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Ferralsol RSG gate (WRB 2022 Ch 4, p 110)

Source: R/diagnostics-rsg-tier2.R
ferralsol.Rd

WRB-canonical: ferralic horizon \<= 150 cm AND no argic horizon starting above (or at the upper limit of) the ferralic, UNLESS the argic in its upper 30 cm or throughout has one or more of:

  • < 10% water-dispersible clay; OR

  • DeltapH (pH_KCl - pH_water) \>= 0; OR

  • \>= 1.4% soil organic carbon.

v0.3.4 enforces all three exception paths. The DeltapH check uses ph_kcl and ph_h2o; the WDC check uses water_dispersible_clay_pct (introduced in v0.3.3 schema), a clay content in % of the fine earth.

Usage

ferralsol(pedon, strict = NULL)

Arguments

pedon

A PedonRecord.

strict

Logical or NULL. When NULL (default) it resolves via getOption("soilKey.rsg_strict", FALSE). TRUE requires two of the three argic exception paths.

Value

A DiagnosticResult recording whether the diagnostic is present, the qualifying layers, and the supporting evidence.

Details

v0.9.310: the ferralic horizon must start <= 150 cm from the mineral soil surface; an argic horizon counts when it starts above or at the upper limit of the ferralic horizon (not only when it lies wholly above it); and an exception must hold throughout the upper 30 cm of the argic horizon (or all of it when it is thinner). Data that do not decide an exception leave the gate undecided (NA).

Tier-3 strict mode (v0.9.98)

When an argic horizon sits above the ferralic, the default gate keeps the profile as a Ferralsol if any one of the three exception paths (WDC \< 10%, DeltapH \>= 0, SOC \>= 1.4%) holds. With strict = TRUE the gate requires at least two of the three – a single weak indicator no longer rescues a profile with a translocated-clay argic from being keyed out of Ferralsols.