remove figure captions manually
+x <- readLines("inst/extdata/FIHS.txt", warn = FALSE)
+f <- readLines("inst/extdata/FIGS.txt", warn = FALSE)
+
+## metadata, added as attributes
+VERSION <- "8.2"
+VERSION_YEAR <- "2018"
+REFERENCE <- "United States Department of Agriculture, Natural Resources Conservation Service. 2018. Field Indicators of Hydric Soils in the United States, Version 8.2. L.M. Vasilas, G.W. Hurt, and J.F. Berkowitz (eds.). USDA, NRCS, in cooperation with the National Technical Committee for Hydric Soils. Available online: <https://www.nrcs.usda.gov/resources/guides-and-instructions/field-indicators-of-hydric-soils>"
+
+#
+##
+## something like this might be able to automate:
+##
+# fd <- pdftools::pdf_data("FIHS.pdf", font_info = TRUE)
+# fd <- do.call('rbind', fd)
+# fd <- subset(fd, !(font_name == "Helvetica-Bold" & font_size == 8))
+##
+## somehow rebuild suitable text vector from `fd` ...
+##
+idx <- grep("^All Soils$|^Sandy Soils$|^Loamy and Clayey Soils$|Test Indicators of Hydric Soils$|^\\f\\fAccessibility Statement$", x)
+x <- gsub("(for use in all LRRs) or Histel (for", "or Histel. ", x, fixed = TRUE)
+x <- gsub("use in LRRs with permafrost). ", "", x, fixed = TRUE)
+x <- gsub("from12 to18 percent", "from 12 to 18 percent", x)
+x <- gsub("dune-and- swale", "dune-and-swale", x)
+x <- gsub("T, U, W, X, Y , and Z", "T, U, W, X, Y, and Z", x)
+x <- gsub("\\b([a-f])\\. ", "(\\1) ", x)
+x <- gsub("fig(s*)\\.", "Figure\\1", x)
+x[grep("A1.\u2014", x) + 1]
+sec.idx <- c(idx - 1, length(x))
+sec.len <- diff(c(0, sec.idx))
+sec.lbl <- c("Field Indicators of Hydric Soils",
+             "All Soils", "Sandy Soils", "Loamy and Clayey Soils",
+             "Test Indicators", "All Soils (Test)", "Sandy Soils (Test)",
+             "Loamy and Clayey Soils (Test)", "End Matter")
+page.idx <- grep("^\\f+", x)
+page.len <- diff(c(0, page.idx))
+page.num <- gsub("^\\f+([0-9iv]+).*(Hydric Soils|Field Indicators of)?", "\\1", x[page.idx])
+page.idx <- page.idx - 1
+page.num[1] <- "i"
+page.num[49] <- page.num[48]
+page.num[48] <- "46"
+page.num <- gsub("\\f", "", page.num)
+
+# break out page numbers and sections for each line of content
+d <- data.frame(
+  row = seq(length(x)),
+  page = unlist(sapply(seq(page.num), function(i) {
+    rep(page.num[i], page.len[i])
+  })),
+  section = unlist(sapply(seq(sec.lbl), function(i) {
+    rep(sec.lbl[i], sec.len[i])
+  })),
+  content = x
+)
+
+# remove page numbers, headers, form feed
+p.idx.keep <- grep("^\\f+([0-9iv]+).*(Hydric Soils|Field Indicators of)?", x, invert = TRUE)
+d <- d[p.idx.keep,]
+
+d2 <- split(d, factor(d$section, levels = unique(d$section)))
+
+
+parseIndicator <- function(x) {
+  un.idx <- grep("^User Notes:", x$content)[1]
+  if (!is.na(un.idx)) {
+    bi <- 1:(un.idx - 1)
+    un <- un.idx:length(x$content)
+  } else {
+    bi <- seq(x$content)
+    un <- 0
+  }
+  res <- cbind(x[1, c("section", "indicator")], data.frame(
+    body = I(list(trimws(strsplit(paste0(x$content[bi], collapse = " "), "\\. ")[[1]]))),
+    note = I(list(trimws(paste0(x$content[un], collapse = " ")))),
+    indicator = x$indicator[1],
+    indicator_name = gsub("(.*)\\. For use in.*", "\\1", x$indicator_name[1]),
+    page = x$page[1]
+  ))
+  rownames(res) <- NULL
+  res
+}
+
+dout <- do.call('rbind', lapply(d2, function(dd) {
+  ind.idx <- grep("([ASFT]+\\d+).\u2014([0-9A-Za-z \\.]*)\\. ", dd$content)
+  indicators <- do.call('rbind', strsplit(gsub("([ASFT]+\\d+).\u2014([\\(\\)0-9A-Za-z \\.]*)\\. .*", "\\1;\\2;",
+                                               dd$content[ind.idx]), ";"))
+  ind.len <- diff(c(0, c(ind.idx - 1, length(dd$content))))
+  ind.lbl <- c(dd$section[1], indicators[, 1])
+  ind.nam <- c(dd$section[1], indicators[, 2])
+
+  dd$content[ind.idx] <- gsub("[ASFT]+\\d+.\u2014[\\(\\)0-9A-Za-z \\.]*\\. (.*)", "\\1", dd$content[ind.idx])
+  dd$indicator <- unlist(sapply(seq(ind.lbl), function(i) {
+    rep(ind.lbl[i], ind.len[i])
+  }))
+  dd$indicator_name <- unlist(sapply(seq(ind.nam), function(i) {
+    rep(ind.nam[i], ind.len[i])
+  }))
+
+  d3 <- split(dd, factor(dd$indicator, levels = unique(dd$indicator)))
+  d4 <- lapply(d3, parseIndicator)
+  d5 <- do.call('rbind', d4)
+  d5
+}))
+rownames(dout) <- NULL
+
+dout$usage <- sapply(dout$body, \(z) ifelse(grepl("^For use (in|along)", z[[1]]), z[[1]], ""))
+dout$criteria <- sapply(dout$body, \(z) na.omit(z[2:length(z)]))
+
+# fix for F21 (misuse of semicolons)
+dout$usage <- gsub("For use in MLRA 127 of LRR N; MLRA 145 of LRR R; and MLRAs 147 and 148 of LRR S;", "For use in MLRA 127 of LRR N, MLRA 145 of LRR R, and MLRAs 147 and 148 of LRR S;", dout$usage)
+
+dout$usage <- gsub("[^;]( for testing in)", ";\\1", dout$usage)
+dout$usage[dout$usage == ""] <- "For use in all LRRs"
+dout$usage_symbols <- gsub("For use[^;]*in LRRs* ([^;]*);*.*$", "\\1", dout$usage)
+dout$usage_symbols <- gsub(",* and ([A-Z])", ", \\1", dout$usage_symbols)
+
+## fix for S1
+dout$usage_symbols <- gsub("and portions of LRR P outside of MLRA 136",
+                           "(except for MLRAs 133A, 133B, 133C, 134, 135A, 135B, 136, 137, and 138)",
+                           dout$usage_symbols)
+
+# fix for F1
+dout$usage_symbols <- gsub("those using A7 (LRRs P, T, U, Z), MLRA 1 of LRR A",
+                           "P, T, U, Z", dout$usage_symbols, fixed = TRUE)
+
+# fix for F13
+dout$usage_symbols <- gsub("MLRA 122 of LRR N", "122", dout$usage_symbols)
+
+# fix for F18
+dout$usage_symbols <- gsub("150\\b", "150A, 150B", dout$usage_symbols)
+
+dout$except_mlra <- gsub(".*\\(except for MLRAs* (.*)\\).*|.*", "\\1", dout$usage_symbols)
+dout$except_mlra <- gsub(",* and ", ", ", dout$except_mlra)
+
+# fix for F1
+dout$except_mlra[which(dout$indicator == "F1")] <- "1"
+
+dout$except_mlra <- lapply(strsplit(dout$except_mlra, ","), trimws)
+dout$usage_symbols <- gsub("(.*)\\(except for MLRAs* .*\\)(.*)", "\\1\\2", dout$usage_symbols)
+
+dout$except_lrrsymbols1 <- gsub("For use in all LRRs, except [for ]*([^;]*).*|.*", "\\1", dout$usage_symbols)
+dout$usage_symbols <- gsub("For use in all LRRs.*", paste0(LETTERS, collapse = ", "), dout$usage_symbols)
+
+dout$usage_mlras <- gsub("and", ",", gsub("of LRR [A-Z]|in|MLRAs*|West Florida portions of|;.*", "", gsub("For use in MLRAs*(.*)|.*", "\\1", dout$usage_symbols)))
+
+# convert to split Alaska LRRs for 2022 spatial
+dout$usage_symbols <- gsub("W, X", "W1, W2, X1, X2", dout$usage_symbols)
+dout$except_lrrsymbols1 <- gsub("W, X", "W1, W2, X1, X2", dout$except_lrrsymbols1)
+
+dout$usage_symbols <- sapply(strsplit(dout$usage_symbols, ","), trimws)
+dout$except_lrrsymbols1 <- sapply(strsplit(dout$except_lrrsymbols1, ","), trimws)
+dout$usage_mlras <- sapply(strsplit(dout$usage_mlras, ","), trimws)
+
+mlra.spec.idx <- sapply(dout$usage_mlras, length) > 0
+dout$usage_symbols[mlra.spec.idx] <- dout$usage_mlras[mlra.spec.idx]
+
+for (u in seq(dout$usage_symbols)) {
+  dout$usage_symbols[[u]] <- setdiff(dout$usage_symbols[[u]], dout$except_lrrsymbols1[[u]])
+}
+
+# subset(dout, grepl("; for testing", dout$usage), select = c(indicator, usage))
+
+dout$test_symbols <- gsub(".*; for testing [io]n (.*)$|.*", "\\1", dout$usage)
+dout$test_except_mlra <- gsub(".*\\(except for MLRAs* (.*)\\).*|.*", "\\1", dout$test_symbols)
+dout$test_symbols <- gsub("(.*)\\(except for MLRAs* .*\\).*|(.*)", "\\1\\2", dout$test_symbols)
+dout$test_symbols <- gsub("(^MLRAs*|^LRRs*|^other MLRAs of LRR| of LRR [A-Z]|^flood plains subject to Piedmont deposition throughout LRRs )",
+                          "", dout$test_symbols)
+dout$test_symbols <- gsub("^all.*", "All other LRRs", dout$test_symbols)
+dout$test_symbols <- trimws(gsub(",* and ", ", ", dout$test_symbols))
+
+test.all.other.idx <- grep("All other LRRs", dout$test_symbols)
+for (i in test.all.other.idx) {
+  dout$test_symbols[i] <- paste0(LETTERS[!LETTERS %in% dout$usage_symbols[i][[1]]], collapse = ", ")
+}
+
+# convert to split Alaska LRRs for 2022 spatial
+dout$test_symbols <- gsub("W, X", "W1, W2, X1, X2", dout$test_symbols)
+
+dout$test_symbols <- lapply(strsplit(dout$test_symbols, ","), trimws)
+dout$test_except_mlra <- lapply(strsplit(dout$test_except_mlra, ","), trimws)
+
+# remove testing exceptions from approved exceptions
+dout$except_mlra <- lapply(seq(dout$except_mlra), function(i) {
+  dout$except_mlra[[i]][!dout$except_mlra[[i]] %in% dout$test_except_mlra[[i]]]
+})
+
+# subset(dout, grepl("; for testing", dout$usage), select = c(indicator, usage, test_symbols))
+
+
+dout$criteria <- sapply(dout$criteria, paste0, collapse = ". \n")
+dout$criteria <- gsub("  ", " ", dout$criteria)
+dout$criteria <- gsub("\\.\\.", ".", dout$criteria)
+
+fihs <- dout
+fihs[[2]] <- NULL
+fihs$body <- NULL
+
+fihs <- subset(fihs, grepl( "T*[ASF]\\d+", fihs$indicator))
+
+replaceUnicodeChars <- function(x) {
+  gsub("\u2264", "<=", x) |>
+    gsub("\u2265", ">=", x = _) |>
+    gsub("\u201c|\u201d", "\"", x = _)
+}
+
+fihs$criteria <- stringi::stri_enc_toascii(replaceUnicodeChars(fihs$criteria))
+fihs$note <- stringi::stri_enc_toascii(replaceUnicodeChars(fihs$note))
+
+fihs_test <- subset(fihs, grepl("(Test)", fihs$section))
+fihs <- subset(fihs, !grepl("(Test)", fihs$section))
+fihs <- fihs[c("section", "indicator", "indicator_name", "page",
+               "usage", "usage_symbols", "except_mlra", "test_symbols", "test_except_mlra",
+               "criteria", "note")]
+
+if (interactive())
+  View(fihs)
+
+attr(fihs, 'version') <- VERSION
+attr(fihs, 'version_year') <- VERSION_YEAR
+attr(fihs, 'reference') <- REFERENCE
+usethis::use_data(fihs, overwrite = TRUE)
+
+## TODO: fihs_test dataset; need to confirm where they are being tested
+## TODO: splice in existing indicators that have testing LRRs? or add additonal column to fihs
+# usethis::use_data(fihs_test, overwrite = TRUE)
diff --git a/data-raw/lrrmlra.R b/data-raw/lrrmlra.R
index e23c2bd..a7299d7 100644
--- a/data-raw/lrrmlra.R
+++ b/data-raw/lrrmlra.R
@@ -1,7 +1,7 @@
 ## code to prepare `lrrmlra` dataset goes here
 library(terra)
 
-x <- vect("/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022")
+x <- vect(hydricsoils::lrrmlra_geometry_dsn())
 
 ## metadata, added as attributes
 VERSION <- "5.2"
diff --git a/data/fihs.rda b/data/fihs.rda
index 688e1bf..0a403c8 100644
Binary files a/data/fihs.rda and b/data/fihs.rda differ
diff --git a/hydricsoils.Rproj b/hydricsoils.Rproj
index b78f519..1be8442 100644
--- a/hydricsoils.Rproj
+++ b/hydricsoils.Rproj
@@ -1,4 +1,5 @@
 Version: 1.0
+ProjectId: 3a15cc37-f02a-4378-81e9-b0348d46bb8a
 
 RestoreWorkspace: Default
 SaveWorkspace: Default
diff --git a/inst/extdata/FIGS.txt b/inst/extdata/FIGS.txt
index 7db8644..0a7ee8f 100644
--- a/inst/extdata/FIGS.txt
+++ b/inst/extdata/FIGS.txt
@@ -1,283 +1 @@
-Figure 1. The soil on the right is hydric. It meets the requirements of indicator S7 (Dark Surface). From the surface and to a depth
-of 10 cm, value is 3 or less and chroma is 1 or less. Below 10 cm, the matrix has chroma of 2 or less.The soil on the left is
-not hydric. It does not have a dark surface layer thick enough to meet the requirements of indicator S7 and does not meet the
-requirements of any other indicator.
-—
-Figure 2. The soil profile above consists of an 8 cm (3.14
-inches) layer of peat and/or mucky peat underlain by
-a 1 cm (0.4 inches) layer of muck.The remaining soil
-layers are sandy soil material. In LRRs R, W, X, and
-Y, observations would begin below the peat, mucky
-peat, and muck layers (9 cm). In LRRs, F, G, H, and M,
-observations would start at the actual soil surface. In all
-remaining LRRs, observations would begin at the muck
-surface (8 cm).
-—
-Figure 3. The left portion of this ped shows moist soil colors,
-and the right portion shows dry soil colors. Moist colors
-are to be used when hydric soils are identified. The moist
-colors in this picture would meet the requirements for
-indicator F6 (Redox Dark Surface), but the dry colors
-would not meet these requirements.
-—
-Figure 4. The lower portion of this soil profile meets the
-color and depth requirements of indicator F3 (Depleted
-Matrix); however, the upper portion of the profile contains
-a layer with chroma of 2 or more that is more than 15 cm
-(6 inches) thick. As a result, indicator F3 (Depleted Matrix)
-is not met.
-—
-Figure 5. Proper installation and monitoring of equipment
-as described in the Hydric Soil Technical Standard is
-required to collect data regarding proposed additions,
-deletions, or other changes to the hydric soil indicators.
-—
-Figure 7. Indicator A1 (Histosol or Histel).This soil has more
-than 40 cm (16 inches) of organic material, starting at the
-soil surface
-—
-Figure 8. Indicators A2 (Histic Epipedon) and A3 (Black
-Histic).This soil meets the depth criterion of A2 and
-the color and depth criteria of A3.The black color, a
-requirement of A3, results from the accumulation of
-organic matter when the soil is saturated and anaerobic.
-—
-Figure 9. Indicator A4 (Hydrogen Sulfide) is most likely to occur in salt marshes and other very wet ecosystems.
-—
-Figure 10. Indicator A5 (Stratified Layers) in sandy material.
-This soil also meets the requirements of indicator A6
-(Organic Bodies).
-—
-Figure 11. Indicator A6 (Organic Bodies). An individual
-organic body generally is about 1 to 3 cm in size.
-—
-Figure 12. Indicator A6 (Organic Bodies). Some organic
-bodies are smaller than 1 cm.
-—
-Figure 13. Indicator A7 (5 cm Mucky Mineral). This soil has
-more than 5 cm of mucky sand, starting at the surface.
-—
-Figure 14. Indicator A9 (1 cm Muck). This soil has more than
-1 cm of muck, starting at 8 cm on the left measuring
-tape. Different LRRs may use the presence of muck or 2
-cm of muck as an indicator of a hydric soil.
-—
-Figure 15. Indicator A11 (Depleted Below Dark Surface).
-This soil has a thin dark surface horizon that meets the
-requirements of indicator A11. Because a depleted matrix
-below the surface horizon starts at a depth of ≤15 cm from
-the soil surface and is at least 5 cm thick, the soil also
-meets the requirements of indicator F3 (Depleted Matrix).
-—
-Figure 16. Indicator A11 (Depleted Below Dark Surface).
-This soil has a thick dark surface horizon that meets the
-requirements of indicator A11. Unlike the matrix in figure
-15, the depleted matrix below the dark surface horizon
-in this soil starts at a depth of about 29 cm, which is too
-deep to meet the requirements of indicator F3 (Depleted
-Matrix). Indicator A11 allows a deeper depleted matrix
-than indicator F3.
-—
-Figure 17. Indicator A12 (Thick Dark Surface). Deep
-observation is needed to determine whether a soil meets
-the requirements of this indicator. In this soil, depth to the
-depleted matrix is about 55 cm.
-—
-Figure 18. Indicator A13 (Alaska Gleyed). The bluish band at
-a depth of about 20 cm indicates the presence of reduced
-soil material.The material below 20 cm reflects both the
-color of the parent material and soil weathering under
-aerobic conditions.
-—
-Figure 19. Indicator A14 (Alaska Redox). The matrix color
-meets the requirements of a gleyed matrix. Reddish
-orange redox concentrations occur along the pores and
-channels of living roots.
-—
-Figure 20. Indicator A15 (Alaska Gleyed Pores). Gleyed colors
-are along root channels. Reduction occurs first along root
-channels, where organic carbon is concentrated.
-—
-Figure 21. Indicator S4 (Sandy Gleyed Matrix).The gleyed
-matrix begins at the surface of the soil.
-—
-Figure 22. Indicator S5 (Sandy Redox).This soil meets the
-requirements of indicator S5, having a matrix chroma
-of 2 or less and at least 2 percent redox concentrations
-starting at a depth of about 10 cm.
-—
-Figure 23. Indicator S5 (Sandy Redox). A close-up of the layer
-in figure 22 that has chroma of 2 or less and at least 2
-percent redox concentrations.
-—
-Figure 24. Indicator S6 (Stripped Matrix).This indicator
-requires diffuse splotchy patterns with rounded areas
-stripped of organic matter or iron, as exemplified in this
-photo.
-—
-Figure 25. Indicator S7 (Dark Surface). This soil has value of
-3 or less and chroma of 1 or less from the surface to a
-depth of 10 cm. Directly below 10 cm, it is the same color,
-meeting the requirement of having chroma of 2 or less.
-—
-Figure 26. Indicator S8 (Polyvalue Below Surface). The diffuse
-splotchy pattern of black (value of 3 or less and chroma of
-1 or less) and gray (value of 4 or more and chroma of 1 or
-less) below a black surface horizon is evidence of organic
-matter that has been mobilized and translocated.This
-soil also meets the requirements of indicator S5 (Sandy
-Redox).
-—
-Figure 27. Indicator S9 (Thin Dark Surface). A dark surface
-horizon about 5 cm thick overlies a thin layer with value
-of 4 or less and chroma of 1 or less. Directly below the
-second layer is a spodic horizon, starting at a depth of
-about 7 cm.
-—
-Figure 28. Indicator F2 (Loamy Gleyed Matrix). The gleyed
-matrix begins at the surface and extends to a depth of
-about 14 cm.
-—
-Figure 29. Indicator F3 (Depleted Matrix).This soil has
-value of 4 or more and chroma of 2 or less and redox
-concentrations starting at a depth of 8 cm. Since the
-depleted matrix starts at a depth of ≤15 cm from the soil
-surface, the minimum thickness requirement is only 5 cm.
-—
-Figure 30. Indicator F6 (Redox Dark Surface). A soil that
-meets the requirements of indicator F6 must have a dark
-surface layer with value of 3 or less and chroma of 2 or
-less and redox concentrations in the dark layer.
-—
-Figure 31. Indicators F6 (Redox Dark Surface) and
-F7 (Depleted Dark Surface). A soil that meets the
-requirements of indicator F7 commonly also meets the
-requirements of indicator F6. If the dark surface layer
-has depletions, it most likely also has concentrations.
-—
-Figure 32. Indicators F6 (Redox Dark Surface) and F7
-(Depleted Dark Surface). An example of both depletions
-and concentrations in a dark matrix.
-—
-Figure 33. Indicator F8 (Redox Depressions). Indicator F8
-requires only 5 percent redox concentrations in the upper
-part of the soil.The matrix does not have chroma of 2 or
-less.
-—
-Figure 34. Indicator F8 (Redox Depressions). Indicator F8
-requires that the soil be in a closed depression subject to
-ponding.This soil is in a backwater depression on a flood
-plain.
-—
-Figure 35. Indicator F10 (Marl). In this profile, marl begins at a
-depth ≤10 cm of the soil surface.The scale is in cm.
-Figure 36. Indicator F12 (Iron-Manganese Masses). Although
-this indicator requires only 40 percent value of chroma
-of 2 or less, at least 2 percent iron-manganese masses is
-needed.These masses are indicated by black splotches in
-this photo.
-—
-Figure 37. Indicator F13 (Umbric Surface).This soil has
-an umbric surface horizon about 44 cm thick. It meets
-the requirements not only of indicator F13 but also of
-indicators A7 (5 cm Mucky Mineral) and A12 (Thick Dark
-Surface).
-—
-Figure 38. Indicator F19 (Piedmont Flood Plain Soils).This
-indicator is restricted to active flood plains. It does not
-require a matrix color with chroma of 2 or less.
-Figure 39. Indicator F20 (Anomalous Bright Loamy Soils).
-This indicator is restricted to areas near estuarine
-marshes or water. It does not require a matrix color with
-chroma of 2 or less.
-—
-Figure 40. Indicator F21 (Red Parent Material).This indicator
-should be used only in areas of red parent material that
-is resistant to reduction. Not all red soils formed in red
-parent material.
-—
-Figure 41. Indicator F3 (Depleted Matrix) in red parent
-material. If a soil that formed in red parent material stays
-wet and anaerobic long enough, it may develop the
-indicator F3.
-—
-Figure 42. Artificial drainage does not alter the hydric status
-of a soil.
-—
-Figure 43. The profile on the right is from a drained wetland
-adjacent to a ditch.The profile on the left is from an
-area not affected by the ditch. Both soils meet the
-requirements for indicators F3 (Depleted Matrix) and A11
-(Depleted Below Dark Surface) and thus are hydric soils.
-—
-Figure 44. Illustration of values and chromas that
-require 2 percent or more distinct or prominent redox
-concentrations and those that do not, for hue 10YR, to
-meet the definition of a depleted matrix. Due to inaccurate
-color reproduction, do not use this page to determine soil
-colors in the field. Background image from the Munsell
-Soil Color Charts reprinted courtesy of Munsell Color
-Services Lab, a part of X-Rite, Inc. (Xrite 2009).
-—
-Figure 45. A depleted matrix with value of 4 or more and
-chroma of 2 or less. Redox concentrations occur as soft
-masses and pore linings.
-—
-Figure 46. Iron concentration with a diffuse boundary
-exhibited by bright colors in the center of the
-concentration and a lighter color away from the center.
-—
-Figure 47. A soil profile with an albic (white) E horizon
-between depths of about 35 and 60 cm.The white color
-results from loss of iron through weathering.
-—
-Figure 48. Relationships among the hues of the Munsell
-Color System. Solid lines represent hues contained in the
-Munsell Soil Color Charts (2009). Dotted lines represent
-all other possible 2.5-unit steps. Moving from one hue line
-to the adjacent hue line represents a delta hue of 1 (2.5
-units). Moving from hue N to any other hue the delta hue
-is 1. Adapted from the Soil Survey Manual (Soil Survey
-Staff, 1993).
-—
-Figure 49. Glauconitic soils typically have gleyed, green,
-or black matrices and can have mottles of weathered
-sulfides that can be mistaken for redox concentrations.
-If the weathered sulfides in this glauconitic soil were
-mistaken for redox concentrations, this nonhydric soil
-would appear to meet the requirements of indicator F6
-(Redox Dark Surface).
-—
-Figure 50. A gleyed matrix must have the colors on one of
-the two pages showing gleyed colors in the Munsell
-Soil Color Book. Values are 4 or more (above the red
-line).
-—
-Figure 51. The gleyed matrix in this soil starts at a depth of
-about 15 cm.The matrix color has value of 4 or more and
-is shown on one of the pages showing gleyed colors in
-the Munsell Soil Color Book.
-—
-Figure 52. A soil with a mollic epipedon, which is a thick,
-black surface horizon that has high base saturation. Soils
-that have a mollic epipedon are classified as Mollisols.
-—
-Figure 53. Percent organic carbon required for organic
-soil material, mucky modified mineral soil material, and
-mineral soil material as it is related to content of clay.
-—
-Figure 54. A redox concentration occurring as a pore lining.
-—
-Figure 55. Redox concentrations occurring as soft masses
-and pore linings. Also, a redox depletion along a root
-channel.
-—
-Figure 56. A wet Spodosol with a splotchy gray and black
-eluvial horizon above a reddish brown spodic horizon.
-—
-Figure 57. Even in wet Spodosols, the spodic horizon may
-be bright colored. If iron occurs in the horizon, redox
-concentrations may be evident in the bright spodic
-material. Some spodic horizons, however, do not have
-iron.
-—
+Figure 1. The soil on the left is a hydric soil. It meets the requirements of indicator F3, Depleted Matrix. The soil on the right has indicators of wetness (redox depletions) too deep in the soil profile to meet the requirements of any field indicator and does not meet the definition of a hydric soil. Figure 2.The soil profile above consists of an 8 cm layer of peat and/or mucky peat underlain by a 1 cm layer of muck. The remaining soil layers are sandy soil material. In LRRs R, W, X, and Y, observations would begin below the peat, mucky peat, and muck layers (9 cm). When using Indicators S2 or S3, observations would start at the actual soil surface (0 cm). In all remaining LRRs, observations would begin at the muck surface (8 cm). Figure 3. The left portion of this ped shows moist soil colors, and the right portion shows dry soil colors. Moist colors are to be used when hydric soils are identified. The moist colors in this picture would meet the requirements for indicator F6, Redox Dark Surface, but the dry colors would not meet these requirements. Figure 4. The lower portion of this soil profile meets the color and depth requirements of indicator F3, Depleted Matrix; however, the upper portion of the profile contains a layer with chroma of 2 or more that is more than 15 cm (6 inches) thick. As a result, the requirements of indicator F3, Depleted Matrix, are not met. Figure 5. Proper installation and monitoring of equipment as described in the Hydric Soil Technical Standard is required to collect data regarding proposed additions, deletions, or other changes to the hydric soil indicators. Figure 6. Map of USDA land resource regions and major land resource areas in the conterminous United States (USDA NRCS, 2022). Figure 7. Map of USDA land resource regions and major land resource areas in the nonconterminous United States (USDA NRCS, 2022). Figure 8. Indicator A1, Histosol or Histel. This soil has more than 40 cm of organic soil material starting at the soil surface. Figure 9. Indicators A2, Histic Epipedon, and A3, Black Histic. This soil meets the depth criterion of A2 and the color and depth criteria of A3. The black color, a requirement of A3, results from the accumulation of organic matter when the soil is saturated and anaerobic. Figure 10. Indicator A4, Hydrogen Sulfide, is most likely to occur in salt marshes and other very wet ecosystems. Figure 11. Indicator A5, Stratified Layers in sandy material. This soil also meets the requirements of indicator A6, Organic Bodies. Figure 12. Indicator A6, Organic Bodies. An individual organic body generally is about 1 to 3 cm in size but could be smaller than 1 cm. Figure 13. Indicator A7, 5 cm Mucky Mineral. This soil has more than 5 cm of mucky sand, starting at the surface. Figure 14. Indicator A9, 1 cm Muck. This soil has more than 1 cm of muck, starting at 8 cm on the left measuring tape. Different LRRs may use the presence of muck or 2 cm of muck as an indicator of a hydric soil. Figure 15. Indicator A11, Depleted Below Dark Surface. This soil has a thin, dark surface horizon that meets the requirements of indicator A11. Because a depleted matrix below the surface horizon starts at a depth of 15 cm or less from the soil surface and is at least 5 cm thick, the soil also meets the requirements of indicator F3, Depleted Matrix. Figure 16. Indicator A11, Depleted Below Dark Surface. This soil has a thick, dark surface horizon that meets the requirements of indicator A11. Unlike the soil profile in fig. 15, which has a depleted matrix starting around 8 cm below the dark surface horizon, this soil has a depleted matrix that starts at a depth of about 29 cm, which is too deep to meet the requirements of indicator F3, Depleted Matrix. Indicator A11 allows a deeper depleted matrix than indicator F3. Figure 17. Indicator A12, Thick Dark Surface. Observations deeper in the profile are needed to determine whether a soil meets the requirements of this indicator. In this soil, depth to the depleted matrix is about 55 cm. Figure 18. Indicator A13, Alaska Gleyed. The bluish band at a depth of about 20 cm indicates the presence of reduced soil material. The material below 20 cm reflects both the color of the parent material and soil weathering under aerobic conditions. Figure 19. Indicator A14, Alaska Redox. The matrix color meets the requirements of a gleyed matrix. Reddish orange redox concentrations occur along the pores and channels of living roots. Figure 20. Indicator A15, Alaska Gleyed Pores. Gleyed colors are along root channels. Reduction occurs first along root channels, where organic carbon is concentrated. Figure 21. Indicator A18, Iron Monosulfide, in loamy/clayey material. This soil has concentrations of black-colored iron monosulfide (FeS) in the upper 25 cm under moist to wet conditions (A). Concentrations of FeS were confirmed in this soil via the application of dilute (3%) hydrogen peroxide to induce rapid oxidation, resulting in a distinct color change (i.e., an increase in Munsell value of 1 or more) (B). Figure 22.  Gleyed colors, for the purpose of the indicators, are colors found on the gleyed pages of the “Munsell Soil Color Book.” They must also be a value of 4 or more or above the red line in this figure. Background image from the “Munsell Soil Color Charts” reprinted courtesy of Munsell Color Services Lab, a part of X-Rite, Inc. (X-Rite, 2009). Figure 23. Indicator S5, Sandy Redox. This soil meets the requirements of indicator S5, having a matrix chroma of 2 or less and at least 2 percent redox concentrations starting at a depth of about 10 cm. Figure 24. Indicator S5, Sandy Redox. A close-up of the layer in figure 23 that has chroma of 2 or less and at least 2 percent redox concentrations. Figure 25. Indicator S6, Stripped Matrix. This indicator requires diffuse splotchy patterns with rounded areas stripped of organic matter or iron as exemplified in this photo of a horizontal cross-section of a profile. Figure 26. Indicator S7, Dark Surface. This soil has value of 3 or less and chroma of 1 or less from the soil surface to a depth of 10 cm. Directly below 10 cm, it is the same color, meeting the requirement of having chroma of 2 or less. Figure 27. Indicator S8, Polyvalue Below Surface. The diffuse splotchy pattern of black (value of 3 or less and chroma of 1 or less) and gray (value of 4 or more and chroma of 1 or less) below a black surface horizon is evidence of organic matter that has been mobilized and translocated. This soil also meets the requirements of indicator S5, Sandy Redox. Figure 28. Indicator S9, Thin Dark Surface. A dark surface horizon about 5 cm thick overlies a thin layer with value of 4 or less and chroma of 1 or less. Directly below the second layer is a spodic horizon, starting at a depth of about 7 cm. Figure 29. Indicator F2, Loamy Gleyed Matrix. The gleyed matrix begins at the soil surface and extends to a depth of about 14 cm. Figure 30. Indicator F3, Depleted Matrix. This soil has value of 4 or more and chroma of 2 or less and redox concentrations starting at a depth of 8 cm. Since the depleted matrix starts at a depth of 10 cm or less from the soil surface, the minimum thickness requirement is only 5 cm to meet the requirements of indicator F3, Depleted Matrix. Figure 31. Indicator F6, Redox Dark Surface. A soil that meets the requirements of indicator F6 must have a dark surface layer with value of 3 or less and chroma of 2 or less and redox concentrations in the dark layer. Figure 32. Indicators F6, Redox Dark Surface, and F7, Depleted Dark Surface. A soil that meets the requirements of indicator F7 commonly also meets the requirements of indicator F6. If the dark surface layer has depletions, it most likely also has concentrations. Figure 33. Indicators F6, Redox Dark Surface, and F7, Depleted Dark Surface. An example of both depletions and concentrations in a dark matrix. Figure 34. Indicator F8, Redox Depressions. F8 requires only 5 percent redox concentrations in the upper part of the soil and has no matrix color requirement. Figure 35. Indicator F8, Redox Depressions. Indicator F8 requires that the soil be in a closed depression subject to ponding. This soil is in a backwater depression on a flood plain. Figure 36. Indicator F10, Marl. In this profile, marl begins at a depth of 10 cm or less from the soil surface. The scale is in cm. chroma of 2 or less and 2 percent or more distinct or prominent redox concentrations occurring as soft iron-manganese masses with diffuse boundaries. The layer starts at a depth of 20 cm (8 inches) or less from the soil surface. Iron- manganese masses have value and chroma of 3 or less. Most commonly, they are black. The thickness requirement is waived if the layer is the mineral soil surface layer. Figure 37. Indicator F12, Iron-Manganese Masses. Although this indicator requires only 40 percent value of 4 or more and chroma of 2 or less, at least 2 percent iron-manganese masses is needed. These masses are indicated by black splotches in this photo. Figure 38. Indicator F13, Umbric Surface. This soil has an umbric surface horizon about 44 cm thick. It meets the requirements not only of indicator F13 but also of indicators A7, 5 cm Mucky Mineral and A12, Thick Dark Surface. Figure 39. Indicator F19, Piedmont Flood Plain Soils. This indicator is restricted to active flood plains. It does not require a matrix color with chroma of 2 or less. Figure 40. Indicator F20, Anomalous Bright Loamy Soils. This indicator is restricted to areas near estuarine marshes or water. It does not require a matrix color with chroma of 2 or less. Figure 41. Indicator F21, Red Parent Material. This indicator should be used only in areas of red parent material that are resistant to reduction. Not all red soils formed in red parent material. Figure 42. Indicator F3, Depleted Matrix, in red parent material. If a soil that formed in red parent material stays wet and anaerobic long enough, it may develop the indicator F3. Figure 43. Artificial drainage does not alter the hydric status of a soil. Figure 44. The profile on the right is from a drained wetland adjacent to a ditch. The profile on the left is from an area not affected by the ditch. Both soils meet the requirements for indicators F3, Depleted Matrix, and A11, Depleted Below Dark Surface, and thus are hydric soils. Figure 45. Illustration of values and chromas that require 2 percent or more distinct or prominent redox concentrations and those that do not, for hue 10YR, to meet the definition of a depleted matrix. Due to inaccurate color reproduction, do not use this page to determine soil colors in the field. Background image from the Munsell Soil Color Charts reprinted courtesy of Munsell Color Services Lab, a part of X-Rite, Inc. (X-Rite, 2009). Figure 46. A depleted matrix with value of 4 or more and chroma of 2 or less. Redox concentrations occur as soft masses and pore linings. Figure 47. Iron concentration with a diffuse boundary exhibited by bright colors in the center of the concentration and a lighter color away from the center. Figure 48. Relationships among the hues of the Munsell Color System. Solid lines represent hues contained in the “Munsell Soil Color Charts” (X-Rite, 2009). Dotted lines represent all other possible 2.5-unit steps. Moving from one hue line to the adjacent hue line represents a delta hue of 1 (2.5 units). Moving from hue N to any other hue the delta hue is 1. Adapted from the “Soil Survey Figure 49. A soil profile with an albic (white) E horizon between depths of about 35 and 60 cm. The white color results from loss of iron through weathering. Figure 50. Glauconitic soils typically have gleyed, green, or black matrices and can have mottles of weathered sulfides that can be mistaken for redox concentrations. If the weathered sulfides in this glauconitic soil were mistaken for redox concentrations, this nonhydric soil would appear to meet the requirements of indicator F6, Redox Dark Surface. Figure 51. A gleyed matrix must have the colors on one of the two pages showing gleyed colors in the “Munsell Soil Color Book” (X-Rite, 2009). Values are 4 or more (above the red line). Figure 52. The gleyed matrix in this soil starts at a depth of about 15 cm. The matrix color has value of 4 or more and is shown on one of the pages showing gleyed colors in the “Munsell Soil Color Book” (X-Rite, 2009). Figure 53.  This flow chart should be used for the identification of iron monosulfides. material. Commonly determined by a significant change in particle-size distribution, mineralogy, etc., that indicates a difference in material from which the horizons formed. Figure 54.  A soil with a mollic epipedon, which is a thick, black surface horizon that has high base saturation. Soils that have a mollic epipedon are classified as Mollisols. cumulative days in normal years or are artificially drained. Figure 55. A redox concentration occurring as a pore lining. Figure 56. Redox concentrations occurring as soft masses and pore linings. The image also shows a redox depletion along a root channel. Figure 57. A wet Spodosol with a splotchy gray and black eluvial horizon above a reddish brown spodic horizon. Figure 58. Even in wet Spodosols, the spodic horizon may be bright colored. If iron occurs in the horizon, redox concentrations may be evident in the bright spodic material. Some spodic horizons, however, do not have iron.
diff --git a/inst/extdata/FIHS.txt b/inst/extdata/FIHS.txt
index d447eea..f3eedf4 100644
--- a/inst/extdata/FIHS.txt
+++ b/inst/extdata/FIHS.txt
@@ -1,1903 +1,1985 @@
-United States
-Department of
-Agriculture
-Natural Resources
-Conservation
-Service
-In cooperation with
-the National Technical
+In cooperation with the National Technical
 Committee for Hydric Soils
 Field Indicators of
 Hydric Soils in the
 United States
 A Guide for Identifying and Delineating
-Hydric Soils, Version 8.2, 2018
+Hydric Soils, Version 9.0, 2024
+S7 A11 F21 A3
+A1 F3 S6 A18
 Field Indicators of Hydric Soils
 in the United States
 A Guide for Identifying and Delineating Hydric Soils
-Version 8.2, 2018
-(Including revisions to versions 8.0 and 8.1)
+Version 9.0, 2024
 United States Department of Agriculture,
 Natural Resources Conservation Service,
-in cooperation with
-the National Technical Committee for Hydric Soils
-Edited by L.M. Vasilas, Soil Scientist, NRCS, Washington, DC; G.W. Hurt, Soil
-Scientist, University of Florida, Gainesville, FL; and J.F. Berkowitz, Soil Scientist,
-USACE, Vicksburg, MS
+in cooperation with the
+National Technical Committee for Hydric Soils
+Edited by L. M. Vasilas, Soil Scientist, NRCS, Washington, DC; A.
+Miller, NRCS, New Mexico; J. F. Berkowitz, Soil Scientist, USACE,
+Vicksburg, MS; Richard Griffin, Prairieview A&M University; and Colby
+Moorberg, Kansas State University
 ii
-In accordance with Federal civil rights law and U.S. Department of Agriculture
-(USDA) civil rights regulations and policies, the USDA, its Agencies, offices, and
-employees, and institutions participating in or administering USDA programs are
-prohibited from discriminating based on race, color, national origin, religion, sex,
-gender identity (including gender expression), sexual orientation, disability, age,
-marital status, family/parental status, income derived from a public assistance
-program, political beliefs, or reprisal or retaliation for prior civil rights activity, in
-any program or activity conducted or funded by USDA (not all bases apply to all
-programs). Remedies and complaint filing deadlines vary by program or incident.
-Persons with disabilities who require alternative means of communication for
-program information (e.g., Braille, large print, audiotape, American Sign Language,
-etc.) should contact the responsible Agency or USDA’s TARGET Center at (202)
-720-2600 (voice and TTY) or contact USDA through the Federal Relay Service
-at (800) 877-8339. Additionally, program information may be made available in
-languages other than English.
-To file a program discrimination complaint, complete the USDA Program
-Discrimination Complaint Form, AD-3027, found online at How to File a
-Program Discrimination Complaint (https://www.ascr.usda.gov/how-file-program-
-discrimination-complaint) and at any USDA office or write a letter addressed to
-USDA and provide in the letter all of the information requested in the form. To
-request a copy of the complaint form, call (866) 632-9992. Submit your completed
-form or letter to USDA by: (1) mail: U.S. Department of Agriculture, Office of the
-Assistant Secretary for Civil Rights, 1400 Independence Avenue, SW, Washington,
-D.C. 20250-9410; (2) fax: (202) 690-7442; or (3) email: program.intake@usda.gov.
+In accordance with Federal civil rights law and U.S. Department of Agriculture (USDA)
+civil rights regulations and policies, the USDA, its agencies, offices, and employees,
+and institutions participating in or administering USDA programs are prohibited from
+discriminating based on race, color, national origin, religion, sex, gender identity
+(including gender expression), sexual orientation, disability, age, marital status, family/
+parental status, income derived from a public assistance program, political beliefs, or
+reprisal or retaliation for prior civil rights activity, in any program or activity conducted
+or funded by USDA (not all bases apply to all programs). Remedies and complaint
+filing deadlines vary by program or incident.
+Persons with disabilities who require alternative means of communication for program
+information (e.g., Braille, large print, audiotape, American Sign Language, etc.) should
+contact the responsible agency or USDA’s TARGET Center at (202) 720-2600 (voice
+and TTY) or contact USDA through the Federal Relay Service at (800) 877-8339.
+Additionally, program information may be made available in languages other than
+English. To file a program discrimination complaint, complete the USDA Program
+Discrimination Complaint Form, AD-3027, found online at How to File a Program
+Discrimination Complaint and at any USDA office or write a letter addressed to USDA
+and provide in the letter all of the information requested in the form. To request a copy
+of the complaint form, call (866) 632-9992. Submit your completed form or letter to
+USDA by: (1) mail: U.S. Department of Agriculture, Office of the Assistant Secretary
+for Civil Rights, 1400 Independence Avenue, SW, Washington, D.C. 20250-9410; (2)
+fax: (202) 690-7442; or (3) email: program.intake@usda.gov.
 USDA is an equal opportunity provider, employer, and lender.
 Copies of this publication can be obtained from:
 NRCS Distribution Center
 1-888-526-3227
 nrcsdistributioncenter@ia.usda.gov
-Information contained in this publication and additional information concerning
-hydric soils are maintained on the website at http://www.nrcs.usda.gov/wps/portal/
-nrcs/main/soils/use/hydric/.
-Citation: United States Department of Agriculture, Natural Resources
-Conservation Service. 2018. Field Indicators of Hydric Soils in the United States,
-Version 8.2. L.M. Vasilas, G.W. Hurt, and J.F. Berkowitz (eds.). USDA, NRCS, in
-cooperation with the National Technical Committee for Hydric Soils.
-Cover: A typical landscape and profile of a hydric soil meeting the requirements
-of indicator F3, Depleted Matrix. Note the close-up of a ped showing a gray matrix
-with redox concentrations characteristic of soils meeting this field indicator. The
-Depleted Matrix indicator is the most commonly used indicator in the United States.
+Information contained in this publication and additional information concerning hydric
+soils are maintained on the NRCS Hydric Soils web page.
+Citation: United States Department of Agriculture, Natural Resources Conservation
+Service. 2024. Field Indicators of Hydric Soils in the United States, Version 9.0.
+Cover: A variety of hydric soil profiles meeting a field indicator of hydric soils. The
+top row of pictures from left to right represent S7, Dark Surface; A11, Depleted Below
+Dark Surface; F21, Red Parent Material; and A3, Black Histic. The bottom row from
+left to right represent A1, Histosol; F3, Depleted Matrix; S6, Stripped Matrix; and A18,
+Iron Monosulfide.
 iii
 Foreword
-Field Indicators of Hydric Soils in the United States has been developed by soil
-scientists of the Natural Resources Conservation Service (NRCS) in cooperation with
-the U.S. Fish and Wildlife Service (FWS); the U.S. Army Corps of Engineers (COE); the
-Environmental Protection Agency (EPA); various regional, state, and local agencies;
-universities; and the private sector. The editors recognize that this guide could not have
-been developed without the efforts of many individuals. Included in this publication are
-the hydric soil indicators approved by the NRCS and the National Technical Committee
-for Hydric Soils (NTCHS) for use in identifying, delineating, and verifying hydric soils
-in the field. Also included are indicators designated as test indicators, which are not
-approved for use but are to be tested so that their utility can be determined.
+“Field Indicators of Hydric Soils in the United States” has been
+developed by soil scientists of the Natural Resources Conservation
+Service (NRCS) in cooperation with the U.S. Fish and Wildlife Service;
+the U.S. Army Corps of Engineers; the Environmental Protection
+Agency; various regional, State, and local agencies; universities; and
+the private sector. The editors recognize that this guide could not have
+been developed without the efforts of many individuals. Included in this
+publication are the hydric soil indicators approved by the NRCS and
+the National Technical Committee for Hydric Soils (NTCHS) for use in
+identifying, delineating, and verifying hydric soils in the field.
 v
 Contents
-Foreword ...................................................................................................................... iii
-Index to Indicators .......................................................................................................vi
-Field Indicators of Hydric Soils in the United States, Version 8.2, 2017 ................1
-Introduction ................................................................................................................1
-Concept ......................................................................................................................2
-Procedure ..................................................................................................................3
-General Guidance for Using the Indicators ................................................................5
-To Comment on the Indicators ...................................................................................6
-Field Indicators of Hydric Soils ...................................................................................9
-All Soils ......................................................................................................................9
-Sandy Soils .............................................................................................................17
-Loamy and Clayey Soils ...........................................................................................21
-Test Indicators of Hydric Soils ..................................................................................29
-All Soils ....................................................................................................................29
-Sandy Soils ..............................................................................................................30
-Loamy and Clayey Soils ...........................................................................................30
-References ..................................................................................................................31
-Glossary ......................................................................................................................33
-Appendices .................................................................................................................43
-Appendix 1: Use Indicators by Land Resource Regions (LRRs) and Certain
-Major Land Resource Areas (MLRAs) ...............................................................43
-Appendix 2: Test Indicators by Land Resource Regions (LRRs) and Certain
-Major Land Resource Regions (MLRAs) ...........................................................44
-Appendix 3: Indicators That Have Been Deleted or Are No Longer Approved
-for Use ...............................................................................................................45
+Foreword ............................................................................................... iii
+Contents .................................................................................................v
+Index to Field Indicators.......................................................................vi
+Introduction ............................................................................................1
+Concept................................................................................................2
+General Guidance for Using the Indicators..........................................4
+To Comment on the Indicators.............................................................7
+Field Indicators of Hydric Soils ..........................................................11
+All Soils..............................................................................................11
+Sandy Soils........................................................................................20
+Loamy and Clayey Soils.....................................................................25
+References ...........................................................................................35
+Glossary ...............................................................................................37
+Appendices ..........................................................................................49
+Appendix 1: Approved Indicators by Land Resource Regions
+(LRRs) and Certain Major Land Resource Areas (MLRAs)............49
+Appendix 2: Test Indicators by Land Resource Regions (LRRs)
+and Certain Major Land Resource Regions (MLRAs)....................50
+Appendix 3: Indicators that Have Been Deleted or Are No Longer
+Approved for Use............................................................................51
 vi
-Index to Indicators
-Field Indicators
-All Soils .................................................................9
-A1.—Histosol or Histel .......................................9
-A2.—Histic Epipedon .........................................9
-A3.—Black Histic ...............................................9
-A4.—Hydrogen Sulfide ....................................10
-A5.—Stratified Layers ......................................10
-A6.—Organic Bodies .......................................11
-A7.—5 cm Mucky Mineral ................................11
-A8.—Muck Presence .......................................12
-A9.—1 cm Muck ...............................................12
-A10.—2 cm Muck .............................................12
-A11.—Depleted Below Dark Surface ...............13
-A12.—Thick Dark Surface ...............................14
-A13.—Alaska Gleyed .......................................15
-A14.—Alaska Redox ........................................15
-A15.—Alaska Gleyed Pores .............................15
-A16.—Coast Prairie Redox ..............................16
-A17.—Mesic Spodic ........................................16
-Sandy Soils .........................................................17
-S1.—Sandy Mucky Mineral ..............................17
-S2.—2.5 cm Mucky Peat or Peat .....................17
-S3.—5 cm Mucky Peat or Peat ........................17
-S4.—Sandy Gleyed Matrix ...............................17
-S5.—Sandy Redox ..........................................17
-S6.—Stripped Matrix ........................................18
-S7.—Dark Surface ...........................................19
-S8.—Polyvalue Below Surface .........................19
-S9.—Thin Dark Surface ...................................20
-S11.—High Chroma Sands..............................20
-S12.—Barrier Islands 1 cm Much.....................21
-Loamy and Clayey Soils ....................................21
-F1.—Loamy Mucky Mineral .............................21
-F2.—Loamy Gleyed Matrix ..............................21
-F3.—Depleted Matrix .......................................21
-F6.—Redox Dark Surface ................................22
-F7.—Depleted Dark Surface ............................22
-F8.—Redox Depressions .................................23
-F10.—Marl .......................................................24
-F11.—Depleted Ochric ....................................24
-F12.—Iron-Manganese Masses ......................24
-F13.—Umbric Surface .....................................25
-F16.—High Plains Depressions .......................25
-F17.—Delta Ochric ..........................................25
-F18.—Reduced Vertic ......................................25
-F19.—Piedmont Flood Plain Soils ...................26
-F20.—Anomalous Bright Loamy Soils .............26
-F21.—Red Parent Material...............................26
-F22.—Very Shallow Dark Surface ...................27
-Test Indicators
-All Soils ...............................................................29
-TA4.—Alaska Color Change ............................29
-TA5.—Alaska Alpine Swales ............................29
-TA6.—Mesic Spodic .........................................29
-Sandy Soils .........................................................30
-TS7.—Barrier Islands Low Chroma Matrix ......30
-Loamy and Clayey Soils ....................................30
+Index to Field Indicators
+All Soils
+A1.—Histosol or Histel............................ 11
+A2.—Histic Epipedon..............................12
+A3.—Black Histic....................................12
+A4.—Hydrogen Sulfide...........................12
+A5.—Stratified Layers.............................12
+A6.—Organic Bodies..............................13
+A7.—5 cm Mucky Mineral.......................14
+A8.—Muck Presence..............................14
+A9.—1 cm Muck.....................................14
+A10.—2 cm Muck...................................15
+A11.—Depleted Below Dark Surface.....15
+A12.—Thick Dark Surface......................17
+A13.—Alaska Gleyed.............................17
+A14.—Alaska Redox..............................18
+A15.—Alaska Gleyed Pores...................19
+A16.—Coast Prairie Redox....................19
+A17.—Mesic Spodic...............................19
+A18.—Iron Monosulfides........................20
+Sandy Soils
+S1.—Sandy Mucky Mineral....................20
+S2.—2.5 cm Mucky Peat or Peat...........21
+S3.—5 cm Mucky Peat or Peat..............21
+S4.—Sandy Gleyed Matrix.....................21
+S5.—Sandy Redox.................................21
+S6.—Stripped Matrix...............................22
+S7.—Dark Surface..................................23
+S8.—Polyvalue Below Surface...............23
+S9.—Thin Dark Surface..........................24
+S11.—High Chroma Sands....................24
+S12.—Barrier Islands 1 cm Muck...........25
+Loamy and Clayey Soils
+F1.—Loamy Mucky Mineral....................25
+F2.—Loamy Gleyed Matrix.....................25
+F3.—Depleted Matrix..............................26
+F6.—Redox Dark Surface......................27
+F7.—Depleted Dark Surface..................28.
+F8.—Redox Depressions.......................28
+F10.—Marl..............................................28
+F11.—Depleted Ochric...........................28
+F12.—Iron-Manganese Masses.............28
+F13.—Umbric Surface............................29.
+F16.—High Plains Depressions.............30
+F17.—Delta Ochric.................................30
+F18.—Reduced Vertic............................30
+F19.—Piedmont Flood Plain Soils..........31
+F20.—Anomalous Bright Loamy Soils...31.
+F21.—Red Parent Material.....................31
+F22.—Very Shallow Dark Surface..........33
 1
-Field Indicators of Hydric Soils in the
-United States, Version 8.2, 2018
 Introduction
-Field Indicators of Hydric Soils in the United States
-is a guide to help identify and delineate hydric soils
-in the field (fig. 1). Field indicators (indicators) are
-not intended to replace or modify the requirements
-contained in the definition of a hydric soil. Proper
-use of the indicators requires a basic knowledge
-of soil-landscape relationships and soil survey
-procedures.
-The National Technical Committee for Hydric
-Soils (NTCHS) defines a hydric soil as a soil that
-formed under conditions of saturation, flooding, or
-ponding long enough during the growing season
-to develop anaerobic conditions in the upper part
-(Federal Register, 1994). Most hydric soils exhibit
-characteristic morphologies that result from repeated
-periods of saturation or inundation that last more
-than a few days. Saturation or inundation, when
-combined with microbial activity in the soil, causes the
-2 Field Indicators of
-depletion of oxygen. Prolonged anaerobic conditions
+“Field Indicators of Hydric Soils in the United
+States” is a guide to help identify and delineate
+hydric soils in the field (fig. 1). Field indicators
+are not intended to replace or modify the
+requirements contained in the definition of a
+hydric soil. Proper use of the indicators requires
+a basic knowledge of soil-landscape relationships
+and soil survey procedures. The National
+Technical Committee for Hydric Soils (NTCHS)
+defines a hydric soil as a soil that formed under
+conditions of saturation, flooding, or ponding long
+enough during the growing season to develop
+anaerobic conditions in the upper part (“Changes
+in Hydric Soils of the United States, 60 Fed.
+Reg. 10349,” 1995). Most hydric soils exhibit
+characteristic morphologies that result from
+repeated periods of saturation or inundation that
+last more than a few days.
+2
+Field Indicators of Hydric Soils
+Saturation or inundation, when combined with
+microbial activity in the soil, causes the depletion
+of oxygen. Prolonged anaerobic conditions
 promote certain biogeochemical processes, such
-as the accumulation of organic matter and the
-reduction, translocation, or accumulation of iron
-and other reducible elements. These processes
-result in distinctive characteristics that persist in the
-soil during both wet and dry periods, making them
-particularly useful for identifying hydric soils in the
-field. The indicators are used to identify the hydric
-soil component of wetlands; however, there are
-some hydric soils that lack any of the currently listed
-indicators. Therefore, the lack of any listed indicator
-does not prevent classification of the soil as hydric.
-Such soils should be studied and their characteristic
-morphologies identified for inclusion in this guide.
+as the accumulation of organic matter,
+denitrification, and the chemical transformation
+and translocation of oxidized iron, manganese,
+and sulfur species. These processes indicate that
+wetland functions are occurring within the soil
+and result in distinctive characteristics that persist
+during both wet and dry periods that are useful for
+identifying hydric soils in the field. The indicators
+are used to identify the hydric soil component of
+wetlands; however, there are some hydric soils
+that lack any of the currently approved indicators.
+Therefore, the failure to meet the requirements of
+an indicator does not prevent classification of the
+soil as hydric. Such soils can be observed and
+documented, and repeated morphologies may be
+used to develop a new field indicator for inclusion
+in this guide.
 The indicators are designed to be regionally
-specific. The description of each indicator identifies
-the land resource regions (LRRs) and/or major land
-resource areas (MLRAs) in which the indicator can be
-applied. The geographic extent of LRRs and MLRAs is
-defined in U.S. Department of Agriculture Handbook
-296 (USDA, NRCS, 2006b). See the map or LRRs
-(fig. 6, page 7) and the list of LRR-specific indicators
+specific. The description of each indicator
+identifies the land resource regions (LRRs) and
+major land resource areas (MLRAs) in which
+the indicator can be applied. The geographic
+extent of LRRs and MLRAs is defined in “U.S.
+Department of Agriculture Handbook 296” (USDA,
+NRCS, 2022). See the map of LRRs (see figs.
+6 and 7) and the list of LRR-specific indicators
 (Appendices 1 and 2).
 The list of indicators is dynamic; changes and
-additions are anticipated with new research and field
-testing. The section “To Comment on the Indicators”
-provides guidance on how to recommend deletions,
-additions, and other changes. Any modifications
-to the indicators must be approved by NRCS and
-the NTCHS. The current version of the indicators is
-available on the NRCS hydric soils website (http://
-www.nrcs.usda.gov/wps/portal/nrcs/main/soils/use/
-hydric/).
+additions are anticipated with new research and
+field testing. The section “To Comment on the
+Indicators” (see p. 7) provides guidance on how to
+recommend updates and other edits. Any
+modifications to the indicators must be approved
+by NRCS and the NTCHS. The user of this
+guidance is required to check the current version
+of the indicators, available on the NTCHS web
+page.
 Concept
-Hydric soil indicators are formed predominantly by
-the accumulation or loss of iron, manganese, sulfur,
-or carbon compounds under saturated and anaerobic
-conditions. The processes and the soil features that
-develop under these conditions are described in the
+Hydric soil indicators are formed predominantly
+by the accumulation, loss, or redistribution of
+manganese, iron, sulfur, or carbon compounds
+under saturated and anaerobic conditions. The
+processes and the soil features that develop
+under these conditions are described in the
 following paragraphs.
 Iron and Manganese Reduction,
 Translocation, and Accumulation
-In an anaerobic environment, soil microbes reduce
-iron from the ferric (Fe3+
-) to the ferrous (Fe2+
-) form
-and manganese from the manganic (Mn4+
-) to the
-manganous (Mn2+
-) form. Of the two, evidence of
-iron reduction is more commonly observed in soils.
-Areas in the soil where iron is reduced often develop
-characteristic bluish gray or greenish gray colors
-known as gley (colors with value of 4 or more on the
-gley pages in the Munsell color book). Ferric iron is
-insoluble, but ferrous iron enters the soil solution,
-where it may be moved or translocated to other areas
-of the soil. Areas that have lost iron typically develop
-characteristic gray or reddish gray colors and are
-known as redox depletions. If a soil reverts to an
-aerobic state, iron that is in solution will oxidize and
-become concentrated in patches as soft masses and
-along root channels or other pores. These areas of
-oxidized iron are called redox concentrations. Since
-water movement in these saturated or inundated
-soils can be multidirectional, redox depletions and
-concentrations can occur anywhere in the soil and
-have irregular shapes and sizes. Soils that are
-saturated and contain ferrous iron at the time of
-sampling may change color upon exposure to the
-air, as ferrous iron is rapidly converted to ferric iron
-in the presence of oxygen. Such soils are said to
-have a reduced matrix (Vepraskas, 1994). Redox
-concentrations, depletions, and reduced matrixes are
-collectively referred to as redoximorphic features.
-While indicators related to iron or manganese
-depletions and/or concentrations are most common
-in hydric soils, they cannot form in soils with parent
-materials that are low in Fe or Mn content. Soils that
-formed in such materials may have low-chroma colors
-that are not related to saturation and reduction. Such
-soils may have hydric soil morphological features that
-formed through accumulation of organic matter.
+In an anaerobic environment, soil microbes
+reduce iron from the ferric (Fe3+
+) to the ferrous
+(Fe2+
+) form and manganese from the manganic
+(Mn4+
+) to the manganous (Mn2+
+) form. Of the two,
+evidence of iron reduction is observed more
+widespread in soils due to the relatively strong
+appearance of even small amounts of its
+rust-colored pigments that ferric minerals impart
+on the soil matrix (predominant color).
+Areas in the soil where iron is reduced often
+develop characteristic bluish-gray or
+greenish-gray colors known as gley (colors with
+value 4 or more on the gley pages in the “Munsell
+Soil Color Book” (X-Rite, 2009)). Ferric iron is
+insoluble, but ferrous iron enters the soil solution
+where it may be moved or translocated to other
+areas of the soil. Areas that have lost iron typically
+develop characteristic gray or reddish-gray colors
+and are known as redox depletions.
+If a soil reverts to an aerobic state, iron that is in
+solution will oxidize and become concentrated in
+patches as soft masses and along root channels
+or other pores. These areas of oxidized iron are
+called redox concentrations. Since water
+movement in these saturated or inundated soils
+can be multidirectional, redox depletions and
+concentrations can occur anywhere in the soil
+and have irregular shapes and sizes. Soils that
+are saturated and contain ferrous iron at the time
+of sampling may change color upon exposure
+to the air, as ferrous iron is rapidly converted to
+ferric iron in the presence of oxygen. Such soils
+are said to have a reduced matrix (Vepraskas,
+1994). Redox concentrations, depletions, and
+reduced matrices are collectively referred to as
+redoximorphic features.
+While indicators related to iron (Fe) or manganese
+(Mn) depletions and concentrations are most
+3
+Field Indicators of Hydric Soils
+common in hydric soils, they cannot form in soils
+with parent materials that are low in Mn or Fe
+content. Soils that formed in such materials may
+have low-chroma colors that are not related to
+saturation and reduction. Such soils may exhibit
+other hydric soil morphologic features that form
+through the accumulation of organic matter.
 Sulfate Reduction
-Sulfur is one of the last elements to be reduced
-by microbes in an anaerobic environment. The
-microbes convert sulfate (SO4
+Sulfur is one of the least thermodynamically
+favorable alternative electron acceptors to
+chemically reduce under anaerobic conditions
+(McBride, 1994). As a result, a reduction of sulfur
+occurs in portions of the landscape that
+experience prolonged periods of persistent
+saturation, flooding, or ponding. When these
+conditions are met, microbial respiration
+induces the conversion of sulfate (SO4
 2-
-) to hydrogen
-sulfide gas (H2
-S). This conversion results in a very
-pronounced “rotten egg” odor in some soils that are
-inundated or saturated for long periods. In soils that
-are not saturated or inundated, sulfate is not reduced
-and there is no rotten egg odor. The presence of
-hydrogen sulfide is a strong indicator of a hydric soil,
-but this indicator occurs only in very wet portions of
-the landscape, in soils that contain sulfur-bearing
-compounds.
-Organic-Matter Accumulation
+) to
+sulfide (S2-
+). The resultant S2-
+can rapidly react to
+form hydrogen sulfide gas (H2
+S), or in the
+presence of reduced iron, can precipitate
+amorphous iron monosulfide (FeS) and other
+compounds. The formation and diffusion of H2
+S
+gas results in a “rotten egg” odor, which can be
+used to identify hydric soils as described in field
+indicator A4, Hydrogen Sulfide. Iron monosulfide
+(FeS) concentrations form as dark-gray or black
+precipitates that coat soil pore linings and ped
+faces (adapted from Vaughan et al., 2016). These
+morphological features are documented using
+multiple rapid field tests that distinguish FeS
+from other dark-colored materials in soil (e.g.,
+organic matter, manganese oxides). Hydric soils
+are present when FeS is observed near the soil
+surface, as described in field indicator A18, Iron
+Monosulfide.
+Organic Matter Accumulation
 Soil microbes use carbon compounds that occur
-in organic matter as an energy source. The rate at
-which soil microbes use organic carbon, however,
-is considerably lower in a saturated and anaerobic
-environment than under aerobic conditions. Therefore,
-3 Hydric Soils
-in saturated soils, partially decomposed organic
-matter may accumulate. The result in wetlands is often
-the development of thick organic surface horizons,
-such as peat or muck, or dark organic-rich mineral
-surface layers.
+in organic matter as an energy source. The
+rate at which soil microbes use organic carbon,
+however, is considerably lower in a saturated
+and anaerobic environment than under aerobic
+conditions. Therefore, in saturated soils, partially
+decomposed organic matter may accumulate.
+The result in wetlands is often the development
+of thick organic surface horizons, such as peat or
+muck, or dark organic-rich mineral surface layers.
 Determining the Texture of Soil Materials
 High in Organic Carbon
 Soil materials fall into three categories based
-upon the organic carbon content: organic soil, mucky
-mineral soil, and mineral soil. In lieu of laboratory
-data, the following field estimation method can be
-used to categorize soil material that is wet or nearly
-saturated with water. This method may be inconclusive
-with loamy or clayey mineral soils. Gently rub the
-wet soil material between forefinger and thumb. If
-upon the first or second rub the material feels gritty,
-it is mineral soil material. If after the second rub the
-material feels greasy, it is either mucky mineral or
-organic soil material. Gently rub the material two or
-three more times. If after these additional rubs it feels
-gritty or plastic, it is mucky mineral soil material; if it
-still feels greasy, it is organic soil material.
-If the material is organic soil material, a further
-division should be made. Organic soil materials are
-classified as muck, mucky peat, or peat. Differentiating
-criteria are based on the percentage of visible fibers
-observable with a hand lens in an undisturbed state
-and after rubbing between thumb and fingers 10
-times. Muck, mucky peat, and peat correspond to the
-textures sapric, hemic, and fibric. If there is a conflict
-between unrubbed and rubbed fiber content, rubbed
-content is used. Live roots are not considered.
+upon the organic carbon content: organic soil,
+mucky mineral soil, and mineral soil. In lieu of
+laboratory data, the following field estimation
+method can be used to categorize soil material
+that is wet or nearly saturated with water. This
+method may be inconclusive with loamy or
+clayey mineral soils. Gently rub the wet soil
+material between forefinger and thumb. If upon
+the first or second rub the material feels gritty,
+it is mineral soil material. If after the second
+rub the material feels greasy, it is either mucky
+mineral or organic soil material. Gently rub
+the material two or three more times. If after
+these additional rubs it feels gritty or plastic,
+it is mucky mineral soil material; if it still feels
+greasy, it is organic soil material. If the material
+is organic soil material, a further division should
+be made. Organic soil materials are classified
+as muck, mucky peat, or peat. Differentiating
+criteria are based on the percentage of visible
+fibers observable with a hand lens in an
+undisturbed state and after rubbing between
+thumb and fingers 10 times. Muck, mucky peat,
+and peat correspond to the textures sapric,
+hemic, and fibric. If there is a conflict between
+unrubbed and rubbed fiber content, rubbed
+content is used. Live roots are disregarded
+in this test. Other methods of determining the
+organic soil matter category, such as applying
+the von Post humification scale (von Post,
+1926), can also be used.
 Cautions
-A soil that is drained or protected (for instance, by
-dikes or levees) meets the definition of a hydric soil if
-the upper part formed under anaerobic conditions in
-an unaltered state. Drained or protected hydric soils
-generally have one or more of the indicators. Not
-all areas that have hydric soils qualify as wetlands.
-For example, a soil that formed under anaerobic
+A soil that is drained or protected (for instance,
+by dikes or levees) meets the definition of
+a hydric soil if the upper part formed under
+anaerobic conditions in an unaltered state.
+Drained or protected hydric soils generally have
+one or more of the indicators. Not all areas
+that have hydric soils qualify as wetlands. For
+example, a soil that formed under anaerobic
 conditions but no longer has wetland hydrology
-or supports hydrophytic vegetation still meets the
-definition of a hydric soil. However, the area will not
-meet the requirements of a wetland determined by
-the three factor approach (presence of hydric soils,
-wetland hydrology, and hydrophytic vegetation).
+nor supports hydrophytic vegetation still meets
+the definition of a hydric soil. However, the
+area will not meet the requirements of a federal
+wetland determined by the three-factor approach
+4
+Field Indicators of Hydric Soils
+(presence of hydric soils, wetland hydrology, and
+hydrophytic vegetation).
 There are hydric soils with morphologies that are
 difficult to interpret. These include soils with black,
-gray, or red parent material; soils with high pH; soils
-high or low in content of organic matter; recently
-developed hydric soils; and soils high in iron inputs.
-In some cases we do not currently have indicators
-to assist in the identification of hydric soils in these
-situations. As long as the soil meets the definition of a
-hydric soil, the lack of an indicator does not preclude
-the soil from being hydric.
+gray, or red parent materials; soils with high pH or
+salts; soils high or low in organic matter content;
+recently developed hydric soils; and soils high in
+iron inputs. In these cases, the current published
+indicators do not always function to identify a
+hydric soil. As long as the soil meets the definition
+of a hydric soil, the lack of an indicator does not
+preclude the soil from being hydric.
 The indicators were developed mostly to identify
-the boundary of hydric soil areas and generally work
-best on the margins. For example, redoximorphic
-features are most likely to occur in soils that cycle
-between anaerobic (reduced) and aerobic (oxidized)
-conditions. In some cases, portions of an area under
-near-constant saturation will not display an indicator.
+the boundary of hydric soil areas and generally
+work best on the margins. Additionally, indicators
+are designed to leverage the most readily
+observable redoximorphic features, which are
+more likely to occur in soils that cycle between
+anaerobic (reduced) and aerobic (oxidized)
+conditions. It is important to acknowledge that
+portions of an area under near-constant
+saturation may not display an indicator. Therefore,
+a prudent investigator might transect across the
+wetland towards the upland position to locate the
+wetland boundary.
 Morphological features of hydric soils indicate that
 saturation and anaerobic conditions have existed
 under either contemporary or former hydrologic
-regimes. Where soil morphology seems inconsistent
-with the landscape, vegetation, or observable
-hydrology, it may be necessary to obtain the
-assistance of an experienced soil or wetland scientist
-to determine whether the soil is hydric.
-Procedure
+regimes. Where soil morphology seems
+inconsistent with the landscape, vegetation,
+or observable hydrology, it is recommended
+to consult with an experienced soil or wetland
+scientist to determine whether the soil is hydric.
+General Guidance for Using the
+Indicators
 Observe and Document the Site
 Before making any decision about the presence
-or absence of hydric soils, the overall site and how
-it interacts with the soil should be considered. The
-steps below, while not required to identify a hydric
-soil, can help to explain why a hydric soil is or is not
-present. Always look at the landscape features of the
-immediate site and compare them to the surrounding
-areas. Try to contrast the features of wet and dry sites
-that are in close proximity. When observing slope
+or absence of hydric soils, the overall site and
+how it interacts with the soil should be
+considered. The steps below, while not required
+to identify a hydric soil, can help to explain why
+a hydric soil is or is not present. Always look at
+the landscape features of the immediate site and
+compare them to the surrounding areas. Try to
+contrast the features of wet and dry sites that
+are in close proximity. When observing slope
 features, look first at the area immediately around
-the sampling point. For example, a nearly level bench
-or depression at the sampling point may be more
-important to the wetness of the site than the overall
-landform on which the bench or depression occurs.
-Understanding how water moves across the site helps
-to clarify the reasons for the presence or absence of
-hydric soil indicators.
+the sampling point. For example, a nearly level
+bench or depression at the sampling point may be
+more important to the wetness of the site than the
+overall landform on which the bench or
+depression occurs. Understanding how water
+moves across the site helps to clarify the reasons
+for the presence or absence of hydric soil
+indicators.
 Observe and Document the Soil
-To observe and document a hydric soil, first remove
-from the soil surface any woody material larger than
-2 cm in cross section that cannot be crushed or
-shredded when rubbed. Do not remove the organic
-surface layers of the soil, which generally consist of
-plant remains in various stages of decomposition. Dig
-4 Field Indicators of
-a hole and describe the soil profile. In general, the
-hole should be dug to the depth needed to document
-an indicator or to confirm the absence of indicators.
-For most soils, the recommended excavation depth is
-approximately 20 inches (50 cm) from the soil surface,
-although a shallower soil pit may suffice for some
-indicators (e.g., A2, Histic Epipedon). Digging may be
-difficult in some areas because of rocks or hardpans.
-Use the completed profile description to determine
-which hydric soil indicators have been met (USDA,
-NRCS, 2006a).
-For soils with thick, dark surface layers, deeper
-examination may be required when field indicators are
-not observed at a depth of ≤20 inches (50 cm) from
-the soil surface. The accumulation of organic matter
-in these soils may mask redoximorphic features in the
-surface layers. Examination to a depth of 40 inches (1
-m) or more may be needed to determine whether the
-soils meet the requirements of indicator A12 (Thick
-Dark Surface). A soil auger or probe may be useful for
-sampling soil materials below a depth of 20 inches.
-Whenever possible, excavate the soil deep enough
-to determine if there are layers or materials present
-that might restrict soil drainage. This determination
-will help to indicate why the soil may or may not
-be hydric. After a sufficient number of exploratory
-excavations have been made to determine the soil
-hydrologic relationships at the site, subsequent
-excavations can be limited to the depth needed
-to identify hydric soil indicators. Consider taking
+To observe and document a hydric soil, first
+remove from the soil surface any woody material
+larger than 2 cm in cross section that cannot be
+crushed or shredded when rubbed. Do not
+remove the organic surface layers of the soil,
+which generally consist of plant remains in
+various stages of decomposition. Dig a hole and
+describe the soil profile. In general, the hole
+should be dug to the depth needed to document
+an indicator or to confirm the absence of
+indicators. For most soils, the recommended
+excavation depth is approximately 50 cm
+(20 inches) from the soil surface, although a
+shallower soil pit may suffice for some indicators
+(e.g., A2, Histic Epipedon). Use the completed
+profile description to determine which hydric soil
+indicators have been met.
+The accumulation of organic matter in these
+soils may mask redoximorphic features in the
+surface layers. For soils with thick, dark surface
+layers, deeper examination may be required when
+field indicators are not observed at a depth of
+50 cm (20 inches) or less from the soil surface.
+Examination to a depth of 1 m (40 inches) or
+more may be needed to determine whether the
+soils meet the requirements of indicator A12,
+Thick Dark Surface. A soil auger or probe may be
+useful for sampling soil materials below a depth of
+20 inches.
+Whenever possible, excavate the soil deep
+enough to determine if there are layers or
+materials present that might restrict soil
+5
+Field Indicators of Hydric Soils
+drainage. This determination will help to indicate
+why the soil may or may not be hydric. After a
+sufficient number of exploratory excavations have
+been made to determine the soil hydrologic
+relationships at the site, subsequent excavations
+can be limited to an adequate depth for
+identifying hydric soil indicators. Consider taking
 photographs of both the soil and the overall site,
 including a clearly marked measurement scale in
 pictures of soil profiles.
-In LRRs R, W, X, and Y, start observations at the
-actual surface for indicators A1, A2, and A3; start
-observations at the muck or mineral surface for A11
-and A12 and for testing indicators that allow muck;
-and start observations at the mineral surface for
-all other indicators. In LRRs F, G, H, and M, start
-observations at the actual soil surface if the soil is
-sandy or when applying indicators A1, A2, and A3
-and at the muck or mineral surface for the remaining
-field indicators. In the remaining LRRs, start
-observations at the top of the muck or mineral surface
-(underneath any peat and/or mucky peat material),
-except for areas of indicators A1, A2, and A3, where
-observations begin at the actual soil surface (fig. 2 ).
+When applying the indicators, the depth at which
+measurements begin differs based on the type of
+soil material encountered and regional differences
+in soils and climate. For indicators A1, A2, A3,
+S2, and S3 in all LRRs, measurements should
+start at the soil surface. For all indicators in R,
+W, X, and Y and for indicators F6 and F7 in all
+LRRs, all measurements should start at the top
+of the uppermost mineral layer. For all other
+indicators, except those in LRRs R, W, X, and Y
+and indicators F6 and F7, measurements should
+start at the top of the uppermost muck or mineral
+layer (fig. 2).
 All colors noted in this guide refer to moist
-Munsell colors (X-Rite, 2009). Dry soils should be
-moistened until the color no longer changes, and wet
-soils should be allowed to dry until they no longer
-glisten (fig. 3). Care should be taken to avoid over-
-moistening dry soil.
+Munsell colors (X-Rite, 2009). Dry soils should
+be moistened until the color no longer changes,
+and wet soils should be allowed to dry until they
+no longer glisten (fig. 3). Care should be taken to
+avoid over-moistening dry soil.
 Soil chromas specified in the indicators do not
 have decimal points; however, intermediate colors
-do occur. Colors should not be rounded to make the
-chroma meet the requirements of an indicator. A
-soil matrix with chroma between 2 and 3 should be
-described as having chroma of 2+. It does not have
-chroma of 2 and would not meet the requirements
-of any indicator that requires chroma of 2 or less.
-Value should be rounded to the nearest color chip
-when using the indicators. For example, a color in
-between a value of 3 and 4 should be rounded and
-not excluded from meeting either F3 Depleted Matrix
-or F6 Redox Dark Surface because the color occurs
-5
-Hydric Soils between color chips. If the value is closer to 3, then
-F6 or some other dark surface indicator should be
-considered. If it is closer to 4, then F3 or some other
-depleted matrix indicator should be considered.
+do occur. Colors should not be rounded to make
+the chroma meet the requirements of an indicator.
+A soil matrix with chroma between 2 and 3 should
+be described as having chroma of 2+. It would not
+meet any indicator that requires chroma of 2 or
+less.
+In contrast, the color value should be rounded to
+the nearest color chip when using the indicators.
+For example, a color in between a value of 3 and
+4 should be rounded and not excluded from
+meeting either F3, Depleted Matrix or F6, Redox
+Dark Surface, because the color occurs between
+color chips. If the value is closer to 3, then F6 or
+some other dark surface indicator should be
+considered. If it is closer to 4, then F3 or some
+other redoximorphic feature indicator should be
+considered.
 Always examine soil matrix colors in the field
-immediately after sampling. Ferrous iron in the soil
-can oxidize rapidly, resulting in the development of
-colors with higher chroma or redder hue. Soils that are
-saturated at the time of sampling may contain reduced
-iron and/or manganese that cannot be detected by the
-eye. Under saturated conditions, redox concentrations
-may be absent or difficult to see, particularly in dark
-colored soils. It may be necessary to let the soil dry
-(for 5 to 30 minutes or more) to a moist state before
-the iron or manganese oxidize and the redoximorphic
-features become visible.
+immediately after sampling. Ferrous iron in the
+soil can oxidize rapidly, resulting in the
+development of colors with higher chroma or
+redder hue. Soils that are saturated at the time of
+sampling may contain reduced iron and/or
+manganese that cannot be detected by the eye.
+Under saturated conditions, redox concentrations
+may be absent or difficult to see, particularly in
+dark-colored soils. It may be necessary to let the
+6
+Field Indicators of Hydric Soils
+soil dry (for 5 to 30 minutes or more) to a moist
+state before the iron or manganese oxidizes and
+the redoximorphic features become visible.
 Pay particular attention to changes in
-microtopography over short distances. Small changes
-in elevation may result in repetitive sequences of
-hydric/nonhydric soil mosaics, making the delineation
-of individual areas of hydric and nonhydric soils
-difficult. Commonly, the dominant condition (hydric
-or nonhydric) is the only reliable interpretation. The
-shape of the local landform can greatly affect the
-movement of water through the landscape. Significant
-changes in parent material or lithologic discontinuities
-in the soil can also affect the hydrologic properties of
-the soil.
-General Guidance for Using the
-Indicators
-Many of the hydric soil indicators were developed
-specifically for purposes of wetland delineation.
-During the development of these indicators, soils in
-the interiors of wetlands were not always examined;
-therefore, there are wetlands that lack any of the
-approved hydric soil indicators in the wettest interior
-portions. Wetland delineators and other users of
-the hydric soil indicators should concentrate their
-sampling efforts near the wetland edge and, if these
-soils are hydric, assume that soils in the wetter,
-interior portions of the wetland also are hydric, even if
-they lack an indicator.
-All mineral layers above any layers meeting the
-requirements of any indicator(s), except for indicators
-A16, S6, S11, F8, F12, F19, F20, and F21, have a
-dominant chroma of 2 or less; or the thickness of the
-layer(s) with a dominant chroma of more than 2 is less
-than 15 cm (6 inches). See figure 4.
-Soil Texture and the indicators
+microtopography over short distances. Small
+changes in elevation may result in repetitive
+sequences of hydric/nonhydric soil mosaics,
+making the delineation of individual areas of
+hydric and nonhydric soils difficult. Procedures
+have been developed to address mosaic scenar
+scenarios (USACE, 2012). The shape of the
+local landform can greatly affect the movement of
+water through the landscape. Significant changes
+in parent material or lithologic discontinuities in
+the soil can also affect the hydrologic properties
+of the soil.
+Indicators that have requirements that allow
+a chroma of greater than 2 can also have a
+chroma of greater than 2 above the layer or
+layers meeting the requirement of the indicator.
+Indicators that require a chroma of 2 or less
+only permit a chroma of 2 or more within a zone
+thinner than 6 inches above it, and the remainder
+of the material above the indicator must have a
+chroma of 2 or less (fig. 4).
+Hydric soil indicators were developed to find
+the hydric soil boundary. Many of the features
+used to identify a soil as a hydric soil are better
+expressed at the wetland boundary and may
+not be evident as you move to the center of the
+wetland. As wetlands dry out, manganese and
+iron diffuse to the boundary so that redoximorphic
+concentrations are more abundant near the
+boundary and may be absent in the middle of a
+wetland.
+Field indicators are best expressed at the
+boundary of a wetland. The interior of a wetland
+7
+Field Indicators of Hydric Soils
+may become depleted in manganese and iron
+or, if currently saturated, any manganese or iron
+could remain in solution and thus not be visible.
+In this case, the soil will lack any redoximorphic
+indicators. However, if you lack an indicator in the
+obvious interior of a wetland, you should transect
+out toward the boundary to see if an indicator is
+more evident toward the wetland boundary.
+Soil Texture and the Indicators
 Hydric soil indicators occur in three groups.
 Indicators for “All Soils” are used for any soil
-regardless of texture (A indicators). Indicators for
-“Sandy Soils” are used for soil layers with USDA
-textures of loamy fine sand or coarser (S indicators).
-Indicators for “Loamy and Clayey Soils” are used
-6 Field Indicators of
-for soil layers of loamy very fine sand and finer (F
-indicators). Both Sandy layers and Loamy or Clayey
-layers can occur in the same soil profile. Therefore, a
-soil that has a loamy surface layer over sand is hydric
-if it meets all of the requirements of matrix color,
-amount and contrast of redox concentrations, depth,
-and thickness for any single indicator or combination
-of indicators.
+layers regardless of texture (A indicators).
+Indicators listed under “Sandy Soils,” (S
+indicators), as well as any language that refers to
+sandy layers or materials, refer to soil materials
+with USDA textures of loamy fine sand or coarser.
+Indicators listed under “Loamy and Clayey Soils,”
+(F indicators), as well as any language that refers
+to loamy or clayey materials or layers, are used
+for soil materials with textures of loamy very fine
+sand and finer. Both sandy layers and loamy or
+clayey layers can occur in the same soil profile.
+If this occurs, you should look for sandy (S)
+indicators in the sandy layers and loamy and
+clayey (F) indicators in the loamy and clayey
+material.
 It is permissible to combine certain hydric soil
-indicators if all requirements of the indicators are met
-except for thickness. The most restrictive requirements
-for thickness of layers in any indicators used must
-be met. Not all indicators are possible candidates
-for combination. For example, indicator F2 (Loamy
-Gleyed Matrix) has no thickness requirement and is
-not a candidate for combination.
+indicators if all requirements of the indicators are
+met except minimum thickness. The most
+restrictive requirements for layer thickness in any
+indicators used must be met. Therefore, a soil is
+hydric if its layers meet the requirements of both
+S and F indicators, except thickness, such that
+when both layers are combined, the more
+restrictive indicator thickness requirement is met.
+For example, if you meet all the requirements of
+one indicator except it requires a minimum
+thickness of 10 cm (4 inches) and all the
+requirements of another indicator in a separate
+layer and it requires a minimum thickness of 15
+cm (6 inches), the cumulative thickness of the two
+layers must be at least 15 cm (6 inches).
+Not all indicators are possible candidates for
+combination. For example, indicator F2, Loamy
+Gleyed Matrix, has no thickness requirement and
+is not a candidate for combination.
 To Comment on the Indicators
 The indicators are revised and updated as field
-data are collected to improve our understanding of
-hydric soil processes. Revisions, additions, and other
-comments regarding field observations of hydric
-soil conditions that cannot be documented using
-the presently recognized hydric soil indicators are
-welcome. Any additions or other modifications must
-be approved by the NTCHS. Guidelines for requesting
-changes to field indicators are as follows:
-1. Adding indicators or changing existing
-indicators: Minimally, the following should
-accompany all requests for additions and changes
-to existing hydric soil indicators in Field Indicators of
-Hydric Soils in the United States:
-a) Detailed descriptions of at least three pedons
-that document the addition or change and
-detailed descriptions of the neighboring
-nonhydric pedons.
-b) Detailed vegetative data collected to represent
-the vegetation of the six pedons.
-c) Saturation/inundation data and oxidation-
-reduction potential (Eh) data for a duration that
-captures the saturation cycle (dry-wet-dry) of at
-least one of the hydric pedons and one of the
-nonhydric pedons. Precipitation and in-situ soil-
-water pH data from the same sites should also
-be provided (fig. 5). Data are to be collected
-according to “The Hydric Soil Technical
-Standard” described in Hydric Soils Technical
-Note 11 (http://www.nrcs.usda.gov/wps/portal/
-nrcs/main/soils/use/hydric/).
-2. Adding or deleting a test indicator: Minimally,
-the following should accompany all requests for
-adding or deleting a test indicator in Field Indicators of
-Hydric Soils in the United States:
-a) Detailed descriptions of at least three pedons
-that document the test indicator and detailed
-descriptions of three neighboring nonhydric
-pedons.
-b) Detailed vegetative data collected to represent
-the vegetation of the six pedons.
-3. All requests involving 1 and 2 above require a
-short written plan that: a) identifies the problem, b)
-explains the rationale for the request, and c) provides
-the following—person responsible and point of contact
-(email and postal addresses and phone number),
-timeline for supporting data and final report to be
-delivered to NTCHS, timeline needed for final NTCHS
-decision, and partners involved in the project.
-Requests, plans, and data should be sent to:
-Lenore Vasilas, Chair NTCHS
-USDA Natural Resources Conservation Service
-5601 Sunnyside Ave.
-Room 1-2126, Stop Code 5471
-Beltsville, MD 20705-5471
-Email: Lenore.Vasilas@wdc.usda.gov
-7
-Hydric
-Soils
-Figure
-6.—Map
-of
-USDA
-land
-resource
-regions.
-9
+data are collected to improve our understanding
+of hydric soil processes. Revisions, additions, and
+other comments regarding field observations of
+hydric soil conditions that cannot be documented
+using the presently recognized hydric soil
+indicators are welcome. Any suggestions for
+modifications must be approved by the NTCHS.
+Guidelines for requesting changes to field
+indicators are as follows:
+1. To propose a new indicator or revision to an
+existing indicator, the following documentation
+is required as a minimum to accompany all
+requests for additions and changes to existing
+hydric soil indicators for consideration into
+future versions of the “Field Indicators of
+Hydric Soils in the United States”:
+a. Detailed descriptions of at least three
+pedons that document the addition or
+change and detailed descriptions of the
+neighboring nonhydric pedons.
+b. Detailed vegetative documentation recording
+the specific plant community at each of
+the six pedon locations summarizing any
+contrasting patterns between the proposed
+upland and hydric positions.
+c. Saturation/inundation data and
+oxidation-reduction potential (Eh) data
+for a duration that captures the saturation
+cycle (dry-wet-dry) of at least one of the
+hydric pedons and one of the nonhydric
+pedons. Precipitation and in-situ soil-water
+pH data from the same sites should also be
+provided (fig. 5). Data are to be collected
+according to the Hydric Soil Technical
+Standard (Berkowitz et al., 2021).
+2. To add or delete a test indicator, the following
+documentation is required to accompany all
+requests for adding or deleting a test indicator
+in “Field Indicators of Hydric Soils in the
+United States”:
+8
+Field Indicators of Hydric Soils
+a. Detailed descriptions of at least three
+hydric pedons that document the test
+indicator and detailed descriptions of three
+neighboring nonhydric pedons.
+b. Detailed vegetative documentation
+recording the specific plant community
+at each of the six pedon locations,
+summarizing any contrasting patterns
+between the proposed upland and hydric
+positions.
+c. All requests involving a and b above
+require a short written description that
+identifies the problem, explains the
+rationale for the request, and provides the
+following:
+• A person responsible and point of
+contact (email and postal addresses
+and phone number)
+• A timeline for supporting data and final
+report to be delivered to NTCHS
+• A timeline requested for final NTCHS
+decision and partners involved in the
+project
+• Requests, plans, and data should be
+sent to the current Chair of the National
+Technical Committee for Hydric Soils.
+9
+Field Indicators of Hydric Soils
+10
 Field Indicators of Hydric Soils
-The indicator descriptions in this section are
-structured as follows:
-1. Alpha-numeric listing (A, S, or F indicators)
+11
+Field Indicators of Hydric Soils
+The indicator descriptions are structured as
+follows:
+1. Alphanumeric listing (A, S, or F indicators)
 2. Short name
-3. Applicable land resource regions (LRRs)
-4. Description of the field indicator
+3. Applicable land resource regions (LRRs in
+italic)
+4. Requirements of the field indicator
 5. User notes
-For example, A2 is the alpha numeric listing for
-the second indicator for All Soils; Histic Epipedon is
-the short name; “For use in all LRRs” indicates the
-applicable LRRs; and “a histic epipedon underlain by
-mineral soil material with chroma of 2 or less” is the
-description. The helpful user notes follow the indicator.
+For example, A2 is the alphanumeric listing for the
+second indicator for “All Soils”; “Histic Epipedon”
+is the short name; “For use in all LRRs” indicates
+the applicable regions; and “a histic epipedon
+underlain by mineral soil material with chroma 2”
+or less is the requirements of the indicator. Any
+accompanying user notes that follow the indicator
+provide useful tips or context to the indicator
+guidance.
 All Soils
-“All Soils” refers to soils with any USDA soil texture.
-All mineral layers above any of the layers meeting
-the requirements of any A indicator(s), except for
-indicator A16, have a dominant chroma of 2 or less, or
-the thickness of the layer(s) with a dominant chroma
-of more than 2 is less than 15 cm (6 inches). In
-addition, nodules and concretions are not considered
-to be redox concentrations for the application of the
-indicators. Use the following A-indicators in all soil
-layers, regardless of texture.
-A1.—Histosol (for use in all LRRs) or Histel (for
-use in LRRs with permafrost). Classifies as a Histosol
-(except Folist) or as a Histel (except Folistel).
-User Notes: In a Histosol, typically 40 cm (16
-inches) or more of the upper 80 cm (32 inches) is
-organic soil material (fig. 7). Organic soil materials
-have organic carbon contents (by weight) of 12 to
-18 percent or more, depending on the clay content
-of the soil. These materials include muck (sapric soil
-material), mucky peat (hemic soil material), and peat
-(fibric soil material). See Keys to Soil Taxonomy (Soil
-Survey Staff, 2014) for a complete definition.
+“All Soils” refers to soil layers with any USDA soil
+texture.
+All mineral layers above any of the layers
+meeting the requirements of any A indicator,
+except for indicators A16 and A18, have a
+dominant chroma of 2 or less, or the thickness
+of the layers with a dominant chroma of more
+than 2 is less than 15 cm (6 inches). In addition,
+nodules and concretions are not considered to
+be redox concentrations for the application of the
+indicators.
+A1.—Histosol or Histel. For use in all LRRs.
+Classifies as a Histosol (except Folist) or as a
+Histel (except Folistel).
+User Notes: In a Histosol, organic soil material is
+typically 40 cm (16 inches) or more of the
+upper 80 cm (32 inches) (fig. 8). Organic soil
+materials have organic carbon content (by weight)
+of 12 percent or more. These materials include
+muck (sapric soil material), mucky peat (hemic
+soil material), and peat (fibric soil material). See
+“Keys to Soil Taxonomy” (Soil Survey Staff, 2022)
+for a complete definition.
+12
+Field Indicators of Hydric Soils
 A2.—Histic Epipedon. For use in all LRRs. A
-histic epipedon underlain by mineral soil material with
+histic epipedon underlain by mineral soil material
+with chroma of 2 or less.
+User Notes: The surface horizon of most histic
+epipedons has organic soil material 20 cm (8
+inches) or more thick (fig. 9). Aquic conditions or
+artificial drainage is required. See “Keys to Soil
+Taxonomy” (Soil Survey Staff, 2022) for a
+complete definition.
+A3.—Black Histic. For use in all LRRs. A layer
+of peat, mucky peat, or muck 20 cm (8 inches) or
+more thick starting at a depth of 15 cm (6 inches)
+or less from the soil surface with a hue of 10YR
+or yellower, value of 3 or less, and chroma of 1
+or less and underlain by mineral soil material with
 chroma of 2 or less.
-User Notes: Most histic epipedons are surface
-horizons 20 cm (8 inches) or more thick of organic soil
-material (fig. 8). Aquic conditions or artificial drainage
-is required. See Keys to Soil Taxonomy (Soil Survey
-Staff, 2014) for a complete definition.
-A3.—Black Histic. For use in all LRRs. A layer of
-peat, mucky peat, or muck 20 cm (8 inches) or more
-thick that starts at a depth of ≤15 cm (6 inches) from
-the soil surface; has hue of 10YR or yellower, value of
-3 or less, and chroma of 1 or less; and is underlain by
-mineral soil material with chroma of 2 or less.
-10 Field Indicators of
 User Notes: Unlike indicator A2, this indicator
-does not require proof of aquic conditions or artificial
-drainage (fig. 8).
+does not require proof of aquic conditions or
+artificial drainage (see fig. 9).
 A4.—Hydrogen Sulfide. For use in all LRRs. A
-hydrogen sulfide odor starting at a depth ≤30 cm (12
-inches) from the soil surface.
+hydrogen sulfide odor starting at a depth of 30 cm
+(12 inches) or less from the soil surface.
 User Notes: This “rotten egg smell” indicates that
-sulfate-sulfur has been reduced to hydrogen sulfide
-gas and therefore the soil is anaerobic (fig. 9).
+sulfate-sulfur has been chemically reduced to
+hydrogen sulfide gas, which indicates the soil is
+anaerobic (fig. 10).
 A5.—Stratified Layers. For use in LRRs C, F, K,
-L, M, N, O, P, R, S, T, and U; for testing in LRRs Q, V
-and Z. Several stratified layers starting at a depth ≤15
-cm (6 inches) from the soil surface. At least one of the
-layers has value of 3 or less and chroma of 1 or less,
-or it is muck, mucky peat, peat, or a mucky modified
-mineral texture. The remaining layers have chroma of
-2 or less. For any sandy material that constitutes the
-layer with value of 3 or less and chroma of 1 or less,
-at least 70 percent of the visible soil particles must be
-masked with organic material, viewed through a 10x
-or 15x hand lens. Observed without a hand lens, the
-particles appear to be close to 100 percent masked.
+L, M, N, O, P, R, S, T, and U; for testing in LRRs
+Q, V, and Z. Several stratified layers starting at
+a depth of 15 cm (6 inches) or less from the soil
+surface. At least one of the layers has value of
+3 or less and chroma of 1 or less, or it is muck,
+mucky peat, peat, or a mucky modified mineral
+texture. The remaining layers in the upper 15
+cm (6 inches) have chroma of 2 or less. For any
+sandy material that constitutes the layer with
+value of 3 or less and chroma of 1 or less, at
+least 70 percent of the visible soil particles must
+be masked with organic material when viewed
+through a 10x or 15x hand lens.
 User Notes: Use of this indicator may require
 assistance from a trained soil scientist with local
-experience. A stratified layer is depositional and not
-pedogenic. The minimum organic-carbon content of
-at least one layer of this indicator is slightly less than
-is required for indicator A7 (5 cm Mucky Mineral). An
-undisturbed sample must be observed. Individual
-11
-strata are dominantly less than 2.5 cm (1 inch)
-thick. A hand lens is an excellent tool to aid in the
-identification of this indicator. Many alluvial soils have
-stratified layers at greater depths; these soils do not
-meet the requirements of this indicator. Many alluvial
-soils have stratified layers at the required depths but
-do not have chroma of 2 or less; these do not meet
-the requirements of this indicator. The stratified layers
-occur in any soil texture (fig. 10).
-A6.—Organic Bodies. For use in LRRs P (except
-for MLRA 136), T, U, and Z. Presence of 2 percent
-or more organic bodies of muck or a mucky modified
-mineral texture starting at a depth ≤15 cm (6 inches)
-from the soil surface.
-User Notes: Organic bodies typically occur at the
-tips of fine roots. In order to meet the Organic Bodies
-indicator, the organic carbon content in organic
-bodies must meet the requirements of muck or mucky
-modified textures. The size of the organic body is not
-specifically defined, but the bodies are commonly
-1 to 3 cm (0.5 to 1 inch) in diameter (figs. 11 and
-12). Many organic bodies do not have the required
-content of organic carbon and as a result do not meet
-this indicator. For example, organic bodies of mucky
-peat (hemic material) and/or peat (fibric material)
-do not meet the requirements of this indicator, nor
-does material consisting of partially decomposed
-root tissue. The Organic Bodies indicator includes the
-indicator previously named “accretions” (Florida Soil
-Survey Staff, 1992).
+experience. A stratified layer is depositional and
+not pedogenic. An undisturbed sample must be
+observed. Individual strata are dominantly less
+than 2.5 cm (1 inch) thick. A hand lens is an
+excellent tool to aid in the identification of this
+indicator. Many alluvial soils have stratified
+layers at greater depths than allowed in the
+requirements of the indicator; these soils do not
+meet the requirements of this indicator.
+13
+Field Indicators of Hydric Soils
+Many alluvial soils have stratified layers at the
+required depths but do not have chroma of 2
+or less; these do not meet the requirements of
+this indicator. The stratified layers occur in any
+soil texture (fig. 11). In sandy textures observed
+without a hand lens, the masked sand particles
+appear to be closer to 100 percent masked with
+organic material when moist. Masked sand grains
+can disappear quickly if a soil has been drained or
+disturbed.
+A6.—Organic Bodies. For use in LRRs P
+(except for MLRA 136), T, U, and Z. Presence
+of 2 percent or more organic bodies of muck or
+a mucky modified mineral texture, starting at a
+depth of 15 cm (6 inches) or less from the soil
+surface.
+User Notes: Organic bodies typically occur at
+the tips of fine roots. In order to meet the Organic
+Bodies indicator, the organic carbon content in
+organic bodies must meet the requirements of
+muck or mucky modified textures. The size of the
+organic body is not specifically defined, but the
+bodies are commonly 1 to 3 cm (0.5 to 1 inch) in
+diameter (fig. 12).
+Many organic bodies do not have the required
+content of organic carbon and as a result do not
+meet this indicator. For example, organic bodies
+of mucky peat (hemic material) and/or peat (fibric
+14
+Field Indicators of Hydric Soils
+material) do not meet the requirements of this
+indicator nor does material consisting of partially
+decomposed root tissue. The Organic Bodies
+indicator includes the indicator previously named
+“accretions” (Florida Soil Survey Staff, 1992).
 A7.—5 cm Mucky Mineral. For use in LRRs P
-(except for MLRA 136), T, U, and Z. A layer of mucky
-modified mineral soil material 5 cm (2 inches) or more
-12 Field Indicators of
-thick, starting at a depth ≤15 cm (6 inches) from the
-soil surface (fig. 13).
+(except for MLRA 136), T, U, and Z. A layer of
+mucky modified mineral soil material 5 cm (2
+inches) or more thick, starting at a depth of 15 cm
+(6 inches) or less from the soil surface (fig. 13).
 User Notes: “Mucky” is a USDA texture modifier
-for mineral soils. The content of organic carbon is at
-least 5 percent and ranges to as high as 18 percent.
-The percentage required depends on the clay content
-of the soil; the higher the clay content, the higher
-the content of organic carbon required. For example,
-a mucky fine sand soil contains between 5 and 12
-percent organic carbon. When the amount of clay
-is increased as in a mucky sandy loam, the organic
-carbon content increases to between 7 and 14
-percent.
+for mineral soils. The content of organic carbon
+ranges from 5 to 12 percent.
 A8.—Muck Presence. For use in LRRs Q, U, V,
 and Z. A layer of muck with value of 3 or less and
-chroma of 1 or less, starting at a depth ≤15 cm (6
-inches) from the soil surface.
+chroma of 1 or less, starting at a depth of 15 cm
+(6 inches) or less from the soil surface.
 User Notes: The presence of muck of any
-thickness at a depth of ≤15 cm (6 inches) is the only
-requirement. Normally, this expression of anaerobiosis
-is at the soil surface; however, it may occur at any
-depth ≤15 cm (6 inches). Muck is sapric soil material
-with a minimum content of organic carbon that ranges
-from12 to18 percent, depending on the content of clay.
-Organic soil material is called muck if virtually all of
-the material has undergone sufficient decomposition
-to prevent the identification of plant parts. Mucky peat
-(hemic material) and/or peat (fibric material) do not
-qualify. Generally, muck is black and has a “greasy”
-feel; sand grains should not be evident.
+thickness at a depth of 15 cm (6 inches) or less
+is the only requirement. Normally, this expression
+of anaerobiosis is at the soil surface; however,
+it may occur at any depth 15 cm (6 inches) or
+less. Muck is sapric soil material with a minimum
+content of 12 percent organic carbon. Organic
+soil material is called muck if virtually all of the
+material has undergone sufficient decomposition
+to prevent the identification of plant parts. Mucky
+peat (hemic material) and/or peat (fibric material)
+do not qualify. Generally, muck is black and has a
+“greasy” feel; sand grains should not be evident.
 A9.—1 cm Muck. For use in LRRs D, F, G, H, P
-(except for MLRA 136), and T; for testing in LRRs C,
-I, J, and O. A layer of muck 1 cm (0.5 inch) or more
-thick with value of 3 or less and chroma of 1 or less
-and starting at a depth ≤15 cm (6 inches) from the soil
-surface.
-User Notes: Unlike indicator A8 (Muck Presence),
-this indicator has a minimum thickness requirement
-of 1 cm (fig. 14). Normally, this expression of
-anaerobiosis is at the soil surface; however, it may
-occur at any depth ≤15 cm (6 inches). Muck is sapric
-soil material with a minimum content of organic
-carbon that ranges from12 to18 percent, depending
-on the content of clay. Organic soil material is called
-muck if virtually all of the material has undergone
-sufficient decomposition to limit the recognition of
-plant parts. Mucky peat (hemic material) and/or peat
-(fibric material) do not qualify. Generally, muck is black
-and has a “greasy” feel; sand grains should not be
-evident.
-A10.—2 cm Muck. For use in LRR M and N;
-for testing in LRRs A, B, E, K, L, and S (except for
-MLRA 148). A layer of muck 2 cm (0.75 inch) or more
-thick with value of 3 or less and chroma of 1 or less,
-starting at a depth ≤15 cm (6 inches) from the soil
-surface.
+(except for MLRA 136), and T; for testing in LRRs
+C, I, J, and O. A layer of muck 1 cm (0.5 inch) or
+more thick with value of 3 or less and chroma of 1
+or less, starting at a depth of 15 cm (6 inches) or
+less from the soil surface.
+15
+Field Indicators of Hydric Soils
+User Notes: Unlike indicator A8, Muck Presence,
+this indicator has a minimum thickness
+requirement of 1 cm (fig. 14).
+Normally, this expression of anaerobiosis is at the
+soil surface; however, it may occur at any depth
+of 15 cm (6 inches) or less. Muck is sapric soil
+material with a minimum content of 12 percent
+organic carbon. Organic soil material is called
+muck if virtually all of the material has
+undergone sufficient decomposition to limit the
+recognition of plant parts. Mucky peat (hemic
+material) and/or peat (fibric material) do not
+qualify. Generally, muck is black and has a
+“greasy” feel; sand grains should not be evident.
+A10.—2 cm Muck. For use in LRRs M and N; for
+testing in LRRs A, B, E, K, L, and S (except for
+MLRA 148). A layer of muck 2 cm (0.75 inch) or
+more thick with value of 3 or less and chroma of 1
+or less, starting at a depth of 15 cm (6 inches) or
+less from the soil surface.
 User Notes: This indicator requires a minimum
-muck thickness of 2 cm. Normally, this expression of
-anaerobiosis is at the soil surface; however, it may
-occur at any depth ≤15 cm (6 inches). Muck is sapric
-soil material with a minimum content of organic
-carbon that ranges from12 to18 percent, depending
-on the content of clay. Organic soil material is called
-muck if virtually all of the material has undergone
-sufficient decomposition to limit the recognition of
-plant parts. Mucky peat (hemic material) and/or peat
-13 Hydric Soils
-(fibric material) do not qualify. Generally, muck is black
-and has a “greasy” feel; sand grains should not be
-evident.
-A11.—Depleted Below Dark Surface. For use in
-all LRRs, except for W, X, and Y; for testing in LRRs
-W, X, and Y. A layer with a depleted or gleyed matrix
-that has 60 percent or more chroma of 2 or less,
-starting at a depth ≤30 cm (12 inches) from the soil
-surface, and having a minimum thickness of either:
-a. 15 cm (6 inches), or
-b. 5 cm (2 inches) if the 5 cm consists of
+muck thickness of 2 cm. Normally, this expression
+of anaerobiosis is at the soil surface; however,
+it may occur at any depth of 15 cm (6 inches) or
+less. Muck is sapric soil material with a minimum
+content of 12 percent organic carbon. Organic
+soil material is called muck if virtually all of the
+material has undergone sufficient decomposition
+to limit the recognition of plant parts. Mucky peat
+(hemic material) and/or peat (fibric material) do
+not qualify. Generally, muck is black and has a
+“greasy” feel; sand grains should not be evident.
+A11.—Depleted Below Dark Surface. For use
+in all LRRs except for W, X, and Y; for testing
+in LRRs W, X, and Y. A layer with a depleted or
+gleyed matrix that has 60 percent or more chroma
+of 2 or less, starting at a depth of 30 cm (12
+inches) or less from the soil surface and having a
+minimum thickness of either
+1. 15 cm (6 inches), or
+2. 5 cm (2 inches) if the 5 cm consists of
 fragmental soil material.
 Organic, loamy, or clayey layer(s) above the
 depleted or gleyed matrix must have value of 3 or
-less and chroma of 2 or less starting at a depth <15
-cm (6 inches) from the soil surface and extend to the
-depleted or gleyed matrix. Any sandy material above
-the depleted or gleyed matrix must have value of 3
-or less and chroma of 1 or less starting at a depth
-≤15 cm (6 inches) from the soil surface and extend to
-the depleted or gleyed matrix. Viewed through a 10x
-or 15x hand lens, at least 70 percent of the visible
-sand particles must be masked with organic material.
-Observed without a hand lens, the sand particles
-appear to be close to 100 percent masked.
-User Notes: This indicator often occurs in Mollisols
-but also applies to soils with umbric epipedons and
-dark colored ochric epipedons (figs. 15 and 16). For
-soils with dark colored epipedons more than 30 cm
-(12 inches) thick, use indicator A12. A depleted matrix
-requires value of 4 or more and chroma of 2 or less.
-Redox concentrations, including soft iron-manganese
-masses and/or pore linings, are required in soils
-14 Field Indicators of
-with matrix colors of 4/1, 4/2, or 5/2. A, E, and calcic
-horizons may have low chromas and high values
-and may therefore be mistaken for a depleted matrix;
-however, they are excluded from the concept of
-depleted matrix unless the soil has common or many
-distinct or prominent redox concentrations occurring
-as soft masses or pore linings.
+less and chroma of 2 or less starting at a depth
+of 15 cm (6 inches) or less from the soil surface
+and extend to the depleted or gleyed matrix. Any
+loamy fine sand and coarser material above the
+depleted matrix must have value of 3 or less
+and chroma of 1 or less starting at a depth of 15
+cm (6 inches) or less from the soil surface and
+extend to the depleted or gleyed matrix. When
+viewed through a 10x or 15x hand lens, at least
+70 percent of the visible sand particles must be
+masked with organic material.
+User Notes: The depleted matrix can occur in
+either sandy soil layers or loamy and clayey soil
+layers. This indicator often occurs in Mollisols but
+16
+Field Indicators of Hydric Soils
+also applies to soils with umbric epipedons and
+dark-colored ochric epipedons (figs. 15 and 16).
+For soils with dark-colored epipedons greater
+than 30 cm (12 inches) thick, use indicator A12.
+A depleted matrix requires value of 4 or more and
+chroma of 2 or less.
+Redox concentrations, including soft iron-
+manganese masses and/or pore linings, are
+required in soils with matrix colors of 4/1, 4/2,
+or 5/2. A, E, and calcic horizons may have low
+chromas and high values and may therefore
+be mistaken for a depleted matrix; however,
+they are excluded from the concept of depleted
+matrix unless the soil layer has 2 percent or
+more distinct or prominent redox concentrations
+occurring as soft masses or pore linings. In
+sandy textures observed without a hand lens, the
+masked sand particles appear to be closer to 100
+percent masked with organic material when moist.
+Masked sand grains can disappear quickly if a
+soil has been drained or disturbed.
+17
+Field Indicators of Hydric Soils
 A12.—Thick Dark Surface. For use in all LRRs.
-A layer at least 15 cm (6 inches) thick with a depleted
-or gleyed matrix that has 60 percent or more chroma
-of 2 or less starting below 30 cm (12 inches) of the
-surface. The layer(s) above the depleted or gleyed
-matrix and starting at a depth <15 cm (6 inches) from
-the soil surface must have value of 2.5 or less and
-chroma of 1 or less to a depth of at least 30 cm (12
-inches) and value of 3 or less and chroma of 1 or less
-in any remaining layers above the depleted or gleyed
-matrix. In any sandy material above the depleted
-or gleyed matrix, at least 70 percent of the visible
-soil particles must be masked with organic material,
-viewed through a 10x or 15x hand lens. Observed
-without a hand lens, the particles appear to be close
-to 100 percent masked.
-User Notes: This indicator applies to soils that
-have a black layer 30 cm (12 inches) or more thick
-and have value of 3 or less and chroma of 1 or less
-in any remaining layers directly above a depleted or
+A layer 15 cm (6 inches) or more thick with a
+depleted or gleyed matrix that has 60 percent
+or more chroma of 2 or less starting at a depth
+below 30 cm (12 inches) from the soil surface.
+The layer(s) above the depleted or gleyed matrix
+and starting at a depth of less than 15 cm (6
+inches) from the soil surface must have value of
+2.5 or less and chroma of 1 or less to a depth of
+30 cm (12 inches) or more and a value of 3 or
+less and chroma of 1 or less in any remaining
+layers above the depleted or gleyed matrix. In
+any loamy fine sand and coarser material above
+the depleted or gleyed matrix, at least 70 percent
+of the particles must be masked with organic
+material when viewed through a 10x or 15x hand
+lens.
+User Notes: The depleted matrix can occur in
+either sandy soil layers or loamy and clayey soil
+layers. This indicator applies to soils that have
+a very dark layer of 30 cm (12 inches) or more
+thick and then can get a little less dark in any
+remaining layers directly above a depleted or
 gleyed matrix (fig. 17). This indicator is most often
 associated with overthickened soils in concave
-landscape positions. A depleted matrix requires
+landscape positions. A depleted matrix requires a
 value of 4 or more and chroma of 2 or less. Redox
 concentrations, including soft iron-manganese
-15 Hydric Soils
 masses and/or pore linings, are required in soils
-with matrix colors of 4/1, 4/2, or 5/2. A, E, and calcic
-horizons may have low chromas and high values
-and may therefore be mistaken for a depleted matrix;
-however, they are excluded from the concept of
-depleted matrix unless the soil has common or many
-distinct or prominent redox concentrations occurring
-as soft masses or pore linings.
-A13.—Alaska Gleyed. For use in LRRs W, X, and
-Y. A mineral layer with a dominant hue of N, 10Y,
-5GY, 10GY, 5G, 10G, 5BG, 10BG, 5B, 10B, or 5PB
-and with value of 4 or more in more than 50 percent
-of the matrix. The layer starts at a depth ≤30 cm (12
-inches) from the mineral surface and is underlain at a
-depth ≤1.5 m (60 inches) from the soil surface by soil
-material with hue of 5Y or redder in the same type of
-parent material.
-User Notes: This indicator can be used for all
-mineral soils, not just sandy soils. The indicator has
-two requirements (fig. 18). First, one or more of the
-specified gley colors occurs ≤30 cm (12 inches) from
+with matrix colors of 4/1, 4/2, or 5/2. A, E, and
+calcic horizons may be mistaken for a depleted
+matrix because they may have low chromas
+and high values. These horizons are excluded
+from the concept of a depleted matrix unless
+they have at least 2 percent distinct or prominent
+concentrations occurring as soft masses or pore
+linings. In sandy textures observed without a
+hand lens, the masked sand particles appear to
+be closer to 100 percent masked with organic
+material when moist. Masked sand grains can
+disappear quickly if a soil has been drained or
+disturbed.
+A13.—Alaska Gleyed. For use in LRRs W, X,
+and Y. A mineral layer with more than 50 percent
+gleyed matrix. The layer starts at a depth of 30
+cm (12 inches) or less from the mineral surface
+and is underlain at a depth 1.5 m (60 inches) or
+less from the soil surface by soil material with
+hue of 5Y or redder in the same type of parent
+material.
+User Notes: The indicator has two requirements
+(fig. 18). First, one or more of the specified gley
+colors occurs at 30 cm (12 inches) or less from
 the soil surface. These must be the colors on the
-pages of the Munsell color book (X-Rite, 2009) that
-show gley colors, not simply gray colors. Second,
-below these gley colors, the color of similar soil
-material is 5Y or redder (2.5Y, 10YR, 7.5YR, etc.).
-The presence of the truly gley colors indicates that
-the soil has undergone reduction. The requirement
-for 5Y or redder colors lower in the profile ensures
-that the gley colors are not simply the basic color
-of the parent material. Tidal sediments, lacustrine
-sediments, loess, and some glacial tills have base
-colors that appear as gley. This indicator proves
-that the near-surface gley colors are not natural soil
-material colors and that they are the result of reduced
-conditions. When comparing the near-surface and
-underlying colors, make sure that both are the same
-type of soil material. Many soils in Alaska consist
-of two or more types of material (e.g., silty loess
-overlying gravelly glacial till or sand and gravel river
-deposits).
+pages of the “Munsell Soil Color Book” (X-Rite,
+2009) that show gley colors, not simply gray colors.
+Second, below these gley colors, the color of
+similar soil material is 5Y or redder (2.5Y, 10YR,
+7.5YR, etc.). The presence of the truly gley colors
+indicates that the soil has undergone reduction.
+18
+Field Indicators of Hydric Soils
+The requirement for 5Y or redder colors lower
+in the profile ensures that the gley colors are
+not simply the basic color of the parent material.
+Some tidal sediments, lacustrine sediments, loess,
+and glacial tills have base colors that appear as
+gley. This indicator proves that the near-surface
+gley colors are the result of anaerobic conditions.
+When comparing the near-surface and underlying
+colors, make sure that both are the same type
+of soil material. Many soils in Alaska consist of
+two or more types of material (e.g., silty loess
+overlying gravelly glacial till or sand and gravel
+river deposits).
 A14.—Alaska Redox. For use in LRRs W, X,
-and Y. A mineral layer that has dominant hue of 5Y
-with chroma of 3 or less, or a gleyed matrix, with
+and Y. A mineral layer that has dominant hue of
+5Y with chroma of 3 or less or a gleyed matrix of
 10 percent or more distinct or prominent redox
 concentrations occurring as pore linings with value
-and chroma of 4 or more. The layer occurs at a depth
-≤30 cm (12 inches) from the soil surface.
+and chroma of 4 or more. The layer occurs at a
+depth of 30 cm (12 inches) or less from the soil
+surface.
 User Notes: In a soil layer that has been
-reduced, one of the first areas where oxygen will be
-reintroduced is along pores and the channels of live
-roots (fig. 19). As oxidation occurs in these areas,
-characteristic reddish orange redox concentrations
-(with value and chroma of 4 or more) will be apparent
-along the pores and linings. These will stand out in
-contrast to the matrix color of the overall soil layer.
-First, determine if the dominant color(s) of the soil
+reduced, one of the first areas where oxygen will
+be reintroduced is along pores and the channels
+of live roots (fig. 19). As oxidation occurs in
+these areas, characteristic reddish orange
+redox concentrations (with value and chroma
+of 4 or more) will be apparent along the pores
+and linings. These will stand out in contrast to
+the matrix color of the overall soil layer. First,
+19
+Field Indicators of Hydric Soils
+determine if the dominant color(s) of the soil
 layer match the chroma 3 or less or gley colors
-indicated. Then break open pieces of the soil and
-look for reddish orange redox concentrations along
-pores and root linings. The occurrence of these
-concentrations indicates that the soil has been
-reduced during periods of saturation and is now
-oxidizing in a drier state.
-A15.—Alaska Gleyed Pores. For use in LRRs W,
-X, and Y. A mineral layer that has 10 percent or more
-hue of N, 10Y, 5GY, 10GY, 5G, 10G, 5BG, 10BG,
-5B, 10B, or 5PB with value of 4 or more along root
-channels or other pores and that starts at a depth ≤30
-cm (12 inches) from the soil surface. The matrix has a
-dominant hue of 5Y or redder.
-16 Field Indicators of
+indicated. Then, break open pieces of the soil
+and look for reddish orange redox concentrations
+along pores and root linings. The occurrence of
+these concentrations indicates that the soil has
+been reduced during periods of saturation and is
+now oxidizing in a drier state.
+A15.—Alaska Gleyed Pores. For use in LRRs
+W, X, and Y. A mineral layer of 10 percent or more
+gleyed matrix colors along root channels or other
+pores and that starts at a depth of 30 cm (12
+inches) or less from the soil surface. The matrix
+has a dominant hue of 5Y or redder.
 User Notes: In a soil layer that is becoming
-anaerobic, reduced conditions will first occur where
-the soil microbes have an ample supply of organic
-carbon. Colder soils, such as those in Alaska,
-normally have a low content of organic carbon, so
-the microbes will congregate along the channels
-containing dead roots. Gley colors will first appear
-along these channels (fig. 20). In a soil layer that is not
-already dominated by gley colors, break open pieces
-of the soil and look closely at the root channels.
-Many of these will be very thin or fine. See if you can
-observe thin coatings along the channels that match
-the gley colors listed in the indicator. If they occur,
+anaerobic, reduced conditions will first occur
+where the soil microbes have an ample supply
+of organic carbon. Colder soils, such as those in
+Alaska, normally have a low content of organic
+carbon, so the microbes will congregate along
+the channels containing dead roots. Gley colors
+will first appear along these channels (fig. 20).
+In a soil layer that is not already dominated by
+gley colors, break open pieces of the soil and
+look closely at the root channels. Many of these
+will be very thin or fine. See if you can observe
+thin coatings along the channels that match the
+gley colors listed in the indicator. If they occur,
 they indicate that the soil experiences anaerobic
 conditions.
 A16.—Coast Prairie Redox. For use in MLRA
 150A of LRR T; for testing in LRR S (except for
-MLRA 149B). A layer starting at a depth ≤15 cm (6
-inches) from the soil surface that is at least 10 cm (4
-inches) thick and has a matrix chroma of 3 or less
-with 2 percent or more distinct or prominent redox
-concentrations occurring as soft masses and/or pore
-linings.
-User Notes: These hydric soils occur mainly
-on depressional landforms and portions of the
-intermound landforms on the Lissie Formation. Redox
-concentrations occur mainly as iron-dominated pore
-linings. Common or many redox concentrations are
-required. Matrix colors with chroma 3 are allowed
-because they may be the color of stripped sand grains
-or because few or common sand-sized reddish chert
-particles occur and may prevent obtaining chroma of
-2 or less.
+MLRA 149B). A layer starting at a depth of 15
+cm (6 inches) or less from the soil surface that is
+10 cm (4 inches) or more thick and has a matrix
+chroma of 3 or less with 2 percent or more distinct
+or prominent redox concentrations occurring as
+soft masses and/or pore linings.
+User Notes: These hydric soils occur mainly on
+depressional landforms and portions of the
+intermound landforms on the Lissie Formation.
+Redox concentrations occur mainly as
+iron-dominated pore linings. Common or many
+redox concentrations are required. Matrix colors
+with chroma 3 are allowed because they may be
+the color of stripped sand grains or because few
+or common sand-sized reddish chert particles
+occur and may prevent obtaining chroma of 2 or
+less.
 A17.—Mesic Spodic. For use in MLRA 144A and
-145 of LRR R and in MLRA 149B of LRR S. A layer
-that is ≥5 cm (2 inches) thick, that starts at a depth
-≤15 cm (6 inches) from the mineral soil surface, that
-has value of 3 or less and chroma of 2 or less, and
-that is directly underlain by either:
-a. One or more layers of spodic materials that
-have a combined thickness of ≥8 cm (3 inches),
-that start at a depth ≤30 cm (12 inches) from
-the mineral soil surface, and that have a value
-and chroma of 3 or less; or
-b. One or more layers that have a combined
-thickness of ≥5 cm (2 inches), that start at a
-depth ≤30 cm (12 inches) from the mineral
-soil surface, that have a value of 4 or more
-and chroma of 2 or less, and that are directly
-underlain by one or more layers that have a
-17 Hydric Soils
-combined thickness of ≥8 cm (3 inches), that
-are spodic materials, and that have a value and
-chroma of 3 or less.
+145 of LRR R and in MLRA 149B of LRR S.
+A layer that is 5 cm (2 inches) or more thick, that
+starts at a depth of 15 cm (6 inches) or less from
+the mineral soil surface, that has value of 3 or
+less and chroma of 2 or less, and that is directly
+underlain by either
+1. one or more layers of spodic materials that
+have a combined thickness of 8 cm (3 inches)
+or more, that start at a depth of 30 cm (12
+inches) or less from the mineral soil surface,
+and that have a value and chroma 3 or less;
+or
+2. one or more layers that have a combined
+thickness of 5 cm (2 inches) or more, that start
+at a depth of 30 cm (12 inches) or less from
+the mineral soil surface, that have a value of 4
+or more and chroma of 2 or less, and that are
+directly underlain by one or more layers that
+have a combined thickness of 8 cm (3 inches)
+or more, that are spodic materials, and that
+have a value and chroma of 3 or less.
+20
+Field Indicators of Hydric Soils
 User Notes: This indicator is used to identify wet
 soils that have spodic materials or that meet the
-definition of Spodosols. The layer or layers described
-above that have value of 4 or more and chroma of 2 or
-less are typically described as E or Eg horizons. The
-layer or layers that are 8 cm (3 inches) or more, that
-have value and chroma 3 or less, and that meet the
-definition of spodic materials (that is, have an illuvial
-accumulation of amorphous materials consisting of
-organic carbon and aluminum with or without Fe) are
-typically described as Bh, Bhs, or Bhsm horizons.
-These Bh, Bhs, or Bhsm horizons typically have
-several color patterns, cementation, or both.
+definition of Spodosols. The layer or layers
+described above that have value of 4 or more and
+chroma of 2 or less are typically described as E or
+Eg horizons. The layer or layers that are 8 cm (3
+inches) or more thick, that have value and chroma
+of 3 or less, and that meet the definition of spodic
+materials (that is, have an illuvial accumulation of
+amorphous materials consisting of organic carbon
+and aluminum with or without Fe) are typically
+described as Bh, Bhs, or Bhsm horizons. These
+Bh, Bhs, or Bhsm horizons typically have several
+color patterns, cementation, or both.
+A18.—Iron Monosulfide. For use in all LRRs.
+Positive identification of dark-gray or black iron
+monosulfide concentrations with value of 4 or less
+and chroma of 2 or less, starting at a depth of 25
+cm (10 inches) or less from the soil surface.
+User Notes: Positive identification of this
+indicator requires a minimum of 2 separate
+observations of iron monosulfide (FeS)
+concentrations in the soil occurring as stains,
+coatings, soft masses, or pore linings. Care
+should be taken to observe the occurrence of FeS
+immediately following excavation as these
+compounds can oxidize rapidly with exposure to
+the atmosphere. The presence of FeS
+concentrations is confirmed by documenting
+dark-gray or black colored areas within the soil
+matrix and its subsequent degradation using
+either: (A) oxidation following exposure to the
+atmosphere or with application of an oxidizing
+agent such as dilute hydrogen peroxide, both of
+which result in an increase in Munsell value of
+1 or more; or (B), the evolution of hydrogen
+sulfide gas following application of dilute
+hydrochloric acid. See the “Glossary” for a
+description of methods to identify FeS (fig. 21).
 Sandy Soils
-“Sandy Soils” have a USDA texture of loamy fine
-sand and coarser. All mineral layers above any of the
-layers meeting the requirements of any S indicator(s),
-except for indicator S6 and S11, have a dominant
-chroma of 2 or less, or the thickness of the layer(s) with
-a dominant chroma of more than 2 is less than 15 cm
-(6 inches). In addition, nodules and concretions are
-not considered to be redox concentrations. Use the
-following S-indicators for sandy mineral soil materials.
-S1.—Sandy Mucky Mineral. For use in all LRRs,
-except for T, U, W, X, Y , and Z and portions of LRR
-P outside of MLRA 136. A layer of mucky modified
-sandy soil material 5 cm (2 inches) or more thick
-starting at a depth ≤15 cm (6 inches) from the soil
+“Sandy Soils” have layers that have a USDA
+texture of loamy fine sand and coarser. All
+mineral layers above any of the layers meeting
+the requirements of any S indicator, except for
+indicators S6 and S11, have a dominant chroma
+of 2 or less, or the thickness of the layer(s)
+with a dominant chroma of more than 2 is less
+than 15 cm (6 inches). In addition, nodules and
+concretions are not considered to be redox
+concentrations. Use the following S indicators for
+soils with mineral layers that are sandy.
+S1.—Sandy Mucky Mineral. For use in all LRRs
+except T, U, W, X, Y, and Z and all but MLRA 136
+of P. A layer of mucky modified sandy soil
+material 5 cm (2 inches) or more thick starting at
+a depth of 15 cm (6 inches) or less from the soil
 surface.
 User Notes: “Mucky” is a USDA texture modifier
-for mineral soils. The content of organic carbon is at
-least 5 percent and ranges to as high as 14 percent
-for sandy soils. The percent required depends on the
-clay content of the soil; the higher the clay content,
-the higher the content of organic carbon required. For
-example, a mucky fine sandy soil contains between 5
-and 12 percent organic carbon.
-S2.—2.5 cm Mucky Peat or Peat. For use in LRRs
-G and H. A layer of mucky peat or peat 2.5 cm (1
-inch) or more thick with value of 4 or less and chroma
-of 3 or less, starting at a depth ≤15 cm (6 inches)
-from the soil surface, and underlain by sandy soil
-material.
+for mineral soils. The content of organic carbon
+is at least 5 percent and ranges to as high as 12
+percent.
+21
+Field Indicators of Hydric Soils
+S2.—2.5 cm Mucky Peat or Peat. For use in
+LRRs G and H. A layer of mucky peat or peat 2.5
+cm (1 inch) or more thick with value of 4 or less
+and chroma of 3 or less, starting at a depth of 15
+cm (6 inches) or less from the soil surface, and
+underlain by sandy soil material.
 User Notes: Mucky peat (hemic soil material) and
 peat (fibric soil material) have a minimum organic
-carbon content of 12 to 18 percent, depending on the
-content of clay. Organic soil material is called peat if
-virtually all of the plant remains are sufficiently intact
-to permit identification of plant remains. Mucky peat
-is at an intermediate stage of decomposition between
-peat and highly decomposed muck. To ascertain if
-mucky peat and/or peat are present, determine the
-percentage of rubbed fibers.
+carbon content of 12 percent. Organic soil
+material is called peat if virtually all of the plant
+remains are sufficiently intact to permit
+identification of plant remains. Mucky peat is at
+an intermediate stage of decomposition between
+peat and highly decomposed muck. To ascertain
+if mucky peat and/or peat are present, determine
+the percentage of rubbed fibers.
 S3.—5 cm Mucky Peat or Peat. For use in LRRs
-F and M; for testing in LRRs K, L, and R. A layer of
-mucky peat or peat 5 cm (2 inches) or more thick with
-value of 3 or less and chroma of 2 or less, starting at
-a depth ≤15 cm (6 inches) from the soil surface, and
-underlain by sandy soil material.
+F and M; for testing in LRRs K, L, and R. A layer
+of mucky peat or peat 5 cm (2 inches) or more
+thick with value of 3 or less and chroma of 2 or
+less, starting at a depth of 15 cm (6 inches) or
+less from the soil surface, and underlain by sandy
+soil material.
 User Notes: Mucky peat (hemic soil material) and
 peat (fibric soil material) have a minimum organic
-carbon content of 12 to 18 percent, depending on the
-content of clay. Organic soil material is called peat if
-virtually all of the plant remains are sufficiently intact
-to permit identification of plant remains. Mucky peat
-is at an intermediate stage of decomposition between
-peat and highly decomposed muck. To ascertain if
-mucky peat and/or peat are present, determine the
-percentage of rubbed fibers.
+carbon content of 12 percent. Organic soil
+material is called peat if virtually all of the plant
+remains are sufficiently intact to permit
+identification of plant remains. Mucky peat is at
+an intermediate stage of decomposition between
+peat and highly decomposed muck. To ascertain
+if mucky peat and/or peat are present, determine
+the percentage of rubbed fibers.
 S4.—Sandy Gleyed Matrix. For use in all LRRs,
-except for W, X, and Y. A gleyed matrix that occupies
-60 percent or more of a layer starting at a depth ≤15
-cm (6 inches) from the soil surface.
-User Notes: Gley colors are not synonymous with
-gray colors (fig. 21). They are the colors on the gley
-color pages in the Munsell color book (X-Rite, 2009)
-that have hue of N, 10Y, 5GY, 10GY, 5G, 10G, 5BG,
-10BG, 5B, 10B, or 5PB and value of 4 or more. For
-this indicator, the gleyed matrix only has to be present
-at a depth ≤15 cm (6 inches) from the surface. Soils
-with gleyed matrices are saturated for periods of a
-significant duration; as a result, there is no thickness
+except for W, X, and Y. A gleyed matrix that
+occupies 60 percent or more of a layer starting at
+a depth of 15 cm (6 inches) or less from the soil
+surface.
+User Notes: Gley colors are not synonymous
+with gray colors (fig. 22). They are the colors on
+the gley color pages in the “Munsell Soil Color
+Book” (X-Rite, 2009) that have hue of N, 10Y,
+5GY, 10GY, 5G, 10G, 5BG, 10BG, 5B, 10B, or
+5PB and value of greater than or equal to 4.
+For this indicator, the gleyed matrix only has
+to be present at a depth of 15 cm (6 inches)
+or less from the surface; there is no thickness
 requirement for the layer.
-S5.—Sandy Redox. For use in all LRRs, except for
-Q, V, W, X, and Y. A layer starting at a depth ≤15 cm (6
-inches) from the soil surface that is at least 10 cm (4
-inches) thick and has a matrix with 60 percent or more
-chroma of 2 or less and 2 percent or more distinct
-or prominent redox concentrations occurring as soft
-masses and/or pore linings.
-User Notes: “Distinct” and “prominent” are defined
-in the Glossary. Redox concentrations include iron
-and manganese masses (reddish mottles) and pore
-linings (Vepraskas, 1994). Included within the concept
-18 Field Indicators of
-of redox concentrations are iron-manganese bodies
-occurring as soft masses with diffuse boundaries.
-Common (2 to less than 20 percent) or many (20
-percent or more) redox concentrations are required
-(USDA, NRCS, 2002). If the soil is saturated at the
-time of sampling, it may be necessary to let it dry to
-a moist condition for redox features to become visible
-(figs. 22 and 23). This is a very common indicator of
-hydric soils and is often used to identify the hydric/
-nonhydric soil boundary in sandy soils.
-S6.—Stripped Matrix. For use in all LRRs, except
-for V, W, X, and Y. A layer starting at a depth ≤15
-cm (6 inches) from the soil surface in which iron-
-manganese oxides and/or organic matter have been
-stripped from the matrix and the primary base color
-of the soil material has been exposed. The stripped
-areas and translocated oxides and/or organic matter
-form a faintly contrasting pattern of two or more colors
-with diffuse boundaries. The stripped zones are 10
-percent or more of the volume and are rounded.
+S5.—Sandy Redox. For use in all LRRs, except
+for Q, V, W, X, and Y. A layer starting at a depth of
+22
+Field Indicators of Hydric Soils
+15 cm (6 inches) or less from the soil surface that
+is 10 cm (4 inches) or more thick and has a matrix
+with 60 percent or more chroma of 2 or less and
+2 or more percent distinct or prominent redox
+concentrations occurring as soft masses and/or
+pore linings.
+User Notes: “Distinct” and “prominent” are
+defined in the “Glossary.” Redox concentrations
+include iron and manganese masses (reddish
+mottles) and pore linings (Vepraskas, 1994).
+Included within the concept of redox
+concentrations are iron-manganese bodies
+occurring as soft masses with diffuse
+boundaries. Common (2 to less than 20
+percent) or many (20 percent or more) redox
+concentrations are required. If the soil is saturated
+at the time of sampling, it may be necessary to
+let it dry to a moist condition for redox features to
+become visible (figs. 23 and 24). This is a very
+common indicator of hydric soils and is often used
+to identify the hydric and nonhydric soil boundary
+in sandy soil layers.
+S6.—Stripped Matrix. For use in all LRRs,
+except for V, W, X, and Y. A layer starting at a
+depth of 15 cm (6 inches) or less from the soil
+surface in which iron-manganese oxides and/
+or organic matter have been stripped from the
+matrix and the primary base color of the soil
+material has been exposed. The stripped areas
+and translocated oxides and/or organic matter
+form a faintly contrasting pattern of two or more
+colors with diffuse boundaries. The stripped zones
+are 10 percent or more of the volume and are
+rounded.
 User Notes: This indicator includes the indicator
-previously named “polychromatic matrix” as well as the
-term “streaking.” Common or many areas of stripped
-(unmasked) soil materials are required. The stripped
-areas are typically 1 to 3 cm (0.5 to 1 inch) in size
-19 Hydric Soils
-but may be larger or smaller (fig. 24). Commonly, the
-stripped areas have value of 5 or more and chroma
-of 2 or less, and the unstripped areas have chroma
-of 3 and/or 4. The matrix (predominant color) may
-not have the material with chroma of 3 and/or 4. The
-mobilization and translocation of oxides and/or organic
-matter is the important process and should result in a
-splotchy pattern of masked and unmasked soil areas.
-This may be a difficult pattern to recognize and is more
-evident when a horizontal slice is observed.
+previously named “polychromatic matrix” as well
+as the term “streaking.” Common or many areas
+of stripped (unmasked) soil materials are
+required. The stripped areas are typically 1 to 3
+cm (0.5 to 1 inch) in size but may be larger or
+smaller (fig. 25). Commonly, the stripped areas
+have a value of 5 or more and chroma of 2 or
+less and the unstripped areas have chroma of 3
+and/or 4. The matrix may not have the material
+with chroma of 3 and/or 4. The mobilization and
+translocation of oxides and organic matter is the
+23
+Field Indicators of Hydric Soils
+important process and should result in a splotchy
+pattern of masked and unmasked soil areas.
+This may be a difficult pattern to recognize and is
+more evident when a horizontal slice is observed.
+Assistance from an experienced soil or wetland
+scientist can aid in identifying this indicator.
 S7.—Dark Surface. For use in LRRs K, L, M, N,
-P, Q, R, S, T, U, V, and Z. A layer 10 cm (4 inches)
-thick, starting at a depth less than or equal to the
-upper 15 cm (6 inches) from the soil surface, with a
-matrix value 3 or less and chroma 1 or less. At least
-70 percent of the visible soil particles must be masked
-with organic material, viewed through a 10x or 15x
-hand lens. Observed without a hand lens, the particles
-appear to be close to 100 percent masked. The matrix
-color of the layer directly below the dark layer must
-have the same colors as those described above or
-any color that has chroma of 2 or less.
+P, Q, R, S, T, U, V, and Z. A layer 10 cm
+(4 inches) thick, starting at a depth of 15 cm (6
+inches) or less from the soil surface, with a matrix
+value of 3 or less and chroma of 1 or less. At
+least 70 percent of the visible soil particles must
+be masked with organic material when viewed
+through a 10x or 15x hand lens. The matrix color
+of the layer directly below the dark layer must
+have the same colors as described above or any
+color with a chroma of 2 or less.
 User Notes: An undisturbed sample must be
-observed (fig. 25). Many wet soils have a ratio of
-about 50 percent soil particles that are masked with
-organic matter and about 50 percent unmasked
-soil particles, giving the soils a salt-and-pepper
-appearance. Where the coverage is less than 70
-percent, the Dark Surface indicator does not occur.
+observed (fig. 26). Many wet soils have a ratio of
+about 50 percent soil particles that are masked
+with organic matter and about 50 percent
+unmasked soil particles, giving the soils a
+salt-and-pepper appearance. Where the organic
+matter coverage is less than 70 percent, the
+Dark Surface indicator does not occur. Observed
+without a hand lens, the masked sand particles
+appear to be closer to 100 percent masked with
+organic material when moist. Masked sand grains
+can disappear quickly if a soil has been drained or
+disturbed.
 S8.—Polyvalue Below Surface. For use in LRRs
-R, S, T, and U; for testing in LRRs K and L. A layer
-with value of 3 or less and chroma of 1 or less starting
-at a depth ≤15 cm (6 inches) from the soil surface. At
-least 70 percent of the visible soil particles must be
-masked with organic material, viewed through a 10x
-or 15x hand lens. Observed without a hand lens, the
-particles appear to be close to 100 percent masked.
-Directly below this layer, 5 percent or more of the soil
-volume has value of 3 or less and chroma of 1 or less,
-and the remainder of the soil volume has value of 4 or
-more and chroma of 1 or less to a depth of 30 cm (12
-inches) or to the spodic horizon, whichever is less.
-User Notes: This indicator applies to soils with
-a very dark gray or black surface or near-surface
-layer that is less than 10 cm (4 inches) thick and
-is underlain by a layer in which organic matter has
-been differentially distributed within the soils by water
-movement (fig. 26). The mobilization and translocation
-of organic matter result in splotchy coated and
-uncoated soil.
-20 Field Indicators of
+R, S, T, and U; for testing in LRRs K and L.
+A layer with a value of 3 or less and chroma of
+1 or less starting at a depth of 15 cm (6 inches)
+or less from the soil surface. At least 70 percent
+of the visible soil particles must be masked with
+organic material when viewed through a 10x or
+15x hand lens. Directly below this layer, 5 percent
+or more of the soil volume has a value of 3 or less
+and chroma of 1 or less, and the remainder of the
+24
+Field Indicators of Hydric Soils
+soil volume has value of 4 or more and chroma of
+1 or less to a depth of 30 cm (12 inches) or to the
+spodic horizon.
+User Notes: This indicator applies to soils with a
+very dark gray or black surface or near-surface
+layer that is typically less than 10 cm (4 inches)
+thick but has no thickness requirement and is
+underlain by a layer in which organic matter has
+been differentially distributed within the soils by
+water movement (fig. 27). The mobilization and
+translocation of organic matter result in splotchy
+coated and uncoated soil. Observed without a
+hand lens, the masked sand particles appear to
+be closer to 100 percent masked with organic
+material when moist. Masked sand grains can
+disappear quickly if a soil has been drained or
+disturbed.
 S9.—Thin Dark Surface. For use in LRRs R, S,
-T, and U; for testing in LRRs K and L. A layer 5 cm (2
-inches) or more thick, starting at a depth ≤15 cm (6
-inches) from the soil surface, with value of 3 or less
-and chroma of 1 or less. At least 70 percent of the
-visible soil particles must be masked with organic
-material, viewed through a 10x or 15x hand lens.
-Observed without a hand lens, the particles appear
-to be close to 100 percent masked. This layer is
-underlain by a layer or layers with value of 4 or less
-and chroma of 1 or less to a depth of 30 cm (12
-inches) or to the spodic horizon, whichever is less.
+T, and U; for testing in LRRs K and L. A layer 5
+cm (2 inches) or more thick, starting at a depth
+of 15 cm (6 inches) or less from the soil surface,
+with value of 3 or less and chroma of 1 or less. At
+least 70 percent of the visible soil particles must
+be masked with organic material when viewed
+through a 10x or 15x hand lens. This layer is
+underlain by a layer or layers with value of 4 or
+less and chroma of 1 or less to a depth of 30 cm
+or a spodic horizon.
 User Notes: This indicator applies to soils with
-a very dark gray or black near-surface layer that is
-at least 5 cm (2 inches) thick and is underlain by
-a layer in which organic matter has been carried
-downward by flowing water (fig. 27). The mobilization
-and translocation of organic matter result in an even
-distribution of organic matter in the eluvial (E) horizon.
-The chroma of 1 or less is critical because it limits
-application of this indicator to only those soils that are
-depleted of iron. This indicator commonly occurs in
-hydric Spodosols, but a spodic horizon is not required.
+a very dark gray or black near-surface layer that
+is 5 cm (2 inches) or more thick and is underlain
+by a layer in which organic matter has been
+carried downward by flowing water (fig. 28). The
+mobilization and translocation of organic
+matter result in an even distribution of organic
+matter in the eluvial (E) horizon. The chroma of
+1 or less is critical because it limits application of
+this indicator to only those soils that are depleted
+of iron. This indicator commonly occurs in hydric
+Spodosols, but a spodic horizon is not required.
+Observed without a hand lens, the masked sand
+particles appear to be closer to 100 percent
+masked with organic material when moist.
+Masked sand grains can disappear quickly if a
+soil has been drained or disturbed.
 S11.—High Chroma Sands. For use along
-shorelines and near shore regions of the Great Lakes
-in LRRs K and L. In coastal zones and dune-and-
-swale complexes, a layer 5 cm (2 inches) or more
-thick starting at a depth ≤10 cm (4 inches) from the
-soil surface with chroma 4 or less and 2% or more
-distinct or prominent redox concentrations.
+shorelines and near shore regions of the Great
+Lakes in LRRs K and L. In coastal zones and
+dune-and-swale complexes, a layer 5 cm (2
+inches) or more thick starting at a depth of 10
+cm (4 inches) or less from the soil surface with
+chroma of 4 or less and 2 percent or more distinct
+or prominent redox concentrations.
 User Notes: Along the shorelines of the Great
-Lakes within LRRs L and K, some wetlands exhibit
-the presence of high chroma sands (often a chroma
-21 Hydric Soils
-3 to 4). These high-chroma, sandy soils occur at the
-landward edge of coastal marshes or in interdunal
-landscape positions of dune-and-swale complexes.
-These soils exhibit redox concentrations as pore
-linings and/or soft masses starting at a depth ≤10 cm
-(4 inches) from the soil surface. In adjacent upland
-areas, redox concentrations are absent or are only
-observed below 15 cm (6 inches). It may be helpful
-to involve a soil scientist to identify those soils that
-qualify for this indicator.
+Lakes within LRRs L and K, some wetlands
+exhibit the presence of high chroma sands (often
+chroma 3 to 4). These high-chroma, sandy soils
+occur at the landward edge of coastal marshes
+or in interdunal landscape positions of dune-
+and-swale complexes. These soils exhibit redox
+25
+Field Indicators of Hydric Soils
+concentrations as pore linings, soft masses, or
+both starting at a depth of 10 cm (4 inches) or
+less from the soil surface. In adjacent upland
+areas, redox concentrations are absent or are
+only observed at a depth 15 cm (6 inches) or
+more from the soil surface. It may be helpful to
+involve a soil scientist to identify soils that qualify
+for this indicator.
 S12.—Barrier Islands 1 cm Muck. For use in
-MLRA 153B and 153D of LRR T. In the swale portion
-of dune-and-swale complexes of barrier islands, a
-layer of muck 1 cm (0.5 inch) or more thick with value
-of 3 or less and chroma of 2 or less and starting at a
-depth ≤15 cm (6 inches) from the soil surface.
+MLRA 153B and 153D of LRR T. In the swale
+portion of dune-and-swale complexes of barrier
+islands, a layer of muck 1 cm (0.5 inch) or more
+thick with value of 3 or less and chroma of 2 or
+less and starting at a depth of 15 cm (6 inches) or
+less from the soil surface.
 User Notes: This indicator is similar to A9 but
-allows chroma of greater than 1, but not greater
-than 2. The indicator is limited to dune-and-swale
+allows chroma of 1 or more but not greater than
+2. The indicator is limited to dune-and-swale
 complexes on barrier islands.
 Loamy and Clayey Soils
-“Loamy and Clayey Soils” have USDA textures
-of loamy very fine sand and finer. All mineral layers
-above any of the layers meeting the requirements
-of any F-indicator(s), except for indicators F8, F12,
-F19, F20, and F21, have a dominant chroma of 2 or
-less, or the thickness of the layer(s) with a dominant
-chroma of more than 2 is less than 15 cm (6 inches).
-(See figure 4.) Also, except for indicator F16, nodules
-and concretions are not considered to be redox
-concentrations. Use the following F-indicators for
-loamy or clayey mineral soil materials.
+“Loamy and Clayey Soils” have layers with USDA
+textures of loamy very fine sand and finer. All
+mineral layers above any of the layers meeting
+the requirements of any F-indicator(s) except for
+indicators F8, F12, F19, F20, and F21 have a
+dominant chroma of 2 or less, or the thickness
+of the layer(s) with a dominant chroma of more
+than 2 is less than 15 cm (6 inches). (See figure
+4.) Also, except for indicator F16, nodules and
+concretions are not considered to be redox
+concentrations. Use the following F indicators for
+mineral layers that are loamy and clayey.
 F1.—Loamy Mucky Mineral. For use in all LRRs,
-except for N, Q, R, S, V, W, X, and Y, those using A7
-(LRRs P, T, U, and Z), and MLRA 1 of LRR A. A layer
-of mucky modified loamy or clayey soil material 10 cm
-(4 inches) or more thick starting at a depth ≤15 cm (6
-inches) from the soil surface.
-User Notes: “Mucky” is a USDA texture modifier for
-mineral soils. The content of organic carbon is at least
-8 percent but can range to as high as 18 percent. The
-percentage required depends on the clay content of
-the soil; the higher the clay content, the higher the
-content of organic carbon required. For example,
-mucky sandy loam requires between 8 and 14 percent
-organic carbon.
+except for N, Q, R, S, V, W, X, and Y, those using
+A7 (LRRs P, T, U, and Z), and MLRA 1 of LRR
+A. A layer of mucky modified loamy or clayey soil
+material 10 cm (4 inches) or more thick starting at
+a depth of 15 cm (6 inches) or less from the soil
+surface.
+User Notes: “Mucky” is a USDA texture modifier
+for mineral soils. The content of organic carbon
+ranges from 5 to 12 percent.
 F2.—Loamy Gleyed Matrix. For use in all LRRs,
-except for W, X, and Y. A gleyed matrix that occupies
-60 percent or more of a layer starting at a depth ≤30
-cm (12 inches) from the soil surface (fig. 28).
+except for W, X, and Y. A gleyed matrix that
+occupies 60 percent or more of a layer starting at
+a depth of 30 cm (12 inches) or less from the soil
+surface (fig. 29).
 User Notes: Gley colors are not synonymous
 with gray colors. They are the colors on the gley
-color pages of the Munsell color book (Xrite, 2006)
-that have hue of N, 10Y, 5GY, 10GY, 5G, 10G, 5BG,
-10BG, 5B, 10B, or 5PB and value of 4 or more. The
-gleyed matrix only has to be present at a depth ≤30
-cm (12 inches) from the surface. Soils with gleyed
-matrices are saturated for periods of a significant
-duration; as a result, there is no thickness requirement
-for the layer.
-F3.—Depleted Matrix. For use in all LRRs, except
-W, X, and Y; for testing in LRRs W, X, and Y. A layer
-that has a depleted matrix with 60 percent or more
-chroma of 2 or less and that has a minimum thickness
-of either:
-a. 5 cm (2 inches) if the 5 cm starts at a depth ≤10
-cm (4 inches) from the soil surface, or
-22 Field Indicators of
-b. 15 cm (6 inches), starting at a depth ≤25 cm
-(10 inches) from the soil surface.
-User Notes: A depleted matrix requires a value
-of 4 or more and chroma of 2 or less (fig. 29). Redox
-concentrations, including soft iron-manganese
-masses and/or pore linings, are required in soils
-with matrix colors of 4/1, 4/2, or 5/2. A, E, and calcic
-horizons may have low chromas and high values
-and may therefore be mistaken for a depleted matrix;
-however, they are excluded from the concept of
-depleted matrix unless the soil has common or many
-distinct or prominent redox concentrations occurring
-as soft masses or pore linings. The low-chroma matrix
-must be the result of wetness and not a weathering or
-parent material feature.
+color pages of the “Munsell Soil Color Book”
+(X-Rite, 2009) that have hue of N, 10Y, 5GY,
+10GY, 5G, 10G, 5BG, 10BG, 5B, 10B, or 5PB and
+value of 4 or more. The gleyed matrix only has to
+be present at a depth of 30 cm (12 inches) or less
+from the soil surface, and there is no thickness
+requirement for the layer.
+26
+Field Indicators of Hydric Soils
+F3.—Depleted Matrix. For use in all LRRs,
+except W, X, and Y; for testing in LRRs W, X,
+and Y. A layer that has a depleted matrix with 60
+percent or more chroma of 2 or less and that has
+a minimum thickness of either
+1. 5 cm (2 inches), starting at a depth of 10 cm
+(4 inches) or less from the soil surface, or
+2. 15 cm (6 inches), starting at a depth of 25 cm
+(10 inches) or less from the soil surface.
+User Notes: This is a very common indicator
+used to delineate wetland soils in many regions
+and landscape positions. A depleted matrix
+requires a value of 4 or more and chroma of 2
+or less (fig. 30). Redox concentrations, including
+soft iron-manganese masses and/or pore linings,
+are required in soils with matrix colors of 4/1, 4/2,
+or 5/2. A, E, and calcic horizons may have low
+chromas and high values and may therefore be
+mistaken for a depleted matrix; however, they
+are excluded from the concept of depleted matrix
+unless the layer has 2 percent or more distinct or
+prominent redox concentrations occurring as soft
+masses or pore linings. The low-chroma matrix
+must be the result of wetness and not a
+weathering or parent material feature.
+27
+Field Indicators of Hydric Soils
 F6.—Redox Dark Surface. For use in all LRRs,
-except W, X, and Y; for testing in LRRs W, X, and Y.
-A layer that is at least 10 cm (4 inches) thick, starting
-at a depth ≤20 cm (8 inches) from the mineral soil
-surface, and has:
-a. Matrix value of 3 or less and chroma of 1
+except W, X, and Y; for testing in LRRs W, X, and
+Y. A layer that is 10 cm (4 inches) or more thick,
+starting at a depth of 20 cm (8 inches) or less
+from the mineral soil surface, and has
+1. matrix value of 3 or less and chroma of 1
 or less and 2 percent or more distinct or
 prominent redox concentrations occurring as
 soft masses or pore linings, or
-b. Matrix value of 3 or less and chroma of 2
-or less and 5 percent or more distinct or
+2. matrix value of 3 or less and chroma of 2 or
+less and 5 percent or more distinct or
 prominent redox concentrations occurring as
 soft masses or pore linings.
-User Notes: This is a very common indicator used
-to delineate wetland soils that have a dark surface
-layer. Redox concentrations in mineral soils with a
-high content of organic matter and a dark surface
-layer are commonly small and difficult to see (figs.
-30, 31, and 32). The organic matter masks some
-or all of the concentrations that may be present.
-Careful examination is required to see what are
-commonly brownish redox concentrations in the
-darkened materials. If the soil is saturated at the time
-of sampling, it may be necessary to let it dry at least
-to a moist condition for redox features to become
-visible. Soils that are wet because of ponding or have
-a shallow, perched layer of saturation may have any
-color below the dark surface. It is recommended
-that delineators evaluate the hydrologic source and
-examine and describe the layer below the dark
-colored surface layer when applying this indicator.
-F7.—Depleted Dark Surface. For use in all LRRs,
-except W, X, and Y; for testing in LRRs W, X, and Y.
-Redox depletions with value of 5 or more and chroma
-of 2 or less in a layer that is at least 10 cm (4 inches)
-thick, starting at a depth ≤20 cm (8 inches) from the
-mineral soil surface, and has:
-a. Matrix value of 3 or less and chroma of 1 or
+User Notes: This is a very common indicator
+used to delineate wetland soils that have a dark
+surface layer. Redox concentrations in mineral
+soils with a high content of organic matter and a
+dark surface layer are commonly small and
+difficult to see (figs. 31, 32, and 33). The organic
+matter masks some or all of the concentrations
+that may be present. Careful examination is
+required to see what commonly brownish redox
+concentrations in the darkened materials are. If
+the soil is saturated at the time of sampling, it may
+be necessary to let it dry at least to a moist
+condition for redox features to become visible.
+28
+Field Indicators of Hydric Soils
+Typically, unless the soil is ponded with
+saturation only occurring near the surface, the
+material below the indicator will have a depleted
+or gleyed matrix. Soils that are subject to ponding
+or have a shallow, perched layer of saturation
+may have any color below the dark surface. It is
+recommended that delineators evaluate the
+hydrologic source and examine and describe the
+layer below the dark-colored surface layer when
+applying this indicator. This indicator is easily
+human-induced if a plow pan or other human-
+made confining layer is present. In these cases,
+the human-induced feature may have caused
+the development of a hydric soil. Removal of the
+feature that is causing the perching of water can
+eliminate the source of water causing anaerobic
+conditions to occur; therefore, the soil is no longer
+actively forming as a hydric soil.
+F7.—Depleted Dark Surface. For use in all LRRs
+except W, X, and Y; for testing in LRRs W, X, and
+Y. Redox depletions with value of 5 or more and
+chroma of 2 or less in a layer that is 10 cm (4
+inches) or more thick, starting at a depth of 20 cm
+(8 inches) or less from the mineral soil surface,
+and has
+1. matrix value of 3 or less and chroma of 1 or
 less and 10 percent or more redox depletions,
 or
-b. Matrix value of 3 or less and chroma of 2 or
+2. matrix value of 3 or less and chroma of 2 or
 less and 20 percent or more redox depletions.
 User Notes: Care should be taken not to mistake
 mixing of an E or calcic horizon into the surface
-layer for depletions. The “pieces” of E and calcic
+layer for depletions. The pieces of E and calcic
 horizons are not redox depletions. Knowledge of
-local conditions is required in areas where E and/or
-calcic horizons may be present. In soils that are wet
-because of subsurface saturation, the layer directly
-below the dark surface layer should have a depleted
-or gleyed matrix. Redox depletions should have
-associated redox concentrations (fig. 32) that occur as
-Fe pore linings or masses within the depletion(s) or
-surrounding the depletion(s).
-23 Hydric Soils
-F8.—Redox Depressions. For use in all LRRs,
-except W, X, and Y; for testing in LRRs W, X, and Y.
-In closed depressions subject to ponding, 5 percent
-or more distinct or prominent redox concentrations
-occurring as soft masses or pore linings in a layer that
-is 5 cm (2 inches) or more thick and starts at a depth
-≤10 cm (4 inches) from the soil surface.
-User Notes: This indicator occurs on depressional
-landforms, such as vernal pools, playa lakes,
-rainwater basins, “Grady” ponds, and potholes (figs.
-33 and 34). It does not occur in microdepressions
-(approximately 1 m) on convex or plane landscapes.
-24 Field Indicators of
+local conditions is helpful in areas where E and/or
+calcic horizons may be present. In soils that are
+wet because of subsurface saturation, the layer
+directly below the dark surface layer will typically
+have a depleted or gleyed matrix. Redox
+depletions should have associated redox
+concentrations (see figs. 32 and 33) that occur as
+Fe pore linings or masses within the depletion(s)
+or surrounding the depletion(s).
+F8.—Redox Depressions. For use in all LRRs
+except W, X, and Y; for testing in LRRs W, X,
+and Y. In closed depressions subject to ponding,
+5 percent or more distinct or prominent redox
+concentrations occurring as soft masses or pore
+linings in a layer that is 5 cm (2 inches) or more
+thick and starts at 10 cm (4 inches) or less from
+the soil surface.
+User Notes: This indicator occurs on
+depressional landforms, such as vernal pools,
+playa lakes, rainwater basins, Grady ponds,
+Carolina Bays, and potholes (figs. 34 and 35).
+This indicator is also common in backwater
+depressions of flood plains such as swamps or
+sloughs. It does not occur in solitary
+microdepressions (approximately 1 m scale) or on
+convex or planar slope shape positions.
 F10.—Marl. For use in LRR K, L, and U. A layer
-of marl with value of 5 or more and chroma 2 or less
-starting at a depth ≤10 cm (4 inches) from the soil
-surface (fig. 35).
-User Notes: Marl is a limnic material deposited in
-water by precipitation of CaCO3
-by algae as defined
-in Soil Taxonomy (Soil Survey Staff, 1999). It has a
-Munsell value of 5 or more and reacts with dilute HCl
-to evolve CO2
-. Marl is not the carbonatic substrate
-material associated with limestone bedrock. Some
-soils have materials with all of the properties of marl,
-except for the required Munsell value. These soils are
-hydric if the required value is present at a depth ≤10
-cm (4 inches) from the soil surface. Normally, this
-indicator occurs at the soil surface.
+of marl with value of 5 or more and chroma of 2 or
+less starting at a depth of 10 cm (4 inches) or less
+from the soil surface (fig. 36).
+User Notes: Marl is a limnic material deposited
+in water by precipitation of calcium carbonate by
+algae as defined in “Soil Taxonomy” (Soil Survey
+Staff, 1999). It has a Munsell value of 5 or more
+and reacts with dilute hydrochloric acid to evolve
+carbon dioxide. Marl is not the carbonatic
+substrate material associated with limestone
+bedrock. Some soils have materials with all of the
+properties of marl, except for the required Munsell
+value. These soils are hydric if the required value
+is present at a depth of 10 cm (4 inches) or less
+from the soil surface. Normally, this indicator
+occurs at the soil surface. There is no thickness
+requirement to meet this indicator.
 F11.—Depleted Ochric. For use in MLRA 151 of
-LRR T. A layer(s) 10 cm (4 inches) or more thick in
-which 60 percent or more of the matrix has value of 4
-or more and chroma of 1 or less. The layer starts at a
-depth ≤15 cm (6 inches) from the soil surface.
+LRR T. A layer 10 cm (4 inches) or more thick in
+which 60 percent or more of the matrix has value
+of 4 or more and chroma of 1 or less. The layer
+starts at a depth 15 cm (6 inches) or less from the
+soil surface.
 User Notes: This indicator is applicable in deltaic
 accreting areas along the Mississippi River.
-F12.—Iron-Manganese Masses. For use in LRRs
-N, O, P, and T; for testing in LRRs D, K, L, M, and
-R. On flood plains, a layer 10 cm (4 inches) or more
-thick with 40 percent or more chroma of 2 or less
-and 2 percent or more distinct or prominent redox
-concentrations occurring as soft iron-manganese
-masses with diffuse boundaries. The layer starts at a
-depth ≤20 cm (8 inches) from the soil surface. Iron-
-manganese masses have value and chroma of 3 or
-less. Most commonly, they are black. The thickness
-requirement is waived if the layer is the mineral
-surface layer.
+F12.—Iron-Manganese Masses. For use in
+LRRs N, O, P, and T; for testing in LRRs D, K,
+L, M, and R. On flood plains, a layer 10 cm (4
+inches) or more thick with 40 percent or more
+29
+Field Indicators of Hydric Soils
 User Notes: These iron-manganese masses
 generally are small (2 to 5 mm in size) and have
-value and chroma of 3 or less (fig. 36). They can be
-dominated by manganese and therefore have a color
-approaching black. The low matrix chroma must be
-the result of wetness and not be a weathering or
-parent material feature. Iron-manganese masses
-25 Hydric Soils
-should not be confused with the larger and redder
-iron nodules associated with plinthite or with
-concretions that have sharp boundaries. This
-indicator occurs on flood plains along rivers, such as
-the Apalachicola, Congaree, Mobile, Savannah, and
-Tennessee Rivers.
-F13.—Umbric Surface. For use in LRRs P, T, and
-U and MLRA 122 of LRR N. A layer 25 cm (10 inches)
-or more thick, starting at a depth ≤15 cm (6 inches)
-from the soil surface, in which the upper 15 cm (6
-inches) has value of 3 or less and chroma of 1 or less
-and in which the lower 10 cm (4 inches) has the same
-colors as those described above or any other color
-that has chroma of 2 or less.
+value and chroma of 3 or less (fig. 37). They
+can be dominated by manganese and therefore
+have a color approaching black. The low matrix
+chroma must be the result of wetness and not
+be a weathering or parent material feature. Iron-
+manganese masses should not be confused with
+the larger and redder iron nodules associated
+with plinthite or with concretions that have sharp
+boundaries. This indicator occurs on flood plains
+along rivers, such as the Apalachicola, Congaree,
+Mobile, Savannah, and Tennessee Rivers.
+F13.—Umbric Surface. For use in LRRs P, T,
+and U and MLRA 122 of LRR N. A layer 25 cm
+(10 inches) or more thick, starting at a depth of
+15 cm (6 inches) or less from the soil surface, in
+which the upper 15 cm (6 inches) has value of 3
+or less and chroma of 1 or less and in which the
+30
+Field Indicators of Hydric Soils
+lower 10 cm (4 inches) has the same colors as
+those described above or any other color that has
+chroma of 2 or less.
 User Notes: The thickness requirements may be
-slightly less than those for an umbric epipedon (fig. 37).
+slightly less than those for an umbric epipedon
+(fig. 38).
 F16.—High Plains Depressions. For use in
 MLRAs 72 and 73 of LRR H; for testing in other
 MLRAs of LRR H. In closed depressions that are
-subject to ponding, a mineral soil that has chroma of
-1 or less to a depth of at least 35 cm (13.5 inches)
-and a layer at least 10 cm (4 inches) thick starting
-at a depth ≤25 cm (10 inches) from the mineral soil
-surface that has either:
-a. One percent or more redox concentrations
+subject to ponding, a mineral soil that has chroma
+of 1 or less to a depth of 35 cm (13.5 inches) or
+more from the soil surface and a layer of 10 cm (4
+inches) or more thick starting at a depth of 25 cm
+(10 inches) or less from the mineral soil surface
+that has either
+1. one percent or more redox concentrations
 occurring as nodules or concretions, or
-b. Redox concentrations occurring as nodules or
-concretions with distinct or prominent corona.
+2. redox concentrations occurring as
+nodules or concretions with distinct or
+prominent corona (halo).
 User Notes: This indicator is applicable in closed
-depressions (Food Security Act “playas”) in western
-Kansas, southwestern Nebraska, eastern Colorado,
-and southeastern Wyoming. It occurs in such soils
-as those of the Ness and Pleasant series. The matrix
-color of the 35-cm (13.5-inch) layer must have chroma
-of 1 or less; chroma-2 matrix colors are excluded;
-value generally is 3. The nodules and concretions are
-rounded, are hard or very hard, range in size from
-less than 1 mm to 3 mm, and most commonly are
-black or reddish black. The corona (halos) generally
-are reddish brown, strong brown, or yellowish brown.
-The nodules and concretions can be removed from
-the soil, and the corona will occur as coatings on
-the concentration or will remain attached to the soil
-matrix. Use of 10x to 15x magnification aids in the
-identification of these features.
-F17.—Delta Ochric. For use in MLRA 151 of LRR
-T. A layer 10 cm (4 inches) or more thick in which
-60 percent or more of the matrix has value of 4 or
-more and chroma of 2 or less and there are no redox
-concentrations. This layer starts at a depth less than
-or equal to the upper 20 cm (8 inches) from the soil
+depressions in western Kansas, southwestern
+Nebraska, eastern Colorado, and southeastern
+Wyoming. It occurs in such soils as those of the
+Ness and Pleasant series. The matrix color of the
+35-cm (13.5-inch) layer must have chroma of less
+than or equal to 1; chroma-2 matrix colors are
+excluded; value generally is 3. The nodules and
+concretions are rounded, are hard or very hard,
+range in size from less than 1 mm to 3 mm, and
+most commonly are black or reddish black. The
+corona generally is reddish brown, strong brown,
+or yellowish brown. The nodules and concretions
+can be removed from the soil, and the corona
+will occur as coatings on the concentration or will
+remain attached to the soil matrix. Use of 10x
+to 15x magnification aids in the identification of
+these features.
+F17.—Delta Ochric. For use in MLRA 151 of
+LRR T. A layer 10 cm (4 inches) or more thick in
+which 60 percent or more of the matrix has value
+of 4 or more and chroma of 2 or less and there
+are no redox concentrations. This layer starts at
+a depth of 20 cm (8 inches) or less from the soil
 surface.
 User Notes: This indicator is applicable in
 accreting areas of the Mississippi River Delta.
 F18.—Reduced Vertic. For use in MLRA 150 of
-LRR T; for testing in all LRRs with Vertisols and Vertic
-intergrades. In Vertisols and Vertic intergrades, a
-positive reaction to alpha-alpha-dipyridyl that:
-a. Is the dominant (60 percent or more) condition
-of a layer at least 10 cm (4 inches) thick
-starting at a depth ≤30 cm (12 inches); or at
-least 5 cm (2 inches) thick staring at a depth of
-15 cm (6 inches) from the mineral or muck soil
-surface,
-b. Occurs for at least 7 continuous days and 28
+LRR T; for testing in all LRRs with Vertisols and
+Vertic intergrades. In Vertisols and Vertic
+intergrades, a positive reaction to
+alpha-alpha-dipyridyl that:
+1. is the dominant (60 percent or more) condition
+of a layer 10 cm (4 inches) or more thick
+starting at a depth of 30 cm (12 inches) or
+less; or 5 cm (2 inches) or more thick starting
+31
+Field Indicators of Hydric Soils
+at a depth 15 cm (6 inches) or less from the
+muck or mineral surface,
+2. occurs for 7 or more continuous days and 28
 cumulative days, and
-26 Field Indicators of
-c. Occurs during a normal or drier season and
-month (within 16 to 84 percent of probable
-precipitation).
+3. occurs during a normal or drier season and
+month.
 User Notes: The time requirements for this
-indicator were identified from research in MLRA 150A
-in LRR T (Gulf Coast Prairies). These requirements
-or slightly modified time requirements may be found
-to identify wetland Vertisols and Vertic intergrades
-in other parts of the Nation. These soils generally
-have thick dark surface horizons, but indicators A11,
-A12, and F6 commonly are not evident, possibly
-because of masking of redoximorphic features by
-organic carbon. The soils are a special case of the
+indicator were identified from research in MLRA
+150A in LRR T (Gulf Coast Prairies). These
+requirements or slightly modified time
+requirements may be used to identify wetland
+Vertisols and Vertic intergrades in other parts of
+the Nation. These soils generally have thick, dark
+surface horizons, but indicators A11, A12, and F6
+commonly are not evident, possibly because of
+masking of redoximorphic features by organic
+carbon. These soils are a special case of the
 “Problem Soils with Thick, Dark A Horizons” listed
-in the Corps of Engineers Wetlands Delineation
-Manual (Environmental Laboratory, 1987). Follow the
-procedures and note the considerations in Hydric
-Soils Technical Note 8, Use of alpha-alpha-Dipyridyl,
-available online at http://www.nrcs.usda.gov/wps/
-portal/nrcs/main/soils/use/hydric/.
-F19.—Piedmont Flood Plain Soils. For use in
-MLRAs 148 and 149A of LRR S; for testing on flood
-plains subject to Piedmont deposition throughout
-LRRs P, S, and T. On flood plains, a mineral layer at
-least 15 cm (6 inches) thick, starting at a depth ≤25
-cm (10 inches) from the soil surface, with a matrix (60
-percent or more of the volume) chroma of less than
-4 and 20 percent or more distinct or prominent redox
+in the “Corps of Engineers Wetlands Delineation
+Manual“ (Environmental Laboratory, 1987).
+F19.—Piedmont Flood Plain Soils. For use
+in MLRAs 148 and 149A of LRR S; for testing
+on flood plains subject to piedmont deposition
+throughout LRRs P, S, and T. On flood plains,
+a mineral layer 15 cm (6 inches) or more thick,
+starting at a depth of 25 cm (10 inches) or less
+from the soil surface, with a matrix (60 percent or
+more of the volume) chroma of less than 4 and
+20 percent or more distinct or prominent redox
 concentrations occurring as soft masses or pore
 linings.
 User Notes: This indicator is for use or testing
-on flood plains in the Mid-Atlantic and Southern
-Piedmont Provinces and areas where sediments
-derived from the Piedmont are being deposited
-on flood plains on the Coastal Plain (fig. 38). This
-indicator does not apply to stream terraces, which
-are associated with a historic stream level and are
-representative of an abandoned flood plain. While
-these soils are found on flood plains, flooding may be
-rare and groundwater is often the source of hydrology.
-F20.—Anomalous Bright Loamy Soils. For use in
-MLRA 149A of LRR S and MLRAs 153C and 153D of
-LRR T; for testing in MLRA 153B of LRR T. Within 200
-meters (656 feet) from estuarine marshes or water
-and at a depth ≤1 m (3.28 feet) of mean high water, a
-mineral layer at least 10 cm (4 inches) thick, starting
-at a depth ≤20 cm (8 inches) from the soil surface,
-with a matrix (60 percent or more of the volume)
-chroma of less than 5 and 10 percent or more distinct
-or prominent redox concentrations occurring as soft
+on flood plains in the mid-Atlantic and southern
+parts of the Piedmont province and in areas
+where sediments derived from the Piedmont are
+being deposited on flood plains on the Coastal
+Plain (fig. 39). This indicator does not apply to
+stream terraces, which are associated with a
+historic stream level and are representative of
+an abandoned flood plain. While these soils are
+found on flood plains, flooding may be rare, and
+groundwater is often the source of hydrology.
+F20.—Anomalous Bright Loamy Soils. For
+use in MLRA 149A of LRR S and MLRAs 153C
+and 153D of LRR T; for testing in MLRA 153B of
+LRR T. Within 200 m (656 feet) from estuarine
+marshes or water and at a depth 1 m (3.28 feet)
+or less of mean high water, a mineral layer 10 cm
+(4 inches) or more thick, starting at a depth of 20
+cm (8 inches) or less from the soil surface, with a
+matrix (60 percent or more of the volume) chroma
+of less than 5 and 10 percent or more distinct or
+prominent redox concentrations occurring as soft
 masses or pore linings and/or depletions.
 User Notes: These soils are expected to occur
 on linear or convex landforms that are adjacent to
-estuarine marshes or water (fig. 39).
+estuarine marshes or water (fig. 40).
 F21.—Red Parent Material. For use in MLRA
-127 of LRR N; MLRA 145 of LRR R; and MLRAs 147
-and 148 of LRR S; for testing in all soils derived from
-red parent materials. A layer derived from red parent
-materials (see Glossary) that is at least 10 cm (4
-inches) thick, starting at a depth ≤25 cm (10 Inches)
-from the soil surface with a hue of 7.5YR or redder.
-The matrix has a value and chroma greater than 2
-and less than or equal to 4. The layer must contain
-10 percent or more depletions and/or distinct or
-prominent concentrations occurring as soft masses or
-pore linings. Redox depletions should differ in color by
-having:
-a. A minimum difference of one value higher and
+127 of LRR N; MLRA 145 of LRR R; and MLRAs
+147 and 148 of LRR S; for testing in all soils
+derived from red parent materials. A layer derived
+from red parent materials (see “Glossary”) that
+is 10 cm (4 inches) or more thick, starting at
+a depth of 25 cm (10 Inches) or less from the
+soil surface with a hue of 7.5YR or redder. The
+matrix has a value and chroma of more than 2
+and 4 or less. The layer must contain 10 or more
+percent depletions and/or distinct or prominent
+concentrations occurring as soft masses or pore
+32
+Field Indicators of Hydric Soils
+linings. Redox depletions should differ in color by
+having
+1. a minimum difference of one value higher and
 one chroma lower than the matrix, or
-b. Value of 4 or more and chroma of 2 or less
-(fig. 40).
+2. value of 4 or more and chroma of 2 or less
+than the matrix (fig. 41).
 User Notes: This indicator was developed for use
-in areas of red parent material, such as residuum
-in the Piedmont Province Triassic lowlands section
-or the Paleozoic “red beds” of the Appalachian
-Mountains, and in alluvium or colluvium derived from
-these materials. This indicator may occur along the
-Red River (Arkansas and Louisiana). In glaciated
-areas, the indicator may form in glacial till, outwash,
-deltaic sediments, or glaciolacustrine sediments
-derived from similar parent materials in the area.
-Soils potentially derived from red parent materials
-should be evaluated to determine the Color Change
-27 Hydric Soils
-Propensity Index (CPPI) and be shown to have CCPI
-values below 30 (Rabenhorst and Parikh, 2000). In
-landscapes where mixing or stratification of parent
-materials occur, it cannot be assumed that sediment
-overlying red parent material is derived solely from
-that parent material. The total percentage of all redox
-concentrations and redox depletions must add up
-to at least 10 percent to meet the threshold for this
-indicator.
-This indicator is typically found at the boundary
-between hydric and non-hydric soils. Other, more
-common indicators may be found on the interior (fig.
-41). It may be helpful to involve a soil scientist familiar
-with these soils to identify those soils that qualify for
+in areas of red parent material, such as
+residuum in the Piedmont Province Triassic
+Lowlands section or the Paleozoic “red beds” of
+the Appalachian Mountains, and in alluvium or
+colluvium derived from these materials. This
+indicator may occur along the Red River
+(Arkansas and Louisiana). In glaciated areas, the
+indicator may form in glacial till, outwash, deltaic
+sediments, or glaciolacustrine sediments derived
+from similar parent materials in the area. Soils
+potentially derived from red parent materials
+should be evaluated to determine the Color
+Change Propensity Index (CPPI) and be shown to
+have CCPI values less than 30 (Rabenhorst and
+Parikh, 2000). In landscapes where mixing or
+stratification of parent materials occur, it cannot
+be assumed that sediment overlying red parent
+material is derived solely from that parent
+material. The total percentage of all redox
+concentrations and redox depletions must add
+up to 10 percent or more to meet the threshold
+for this indicator. This indicator is typically found
+at the boundary between hydric and non-hydric
+33
+Field Indicators of Hydric Soils
+soils. Other, more common indicators may be
+found on the interior (fig. 42). Mack et al. (2019)
+provides maps of soils and geologic features
+associated with red parent materials. It may be
+helpful to involve a soil scientist familiar with
+these soils to identify those soils that qualify for
 this indicator.
 F22.—Very Shallow Dark Surface. For use in
-MLRA 138 and West Florida portions of MLRA 152A
-of LRR T and MLRA 154 of LRR U; for testing in all
-other MLRAs and LRRs. In depressions and flood
-plains subject to frequent ponding and/or flooding,
-one of the following must be observed:
-a. If bedrock occurs between 15 cm (6 inches)
-and 25 cm (10 inches) of the soil surface, a
-layer at least 15 cm (6 inches) thick starting at
-a depth ≤10 cm (4 inches) from the soil surface
-with value 2.5 or less and chroma 1 or less,
-and the remaining soil to bedrock must have
-the same colors as above or any other color
-that has chroma 2 or less; or
-b. If bedrock occurs at a depth ≤15 cm (6
-inches) from the soil surface, more than half
-of the soil thickness must have value 2.5 or
+MLRA 138 and west Florida portions of MLRA
+152A of LRR T and MLRA 154 of LRR U; for
+testing in all other MLRAs and LRRs. In
+depressions and flood plains subject to frequent
+ponding and/or flooding, one of the following must
+be observed:
+1. If bedrock occurs between 15 cm
+(6 inches) and 25 cm (10 inches) of the soil
+surface, a layer of 15 cm (6 inches) or more
+thick starting at a depth 10 cm (4 inches) or
+less from the soil surface with value of 2.5 or
 less and chroma 1 or less, and the remaining
-soil to bedrock must have the same color as
-above or any other color that has a chroma 2
-or less.
-29
-Test Indicators of Hydric Soils
-The indicators listed under the heading “Field
-Indicators of Hydric Soils” should be tested for use
-in LRRs other than those listed. Other indicators for
-testing are listed below. The test indicators are not to
-be used for the purpose of delineating hydric soils.
-Users of the indicators are encouraged to submit
-descriptions of other soil morphologies that they think
-are indicative of hydric soils along with supporting
-data for inclusion in subsequent editions of Field
-Indicators of Hydric Soils in the United States.
-All Soils
-TA4.—Alaska Color Change. For testing in LRRs
-W, X, and Y. A mineral layer 10 cm (4 inches) or
-more thick, starting at a depth ≤30 cm (12 inches)
-from the surface, that has a matrix value of 4 or more
-and chroma of 2 or less and that within 30 minutes
-becomes redder by one or more Munsell unit in hue
-and/or chroma when exposed to air.
-User Notes: The soil should be at or near
-saturation when examined. Care must be taken to
-immediately obtain an accurate color of the soil
-sample upon excavation. The colors should then be
-closely examined again after several minutes. Do not
-allow the sample to begin drying, as drying will result
-in a color change. Care must be taken to closely
-observe the colors. As always, do not obtain colors
-while wearing sunglasses. Colors must be obtained in
-the field under natural lighting and not under artificial
-light. Also, look for the presence of other indicators.
-TA5.—Alaska Alpine Swales. For testing in LRRs
-W, X, and Y. On concave landforms, the presence of
-a surface mineral layer 10 cm (4 inches) or more thick
-having hue of 10YR or yellower, value of 2.5 or less,
-and chroma of 2 or less. The dark surface layer is at
-least twice as thick as the mineral surface layer of
-soils in the adjacent convex micro-positions.
-User Notes: Soils with this indicator occur in
-concave areas where moisture accumulates. In
-these areas the source of the hydrology is meltwater
-from adjacent snowpacks that persist well into
-the growing season. The landscape generally is a
-complex microtopography of concave depressions
-and adjacent convex microhighs. Soils should be
-examined in both landscape positions and compared.
-If both positions have a mineral surface layer of the
-same color, but the dark surface layer is at least
-twice as thick in the concave position, the soil in the
-concave position is considered hydric. Make sure that
-there is reasonable evidence of the hydrology source,
-including either direct observation of the melting
-snowpack or aerial imagery that shows snowpack at
-that location earlier in the growing season.
-TA6.—Mesic Spodic. For testing in MLRAs 144A
-and 145 of LRR R and MLRA 149B of LRR S. A layer
-5 cm (2 inches) or more thick, starting at a depth
-≤15 cm (6 inches) from the mineral soil surface, that
-has value of 3 or less and chroma of 2 or less and is
-underlain by either:
-a. One or more layers 8 cm (3 inches) or more
-thick occurring at a depth ≤30 cm (12 inches)
-from the mineral soil surface, having value and
-chroma of 3 or less, and showing evidence of
-spodic development; or
-b. One or more layers 5 cm (2 inches) or more
-thick occurring at a depth ≤30 cm (12 inches)
-from the mineral soil surface, having value of 4
-or more and chroma of 2 or less, and directly
-underlain by a layer(s) 8 cm (3 inches) or more
-thick having value and chroma of 3 or less and
-showing evidence of spodic development.
-User Notes: This indicator is used to identify wet
-soils that have spodic materials or that meet the
-definition of Spodosols. The layer that has value of 4
-or more and chroma of 2 or less is typically described
-as an E or Eg horizon (typically having a color pattern
-referred to as stripped or partially stripped matrices).
-The layers with evidence of the accumulation of
-translocated organic matter typically are described
-as Bh, Bhs, Bhsm, Bsm, or Bs horizons. These layers
-typically have several color patterns or cementation
-indicative of translocated iron, aluminum, and/or
-organic matter.
-30
-Sandy Soils
-TS7.—Barrier Islands Low Chroma Matrix. For
-testing in MLRA 153B and 153D of LRR T. In the
-swale portion of the swale-and-dune complexes of
-barrier islands, a surface layer 1 cm (0.5 inches) or
-more thick with value 4 or less and chroma 2 or less.
-Below the dark surface, one or more layers 10 cm (4
-inches) or more thick occurs with a dominant hue of
-2.5Y or yellower and value 4 or more and chroma less
-than 2 starting at a depth ≤15 cm (6 inches) from the
-soil surface.
-User Notes: The requirement of a dark surface
-layer above the low chroma layer excludes sediments
-from recent depositional events (especially common
-in overwash areas) which are not hydric. Low chroma
-colors in recent deposits are likely due to the nature of
-the parent material and not related to hydrology. There
-is no color requirement for any layer(s) between the
-dark surface and the low chroma matrix. This indicator
-is limited to sandy soils in dune-and-swale complexes
-of barrier islands.
-Loamy and Clayey Soils
-As of this printing, no test indicators are approved
-for loamy and clayey soils. To propose a new test
-indicator, contact the National Technical Committee
-for Hydric Soils.
-31
+soil to bedrock must have the same colors as
+above or any other color that has chroma of 2
+or less; or
+2. If bedrock occurs at a depth of 15 cm (6
+inches) or less from the soil surface, more
+than half of the soil thickness must have value
+of 2.5 or less and chroma 1 or less, and the
+remaining soil to bedrock must have the same
+color as above or any other color that has a
+chroma of 2 or less.
+35
 References
-Elless, M.P., and M.C. Rabenhorst. 1994. Hematite in the shales of the Triassic
-Culpeper Basin of Maryland. Soil Science 158:150–154.
-Elless, M.P., M.C. Rabenhorst, and B.R. James. 1996. Redoximorphic features in soils
-of the Triassic Culpeper Basin. Soil Science 161:58–69.
-Environmental Laboratory. 1987. Corps of Engineers wetlands delineation manual.
-United States Army Corps of Engineers. Waterways Experiment Station Technical
-Report Y-87-1.
-Federal Register. July 13, 1994. Changes in Hydric Soils of the United States.
-Washington, DC. (Definition of hydric soils.)
-Florida Soil Survey Staff. 1992. Soil and water relationships of Florida’s ecological
-communities. G.W. Hurt (editor). USDA, Soil Conservation Service, Gainesville, FL.
-Mausbach, M.J., and J.l. Richardson. 1994. Biogeochemical processes in hydric soils.
-Current Topics in Wetland Biogeochemistry 1:68–127. Wetlands Biogeochemistry
-Institute, Louisiana State University, Baton Rouge, LA.
-National Research Council. 1995. Wetlands: Characteristics and boundaries. National
-Academy Press, Washington, DC.
-National Technical Committee for Hydric Soils (NTCHS). Use of alpha-alpha-dipyridyl.
-Hydric Soils Technical Note 8. https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/
-use/hydric/?cid=nrcs142p2_053983 (accessed 19 September 2016).
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-DOCUMENTS/nrcs142p2_051608.pdf (accessed 19 September 2016).
-Rabenhorst, M.C., and S. Parikh. 2000. Propensity of soils to develop redoximorphic
-color changes. Soil Science Society of America Journal 64:1904–1910.
-Schoeneberger, P.J., D.A. Wysocki, E.C. Benham, and W.D. Broderson (editors).
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-Conservation Service, National Soil Survey Center, Lincoln, NE.
-Soil Science Society of America. 1993. Proceedings of the Symposium on Soil Color,
-October 21-26, 1990, San Antonio, TX. J.M. Bigham and E.J. Coilkosz (editors). Soil
-Science Society of America, Madison, WI, Special Publication 31.
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-Society of America, Madison, WI. https://www.soils.org/publications/soils-glossary
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-Department of Agriculture Handbook 18. http://www.nrcs.usda.gov/wps/portal/nrcs/
-detail/soils/ref/?cid=nrcs142p2_054262 (accessed 19 September 2016).
-32
-Soil Survey Staff. 1999. Soil Taxonomy: A basic system of soil classification for making
-and interpreting soil surveys. U.S. Department of Agriculture Handbook 436. http://
-www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/class/taxonomy/ (accessed 19
-September 2016).
-Soil Survey Staff. 2014. Keys to soil taxonomy, 12th ed. USDA, Natural Resources
-Conservation Service. http://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/
-class/taxonomy/?cid=nrcs142p2_053580 (accessed 19 September 2016).
-United States Department of Agriculture, Natural Resources Conservation Service.
-1996. Field indicators of hydric soils in the United States, version 3.2. G.W. Hurt,
-P.M. Whited, and R.F. Pringle (editors). In cooperation with the National Technical
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-United States Department of Agriculture, Natural Resources Conservation Service.
-1998. Field indicators of hydric soils in the United States, version 4.0. G.W. Hurt,
-P.M. Whited, and R.F. Pringle (editors). In cooperation with the National Technical
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-United States Department of Agriculture, Natural Resources Conservation Service.
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-P.M. Whited, and R.F. Pringle (editors). In cooperation with the National Technical
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-L.M. Vasilas (editors). In cooperation with the National Technical Committee for Hydric
-Soils.
+Berkowitz J. F., Vepraskas M. J., Vaughan K. L., and Vasilas L.M. (2021).
+Development and application of the Hydric Soil Technical Standard. Soil
+Science Society of America Journal 85(3), 469–487. https://doi.org/10.1002/
+saj2.20202
+Duball, C., Vaughan, K., Berkowitz, J. F., Rabenhorst, M. C., and VanZomeren,
+C. M. (2020). Iron monosulfide identification: Field techniques to provide
+evidence of reducing conditions in soils. Soil Science Society of America
+Journal 84(2), 303–313. https://doi.org/10.1002/saj2.20044
+Elless, M. P., and Rabenhorst, M. C. (1994). Hematite in the shales of the
+Triassic Culpeper Basin of Maryland. Soil Science 158(2), 150–154.
+Elless, M.P., Rabenhorst, M. C., and James, B. R. (1996). Redoximorphic
+features in soils of the Triassic Culpeper Basin. Soil Science 161(1), 58–69.
+Environmental Laboratory. (1987). Corps of Engineers wetlands delineation
+manual (Technical Report Y-87-1). United States Army Corps of Engineers.
+Waterways Experiment Station.
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+24, 1995).
+Florida Soil Survey Staff. (1992). Soil and water relationships of Florida’s
+ecological communities. USDA, Soil Conservation Service.
+Mack, S. C., Berkowitz J. F., and Rabenhorst M. C. (2019). Improving hydric
+soil identification in areas containing problematic red parent materials: a
+nationwide collaborative mapping approach. Wetlands 39, 685–703.
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+1904–1910. https://doi.org/10.2136/sssaj2000.6451904x
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+Field Indicators of Hydric Soils
+36
+Soil Survey Staff. (2023). Soil Survey Technical Note 430-SS-2 Soil Color
+Contrast.
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-State University, Raleigh, NC.
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-33
+Service. (2010). National Food Security Act manual, 5th edition, title 180, part
+510.
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+Service. (2022). Land resource regions and major land resource areas of the
+United States, the Caribbean, and the Pacific Basin (Agriculture Handbook
+296). U.S. Government Printing Office.
+Vaughan, K. L., Miller, F., Navarro, N., and Appel, C. (2016). Visual
+assessment of sulfate reduction to identify hydric soils. Soil Science Society of
+America Journal, 80(4), 1114–1119. https://doi.org/10.2136/sssaj2016.02.0035
+Vepraskas, M. J. (1994). Redoximorphic features for identifying aquic
+conditions (Technical Bulletin 301). North Carolina Agricultural Research
+Service, North Carolina State University.
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+Geologiska Undersökning C35, 19(2).
+X-Rite. 2009. Munsell soil color charts (rev. ed.).
+37
 Glossary
-As defined in this Glossary, terms marked with an asterisk (*) have definitions that
-are slightly different from the definitions in the referenced materials. The definitions in
-the Glossary are intended to assist users of this document and are not intended to add
-to or replace definitions in the referenced materials.
-A horizon. A mineral soil horizon that formed at the
-surface or below an O horizon where organic
-material is accumulating. See Soil Taxonomy
-(Soil Survey Staff, 1999) for a complete
-definition.
-Accreting areas. Landscape positions in which soil
-material accumulates through deposition from
+As defined in this Glossary, terms marked with an asterisk (*) have definitions that are slightly different
+from the definitions in the referenced materials. The definitions in the Glossary are intended to assist
+users of this document and are not intended to add to or replace definitions in the referenced materials.
+A horizon. A mineral soil horizon that formed at
+the surface or below an O horizon where organic
+material is accumulating. See “Soil Taxonomy”
+(Soil Survey Staff, 1999) for a complete definition.
+Accreting areas. Landscape positions in which
+soil material accumulates through deposition from
 higher elevations or upstream positions more
 rapidly than the rate at which soil material is being
 lost through erosion.
-Anaerobic. A condition in which molecular oxygen is
-virtually absent from the soil.
+Anaerobic. A condition in which molecular
+oxygen is virtually absent from the soil.
 Anaerobiosis. Microbiological activity under
 anaerobic conditions.
-Aquic conditions. Conditions in the soil represented
-by depth of saturation, occurrence of reduction,
-and redoximorphic features. See Soil Taxonomy
-(Soil Survey Staff, 1999) for a complete definition.
-*Artificial drainage. The use of human efforts and
-devices to remove free water from the soil surface
-or from the soil profile (figs. 42 and 43). The
+Aquic conditions. Conditions in the soil
+represented by depth of saturation, occurrence of
+reduction, and redoximorphic features. See “Soil
+Taxonomy” (Soil Survey Staff, 1999) for a
+complete definition.
+*Artificial drainage. The use of human efforts
+and devices to remove free water from the soil
+surface or from the soil profile (fig 43). The
 hydrology may also be modified by levees and
-dams, which keep water from entering a site.
-CaCO3
-equivalent. The acid neutralizing capacity of a
-soil expressed as a weight percentage of CaCO3
-(molecular weight of CaCO3
-equals 100).
+dams, which keep water from entering a site
+(fig. 44).
 Calcic horizon. An illuvial horizon in which
 carbonates have accumulated to a significant
-extent. See Soil Taxonomy (Soil Survey Staff,
+extent. See “Soil Taxonomy” (Soil Survey Staff,
 1999) for a complete definition.
 Calcium carbonate. Calcium carbonate has the
 chemical formula of CaCO3
 . It effervesces when
 treated with cold hydrochloric acid.
 Closed depressions. Low-lying areas that are
-surrounded by higher ground and have no natural
-outlet for surface drainage.
-COE. U.S. Army Corps of Engineers.
-Common. When referring to redox concentrations,
-redox depletions, or both, “common” represents 2
-to 20 percent of the observed surface.
+surrounded by higher ground and have no
+natural outlet for surface drainage.
+38
+Field Indicators of Hydric Soils
+Common. When referring to redox
+concentrations, redox depletions, or both,
+“common” represents 2 to 20 percent of the
+observed surface.
 Concave landscapes. Landscapes in which the
 surface curves downward.
-34 Field Indicators of
-*Depleted matrix. For loamy and clayey material (and
-sandy material in areas of indicators A11 and
-A12), a depleted matrix refers to the volume of a
-soil horizon or subhorizon in which the processes
+Concretions. Firm to extremely firm, irregularly
+shaped bodies with sharp to diffuse boundaries.
+When broken in half, concretions have concentric
+layers. See Vepraskas (1994) for a complete
+discussion.
+*Depleted matrix. For mineral soil layers, a
+depleted matrix refers to the volume of a soil
+horizon or subhorizon in which the processes
 of reduction and translocation have removed or
 transformed iron, creating colors of low chroma
-and high value (fig. 44). A, E, and calcic horizons
+and high value (fig. 45). A, E, and calcic horizons
 may have low chromas and high values and
 may therefore be mistaken for a depleted matrix;
 however, they are excluded from the concept of
 depleted matrix unless the soil has common or
 many distinct or prominent redox concentrations
-occurring as soft masses or pore linings. In
-some areas the depleted matrix may change
-color upon exposure to air (see Reduced matrix);
-this phenomenon is included in the concept of
+occurring as soft masses or pore linings. In some
+areas the depleted matrix may change color upon
+exposure to air (see “Reduced matrix”); this
+phenomenon is included in the concept of
 depleted matrix. The following combinations of
 value and chroma identify a depleted matrix:
 1. Matrix value of 5 or more and chroma of 1
 or less with or without redox concentrations
-occurring as soft masses and/or pore linings; or
+occurring as soft masses and/or pore linings;
+or
 2. Matrix value of 6 or more and chroma of 2
 or less with or without redox concentrations
-occurring as soft masses and/or pore linings; or
-3. Matrix value of 4 or 5 and chroma of 2 and 2
+occurring as soft masses and/or pore linings;
+or
+39
+Field Indicators of Hydric Soils
+3. Matrix value of 4 or 5, chroma of 2, and 2
 percent or more distinct or prominent redox
-concentrations occurring as soft masses and/or
-pore linings; or
-4. Matrix value of 4 and chroma of 1 and 2
+concentrations occurring as soft masses and/
+or pore linings; or
+4. Matrix value of 4, a chroma of 1, and 2
 percent or more distinct or prominent redox
-concentrations occurring as soft masses and/or
-pore linings (fig. 45).
-Diffuse boundary. Used to describe redoximorphic
-features that grade gradually from one color to
-another (fig. 46). The color grade is commonly
-more than 2 mm wide. “Clear” is used to describe
-boundary color gradations intermediate between
-sharp and diffuse.
-With or without redox
-concentrations
-2% or more distinct
-or prominent redox
-concentrations
-35 Hydric Soils
+concentrations occurring as soft masses and/
+or pore linings (fig. 46).
+Diffuse boundary. Used to describe
+redoximorphic features that grade gradually from
+one color to another (fig. 47). The color grade is
+commonly 2 mm or more wide.
 Distinct. Readily seen but contrasting only
 moderately with the color to which compared. The
-contrast is distinct if:
-1. Delta hue = 0, then
-a) Delta value <2 and delta chroma >1 to <4, or
-b) Delta value >2 to <4 and delta chroma <4.
-2. Delta hue = 1, then
-a) Delta value <1 and delta chroma >1 to <3, or
-b) Delta value >1 to <3 and delta chroma <3.
-3. Delta hue = 2, then
-a) Delta value = 0 and delta chroma >0 to <2,
-or
-b) Delta value >0 to <2 and delta chroma <2.
-Regardless of the magnitude of hue difference,
-where both colors have value <3 and chroma
-<2, the contrast is faint.
-E horizon. A mineral horizon in which the dominant
-process is loss of silicate clay, iron, and/or
-aluminum, leaving a concentration of sand and silt
-particles (fig. 47). See Soil Taxonomy (Soil Survey
+contrast is distinct for the following:
+1. Delta hue equal to 0, then
+a. delta value of 2 or less and delta chroma
+1 to less than 4, or
+b. delta value of 2 to less than 4 and delta
+chroma less than 4.
+2. Delta hue equal to 1, then
+a. delta value of 1 or less and delta chroma
+more than 1 to less than 3, or
+b. delta value greater than 1 to less than 3
+and delta chroma less than 3.
+3. Delta hue equal to 2, then
+a. delta value equal to 0 and delta chroma
+greater than 0 to less than 2, or
+b. delta value greater than 0 to less than 2
+and delta chroma less than 2.
+Exception: if the compared colors have both a
+value of 3 or less and a chroma 2 or less, then the
+color contrast is faint regardless of hue difference
+(fig. 48).
+For a more detailed explanation of how to
+determine color contrast, see “Soil Survey
+Technical Note 430-SS-2” on “Soil Color Contrast”
+(Soil Survey Staff, 2023).
+E horizon. A mineral horizon in which the
+dominant process is loss of silicate clay, iron, and/
+or aluminum, leaving a concentration of sand and
+silt particles (fig. 49). See “Soil Taxonomy” (Soil
+Survey Staff, 1999) for a complete definition.
+Epipedon. A horizon that has developed at the
+soil surface. See “Soil Taxonomy” (Soil Survey
 Staff, 1999) for a complete definition.
-EPA. U.S. Environmental Protection Agency.
-Epipedon. A horizon that has developed at the soil
-surface. See Soil Taxonomy (Soil Survey Staff,
-1999) for a complete definition.
-Faint. Evident only on close examination. The contrast
-is faint if:
-1. Delta hue = 0, then delta value ≤2 and delta
-chroma ≤1, or
-2. Delta hue = 1, then delta value ≤1 and delta
-chroma ≤1, or
-3. Delta hue = 2, then delta value = 0 and delta
-chroma = 0, or
-36 Field Indicators of
-Any delta hue if both colors have value ≤3 and
-chroma ≤2 (fig. 48).
-Upper Threshold for Faint
-Delta Delta Delta
-Hue Value Chroma
-0		 ≤2 ≤1
-1		 ≤1 ≤1
-2		 0 0
-Hue Value Chroma
-Any		 ≤3 ≤2
+Faint. Evident only on close examination. The
+contrast is faint if
+1. delta hue equal to 0, then delta value of 2 or
+less and delta chroma of 1 or less, or
+2. delta hue equal to 1, then delta value of 1 or
+less and delta chroma of 1 or less, or
+40
+Field Indicators of Hydric Soils
+Manual” (Soil Survey Staff, 2017).
+3. delta hue equal to 2, then delta value equal to
+0 and delta chroma equal to 0, or
+4. any delta hue if both colors have a value of 3
+or less and chroma 2 or less (table 1).
+Table 1: Upper Threshold for Faint
+Δ Hue Δ Value Δ Chroma
+0 2 or less 1 or less
+1 1 or less 1 or less
+2 0 0
+Δ Hue If Value If Chroma
+Any 3 or less 2 or less
 Any feature above the upper threshold for faint
 features would be considered either distinct or
 prominent. If an indicator requires distinct or
-prominent features then those features at or
-below the faint threshold do not count.
+prominent features, then the features at or
+below the faint threshold are not considered.
 Fe-Mn concretions. Firm to extremely firm,
 irregularly shaped bodies with sharp to diffuse
 boundaries. When broken in half, concretions
@@ -1908,60 +1990,65 @@ shaped bodies with sharp to diffuse boundaries.
 When broken in half, nodules do not have visibly
 organized internal structure. See Vepraskas
 (1994) for a complete discussion.
-Few. When referring to redox concentrations, redox
-depletions, or both, “few” represents less than 2
-percent of the observed surface.
-Fibric. See Peat.
+Few. When referring to redox concentrations,
+redox depletions, or both, “few” represents fewer
+than 2 percent of the area in an exposed face of a
+soil profile.
+41
+Field Indicators of Hydric Soils
+Fibric. See “Peat.”
+Flooded. A condition in which the soil surface is
+temporarily covered with flowing water from any
+source, such as streams overflowing their banks,
+runoff from adjacent or surrounding slopes, inflow
+from high tides, or any combination of sources.
 Flood plain. The nearly level plain that borders a
-stream and is subject to inundation under flood-
-stage conditions unless protected artificially. It is
-usually a constructional landform built of sediment
-deposited during overflow and lateral migration of
-the stream.
-Fragmental soil material. Soil material that consists
-of 90 percent or more rock fragments. Less than
-10 percent of the soil consists of particles 2 mm
-or smaller.
-Frequently flooded or ponded. A frequency class in
-which flooding or ponding is likely to occur often
-under usual weather conditions (a chance of more
-than 50 percent in any year, or more than 50
-times in 100 years).
-FWS. U.S. Department of the Interior, Fish and
-Wildlife Service.
-*g. A horizon suffix indicating that the horizon is gray
-because of wetness but not necessarily that it is
-gleyed. All gleyed matrices (defined below) should
-have the suffix “g”; however, not all horizons with
-the “g” suffix are gleyed. For example, a horizon
-with the color 10YR 6/2 that is at least seasonally
-wet, with or without other redoximorphic features,
-should have the “g” suffix.
+stream and is subject to inundation under
+flood-stage conditions unless protected
+artificially. It is usually a constructional landform
+built of sediment deposited during overflow and
+lateral migration of the stream.
+Fragmental soil material. Soil material that
+consists of 90 percent or more rock fragments.
+Less than 10 percent of the soil consists of
+particles 2 mm or smaller.
+Frequently flooded or ponded. A frequency
+class in which flooding or ponding is likely to
+occur often under usual weather conditions (a
+chance of greater than 50 percent in any year or
+greater than 50 times in 100 years).
 Glauconitic. Refers to a mineral aggregate that
 contains a micaceous mineral resulting in a
 characteristic green color, e.g., glauconitic shale
-or clay (fig. 49).
-*Gleyed matrix. Soils with a gleyed matrix have the
-following combinations of hue, value, and chroma
-(the soils are not glauconitic):
-1. 10Y, 5GY, 10GY, 10G, 5BG, 10BG, 5B, 10B, or
-5PB with value of 4 or more and chroma of 1;
-or
+or clay (fig. 50).
+*g. A horizon suffix indicating that the horizon
+is gray because of wetness but not necessarily
+that it is gleyed. All gleyed matrices (defined
+below) should have the suffix “g”; however, not
+all horizons with the “g” suffix are gleyed. For
+example, a horizon with the color 10YR 6/2 that
+is at least seasonally wet, with or without other
+redoximorphic features, should have the “g” suffix.
+*Gleyed matrix. Soils with a gleyed matrix have
+the following combinations of hue, value, and
+chroma (the soils are not glauconitic):
+1. 10Y, 5GY, 10GY, 10G, 5BG, 10BG, 5B, 10B,
+or 5PB with value of 4 or more and chroma of
+1; or
 2. 5G with value of 4 or more and chroma of 1 or
 2; or
 3. N with value of 4 or more; or
-In some places the gleyed matrix may change
-color upon exposure to air. (See Reduced matrix).
-This phenomenon is included in the concept of
-gleyed matrix (figs. 50 and 51).
-*Hemic. See Mucky peat.
-Histels. Organic soils that overlie permafrost
-and show evidence of cryoturbation. See Soil
-Taxonomy (Soil Survey Staff, 1999) for a complete
-definition.
-37 Hydric Soils
-Histic epipedon. A thick (20- to 60-cm, or 8- to 24-
-inch) organic soil horizon that is saturated with
+4. in some places the gleyed matrix may change
+color upon exposure to air. (See “Reduced
+matrix”). This phenomenon is included in the
+concept of gleyed matrix (figs. 50, 51, and 52).
+*Hemic. See “Mucky peat.”
+Histels. Organic soils that overlie permafrost and
+show evidence of cryoturbation. See “Soil
+Taxonomy” (Soil Survey Staff, 1999) for a
+complete definition.
+Histic epipedon. A thick (20- to 60-cm, or 8- to
+24-inch) organic soil horizon that is saturated with
 water at some period of the year (unless the soil
 is artificially drained) and that is at or near the
 surface of a mineral soil.
@@ -1970,168 +2057,163 @@ materials in more than half of the upper 80 cm
 (32 inches) or that have organic materials of
 any thickness if they overlie rock or fragmental
 materials that have interstices filled with organic
-soil materials. See Soil Taxonomy (Soil Survey
+42
+Field Indicators of Hydric Soils
+soil materials. See “Soil Taxonomy” (Soil Survey
 Staff, 1999) for a complete definition.
 Horizon. A layer, approximately parallel to the
 surface of the soil, distinguishable from adjacent
 layers by a distinctive set of properties produced
-by soil-forming processes. See Soil Taxonomy
-(Soil Survey Staff, 1999) for a complete
-definition.
-Hydric soil definition (1994). A soil that formed
-under conditions of saturation, flooding, or
-ponding long enough during the growing season
-to develop anaerobic conditions in the upper
-part.
+by soil-forming processes. See “Soil Taxonomy”
+(Soil Survey Staff, 1999) for a complete definition.
+Hydric soil definition. A soil that formed under
+conditions of saturation, flooding, or ponding long
+enough during the growing season to develop
+anaerobic conditions in the upper part (“Changes
+in Hydric Soils of the United States, 60 Fed. Reg.
+10349,” 1995).
 Hydrogen sulfide odor. The odor of H2
-S. It is similar
-to the smell of rotten eggs.
-Hydromorphic features. Features in the soil caused
-or formed by water.
-38 Field Indicators of
-Layer(s). A horizon, subhorizon, or combination of
-contiguous horizons or subhorizons sharing the
+S. It is
+similar to the smell of rotten eggs.
+Iron monosulfide (FeS). Dark-gray or black
+precipitates with matrix of 4 or less and chroma of
+2 or less occurring in the soil as stains, coatings,
+soft masses, or pore linings (Duball et al., 2020).
+These compounds rapidly oxidize when exposed
+to the atmosphere resulting in a 1 or more unit
+increase in Munsell value. Proper identification
+of FeS is critical to differentiate it from other
+dark soil materials such as organic matter and
+manganese oxides. The flowchart (fig. 53) should
+be employed to identify FeS features.
+Layer(s). A horizon, subhorizon, or combination
+of contiguous horizons or subhorizons sharing the
 properties required by the indicator.
-Lithologic discontinuity. Occurs in a soil that has
-developed in more than one type of parent
-material. Commonly determined by a significant
-change in particle-size distribution, mineralogy,
-etc. that indicates a difference in material from
-which the horizons formed.
-LRR. Land resource region. LRRs are geographic
-areas characterized by a particular pattern
-of soils, climate, water resources, and land
-use. Each LRR is assigned a different letter of
-the alphabet (A-Z). LRRs are defined in U.S.
-Department of Agriculture Handbook 296 (USDA,
-NRCS, 2006b).
-Many. When referring to redox concentrations, redox
-depletions, or both, “many” represents more than
-20 percent of the observed surface.
-Marl. An earthy, unconsolidated deposit consisting
-chiefly of calcium carbonate mixed with clay in
-approximately equal proportions; formed primarily
-under freshwater lacustrine conditions. See Soil
-Taxonomy (Soil Survey Staff, 1999) for a complete
-definition.
+Lithologic discontinuity. Occurs in a soil that
+has developed in more than one type of parent
+43
+Field Indicators of Hydric Soils
+LRR. Land resource region. LRRs are
+geographic areas characterized by a particular
+pattern of soils, climate, water resources, and
+land use. Each LRR is assigned a different
+letter of the alphabet (A-Z). LRRs are defined in
+“U.S.Department of Agriculture Handbook 296”
+(USDA, NRCS, 2022).
+Many. When referring to redox concentrations,
+redox depletions, or both, “many” represents
+greater than 20 percent of the observed surface.
+Marl. An earthy, unconsolidated deposit
+consisting chiefly of calcium carbonate mixed with
+clay in approximately equal proportions; formed
+primarily under freshwater lacustrine conditions.
+See “Soil Taxonomy” (Soil Survey Staff, 1999) for
+a complete definition.
 *Masked. Through redoximorphic processes, the
 color of soil particles is hidden by organic
 material, silicate clay, iron, aluminum, or some
 combination of these.
-Matrix. The dominant soil volume that is continuous
-in appearance. When three colors occur, such as
-when a matrix, depletions, and concentrations are
-present, the matrix may represent less than 50
-percent of the total soil volume.
-MLRA. Major land resource areas. MLRAs are
+Matrix. The dominant soil volume that is
+continuous in appearance. When three colors
+occur, such as when a matrix, depletions, and
+concentrations are present, the matrix may
+represent less than 50 percent of the total soil
+volume.
+MLRA. Major land resource area. MLRAs are
 geographically associated divisions of land
-resource regions. MLRAs are defined in U.S.
-Department of Agriculture Handbook 296 (USDA,
-NRCS, 2006b).
-Mollic epipedon. A mineral surface horizon that is
-relatively thick, dark colored, and humus rich
-and has high base saturation (fig. 52). See Soil
-Taxonomy (Soil Survey Staff, 1999) for a complete
-definition.
-Mollisols. Mineral soils that have a mollic epipedon.
-See Soil Taxonomy (Soil Survey Staff, 1999) for a
+resource regions. MLRAs are defined in “U.S.
+Department of Agriculture Handbook 296” (USDA,
+NRCS, 2022).
+Mollic epipedon. A mineral surface horizon that
+is relatively thick, dark colored, and humus rich
+and has high base saturation (fig. 54). See “Soil
+Taxonomy“ (Soil Survey Staff, 1999) for a
 complete definition.
-*Muck. Sapric organic soil material in which virtually
-all of the organic material is so decomposed that
-identification of plant forms is not possible. Bulk
-density is normally 0.2 or more. Muck has less
-than one-sixth fibers after rubbing, and its sodium
-pyrophosphate solution extract color has lower
-value and chroma than 5/1, 6/2, and 7/3.
-*Mucky modified mineral soil material. A USDA soil
-texture modifier, e.g., mucky sand. Mucky modified
-mineral soil material that has 0 percent clay has
-between 5 and 12 percent organic carbon. Mucky
-modified mineral soil material that has 60 percent
-clay has between 12 and 18 percent organic
-carbon. Soils with an intermediate amount of clay
-have intermediate amounts of organic carbon.
-Where the organic component is peat (fibric
-material) or mucky peat (hemic material), mucky
-mineral soil material does not occur.
-*Mucky peat. Hemic organic material, which
+Mollisols. Mineral soils that have a mollic
+epipedon. See “Soil Taxonomy” (Soil Survey Staff,
+1999) for a complete definition.
+Muck. Sapric organic soil material in which
+virtually all of the organic material is so
+decomposed that identification of plant forms is
+not possible. Use only with organic horizons (of
+any thickness) of mineral and organic soils that
+are saturated for 30 or more cumulative days in
+normal years or are artificially drained.
+*Mucky modified mineral soil material. A USDA
+soil texture modifier, e.g., mucky sand. Mucky
+modified mineral soil material has between 5 and
+12 percent organic carbon. Where the organic
+component is peat (fibric material) or mucky peat
+(hemic material), mucky mineral soil material
+does not occur.
+Mucky peat. Hemic organic material, which
 is characterized by decomposition that is
 intermediate between that of peat (fibric material)
-and that of muck (sapric material). Bulk density is
-normally between 0.1 and 0.2 g/cm3
-. Mucky peat
-does not meet the fiber content (after rubbing)
-or sodium pyrophosphate solution extract color
-requirements for either peat (fibric) or muck
-(sapric) soil material.
-39 Hydric Soils
-Nodules. See Fe-Mn nodules.
+and that of muck (sapric material). Use only with
+organic horizons (of any thickness) of mineral and
+organic soils that are saturated for 30 or more
+44
+Field Indicators of Hydric Soils
+Nodules. Firm to extremely firm, irregularly
+shaped bodies with sharp to diffuse boundaries.
+When broken in half, nodules do not have visibly
+organized internal structure. See Vepraskas
+(1994) for a complete discussion.
 NRCS. USDA, Natural Resources Conservation
 Service (formerly Soil Conservation Service).
 NTCHS. National Technical Committee for Hydric
 Soils.
-Organic matter. Plant and animal residue in the soil
-in various stages of decomposition.
-Organic soil material. Soil material that is saturated
-with water for long periods or artificially drained
-and, excluding live roots, has 18 percent or more
-organic carbon with 60 percent or more clay or
-12 percent or more organic carbon with 0 percent
-clay. Soils with an intermediate amount of clay
-have an intermediate amount of organic carbon.
-If the soil is never saturated for more than a few
-days, it contains 20 percent or more organic
-carbon. Organic soil material includes muck,
-mucky peat, and peat (fig. 53).
-*Peat. Fibric organic soil material. The plant forms can
-be identified in virtually all of the organic material.
-Bulk density is normally <0.1. Peat has three-
-fourths or more fibers after rubbing, or it has two-
-fifths or more fibers after rubbing and has sodium
-pyrophosphate solution extract color of 7/1, 7/2,
-8/2, or 8/3.
-Ped. A unit of soil structure such as a block, column,
-granule, plate, or prism, formed by natural
-processes (in contrast with a clod, which is
-formed artificially).
-Plinthite. The sesquioxide-rich, humus-poor, highly
-weathered mixture of clay with quartz and other
-diluents. See Soil Taxonomy (Soil Survey Staff,
-1999) for a complete discussion.
-Ponding. Standing water in a closed depression that
-is removed only by percolation, evaporation, or
-transpiration. The ponding lasts for more than 7
-days.
+Organic matter. Plant and animal residue in the
+soil in various stages of decomposition.
+Organic soil material. Soil material that is
+saturated with water for long periods or artificially
+drained and, excluding live roots, has 12 percent
+or more (by weight) organic carbon. If the soil
+is never saturated for more than a few days, it
+contains 20 percent or more organic carbon.
+Organic soil material includes muck, mucky peat,
+and peat. See “Soil Taxonomy” (Soil Survey Staff,
+1999) for a complete definition.
+Peat. Fibric organic soil material. The plant forms
+can be identified in virtually all of the organic
+material. Use only with organic horizons (of any
+thickness) of mineral and organic soils that are
+saturated for 30 or more cumulative days in
+normal years or are artificially drained. Peat has
+three-fourths or more fibers after rubbing.
+Ped. A unit of soil structure such as a block,
+column, granule, plate, or prism, formed by
+natural processes (in contrast with a clod, which
+is formed artificially).
+Plinthite. The sesquioxide-rich, humus-poor,
+highly weathered mixture of clay with quartz and
+other diluents. See “Soil Taxonomy” (Soil Survey
+Staff, 1999) for a complete discussion.
+45
+Field Indicators of Hydric Soils
+Ponding. Standing water in a closed depression
+that is removed only by percolation, evaporation,
+or transpiration. The ponding lasts for greater
+than 7 days.
 Pore linings. Zones of accumulation that may be
 either coatings on a ped or pore surface or
 impregnations of the matrix adjacent to the pore
-or ped (fig. 54). See Vepraskas (1994) for a
+or ped (fig. 55). See Vepraskas (1994) for a
 complete discussion.
 Prominent. Contrasts strongly in color. Color
 contrasts more contrasting than faint and distinct
 are prominent.
 Red parent material. The parent material with a
 natural inherent reddish color attributable to the
-presence of iron oxides, typically hematite (Elless
-and Rabenhorst, 1994; Elless et al., 1996),
-occurring as coatings on and occluded within
-mineral grains. Soils that formed in red parent
-material have conditions that greatly retard the
-development and extent of the redoximorphic
+presence of iron oxides, typically hematite
+(Elless and Rabenhorst, 1994; Elless et al.,
+1996), occurring as coatings on and occluded
+within mineral grains. Soils that formed in red
+parent material have conditions that greatly retard
+the development and extent of the redoximorphic
 features that normally occur under prolonged
 aquic conditions. They typically have a Color
-Percent Clay
-Percent
-Organic
-Carbon
-Mineral Soil Material
-Mucky Modified Mineral Soil Material
-Organic Soil Material
-Peat (Fibric)
-Mucky Peat (Hemic)
-Much (Sapric)
-40 Field Indicators of
-Change Propensity Index (CCPI) of <30
+Change Propensity Index (CCPI) of less than 30
 (Rabenhorst and Parikh, 2000). Most commonly,
 the material consists of dark red, consolidated
 Mesozoic or Paleozoic sedimentary rocks, such
@@ -2140,30 +2222,29 @@ materials derived from such rocks. Assistance
 from a local soil scientist may be needed to
 determine where red parent material occurs.
 Redox concentrations. Bodies of apparent
-accumulation of Fe-Mn oxides (figs. 54 and
-55). Redox concentrations include soft masses,
-pore linings, nodules, and concretions. For
-the purposes of the indicators, nodules and
+accumulation of Fe-Mn oxides (figs. 55 and 56).
+Redox concentrations include soft masses, pore
+linings, nodules, and concretions. For the
+purposes of the indicators, nodules and
 concretions are excluded from the concept of
 redox concentrations unless otherwise specified
 by specific indicators. See Vepraskas (1994) for a
 complete discussion.
-Redox depletions. Bodies of low chroma (2 or less)
-having value of 4 or more where Fe-Mn oxides
-have been stripped or where both Fe-Mn oxides
-and clay have been stripped (fig. 55). Redox
-depletions contrast distinctly or prominently with
-the matrix. See Vepraskas (1994) for a complete
-discussion.
-Redoximorphic features. Features formed by the
-processes of reduction, translocation, and/or
-oxidation of Fe and Mn oxides (figs. 54 and 55);
+Redox depletions. Bodies of low chroma (2 or
+less) having value of 4 or more where Fe-Mn
+oxides have been stripped or where both Fe-Mn
+oxides and clay have been stripped (fig. 56). See
+Vepraskas (1994) for a complete discussion.
+Redoximorphic features. Features formed by
+the processes of reduction, translocation, and/or
+oxidation of Fe and Mn oxides (figs. 55 and 56);
 formerly called mottles and low-chroma colors.
 See Vepraskas (1994) for a complete discussion.
-Reduced matrix. A soil matrix that has low chroma
-and high value, but in which the color changes
-in hue or chroma when the soil is exposed to air.
-See Vepraskas (1994) for a complete discussion.
+Reduced matrix. A soil matrix that has low
+chroma and high value, but in which the color
+changes in hue or chroma when the soil is
+exposed to air. See Vepraskas (1994) for a
+complete discussion.
 *Reduction. For the purpose of the indicators,
 reduction occurs when the redox potential (Eh) is
 below the ferric-ferrous iron threshold as adjusted
@@ -2176,183 +2257,178 @@ Relict features. Soil morphological features that
 reflect past hydrologic conditions of saturation
 and anaerobiosis. See Vepraskas (1994) for a
 complete discussion.
-*Sapric. See Muck.
-Saturation. Wetness characterized by zero or positive
-pressure of the soil water. Almost all of the soil
-pores are filled with water.
-Sharp boundary. Used to describe redoximorphic
-features that grade sharply from one color to
-another. The color grade is commonly less than
-0.1 mm wide.
-Soft masses. Noncemented redox concentrations,
-frequently within the soil matrix, that are of various
-shapes and cannot be removed as discrete units.
-Soil texture. The relative proportions, by weight, of
-sand, silt, and clay particles in the soil material
-less than 2 mm in size.
+46
+Field Indicators of Hydric Soils
+*Sapric. See “Muck.”
+Saturation. Wetness characterized by zero or
+positive pressure of the soil water. Almost all of
+the soil pores are filled with water.
+Sharp boundary. Used to describe
+redoximorphic features that grade sharply from
+one color to another. The color grade is
+commonly less than 0.1 mm wide.
+Soft masses. Noncemented redox
+concentrations, frequently within the soil matrix,
+that are of various shapes and cannot be
+removed as discrete units (see fig. 56).
+Soil pH. A measure of the acidity or alkalinity in
+the soil.
+Soil texture. The relative proportions, by weight,
+of sand, silt, and clay particles less than 2 mm in
+size in the soil material.
 Spodic horizon. A mineral soil horizon that is
 characterized by the illuvial accumulation of
-amorphous materials consisting of aluminum
-41 Hydric Soils
-and organic carbon with or without iron (figs.
-56 and 57). The spodic horizon has a minimum
+amorphous materials consisting of aluminum and
+organic carbon with or without iron (figs. 57 and
+58). The spodic horizon has a minimum
 thickness, a minimum quantity of oxalate
 extractable carbon plus aluminum, and/or specific
 color requirements.
-Stream terrace. Flat-topped landforms in a stream
-valley that flank and are parallel to the stream
-channel, originally formed by previous stream
-level, and representing the abandoned flood plain,
-stream bed, or valley floor produced during a past
-state of fluvial erosion or deposition (i.e., currently
-very rarely or never flooded; inactive cut and fill
-and/or scour and fill processes). Stream terraces
-may occur singularly or as a series. Erosional
-surfaces cut into bedrock and thinly mantled
-with stream deposits (alluvium) are called “strath
-terraces.” Remnants of constructional valley floors
-thickly mantled with alluvium are called “alluvial
-terraces.”
+Stream terrace. Flat-topped landforms in a
+stream valley that flank and are parallel to the
+stream channel, originally formed by previous
+stream level, and representing the abandoned
+flood plain, stream bed, or valley floor produced
+during a past state of fluvial erosion or deposition
+(i.e., currently very rarely or never flooded;
+inactive cut and fill and/or scour and fill
+processes). Stream terraces may occur singularly
+or as a series. Erosional surfaces cut into
+bedrock and thinly mantled with stream deposits
+(alluvium) are called “strath terraces.” Remnants
+of constructional valley floors thickly mantled with
+alluvium are called “alluvial terraces.”
 Umbric epipedon. A thick, dark mineral surface
 horizon with base saturation of less than 50
-percent. See Soil Taxonomy (Soil Survey Staff,
+percent. See “Soil Taxonomy” (Soil Survey Staff,
 1999) for a complete definition.
-Vertisol. A mineral soil with 30 percent or more clay
-in all layers. These soils expand and shrink,
-depending on moisture content, and have
-slickensides or wedge-shaped peds. See Soil
-Taxonomy (Soil Survey Staff, 1999) for a complete
-definition.
-Wetland. An area that has hydrophytic vegetation,
-hydric soils, and wetland hydrology, as per the
-National Food Security Act Manual and the 1987
-Corps of Engineers Wetlands Delineation Manual
+47
+Field Indicators of Hydric Soils
+Vertisol. A mineral soil with 30 percent or
+more clay in all layers. These soils expand and
+shrink, depending on moisture content, and
+have slickensides or wedge-shaped peds. See
+“Soil Taxonomy” (Soil Survey Staff, 1999) for a
+complete definition.
+Wetland. An area that has hydrophytic
+vegetation, hydric soils, and wetland hydrology,
+as per the “National Food Security Act Manual”
+(USDA NRCS, 2010) and the “1987 Corps
+of Engineers Wetlands Delineation Manual”
 (Environmental Laboratory, 1987).
-43
+49
 Appendices
-Appendix 1: Use Indicators by Land Resource Regions (LRRs) and
+Appendix 1: Approved Indicators by Land Resource Regions (LRRs) and
 Certain Major Land Resource Areas (MLRAs)
-LRR						Indicators
-A A1, A2, A3, A4, A11, A12, S1, S4, S5, S6, F1 (except for MLRA 1), F2, F3, F6, F7, F8
-B A1, A2, A3, A4, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-C A1, A2, A3, A4, A5, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-D A1, A2, A3, A4, A9, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-E A1, A2, A3, A4, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-F A1, A2, A3, A4, A5, A9, A11, A12, S1, S3, S4, S5, S6, F1, F2, F3, F6, F7, F8
-G A1, A2, A3, A4, A9, A11, A12, S1, S2, S4, S5, S6, F1, F2, F3, F6, F7, F8
-H A1, A2, A3, A4, A9, A11, A12, S1, S2, S4, S5, S6, F1, F2, F3, F6, F7, F8, F16 (MLRAs 72 and 73)
-I A1, A2, A3, A4, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-J A1, A2, A3, A4, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
-K A1, A2, A3, A4, A5, A11, A12, S1, S4, S5, S6, S7, S11, F1, F2, F3, F6, F7, F8, F10
-L A1, A2, A3, A4, A5, A11, A12, S1, S4, S5, S6, S7, S11, F1, F2, F3, F6, F7, F8, F10
-M A1, A2, A3, A4, A5, A10, A11, A12, S1, S3, S4, S5, S6, S7, F1, F2, F3, F6, F7, F8
-N A1, A2, A3, A4, A5, A10, A11, A12, S1, S4, S5, S6, S7, F2, F3, F6, F7, F8, F12, F13 (MLRA 122), F21
-(MLRA 127)
-O A1, A2, A3, A4, A5, A11, A12, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8, F12
-P A1, A2, A3, A4, A5, A6 (except for MLRA 136), A7 (except for MLRA 136), A9 (except for MLRA 136),
-A11, A12, S1 (MLRA 136), S4, S5, S6, S7, F1 (MLRA 136), F2, F3, F6, F7, F8, F12, F13, F22 (MLRA
-138 and West Florida portion of 152A)
-Q A1, A2, A3, A4, A8, A11, A12, S1, S4, S6, S7, F2, F3, F6, F7, F8
-R A1, A2, A3, A4, A5, A11, A12, A17, S1, S4, S5, S6, S7, S8, S9, F2, F3, F6, F7, F8, F21 (MLRA 145)
-S A1, A2, A3, A4, A5, A11, A12, A17, S1, S4, S5, S6, S7, S8, S9, F2, F3, F6, F7, F8, F19 (MLRAs 148 and
-149A), F20 (MLRA 149A), F21 (MLRA 147 and 148)
-T A1, A2, A3, A4, A5, A6, A7, A9, A11, A12, A16 (MLRA 150A), S4, S5, S6, S7, S8, S9, S12 (MLRA 153B
-and 153D), F2, F3, F6, F7, F8, F11 (MLRA 151), F12, F13, F17 (MLRA 151), F18 (MLRA 150), F20
-(MLRAs 153C and 153D)
-U A1, A2, A3, A4, A5, A6, A7, A8, A11, A12, S4, S5, S6, S7, S8, S9, F2, F3, F6, F7, F8, F10, F13, F22
-(MLRA 154)
-V A1, A2, A3, A4, A8, A11, A12, S1, S4, S7, F2, F3, F6, F7, F8
-W A1, A2, A3, A4, A12, A13, A14, A15
-X A1, A2, A3, A4, A12, A13, A14, A15
-Y A1, A2, A3, A4, A12, A13, A14, A15
-Z A1, A2, A3, A4, A6, A7, A8, A11, A12, S4, S5, S6, S7, F2, F3, F6, F7, F8
-44 Field Indicators of
+LRR						 Indicators
+A		 A1, A2, A3, A4, A11, A12, A18, S1, S4, S5, S6, F1 (except for MLRA 1), F2, F3, F6, F7, F8
+B		 A1, A2, A3, A4, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+C		 A1, A2, A3, A4, A5, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+D		 A1, A2, A3, A4, A9, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+E		 A1, A2, A3, A4, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+F		 A1, A2, A3, A4, A5, A9, A11, A12, A18, S1, S3, S4, S5, S6, F1, F2, F3, F6, F7, F8
+G		 A1, A2, A3, A4, A9, A11, A12, A18, S1, S2, S4, S5, S6, F1, F2, F3, F6, F7, F8
+H		 A1, A2, A3, A4, A9, A11, A12, A18, S1, S2, S4, S5, S6, F1, F2, F3, F6, F7, F8, F16 (MLRAs 72
+		 and 73)
+I		 A1, A2, A3, A4, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+J		 A1, A2, A3, A4, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8
+K		 A1, A2, A3, A4, A5, A11, A12, A18, S1, S4, S5, S6, S7, S11, F1, F2, F3, F6, F7, F8, F10
+L		 A1, A2, A3, A4, A5, A11, A12, A18, S1, S4, S5, S6, S7, S11, F1, F2, F3, F6, F7, F8, F10
+M		 A1, A2, A3, A4, A5, A10, A11, A12, A18, S1, S3, S4, S5, S6, S7, F1, F2, F3, F6, F7, F8
+N		 A1, A2, A3, A4, A5, A10, A11, A12, A18, S1, S4, S5, S6, S7, F2, F3, F6, F7, F8, F12, F13 (MLRA
+		 122), F21 (MLRA 127)
+O		 A1, A2, A3, A4, A5, A11, A12, A18, S1, S4, S5, S6, F1, F2, F3, F6, F7, F8, F12
+P		 A1, A2, A3, A4, A5, A6 (except MLRA 136), A7 (except for MLRA 136), A9 (except for MLRA 136),
+		 A11, A12, A18, S1 (except MLRA 136), S4, S5, S6, S7(MLRA 136), F2, F3, F6, F7, F8, F12,
+		 F13, F22 (MLRA 138 and West Florida portion of 152A)
+Q		 A1, A2, A3, A4, A8, A11, A12, A18, S1, S4, S6, S7, F2, F3, F6, F7, F8
+R		 A1, A2, A3, A4, A5, A11, A12, A17 (MLRA 144A and 145), A18, S1, S4, S5, S6, S7, S8, S9, F2,
+		 F3, F6, F7, F8, F21 (MLRA 145)
+S		 A1, A2, A3, A4, A5, A11, A12, A17 (MLRA 149B), A18, S1, S4, S5, S6, S7, S8, S9, F2, F3, F6, F7,
+		 F8, F19 (MLRAs 148 and 149A), F20 (MLRA 149A), F21 (MLRA 147 and 148)
+T		 A1, A2, A3, A4, A5, A6, A7, A9, A11, A12, A16 (MLRA 150A), A18, S4, S5, S6, S7, S8, S9, S12
+		 (MLRA 153B and 153D), F2, F3, F6, F7, F8, F11 (MLRA 151), F12, F13, F17 (MLRA 151),
+		 F18 (MLRA150), F20 (MLRAs 153C and 153D), F22 (MLRA 138 and west Florida portion of
+		 152A)
+U		 A1, A2, A3, A4, A5, A6, A7, A8, A11, A12, A18, S4, S5, S6, S7, S8, S9, F2, F3, F6, F7, F8, F10,
+		 F13, F22 (MLRA 154)
+V		 A1, A2, A3, A4, A8, A11, A12, A18, S1, S4, S7, F2, F3, F6, F7, F8
+W		 A1, A2, A3, A4, A12, A13, A14, A15, A18
+X		 A1, A2, A3, A4, A12, A13, A14, A15, A18
+Y		 A1, A2, A3, A4, A12, A13, A14, A15, A18
+Z		 A1, A2, A3, A4, A6, A7, A8, A11, A12, A18, S4, S5, S6, S7, F2, F3, F6, F7, F8
+50
+Field Indicators of Hydric Soils
 Appendix 2: Test Indicators by Land Resource Regions (LRRs) and
 Certain Major Land Resource Regions (MLRAs)
-LRR		 Indicators
-A A10, F22
-B A10, F18, F22
-C A9, F18 (MLRA 14), F22
-D F12, F22
-E A10, F22
-F F18 (MLRA 56), F22
-G F22
-H F16 (except for MLRAs 72 and 73),
-F22
-I A9, F22
-J A9, F18 (MLRA 86), F22
-K A10, S3, S8, S9, F12, F22
-L A10, S3, S8, S9, F12, F22
-M F12, F22
-N F22
-O A9, F18 (MLRA 131), F21 (MLRA
-131C), F22
-P F18 (MLRA 135), F19, F22 (except
-for MLRA 138 and West Florida
-portion of MLRA 152A
-Q A5, F22
-R S3, F12, F22, TA6 (MLRAs 144A
-and 145)
-S A10 (except for MLRA 148), A16
-(except for MLRA 149B), F19
-(except for MLRAs 148 and
-149A ), TA6 (MLRA 149B), F22
-T F19, F20 (MLRA 153B), F22, TS7
-(153B and 153D)
-U F22 (except for MLRA 154)
-V A5, F22
-W A11, F3, F6, F7, F8, F22, TA4, TA5
-X A11, F3, F6, F7, F8, F22, TA4, TA5
-Y A11, F3, F6, F7, F8, F22, TA4, TA5
-Z A5, F22
-45 Hydric Soils
-Appendix 3: Indicators That Have Been Deleted or Are No Longer
-Approved for Use
+LRR						 Indicators
+A		 A10, F21, F22
+B		 A10, F18, F21, F22
+C		 A9, F18 (MLRA 14), F21, F22
+D		 F12, F21,F22
+E		 A10, F21, F22
+F		 F18 (MLRA 56), F21, F22
+G		 F21, F22
+H		 F16 (except for MLRAs 72 and 73), F21, F22
+I		 A9, F21, F22
+J		 A9, F18 (MLRA 86), F21, F22
+K		 A10, S3, S8, S9, F12, F21, F22
+L		 A10, S3, S8, S9, F12, F21, F22
+M		 F12, F21, F22
+N		 F21, F22
+O		 A9, F18 (MLRA 131), F21 (MLRA 131C), F22
+P		 F18 (MLRA 135), F19, F21, F22 (except for MLRA 138 and West Florida portion of MLRA 152A
+Q		 A5, F21, F22
+R		 S3, F12, F21, F22, TA6 (MLRAs 144A and 145)
+S		 A10 (except for MLRA 148), A16 (except for MLRA 149B), F19 (except for MLRAs 148 and
+		 149A), TA6 (MLRA 149B), F21, F22
+T		 F19, F20 (MLRA 153B), F21, F22, TS7 (153B and 153D)
+U		 F21, F22 (except for MLRA 154)
+V		 A5, F21, F22
+W		 A11, F3, F6, F7, F8, F21, F22
+X		 A11, F3, F6, F7, F8, F21, F22
+Y		 A11, F3, F6, F7, F8, F21, F22
+Z		 A5, F21, F22
+51
+Field Indicators of Hydric Soils
+Appendix 3: Indicators that Have Been Deleted or
+Are No Longer Approved for Use
 S10. Alaska Gleyed.—This indicator is now indicator A13 (Alaska Gleyed).
-F4. Depleted Below Dark Surface.—This indicator is now indicator A11 (Depleted Below Dark Surface).
-F5.Thick Dark Surface.—This indicator is now indicator A12 (Thick Dark Surface).
-F9.—Vernal Pools. This indicator has been deleted and its concepts are included in Field Indicator F3 (Depleted
-Matrix).
+F4. Depleted Below Dark Surface.—This indicator is now indicator A11 (Depleted Below Dark
+		 Surface).
+F5. Thick Dark Surface.—This indicator is now indicator A12 (Thick Dark Surface).
+F9. Vernal Pools.—This indicator has been deleted and its concepts are included in Field Indicator F3
+(Depleted Matrix).
 F14. Alaska Redox Gleyed.—This indicator is now indicator A14 (Alaska Redox).
 F15. Alaska Gleyed Pores.—This indicator is now indicator A15 (Alaska Gleyed Pores).
 TA1. Playa Rim Stratified Layers.—This test indicator has been deleted.
 TA2. Structureless Muck.—This test indicator has been deleted.
-TA3. Coast Prairie Redox.—This test indicator has been approved for use and is now A16 (Coast Prairie Redox).
+TA3. Coast Prairie Redox.—This test indicator has been approved for use and is now A16 (Coast
+Prairie Redox).
 TS1. Iron Staining.—This test indicator has been deleted.
-TS2.Thick Sandy Dark Surface.—This test indicator has been deleted. Its concepts have been approved for use
-and are now included with indicator A12 (Thick Dark Surface).
-TS3. Dark Surface 2.—This test indicator has been deleted. It is now the same as indicator S7 (Dark Surface).
-TS4. Sandy Neutral Surface.—This test indicator has been deleted. Most of its concepts have been approved for
-use and are now included in indicator A11 (Depleted Below Dark Surface).
-TS5. Chroma 3 Sandy Redox.—This test indicator has been deleted. It has been approved for use as indicator
-A16 (Coast Prairie Redox).
+TS2. Thick Sandy Dark Surface.—This test indicator has been deleted. Its concepts have been
+approved for use and are now included with indicator A12 (Thick Dark Surface).
+TS3. Dark Surface 2.—This test indicator has been deleted. It is now the same as indicator S7 (Dark
+Surface).
+TS4. Sandy Neutral Surface.—This test indicator has been deleted. Most of its concepts have been
+approved for use and are now included in indicator A11 (Depleted Below Dark Surface).
+TS5. Chroma 3 Sandy Redox.—This test indicator has been deleted. It has been approved for use as
+		 indicator A16 (Coast Prairie Redox).
 TF1. ? cm Mucky Peat or Peat.—This test indicator has been deleted.
-TF2. Red Parent Material.—This test indicator has been deleted. Its concept has been approved for use as
-indicator F21 (Red Parent Material).
+TF2. Red Parent Material.—This test indicator has been deleted. Its concept has been approved for
+use as indicator F21 (Red Parent Material).
 TF3. Alaska Concretions.—This test indicator has been deleted.
 TF4. 2.5Y/5Y Below Dark Surface.—This test indicator has been deleted.
 TF5. 2.5Y/5Y Below Thick Dark Surface.—This test indicator has been deleted.
 TF6. Calcic Dark Surface.—This test indicator has been deleted.
-TF7.Thick Dark Surface 2/1.—This test indicator has been deleted. Its concepts have been approved for use and
-are now included in indicator A12 (Thick Dark Surface).
+TF7. Thick Dark Surface 2/1.—This test indicator has been deleted. Its concepts have been approved
+		 for use and are now included in indicator A12 (Thick Dark Surface).
 TF8. Redox Spring Seeps.—This test indicator has been deleted.
-TF9. Delta Ochric.—This test indicator has been approved for use and is now indicator F17 (Delta Ochric).
+TF9. Delta Ochric.—This test indicator has been approved for use and is now indicator F17 (Delta
+		 Ochric).
 TF10. Alluvial Depleted Matrix.—This test indicator has been deleted.
-TF11. Reduced Vertic. This test indicator has been approved for use and is now indicator F18 (Reduced Vertic).
-TF12. Very Shallow Dark Surface.—This test indicator has been approved for use and is now indicator F22 (Very
-Shallow Dark Surface).
-Accessibility Statement
-The U.S. Department of Agriculture is committed to making its electronic and
-information technologies accessible to individuals with disabilities by meeting or
-exceeding the requirements of Section 508 of the Rehabilitation Act (29 U.S.C. 794d),
-as amended in 1998. Section 508 is a federal law that requires agencies to provide
-individuals with disabilities equal access to electronic information and data comparable
-to those who do not have disabilities, unless an undue burden would be imposed on
-the agency. The Section 508 standards are the technical requirements and criteria that
-are used to measure conformance within this law. More information on Section 508
-and the technical standards can be found at www.section508.gov.
-If you require assistance or wish to report an issue related to the accessibility of any
-content on this website, please email Section508@oc.usda.gov. If applicable, please
-include the web address or URL and the specific problems you have encountered. You
-may also contact a representative from the USDA Section 508 Coordination Team.
-
+TF11. Reduced Vertic.—This test indicator has been approved for use and is now indicator F18
+(Reduced Vertic).
+TF12. Very Shallow Dark Surface.—This test indicator has been approved for use and is now
+		 indicator F22 (Very Shallow Dark Surface).
+
diff --git a/inst/tinytest/test_hydricsoils.R b/inst/tinytest/test_hydricsoils.R
index 98944e3..c0ca8f4 100644
--- a/inst/tinytest/test_hydricsoils.R
+++ b/inst/tinytest/test_hydricsoils.R
@@ -3,13 +3,13 @@ data(fihs, package = "hydricsoils")
 has_terra_and_spatial <- !inherits(try(requireNamespace("terra", quietly = TRUE), silent = TRUE), 'try-error') && file.exists(file.path(tools::R_user_dir("hydricsoils", "data"), "lrrmlra.gpkg"))
 
 # basic checks on parsing of FIHS ----
-expect_equal(nrow(fihs), 44)
+expect_equal(nrow(fihs), 45)
 
 # Indicator A9 "1 cm Muck"  ----
 # - several LRRs in use, with an exception
 # - testing in several LRRs
 a9 <- subset(fihs, indicator == "A9")
-expect_equal(a9$page, "13")
+expect_equal(a9$page, "15")
 expect_equal(a9$usage_symbols[[1]], c("D", "F", "G", "H", "P", "T"))
 expect_equal(a9$except_mlra[[1]], "136")
 expect_equal(a9$test_symbols[[1]], c("C", "I", "J", "O"))
@@ -18,7 +18,7 @@ expect_equal(a9$test_symbols[[1]], c("C", "I", "J", "O"))
 # - approved in FIHS2018 for use in Alaska (W, X, Y LRRs)
 # - in MLRA2022 database we have W1, W2, X1, X2, and Y LRRs
 a13 <- subset(fihs, indicator == "A13")
-expect_equal(a13$page, "16")
+expect_equal(a13$page, "18")
 expect_equal(a13$usage_symbols[[1]], c("W1", "W2", "X1", "X2", "Y"))
 expect_equal(a13$except_mlra[[1]], character(0))
 expect_equal(a13$test_symbols[[1]], character(0))
@@ -28,7 +28,7 @@ expect_equal(a13$test_except_mlra[[1]], character(0))
 # - approved for use in one MLRA
 # - tested in one LRR (except for one MLRA)
 a16 <- subset(fihs, indicator == "A16")
-expect_equal(a16$page, "17")
+expect_equal(a16$page, "20")
 expect_equal(a16$usage_symbols[[1]], c("150A"))
 expect_equal(a16$except_mlra[[1]], character(0))
 expect_equal(a16$test_symbols[[1]], c("S"))
@@ -46,12 +46,17 @@ expect_equal(name_to_indicator(c("Depleted Below Dark Surface", "2 cm Muck", NA,
 
 ## indicator to usesym
 expect_equal(indicator_to_usesym(c("A11", "A10", NA, "F1", "A8")),
-             structure(list(c("A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "Z"), c("M", "N"), NULL, c("A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "O"), c("Q", "U", "V", "Z")), names = c("A11", "A10", NA, "F1", "A8")))
+             structure(list(c("A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "N", "O", "P", "Q", "R", "S", "T", "U", "V", "W1", "W2", "X1", "X2", "Y", "Z"),
+                            c("M", "N"),
+                            NULL,
+                            c("A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "K", "L", "M", "O"),
+                            c("Q", "U", "V", "Z")),
+                       names = c("A11", "A10", NA, "F1", "A8")))
 
 ## usesym to indicator (by symbol)
 expect_equal(usesym_to_indicator(c("18", "150A")),
-             list(`18` = c("A1", "A2", "A3", "A4", "A5", "A11", "A12", "S1", "S4", "S5", "S6", "F1", "F2", "F3", "F6", "F7", "F8"),
-                  `150A` = c("A1", "A2", "A3", "A4", "A5", "A6", "A7", "A9", "A11", "A12", "A16", "S4", "S5", "S6", "S7", "S8", "S9", "F2", "F3", "F6", "F7", "F8","F13", "F18")))
+             list(`18` = c("A1", "A2", "A3", "A4", "A5", "A11", "A12", "A18", "S1", "S4", "S5", "S6", "F1", "F2", "F3", "F6", "F7", "F8"),
+                  `150A` = c("A1", "A2", "A3", "A4", "A5", "A6", "A7", "A9", "A11", "A12", "A16", "A18", "S1", "S4", "S5", "S6", "S7", "S8", "S9", "F2", "F3", "F6", "F7", "F8","F13", "F18")))
 
 ## usesym to indicator (multisymbol)
 # gives indicators used in BOTH 18 and 150A
diff --git a/man/hydricsoils_data_dir.Rd b/man/hydricsoils_data_dir.Rd
new file mode 100644
index 0000000..7b19500
--- /dev/null
+++ b/man/hydricsoils_data_dir.Rd
@@ -0,0 +1,20 @@
+% Generated by roxygen2: do not edit by hand
+% Please edit documentation in R/hydricsoils.R
+\name{hydricsoils_data_dir}
+\alias{hydricsoils_data_dir}
+\title{hydricsoils Data Directory}
+\usage{
+hydricsoils_data_dir()
+}
+\value{
+\code{hydricsoils_data_dir()}: character. Path to hydricsoil package user
+data directory. Default: \code{tools::R_user_dir("hydricsoils", which = "data")}
+}
+\description{
+hydricsoils Data Directory
+}
+\examples{
+
+hydricsoils_data_dir()
+
+}
diff --git a/man/lrrmlra-geometry.Rd b/man/lrrmlra-geometry.Rd
index a71b3a4..7aacb66 100644
--- a/man/lrrmlra-geometry.Rd
+++ b/man/lrrmlra-geometry.Rd
@@ -4,24 +4,19 @@
 \alias{cache_lrrmlra_geometry}
 \alias{clear_lrrmlra_geometry}
 \alias{lrrmlra_geometry}
+\alias{lrrmlra_geometry_dsn}
 \title{Download and Cache or Load Latest 'MLRA Geographic Database'}
 \source{
 The default source is a ZIP file containing an ESRI Shapefile. The direct download URL is \url{https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip}, which can be found \href{https://www.nrcs.usda.gov/resources/data-and-reports/major-land-resource-area-mlra}{here}.
 }
 \usage{
-cache_lrrmlra_geometry(
-  overwrite = FALSE,
-  dsn =
-    "/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022"
-)
+cache_lrrmlra_geometry(overwrite = FALSE, dsn = lrrmlra_geometry_dsn())
 
 clear_lrrmlra_geometry()
 
-lrrmlra_geometry(
-  overwrite = FALSE,
-  dsn =
-    "/vsizip//vsicurl/https://www.nrcs.usda.gov/sites/default/files/2022-10/MLRA_52_2022.zip/MLRA_52_2022"
-)
+lrrmlra_geometry(overwrite = FALSE, dsn = lrrmlra_geometry_dsn())
+
+lrrmlra_geometry_dsn()
 }
 \arguments{
 \item{overwrite}{Overwrite existing file? Passed to \code{terra::writeVector()}. Default: \code{FALSE}}
@@ -34,6 +29,8 @@ lrrmlra_geometry(
 \code{clear_lrrmlra_geometry()}: logical. Called for the side-effect of removing the MLRA geometry file from the cache. Returns \code{TRUE} if \code{"lrrmlra.gpkg"} is successfully removed from user data cache.
 
 \code{lrrmlra_geometry()}: A terra \emph{SpatVector} object containing \code{lrrmlra} attributes and geometry.
+
+\code{lrrmlra_geometry_dsn()}: character. Path to MLRA Geographic Database source.
 }
 \description{
 Creates a local copy of the latest 'MLRA Geographic Database' in the user's package data cache. This file/directory is separate from the package installation.
diff --git a/vignettes/fihs.Rmd b/vignettes/fihs.Rmd
index 29b0b99..a468b30 100644
--- a/vignettes/fihs.Rmd
+++ b/vignettes/fihs.Rmd
@@ -89,6 +89,6 @@ for (i in seq(nrow(fihs))) {
 
 ## References
 
-United States Department of Agriculture, Natural Resources Conservation Service. 2018. Field Indicators of Hydric Soils in the United States, Version 8.2. L.M. Vasilas, G.W. Hurt, and J.F. Berkowitz (eds.). USDA, NRCS, in cooperation with the National Technical Committee for Hydric Soils. Available online: <https://www.nrcs.usda.gov/resources/guides-and-instructions/field-indicators-of-hydric-soils>
+United States Department of Agriculture, Natural Resources Conservation Service. 2024. Field Indicators of Hydric Soils in the United States, Version 9.0. Available online: <https://www.nrcs.usda.gov/resources/guides-and-instructions/field-indicators-of-hydric-soils>
 
 United States Department of Agriculture, Natural Resources Conservation Service. 2022. Land resource regions and major land resource areas of the United States, the Caribbean, and the Pacific Basin. U.S. Department of Agriculture, Agriculture Handbook 296. Available online: <https://www.nrcs.usda.gov/resources/data-and-reports/major-land-resource-area-mlra>