21  Horizon names

21.1 Conventional horizons

Horizon names operate as a shorthand for describing the full profile, making it easier to compare and contrast groups of profiles, and easier to classify them. Horizons are given a particular designation according to their position in the profile and according to soil properties that reflect the kind and degree of pedogenic alteration. As designations are made in the field, they are defined mainly by morphological properties that differentiate horizons from those above or below, or from a presumed parent material. Laboratory data may be needed to confirm identification, especially in marginal cases.

This scheme was developed from the system used in England and Wales (Avery 1980) by Clayden and Hewitt (2015), and is broadly similar to those used overseas (e.g. WRB (2022)). However, note that significant differences in suffix use exist between all of these systems as they have become adapted to regional conditions.

21.1.1 Primary Divisions

These codes can be used by themselves for rapid assessment, or where criteria for secondary divisions are not met.

Table 21.1: Primary horizon divisions

Code	Name	Description
L	Litter	Fresh litter deposited during the previous annual cycle. It is normally loose and the original plant structures are little altered.
F	Fibric	Partly decomposed litter deposited or accumulated at the surface and not saturated with water for more than ~1 month at a time.
H	Humic	Well-decomposed litter deposited or accumulated at the surface and not saturated with water for more than ~1 month at a time. Original plant structures cannot be seen.
O	Peat	Organic horizon accumulated under wet conditions. It is saturated with water for at least 30 consecutive days in most years, or has been artificially drained.
A	Surface	Mineral horizon formed at the surface, or below an organic horizon. It is characterised by incorporation of humified organic matter, or properties resulting from disturbance by cultivation. The organic matter has been incorporated by biological activity or by mixing through cultivation rather than by translocation.
E	Eluviated	Subsurface mineral horizon that contains less organic matter and/or iron and/or clay than the horizon immediately below, as a result of downward or lateral movement. It is identified by having all of the following: A moist colour value of 4 or more, or a dry colour value of 5 or more, with or without silty or sandy coatings (skeletans, @brewer1964), observable in a dry specimen. Higher colour value or lower chroma and less well developed pedality than an underlying B horizon. Less organic matter and higher colour value than an overlying H, O or A horizon. The colour of the horizon can be that of uncoated sand and silt grains but E horizons are also recognised where coats of iron oxides or other minerals mask the colour of the primary particles.
B	Subsoil	Subsurface mineral horizon without rock structure (including fine stratification in soft sediments), characterised by one or more of the following: Illuvial concentration of silicate clay, iron, aluminium or organic matter, alone or in some combination. Coatings of sesquioxides that give the horizon a lower colour value, a higher chroma, or redder hue than the horizons above and below, without apparent illuviation of iron. Alteration that has formed silicate clay or liberated oxides or both, and that leads to ped formation. Evidence of solution and removal of carbonates. A B horizon is differentiated from adjacent horizons by moist and dry colour and/or pedality and normally underlies an A or E horizon.
C	Regolith	Unconsolidated or weakly consolidated mineral horizon that is little affected by pedogenic processes and lacks properties of A, E or B horizons. The material may be either like or unlike that from which the solum presumably formed. A C horizon may have been modified by: Gleying and other processes caused by saturation with water. Accumulation of carbonates or more soluble salts. Some highly weathered materials like saprolite are designated C if the material does not meet the requirements of A, E or B horizons.
R	Rock	Hard or very hard bedrock that is impracticable to dig with a spade.

21.1.2 Secondary Divisions

21.1.2.1 O horizons

Table 21.2: Secondary O horizon divisions

Code	Name	Description
Of	Fibric peat	Peat dominated by well-preserved plant remains, with at least 75% fibre content after rubbing (e.g. preserved timber)
Om	Mesic peat	Peat intermediate in composition between Of and Oh.
Oh	Humic peat	Peat dominated by strongly decomposed plant remains, with less than 15% fibre content after rubbing. Plant species cannot be directly identified.

• Add the p suffix wherever the O horizon is affected by cultivation e.g. Ohp.

21.1.2.2 A Horizons

Table 21.3: Secondary A horizon divisions

Code	Name	Description
Ah	Natural	An A horizon in which there is no evident disturbance due to cultivation or pastoral land use.
Ap	Agricultural	An A horizon in which incorporation of organic matter has involved mixing due to cultivation or to increased biological activity associated with topdressing or manuring. It may contain material from pre-existing E, B or C horizons.
App	Recently tilled	An Ap horizon consisting mainly of clods and fragments with little pedal material, caused by cultivation during the past year.

• Add the g suffix wherever the A horizon has ≥ 2% redox segregations.
  Note: As A horizons are expected to generally be dark and/or low-chroma from elevated organic matter, the other redox modifiers available in deeper horizons may not be applied.

21.1.2.3 E horizons

Table 21.4: Secondary E horizon divisions

Code	Name	Description
Ea	Leached	No redox segregations; grains largely uncoated. Can be very pale if quartz-dominated. Rarely saturated, usually overlies Bh or Bs.
Ew	Weathered	Both of the following: a moist chroma of 4 or more but less than 6, and < 2% redox segregations.

21.1.2.4 B Horizons

Table 21.5: Secondary B horizon divisions

Code	Name	Description
Bfm	Placic	Sharply defined, cemented, pan-like B horizon usually less then 10 mm thick but the same designation is given to horizons up to 25 mm thick. It is black to reddish brown or dark red in colour, and a black upper part can often be distinguished from a reddish brown lower part. It lies roughly parallel to the soil surface but is commonly wavy or convolute. A Bfm horizon usually occurs as a single pan but in places it can be bifurcated. It forms a barrier to most roots and restricts water movement. The Bfm horizon is equivalent to the concept of the placic horizon (Soil Survey Staff 1975) except that New Zealand ironpans are enriched in iron and organic matter without significant accumulations of manganese [@clayden1990].
Bw	Weathered	Both of the following: a moist chroma of 4 or more but less than 6, and < 2% redox segregations.
Bh	Humose	Dark-coloured B horizon of podzolised soils enriched in organic matter, associated with aluminium, or iron and aluminium, as a result of illuviation. It has a moist value and chroma of 3 or less, or a value of 4 if chroma is 2, dominant in the matrix, and contains 1% or more organic carbon. The fabric has sand- or silt- size pellet-like aggregates, coats on mineral grains, or both. In some horizons (including humus-pans, Bhm), coatings have coalesced to fill pores and cement the horizon.
Bo	Ochreous	A strongly weathered B horizon formed in mixed crystalline iron and aluminium oxides and kaolin minerals, with low activity clay properties. It must meet all the following requirements: Weak primary ped and soil strength at moist to dry soil water states. Unconfined failure is friable or very friable over very moist to dry soil water states. Materials fail to predominantly 3 mm or smaller microaggregates comprising silt- and sand-sized polyhedra and spheroids. Primary peds slake rapidly in water to stable microaggregates which show no or slight dispersion after 100 inversions using the method of [@mcqueen1981]. Negative reaction to the sodium fluoride test [@fieldes1966]. Bo horizons are clayey with measured clay contents commonly exceeding 60%. Measured clay % is usually larger than in overlying A horizons, but clay increase is not a defining criterion due to the difficulties of clay measurement in materials that are frequently difficult to disperse. Materials are only slightly sticky and plastic in relation to clay content. Clay coatings are either absent or only present at frequencies of about 1%. The Bo horizon has low activity clay accessory properties with ECEC and CEC less than 12 and 16 me.100 g clay respectively.
Bs	Sesquioxides	Ochreous B horizon of podzolised soils containing illuvial aluminium, iron, or both, that is closely associated, or complexed, with illuvial organic matter. The aluminium and iron is apparently mainly present as minerals with short-range order (especially allophane and ferrihydrite), though some aluminium is often present as aluminium-humus. The designation Bs should be used for B horizons that: occur below an Ea, Bh, Bfm or a strongly acid A horizon, and have a moist value and chroma both of more than 3, and have a rapid positive reaction to the sodium fluoride test. It is not possible to define the morphology of a Bs horizon such that it can be distinguished from certain Bw horizons enriched in iron and aluminium due to weathering in situ. Characteristic features of Bs horizons are: Reddest hue and highest chroma at the top of the horizon. Earthy apedal fabric with fine spheroids, or weakly developed blocks or polyhedrons. Very weak or moderately weak soil strength when moist or dry. A greasy or smeary feel when very moist. Low plasticity in relation to clay content. Sand- or silt-size pellet-like aggregates, sesquioxidic coats on mineral grains or both.
Bt	Translocated	B horizon containing translocated clay. It is required to have clay coatings that have a waxy lustre when dry and/or sufficient thickness to envelop fine sand grains, on ped faces or in pores, lamellae, or forming bridges between mineral grains, or if there is an overlying E or AE horizon with no lithological discontinuity at its base, sufficiently more clay than the eluvial horizon to be detectable by hand texturing (i.e. 5% more clay).
Bw	Weathered	B horizon that shows evidence of alteration under well aerated conditions and does not qualify as Bh, Bs or Bt. To qualify as a Bw rather than BC or C it must meet at least one of the following requirements: Redder hue or higher chroma than an underlying horizon in similar materials (‘colour B’). Have spheroids, blocks, polyhedrons, tablets, prisms, columns or plates which distinguish the horizon from a BC or C horizon below (‘structural B’). Evidence of either partial or complete decalcification, i.e. less CaCO3 than the underlying horizon which may contain redeposited carbonates. A Bw horizon has less than 2% redox segregations. It is otherwise distinguished by the following colour requirements: With moist values less than 5, chromas must be 3 or more. With moist values 5 or more, chromas must be 4 or more.
BC	B-ish	A horizon transitional in character between a B and a C horizon, usually below a B horizon. It is distinguished from a B horizon in similar material by lacking some required characteristic of colour, pedality or degree of weathering. It differs from a C horizon by having some B horizon feature, albeit weakly expressed. The same designation is also applied to morphologically similar subsurface horizons in profiles without a B horizon.

21.1.2.5 C Horizons

Table 21.6: Secondary C horizon divisions

Code	Name	Description
CR	Consolidated	A weakly consolidated C horizon that is sufficiently dense and coherent to form a significant barrier to roots. Soft rocks (with a hardness on Moh's scale of < 3) such as shale and siltstone, and some exceptionally dense glacial tills are included. The material can be dug with difficulty with a spade when moist. The concept of the CR horizon is similar to that of the material underlying a paralithic contact, but without the restrictive requirement for the spacing of cracks.
Cu	Unconsolidated	Unconsolidated C horizon without evidence of strong gleying, accumulation of carbonates or more soluble salts. It is normally apedal, may show stratification and has less than 2% redox segregations.

21.1.2.6 R Horizons

Table 21.7: Secondary R horizon divisions

Code	Name	Description
R	Rock	Hard or very hard bedrock that is impracticable to dig with a spade. The rock may contain cracks, but these are generally too few and too small for significant root development. However, trees and shrubs do root into fissures in R horizons and the definition is intended to be broader than the specifications for rock material below a lithic contact.

21.1.2.7 Transitional Horizons

Apart from the BC and CR described above, Two main kinds of transitional horizons are distinguished by specific conventions.

1. Transitional horizons having properties of two master horizons as in gradational horizons in vertical sequence, e.g. Ap, AB, Bw. In other cases a horizon can be designated as transitional even if one of the master horizons to which it is apparently transitional is not present. For example, an AB horizon can be recognised where the underlying layer is bedrock (R), and a BC horizon can be recognised even if no underlying C horizon is identified.  Lower case suffixes are used following the two capital letters where the property denoted by the suffix applies to the whole horizon, e.g., ABg, BCt, BCx.
2. Transitional horizons in which discrete parts have recognisable properties of two kinds of master horizon, e.g., where pieces of A horizon are incorporated in a B horizon or where horizons interfinger. In this case the horizon is designated by two capital letters separated by a solidus, e.g. B/C. Appropriate suffixes should be used where the components of the material are clearly identifiable, e.g. Ap/Bw.

For simplicity the capital letters for all transitional horizons are used in the order A, E, B, C irrespective of which properties dominate. For example, all horizons transitional between A and B horizons are designated AB or A/B, with suffixes as appropriate.

21.1.3 Redox suffixes

The following suffixes can be added to most E, B, or C horizons to signify the degree to which they have been affected by water saturation and reducing conditions, e.g. Bg. Some exceptions exist:

• g and r suffixes cannot be used with Ew or Bw horizons, which are defined by their development under well-aerated conditions.
• g and r suffixes cannot be used with Cu, as it is partly defined by a lack of strong gleying.

Per below, low-chroma colours have:

• moist chroma of 2 or less, or
• moist chroma of 3 with values of 6 or more.

Table 21.8: Redox suffixes

Code	Name	Description
no code	Unaffected	< 2% redox segregations, no low-chroma colours
(f)	Slightly reduced	≥ 2% redox segregations, no low-chroma colours
(g)	Reduced	≥ 2% redox segregations, matrix and/or ped faces have < 50% low-chroma colours
g	Very reduced	≥ 2% redox segregations, matrix has 50-85% low chroma colours, and/or ped faces have > 50% low-chroma colours
r	Completely reduced	Matrix has > 85% low-chroma colours.

21.1.4 Other suffixes

One or more of these suffixes may be added to the designations defined above to provide more specific information about a horizon. For example, a Bg horizon containing more than 5% by volume of concretions is designated Bgc.

Table 21.9: Other suffixes

Code	Name	Description
c	Concretionary	> 5% by volume of concretions. May be combined with j, k, l, y, or z to further define the nature of the concretions.
d	Densipan	To denote an E horizon with densipan properties, usually Erd. Either unconfined strength as measured by a resistance to crushing test is hard or very hard at soil water states from near wet to dry, or soil penetration resistance measured by a 6.5 mm flat-tipped penetrometer exceeds 4000 kPa at soil water states from near wet to dry, and Moist and dry samples slake in water.
e	Unripe	To denote an unripe horizon, distinguished by having a moderately fluid or very fluid fluidity class.
(h)	Cutanic	To denote a horizon with cutanic horizon properties. It has dark coloured coats on ped faces, in pores and on rock fragments. The coats have a moist value of 4 or less, or value 5 and chroma 3, and are assumed to be a complex of organic matter with clay and/or sesquioxides. Similar features are described as organic coatings by @bullock1985 and as “organans” by @brewer1964. In coarse textured, apedal horizons, the translocated material can penetrate the matrix to the extent that patches of the whole horizon have the colour given above. In such cases the horizon can only be distinguished from a Bh of a podzolised soil by its relationship to adjacent horizons, or by a negative reaction to the sodium fluoride test, except for soil in volcaniclastic materials. The suffix is used with Bs, Bt, Bw and BC horizons and also with Ea, Eg and Er horizons below hurnose or peaty surface layers.
i	Nodular	To denote that the horizon contains more than 15% by volume of nodules, subrounded or irregular segregations of iron or aluminium oxyhydroxides with some kaolin.
j	Jarositic	To denote the presence of straw-coloured jarosite, most commonly in g or r horizons.
k	Calcareous	To denote an accumulation of secondary carbonate, CaCO3.
l	Gibbsitic	To denote an accumulation of gibbsite, Al(OH)3.
m	Cemented	To denote a continuously cemented horizon that is strong enough to resist root penetration.
n	Sodic	To denote an accumulation of sodium (identified in the field).
q	Silicic	To denote an accumulation of secondary silica. A duripan is designated q.
v	Variegated	To denote a horizon with mottles or variegated colour pattern due to differential weathering of mineral components and not attributable to reduction and segregation of iron caused by saturation with water.
x	Fragic	To denote a horizon with fragipan properties, usually BCxg, BCx(g) or BCx. A fragipan must fulfill all of the following requirements: An air-dried clod slakes when fully immersed in water. It has brittle failure when moist. The horizon may contain rock fragments, but the fine earth must be sufficiently coherent to allow brittle fracture. It has at least slightly firm moist soil strength. Either a. Extremely coarse or gross prismatic peds: the prisms have apedal-massive interiors, or break to secondary peds with horizontal dimensions of 100 mm or more, and the prism faces are defined by colours of chroma 3 or less, or b. The horizon is apedal-massive throughout, or has extremely coarse or gross prismatic peds, and the moist soil strength is very firm. If roots are present, they are confined predominantly to planar voids between prisms or to worm galleries. Moist penetration resistance measured by a 6.5 mm flat-tipped penetrometer is 3100 kPa or more. It does not occur within an E horizon. A fragipan usually has clay coatings on fissures or in pores between fissures. Their presence is not indicated by an additional suffix t. Likewise, the use of the additional suffix p with *g or *(g) to denote perched water is superfluous.
(x)	Almost fragic	To denote a brittle horizon that does not meet all the requirements of a fragipan, e.g. Bw(x).
y	Gypsic	To denote an accumulation of gypsum, CaSO4.
z	Salty	To denote an accumulation of salts more soluble than gypsum.

21.1.5 Lithological discontinuities

Numbers 1-N may be used to signify lithological discontinuities, where the parent material changes significantly between layers e.g. 2C. Such discontinuities are identified by a significant difference between adjacent horizons, in the particle-size distribution of fractions coarser than 2 µm or in mineralogy, that cannot be attributed to pedogenic processes and/or by significant differences in age.

The main purpose of recognising lithological differences is to draw attention to inherited layering that can significantly influence physical properties, particularly permeability. Horizons comprising the uppermost parent material layer are not specifically designated, the prefix 1 being understood. Those comprising succeeding layers are numbered 2, 3, etc. consecutively with depth. When the material below horizon 2 is similar to the material above horizon 2, it is still given the label 3. Where two or more consecutive horizons have formed in the same kind of material, the same prefix number is applied to all the horizons in the material, eg. Ap, Ew, Bt1, 2Bt2, 2Bt3, 2BC.

21.1.6 Numbering identical horizons

If a horizon needs be subdivided, append a number onto the end of the name. The horizon names must otherwise be identical, e.g. Bt1, Bt2, Btg1, Btg2 is correct, but Bt1, Bt2, Btg3, Btg4 is not. This convention can, however, cross lithological discontinuities, e.g. Bw1, Bw2, 2Bw3, 2Bw4.

21.1.7 Buried horizons

Pedogenic horizons that have been buried by deposition of additional material and little modified subsequently are called buried horizons and denoted by the prefix ‘b’. A buried horizon is obviously not in the same deposit as overlying horizons. Some buried horizons, however, are formed in material that is lithologically similar to the overlying deposit. The symbol is not used in Organic Soils or to separate an organic layer from a mineral layer.

The notation for a buried Ah horizon in material similar to the overlying deposit is bAh, and that for a buried Ah horizon in dissimilar material is 2bAh.The horizons of a sequence of buried soils are given consecutive numbers for each soil following the prefix b, independently of the numbers for lithological discontinuities that are placed before the b.

21.2 Functional horizons

Functional horizons provide a shorthand for groups of soil morphology properties that have been linked to soil physical behaviour. Functional horizons help define level 5 of the New Zealand Soil Classification, the soil sibling (see Section 24.2).

21.2.1 Code Components

Each functional horizon is built from a set of components - topsoil status, tephric character, generalised stone and texture content, degree of structural development and consistence.

21.2.1.1 Topsoil

Table 21.10: Functional horizon - topsoils

Code	Name	Description
t	Topsoil	Surface functional horizon(s) - conventional A, AB or O designation. L/F/H horizons are ignored. Must have more than 25% roots by volume.
leave blank	Subsoil	Non-topsoil functional horizons. Conventional designation generally B, E, or C.

The topsoil code can be prefixed to any horizon - it is not restricted to the first functional horizon in the profile. This enables buried topsoils or multi-horizon topsoils to be adequately described.

21.2.1.2 Tephric character

Table 21.11: Functional horizon - tephric materials

Code	Name	Description
z	Acidic tephric	Acidic tephra (rhyolite-sourced, or similar) that qualifies as allophanic or vitric soil material
b	Basic tephric	Basic or intermediate tephra (basalt or andesite-sourced, or similar) that qualifies as allophanic or vitric soil material
leave blank	Non-tephric	non-volcanic materials, or volcanic materials that do not qualify as allophanic or vitric soil material

Tephric codes cannot be used in combination with O*, J or Q functional horizon textures (see below).

21.2.1.3 Stone content

Use the volumetric stone content assessments made in Section 14.2.1 to classify stone content of functional horizons.

Table 21.12: Functional horizon - stone content

Code	Name	Description
S	Stony	> 5% - 35%
V	Very stony	> 35% - 70%
X	Extremely stony	> 70%
leave blank	Non-stony	≤ 5%

21.2.1.4 Texture

Table 21.13: Functional horizon - texture class

Code	Name	Description
A	Sandy	Sandy texture classes
L	Loamy or Silty	Loamy and Silty texture classes
Y	Clayey	Clayey texture classes
O	Organic	Organic soil materials
J	Fluid	Moderately or very fluid materials
Q	Pan	Indurated pan
P	Placic	Placic horizon

• Texture J is used where fluid behaviour is observed (generally in saturated loose fine sediments below the permanent water table) and is not used in concert with any other codes.
• Texture Q is used where a pan is observed and is not used in concert with any other codes.
• Texture P is used where a placic horizon is observed and is not used in concert with any other codes.

21.2.1.5 Texture suffixes

Table 21.14: Functional horizon - texture class modifiers

Code	Name	Description
a	Dune sand	Clean, medium to coarse sand
x	Fragmental	> 85% rock fragments with minimal interstitial material
h	Humified	Non-fibrous peats - conventional horizons Om, Oh
r	Fibrous	Fibrous peats and thick litter layers - conventional horizons Of, H, F

• Texture suffix a can only be used with Sandy textures (e.g. Aa)
• Texture suffix x can only be used where extremely stony (e.g. Xx)
• Texture suffixes r and h can only be used with Organic texture (e.g. Oh)

21.2.1.6 Structure

Table 21.15: Functional horizon - structure classes

Code	Name	Description
C	Coarse	At least 50% peds of size > 20 mm (‘coarse’), or apedal massive structure
F	Fine	At least 50% peds of size < 20 mm (‘coarse’), including horizons where coarse structure breaks to finer nested peds
E	Earthy	Weak soil strength with very weak ped strength
K	Platy	At least 50% peds of any size, with a platy shape

• Structure codes (C, F) can only be used with L or Y texture codes, and only where consistence is not w.
• Structures E and K can only be used with texture L.

21.2.1.7 Consistence

Table 21.16: Functional horizon - consistence classes

Code	Name	Description
w	weak	Fails under gentle force (strength class 1–2)
ws	weak + slightly firm	Contains a mix of weak and slightly firm peds
s	slightly firm	Fails under moderate force (strength class 3)
f	firm	Fails under strong force (strength class 4+)
l	loose	Easily dislodged by spade or pick; does not maintain a vertical face, > 35% stone and/or sandy
c	compact	Intermediate between loose and dense, > 35% stone
d	dense	Difficult to dislodge except with spade and by removing individual fragments; maintains a stable vertical face, > 35% stone

• Consistence ws can only be used with texture Y.
• Consistence w, ws, s, and f can only be used with non-stony or stony (S) codes. V and X codes use consistence l, c, or d instead.

21.2.1.8 Permeability

The permeability class represents saturated hydraulic conductivity (K_sat) measured as the rate of water infiltrating into a soil horizon when water is ponded at 10 mm deep at the top of the horizon. Assign one of the classes in Table 21.17 to each horizon. Note that ‘xs’ represents effective impermeability. The classes have been slightly simplified from those in Griffiths (1991) and Griffiths et al (1999).

Permeability is very difficult to assess in the field, but considerable work has been done to associate particular ranges of values with the components of the functional horizon. As such, each functional horizon has a default permeability class and usually one or more additional allowable classes. Use the functional horizon name to narrow down the appropriate choice of permeability rating, per Table 21.18 below.

Table 21.17: Horizon-level permeability classes

Code	Name	Description
xs	Extremely slow	< 0.1 mm/h
s	Slow	0.1 - 4 mm/h
ms	Moderately slow	4 - 18 mm/h
m	Moderate	18 - 72 mm/h
r	Rapid	> 72 mm/h

21.2.2 Functional horizon names

Valid combinations of the above components are listed below, along with associated permeability classes.

• The t prefix can be added to any of these.
• The z or b prefix can be added to any of these, except for Oh, Or, J, and Q.
• A good reason is needed to deviate from the default permeability (e.g. an Lw with r permeability would need a low clay content).

Table 21.18: Functional horizon names and allowed permeability classes. Default permeabilities are bolded

Code	Name	Allowed permeabilities	Topsoil allowed permeabilities
J	Fluid	xs	xs
Or	Fibric organic	r m	r m
Oh	Humic organic	m ms s	m ms
OhA	Sandy humic organic	m ms	m ms
OhL	Loamy humic organic	ms s	m ms
OhY	Clayey humic organic	s	m ms s
Q	Indurated pan (massive, hard)	xs	xs
P	Placic horizon (non-indurated pan)	ms, s	s
Xx	Extremely stony fragmental	r	r
XA	Extremely stony sandy	r	r
XL	Extremely stony loamy	r m	r m
XY	Extremely stony clayey	s	m ms s
VAl	Very stony sandy loose	r	r
VAc	Very stony sandy compact	m ms	r m
VAd	Very stony sandy dense	s	ms s
SAl	Stony sandy loose	r	r
SAw	Stony sandy weak	r	r
SAs	Stony sandy slightly firm	m r	r
SAf	Stony sandy firm	m ms s	m ms
Aa	Sandy loose (dune sand)	r	r
Al	Sandy loose	r	r
Aw	Sandy weak	r	r
As	Sandy slightly firm	m r	r
Af	Sandy firm	m ms	m ms
VLl	Very stony loamy loose	r m	r m
VLc	Very stony loamy compact	m ms s	m ms
VLd	Very stony loamy dense	s xs	s
SLw	Stony loamy weak	m r	m r
SLFs	Stony loamy fine, slightly firm	m ms	m ms
SLFf	Stony loamy fine, firm	ms s	m ms
SLCs	Stony loamy coarse, slightly firm	m ms s	m ms
SLCf	Stony loamy coarse, firm	s xs	ms s
LEw	Loamy earthy weak	r m	r m
Lw	Loamy week	r m	r m
LFs	Loamy fine slightly firm	m ms	m ms
LFf	Loamy fine firm	ms s	m ms
LCs	Loamy coarse slightly firm	m ms s	m ms
LCf	Loamy coarse firm	s xs	ms s
LK	Loamy platy (> weak)	s	ms s
VYl	Very stony clayey loose	r m ms	r m
VYc	Very stony clayey compact	ms s	m ms
VYd	Very stony clayey dense	s xs	s
SYw	Stony clayey fine weak	r m	r m
SYFs	Stony clayey fine slightly firm	m ms	r m ms
SYFws	Stony clayey fine weak + slightly firm	r m ms	r m ms
SYFf	Stony clayey fine firm	ms s	m ms
SYC	Stony clayey coarse	s	ms s
Yw	Clayey weak	r m	r m
YFs	Clayey fine slightly firm	m ms	r m ms
YFws	Clayey fine weak + slightly firm	r m ms	r m ms
YFf	Clayey fine firm	ms s	m ms
YC	Clayey coarse firm	s	m ms s

Avery BW 1980. Soil classification for england and wales (higher categories). Rothamstead Experimental Station, Harpenden, England: Soil Survey of England; Wales.

Clayden B, Hewitt AE 2015. Horizon notation for new zealand soils. [Internet]. 4th ed. Lincoln, New Zealand: Manaaki Whenua Press. https://doi.org/10.7931/DL1001

Griffiths E 1991. Assessing soil permeability class from soil morphology. [Internet]. Havelock North, New Zealand. http://digitallibrary.landcareresearch.co.nz.landcareresearch.idm.oclc.org/digital/collection/p20022coll26/id/2/rec/23

Griffiths E, Webb TH, Watt JPC, Singleton PL 1999. Development of soil morphological descriptors to improve field estimation of hydraulic conductivity. Soil Research [Internet]. 37(5):971. https://doi.org/10.1071/SR98066

IUSS Working Group WRB 2022. World reference base for soil resources: International soil classification system for naming soils and creating legends for soil maps. 4th ed. Vienna, Austria: International Union of Soil Scientists.