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Podosol diagnostic horizons

Bs horizon

The usually bright colours indicate that iron compounds are strongly dominant or co-dominant and there is some but little evidence of organic compounds.

figure 1

Photo credit: tba

Bhs horizon

Iron and organic compounds are both prominent with the organic compounds distributed as streaks, patches or lumps so that concentrations of iron, aluminium and organic compounds have marked spatial variation.

figure 1

Photo credit: Agriculture Victoria

Bh horizon

Organic-aluminium compounds are strongly dominant with little or no evidence of iron compounds.

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Photo credit: CSIRO

Bh/Basi horizon

These are brown, yellow-brown or pale brown cemented horizons that immediately underlie Bh horizons in some poorly drained Podosols.

The 'asi' subscripts for this B horizon do not align with horizon notation described in the Australian Soil and Land Field Survey Handbook (Fourth Edition). In this case the subscripts are meant to represent the following minerals:

  • a = allophane
  • s = sesquioxides (iron and aluminium oxyhydroxides)
  • i = imogolite

    figure 1

    Photo credit: Robyn Doyle, Doyle Soil Consulting

    Pipey horizon

    Pipey B horizons are characterised by pipes of bleached A2 horizon that penetrate both vertically and sometimes laterally >0.5 m into the B horizon, giving a tongued boundary on a profile face.

    figure 1

    Photo credit: tba