Ideas for a more general level of WRB -- "Supergroups"?

[cyrus621]

The idea here is to group 32 RSG, which are a lot to remember, and some of which are fairly specific and limited geographically, into what I call "supergroups" (I'm not in love with that name -- can you think of something else?). I started with WRB 4th Table 1.2 "Simplified guide to the WRB Reference Soil Groups", but that is a heterogeneous ad-hoc grouping, some based on land use (rooting restrictions) and some on pedogenesis. My aim was to get to 10-12 "supergroups" mainly on pedogenesis and its results. These are intended as a more general level of organization.

Not to be used as a key, the classifier still has to find the RSG by the keys. This grouping provides a framework for discussing major soil-forming processes/results of pedogenesis, it could for example be used as chapter headings in a WRB explanatory book.

I attach my draft proposal, and copy it at the end of this post.

Q1: Comments on the whole concept of Supergroups
Q2: Any proposed revisions?
Q3: Can we think of names for these Supergroups? Avoiding names of any RSG (even if only one RSG in the supergroup, i.e., Histosol, Cryosols) or names prominant in other systems (e.g., Aridosols)

Here is the proposal:

Proposed Supergroups based on dominant processes and/or results of pedogenesis:

1. Soils with thick organic layers

Histosols HS

2. Soils with strong human influence

With long and intensive agricultural use: Anthrosols AT
Containing significant amounts of artefacts: Technosols TC

3. Permafrost-affected soils

Cryosols CR

4. Soils dominated by permanent or seasonal water saturation (or, hydromorphic soils)

Groundwater-affected, underwater or in tidal areas: Gleysols GL
Stagnant water, abrupt textural difference: Planosols PL
Stagnant water, structural difference and/or moderate textural difference: Stagnosols ST

5. Soils with pronounced accumulation of organic matter in the mineral topsoil

Very dark topsoil, secondary carbonates: Chernozems CH
Dark topsoil, secondary carbonates: Kastanozems KS
Dark topsoil, no secondary carbonates (unless very deep), high base status: Phaeozems PH
Dark topsoil, low base status: Umbrisols UM

6. Soils with accumulation of soluble salts or non-saline substances

High concentration of soluble salts: Solonchaks SC
With a high content of exchangeable Na: Solonetz SN
Accumulation of, and cementation by, secondary silica: Durisols DU
Accumulation of secondary gypsum: Gypsisols GY
Accumulation of secondary carbonates: Calcisols CL

7. Fe-dominated soils, primarily of the tropics:

Accumulation and redistribution of Fe: Plinthosols PT
Low-activity clays, P fixation, many Fe oxides, strongly structured: Nitisols NT
Dominance of kaolinite and oxides: Ferralsols FR

8. Soils with clay-enriched subsoil

Alternating wet-dry conditions, shrink-swell clay minerals: Vertisols VR
Interfingering of coarser-textured, lighter-coloured material into a finer-textured, stronger coloured layer: Retisols RT
Low-activity clays, low base status: Acrisols AC
Low-activity clays, high base status: Lixisols LX
High-activity clays, low base status: Alisols AL
High-activity clays, high base status: Luvisols LV

9. Spodic and Andic soils, or Metal-organic complexation soils

Allophanes and/or Al-humus complexes: Andosols AN
Subsoil accumulation of humus and/or oxides: Podzols PZ

10. Soils with little or no profile differentiation

Moderately developed: Cambisols CM
Sandy throughout: Arenosols AR
Stratified fluviatile, marine or lacustrine sediments: Fluvisols FL
Thin or with many coarse fragments: Leptosols LP
No significant profile development: Regosols RG

Supergroups_v1.txt

[StephanMantelISRIC]

I can't agree more David. I have made similar groupings for lectures to first year students. This is helpful for people that are introduced to soils of the world and provides some structure.

[cyrus621]

Already implemented at https://wrb.isric.org/system.html It does seem useful.

[Juilleret]

I like the idea, here a proposal

1 | Soils with thick organic layers | Organoterra | Histosols (HS)
2 | Soils with strong human influence | Anthroterra | Anthrosols (AT), Technosols (TC)
3 | Soils with limitations to root growth | Dysterra | Cryosols (CR), Leptosols (LP), Solonetz (SN), Vertisols (VR), Solonchaks (SC)
4 | Soils distinguished by Fe/Al chemistry | Ferralterra | Gleysols (GL), Andosols (AN), Podzols (PZ), Plinthosols (PT), Planosols (PL), Stagnosols (ST), Nitisols (NT), Ferralsols (FR)
5 | Pronounced accumulation of organic matter in the mineral topsoil | Humiterra | Chernozems (CH), Kastanozems (KS), Phaeozems (PH), Umbrisols (UM)
6 | Accumulation of moderately soluble salts or non-saline substances | Aridoterra | Durisols (DU), Gypsisols (GY), Calcisols (CL)
7 | Soils with clay-enriched subsoil | Argilloterra | Retisols (RT), Acrisols (AC), Lixisols (LX), Alisols (AL), Luvisols (LV)
8 | Soils with little or no profile differentiation | Neoterra | Cambisols (CM), Fluvisols (FL), Arenosols (AR), Regosols (RG)