Soil Diagnostic Features & Characteristics"

In SoilTaxonomy: A System of Soil Classification for Making and Interpreting Soil Surveys

knitr::opts_chunk$set(
  collapse = TRUE,
  comment = "#>"
)

library(SoilTaxonomy)

Data from the latest version of the Keys to Soil Taxonomy related to diagnostic features and characteristics are stored in the package dataset ST_features.

You can load the full supporting data directly with:

data(ST_features, package = "SoilTaxonomy")

A wrapper function, get_ST_features(), is provided to help with obtaining information of interest to specific features or groups of features.

We will inspect the "Mollic Epipedon" information to see the structure of the ST_features data.frame.

We can use get_ST_features(name=...) to get features by name (case-insensitive)

str(get_ST_features(name = "mollic epipedon"))

Columns included in the ST_features, and usable for filtering as arguments to get_ST_features() include:

• group - Diagnostic feature or characteristic group name
• name - Diagnostic feature or characteristic name
• chapter - Chapter number in Keys to Soil Taxonomy (latest edition)
• page - Page number in Keys to Soil Taxonomy (latest edition)
• description - Narrative description (may not be present for all features)
• criteria - "Key" to identifying the feature; logical criteria separated by AND/Or

Say we are interested in finding criteria to distinguish the epipedons (surface diagnostic horizons).

We can use the group=... argument to get all of the "surface" features as a data.frame.

epipedons <- get_ST_features(group = "surface")

There are r nrow(epipedons) features in this result set.

str(epipedons)

We can then select specific items by name, such as the "description" and "criteria":

subset(epipedons, name == "Anthropic Epipedon")$description

subset(epipedons, name == "Anthropic Epipedon")$criteria

If we want to compare the basic definitions in Chapter 2 with the features in Chapter 3, we can subset ST_features using the chapter or page number (or range).

get_ST_features(chapter = 2)$name

get_ST_features(chapter = 3)$name

If we want to get the definitions found on pages 18 to 20 (latest Keys to Soil Taxonomy), we can specify a vector containing desired levels of page:

get_ST_features(page = 18:20)$name

SoilTaxonomy documentation built on Nov. 17, 2023, 1:07 a.m.