Classify a pedon under the Canadian System of Soil Classification

Keys a PedonRecord through the Canadian System of Soil Classification, 3rd edition (Soil Classification Working Group 1998). Experimental: this release keys the ten orders (Key to Soil Orders, Ch 3, pp. 33-34), their 31 great groups (Key to Soil Great Groups, pp. 35-36) and their 231 subgroups (Key to Soil Subgroups, pp. 37-51). The name is the deepest class assigned: the subgroup (e.g. "Terric Mesisol"), or the great group (e.g. "Solonetz") when no subgroup can be given: the Solonetzic subgroups are named by the colour of the A, and the key has no other subgroup for a Solonetzic soil without an A (one eroded down to its solonetzic B); the order is in rsg_or_order and every level in levels.

Usage

classify_cssc3(
  pedon,
  rules = NULL,
  on_missing = c("warn", "silent", "error"),
  gapfill = FALSE
)

Arguments

pedon: A PedonRecord.
rules: Optional pre-loaded rule set (load_rules("cssc3")).
on_missing: One of "warn" (default), "silent", "error".
gapfill: Opt-in within-pedon gap-fill, as in classify_usda.

Value

A ClassificationResult with system_id "cssc3", the deepest class assigned in name, the order in rsg_or_order, every level in levels, the key trace, and provisional_because.

Details

The Canadian keys are written largely in terms of horizon designations, which the book defines partly by measurable properties. Each diagnostic reads the measured properties first (podzolic B chemistry with pyrophosphate-extractable Fe and Al, the Bt clay increase, the solonetzic B Ca/Na ratio, the chernozemic A, the gley colours) and the surveyor's designations in the Canadian notation second (Bt, Bf, Bm, Btj, Bn, Bv, Bss, Bg, Cz...). When the assigned order rests on designations alone, a warning says so. A profile that declares the FAO notation in site$designation_system ("fao2006", as isis_profile_to_pedon sets it, "fao", "wrb" or "wrb2022") is read through a translation of its designations into the Canadian notation where the letters mean the same (the book's Table 6: E = Ae, Bw = Bm, Bs = Bf, Btn = Bnt, f = z, z = s ...); the letters with no Canadian equivalent are not read, and the evidence lists what each designation was read as. The choices where the book is silent are listed in system.file("rules", "cssc3", "readings.yaml", package = "soilKey").

The chernozemic A horizon includes a soil-climate criterion (mean annual soil temperature at least 0 C, moisture subclass drier than humid), read from site$mean_annual_soil_temp_C and site$soil_moisture_subclass, or approximated from the USDA regimes. Without it the Chernozemic order is undecided and any order keyed after it is reported as provisional ($provisional_because). The Gray and Dark Gray subgroups of the Solods and Solodized Solonetz also ask for a subhumid climate (site$soil_moisture_subclass).

References

Soil Classification Working Group (1998). The Canadian System of Soil Classification, 3rd ed. Agriculture and Agri-Food Canada Publication 1646. NRC Research Press, Ottawa.

Examples

res <- classify_cssc3(make_cssc3_example("podzolic"), on_missing = "silent")
res$name
#> [1] "Orthic Humo-Ferric Podzol"