Gleyic properties (WRB 2022)

Tests whether the profile shows gleyic properties (WRB 2022 Ch 3.2.6, p. 75) in a layer starting within the upper max_top_cm (default 50). Gleyic properties qualify the Gleysols and many other RSGs (Gleyic, Endogleyic, Epigleyic qualifiers).

Usage

gleyic_properties(
  pedon,
  max_top_cm = 50,
  min_redox_pct = 5,
  stagnic_decay_factor = 3
)

Arguments

pedon

A PedonRecord.

max_top_cm

Maximum top depth (cm) of a candidate layer (default 50).

min_redox_pct

The oximorphic features of criterion 2 are more than this % of the layer (default 5).

stagnic_decay_factor

Not used since v0.9.312 (the decay test was removed); kept so that existing calls still work.

Value

A DiagnosticResult.

Details

Since v0.9.312 the layer reading follows the text and Hugo's reading of it for field descriptions that do not say where the mottles sit: a layer has gleyic properties when its matrix has a reductimorphic colour, moist (criterion 1: hue N, 10Y, GY, G, BG, B or PB, or hue 2.5Y or 5Y with a chroma of 2 or less; with more than 5% oximorphic features these are read as the gleyic features of criterion 2 over a reduced matrix); when it has more than 5% oximorphic features and lies directly on a layer with such a matrix (criterion 3); or when it has them and the site records groundwater within 150 cm that is not perched (site$groundwater_kind, site$groundwater_depth_cm). A mottled layer with none of these is NA, unless the site records no groundwater, a perched water table or a deeper one, or a claric layer lies directly above it: its features are then stagnic. Continuous rock has no gleyic properties. Until v0.9.311 the features also had to continue with depth (a "decay" test that is not in WRB 2022 and failed the textbook oximorphic-over-reductimorphic sequence).

v0.9.72 designation morphological inference (opt-in)

Field-described Brazilian Gleissolos profiles (e.g.\ the Embrapa Redape curated dataset) routinely encode gleyic properties via the designation suffix g (e.g.\ Cg, Cg1, Cgn, Apg) plus low-chroma Munsell colours (chroma \<= 2), without recording redoximorphic_features_pct as a numeric percent.

With options(soilKey.gleyic_designation_inference = TRUE) the function accepts a layer as gleyic when the reading above does not pass, the designation matches [A-Z][a-z0-9]*g and munsell_chroma_moist <= 2 (or no Munsell colour). Default is FALSE.

References

IUSS Working Group WRB (2022), Chapter 3.2.6, Gleyic properties.