Funded by Caring for our Country and
Dept. Water land and Biodiversity
Conservation
Managed by ABA and MacKillop FMG
The Soil BookRepresentative soils of
the Upper SE
Produced from work by DWLBC and RSSA staff
Disclaimer
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regarding the use, or results of the use, of the information contained herein as
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SA and its employees expressly disclaim all liability or responsibility to any person
using the information or advice.
© Rural Solutions SA
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1
INTRODUCTION
4
2
INTERPRETING SOIL TESTS
5
3
SUMMARY OF COMMON SOIL CONSTRAINTS
8
4
DEEP SAND
13
5
SAND OVER CLAY
16
6
SHALLOW SAND OVER CLAY ON CALCRETE
33
7
SHALLOW RED LOAM ON CALCRETE
36
8
LOAM OVER CLAY
39
9
CRACKING CLAY
51
-3-
1
INTRODUCTION
This soils book has been compiled from a selection of representative soil data sheets from
the Dept of Water Land and Biodiversity Conservation’s “Land Resource Information”
series. The full set of soil descriptions, along with associated maps and interpretive
information can be obtained through DWLBC.
This document aims to assist landowners in understanding their soils, and is designed to
be a useful guide in making appropriate land management decisions.
Each soil profile detailed in the book is described in a way to identify its key physical and
chemical attributes. These are then interpreted to outline the main properties of the soil
and its behaviour. Comments are also made regarding possible management options for
gaining the best performance out of a soil with these properties. Each soil profile is also
accompanied by a table of chemical attributes that relate to soil quality and plant nutrition.
A set of explanatory notes to assist with interpreting these numbers is provided in the next
chapter.
-4-
INTERPRETING SOIL TESTS
2
SOIL TEST METHODS & GUIDELINES
FOR INTERPRETATION OF SOIL
RESULTS
Prepared by Brian Hughes, Jim Jacka, Dale Lewis and Tim Prance with assistance from PIRSA and SARDI staff.
pH
There are two standard pH tests in the report. pH (water) is measured in a 1:5 soil/water suspension. pH
(calcium chloride) is measured in a 1:5 soil/0.01M calcium chloride suspension. pH (calcium chloride) is
normally 0.5 - 1.2 units lower than pH (water).
Criteria – pH (water)
Strongly acidic
≤ 5.4
Slightly alkaline
7.1 - 7.5
7.6 - 8.3
Moderately acidic
5.5 - 6.4
Moderately alkaline
Slightly acidic
6.5 - 6.9
Strongly alkaline
Neutral
≥ 8.4
7.0
EXTRACTABLE PHOSPHORUS (Colwell) (mg/kg)
A 1:100 soil/0.5M sodium bicarbonate extract is shaken for 16 hours and the phosphorus concentration
determined by colorimetry.
Criteria
120
Non-calcareous
Very Low
Pastures
Crops
Potatoes
Other
Vegetables
Calcareous
<10
<15
<10
<20
<40
Low
10 - 20
15 - 25
10 - 18
20 - 40
40 - 80
Marginal
20 - 30
25 - 35
18 - 25
40 - 55
80 - 120
Adequate
30 - 45
35 - 45
25 - 45
55 - 100
120 - 150
>45
>45
>45
>100
>150
High
Vines/apples
>80
These figures are a guide only. Actual phosphorus requirements will be based on crop yield, stocking rate,
production targets as well as soil phosphorus status.
EXTRACTABLE POTASSIUM (mg/kg)
Identical extraction method as used for phosphorus. The concentration of potassium is measured by flame
atomic absorption.
Permanent pastures
Potatoes
Other vegetables
<80
<120
<150
Marginal
80 - 120
120 - 250
150 – 250
Adequate
120 - 250
>250
>250
Low
High
>250
-5-
EXTRACTABLE SULPHUR (mg/kg)
FREE LIME
(KCI-40)
Soil sulphur is extracted with 0.25M potassium
chloride heated at 40°C for 3 hours. The sulphur
concentration is determined using an ICP
spectrometer.
1 N hydrochloric acid is added to the soil and the
degree of effervescence is evaluated. The following
categories are defined.
NIL
Non-calcareous
SLIGHT
Criteria ( for permanent pastures)
Low
MODERATE
HIGH
VERY HIGH
<5
Marginal
5 - 10
Adequate
>10
These values are a guide only. Rainfall, soil type,
crop type (eg canola) and past fertiliser history are
important factors to take into consideration when
estimating sulphur requirements.
ORGANIC CARBON (%)
(Walkley/Black)
Organic carbon is measured by digestion in strong
acid/dichromate solution and the colour
development assessed against standard sucrose.
Criteria
Texture
Calcareous
TEXTURE
Assessed using field texturing techniques. The
following classes are reported.
SAND
SANDY LOAM
LOAM
CLAY LOAM
CLAY
HEAVY CLAY
NITRATE NITROGEN (mg/kg)
Extracted with 1:5 soil/1.0M potassium chloride for
one hour.
Tentative guide only
<5 considered low – nitrogen applications should be
determined by yield expectations, crop type, soil
type, rainfall, past and present management factors
etc.
Low
Moderate
High
Sand
<0.5
0.5 - 1.0
>1.0
Sandy loam
<0.7
0.7 - 1.4
>1.4
Loam
<0.9
0.9 - 1.8
>1.8
Clay loam/clay
1.2 - 2.0
ION-EXCHANGE PROPERTIES
<1.2
>2.0
Physical and chemical properties of most soils are
influenced by their ion-charge characteristics,
including the amount and balance of individual ions.
Of particular importance are the exchangeable
cations (calcium, magnesium, sodium, potassium
and aluminium) and the cation exchange capacity.
SALINITY
The electricity conductivity (EC) of the 1:5 soil/water
suspension is measured and the results are
expressed in decisiemens/metre (dS/m).
The value for EC (1:5 soil/water) is converted to an
estimated electrical conductivity of a saturation
paste extract (ECe) by multiplying by a texture
factor.
Note: dS/m are the same units as mS/cm.
Criteria
ECe (estimated)
Low salinity
0-2
Sensitive plants affected
2-4
Many plants affected
4-8
Tolerant plants affected
8 - 16
CATION EXCHANGE CAPACITY (CEC)
(mequiv/100)
The CEC is a measure of the soils ability to hold
cations. In surface soils the cation exchange
capacity is associated with clay content, organic
matter and type and retention of cations. The higher
the CEC the higher the potential fertility of the soils.
Where total cation exchange capacity is less than 5
this indicates low inherent fertility of the soil.
High salinity
>16
Use the salinity fact sheet for the tolerance of
various crops and pastures
-6-
The presence of salts, gypsum or lime can lead to
over estimation of exchangeable cations and hence
CEC. The CEC in this procedure is calculated by
adding the 5 cations and as such is the EFFECTIVE
CEC.
EXCHANGEABLE CATIONS (mequiv/100 g)
(calcium, magnesium, sodium, potassium,
aluminium)
No pretreatment for soluble salts. The soil is
extracted at a ratio of 1:10 with (0.1M ammonium
chloride/0.1M barium chloride) for two hours.
Desirable levels of individual cations vary for crops
and soil type. As a general guide for vegetables on
loamy soils, adequate levels for exchangeable
calcium are 6.0 – 7.5 mequiv/100g and
exchangeable magnesium are 1.6 – 2.0
mequiv/100g.
Adequate levels are considerably less for sandier
soils.
Cation ratios
(all calculated ratios are based on figures in
mequiv/100g)
Cation ratios are the percentage of the total cation
exchange capacity which are attributed to that
particular cation.
A guide to desirable ranges are:
Exch. Calcium
Exch. Magnesium
Exch. Sodium
Exch. Potassium
Exch. Aluminium
65 – 75%
10 – 15%
0 – 4%
3 – 8%
0 – 5%
(mg/kg) (copper, zinc manganese, iron))
Extracted with 1:5 soil/0.02M EDTA (pH 4.9) for one
hour.
Plant analysis is the preferred method of
determining trace element deficiencies. Soil
testing interpretation is difficult as critical
concentrations vary between soil types and plants.
Suspected deficiencies should be confirmed by
using plant analysis. Manganese and iron are less
available in high pH calcareous soils, resulting in low
values.
Extractable Copper (mg/kg)
For pastures 0.5 is low and 1 - 2 adequate. For
intensive crops (eg Vegetables) 4 is adequate.
Extractable Zinc ( mg/kg)
For pastures 0.7 is low and 1.2 - 2 adequate. For
intensive crops 4 adequate,
Extractable Manganese (mg/kg)
As a general guide < 10 is low and > 50 high for
manganese. No critical concentrations have yet
been established.
EXTRACTABLE ALUMINIUM (mg/kg)
Extracted with 1:5 soil/0.01M calcium chloride
solution for one hour.
For brassicas and apples it is important to aim for a
calcium/magnesium ratio 3.5:1 to 5.5:1.
If the ratio of calcium:magnesium is <2 structural
problems may occur in some soils.
Grass Tetany (hypomagnesia)
The ratio of
Exch. Potassium
Exch. calcium + Exch. Magnesium
can be used as an indicator of potential grass
tetany. On soils where this ratio is > 0.07 to 0.08
grass tetany may occur. Plant tests need to be used
to confirm grass tetany potential.
Exchangeable Sodium Percentage (ESP)
ESP is used to indicate if soils have sodic properties
ie: the cation exchange complex is saturated with
too much sodium. Sodic soils are often dispersive
with poor structural characteristics.
Classification:
EXTRACTABLE TRACE ELEMENTS
Extractable aluminium closely follows the pH of the
soil and becomes a problem when the pH (water) is
less than 5.5 (in soils which contain significant
aluminium). Where extractable aluminium is > 2,
sensitive plants will be affected. Agricultural lime
which raises pH will therefore reduce high
extractable aluminium.
EXTRACTABLE BORON (mg/kg)
Extracted with 1:2 soil/0.01M calcium chloride
solution, refluxed for 10 minutes.
Boron deficiencies may occur if extractable boron
concentrations are <0.5 in most crops or <1.0 in
crops with high boron requirements eg brassicas.
Boron toxicity may occur in sensitive crops if > 5.
Toxic layers frequently occur at depth. For cereal
crops the most reliable indicator for boron toxicity is
analysis of the grain.
CHLORIDE (mg/kg)
<6%
non sodic
6-15% sodic
>15% strongly sodic
Extracted with 1:5 soil/water for one hour.
If soils are sodic or strongly sodic and disperse, an
application of gypsum should improve stability in the
short term.
-7-
Critical levels for salinity are:
120 sands to sandy loam
180 loam to clay loam
300 clays.
Above these figures salinity damage may occur
depending on soil drainage and plant tolerance
3
SUMMARY OF COMMON SOIL CONSTRAINTS
3.1 SHALLOW A HORIZON
The thin topsoil horizon is underlain by shallow, relatively hard, sodic subsoil layer
which restricts root development, thereby reducing the plant available water holding
capacity. In dry finishes, this may cause early haying off and affect grain filling of
crops. Thin topsoils may be susceptible to compaction.
Due to the limited water holding capacity of the soil surface, and the very slow
drainage of the subsoil, these soils are prone to waterlogging.
3.1.1 Management
•
•
•
Avoid excessive or unnecessary traffic, particularly when the soil is wet.
Investigate for surface and subsurface compaction layers.
Mixing the surface (A) and subsoil (B) horizons by processes such as deep
ripping or delving may reduce soil strength and improve drainage. Where soils are
sodic (dispersive/hardsetting), the addition of gypsum in this process may also be
of some benefit.
3.2 LOW FERTILITY A1
The sandy top soil horizon is of low inherent fertility, indicated by a low cation
exchange capacity and low nutrient status. It has low buffering capacity, and so has
a relatively low ability to retain nutrients and can be prone to leaching of nutrients,
including phosphorus, below the plant root zone.
3.2.1 Management
•
•
Annual applications of fertilisers, particularly phosphorous and sulphur, are
required. Trace element applications may be required and should be monitored
with plant analysis.
Clay spreading or delving to increase the clay content helps to improve water
holding capacity, introduce important nutrients and cations (ie Ca, Mg, K and
raise the cation exchange capacity, thereby improving the soils ability to retain
nutrients. Clays are high in iron, and consequently improve the ability of soils to
retain phosphorus. High amounts of clay clods left on the soil surface may lead to
surface sealing and reduced germination. Should this be the case, the clay should
be cultivated into the soil more thoroughly (and usually more deeply), and/or
gypsum may be applied.
3.3 NON WETTING SAND A1
The surface sand exhibits water repellence causing the water to be held on or near
the surface where it is more prone to loss by evaporation or bypass the root zone via
preferred flow pathways. Water infiltration into the soil is poor and results in the soil
being difficult and slow to wet up after rain. The sowing window of water repellent
sands is severely reduced as they dry out relatively quickly. Germination of crops
and pastures can be poor and patchy.
-8-
The rapid drying out of water repellent sands can reduce the availability of nutrients
to plants, and reduce soil microbial activity and mineralisation of organic matter. This
surface drying can result in deficiencies of elements at critical times.
3.3.1 Management
• Clay spreading or delving to increase the clay content helps to improve water
•
infiltration and water holding capacity. It also introduces important nutrients and
cations (ie Ca, Mg, K), and raises the cation exchange capacity, thereby
improving the soils ability to retain nutrients.
Where clay is unavailable, consider using press wheels or wetting agents, and
sowing perennial pastures.
3.4 WIND EROSION
Soils with a sandy surface horizon are extremely susceptible to wind erosion,
resulting in loss of important nutrients and organic matter, and damage to crops and
pastures in the early growth stages. Heavier soils that are worked to a fine tilth, or
have a dusty surface, are also susceptible to significant losses.
3.4.1 Management
•
•
Maintain surface cover, particularly over summer, through careful attention to
stocking rates and cropping practices. Maintain stubbles through conservation
tillage and avoid burning of crop residues.
Clay spreading or delving to increase the clay content can directly reduce the risk
of wind erosion. The clay also tends to improve productivity and surface
vegetative cover.
3.5 BLEACHED A2
The pale (bleached) sand subsurface horizon has low water holding capacity, very
low inherent fertility and also low buffering capacity, which gives it poor ability to
retain nutrients and trace elements. The low nutrient status impedes the potential for
plant root growth in the subsurface and therefore the potential for plants to use all the
available water down the profile. Bleached horizon which is overlying clay at
moderate depth can be prone to compaction.
3.5.1 Management
•
•
•
Clay spreading or delving to increase the clay content helps to improve soil
physical and nutritional properties. Delving is the preferred option where possible
as it places more clay throughout the bleached layer and has a ripping effect on
the often sodic clay subsoils thereby increasing effective soil depth. Clay spread
on the surface should be worked deeply into the soil so as to improve as much of
the bleached A2 as possible.
Improve organic matter content. This will require such techniques as the addition
of clay or the use of perennial plants.
Investigate use of subsoil trace elements and nutrition. Placing these at depth
may improve their availability to the plant when the surface topsoil is dry.
-9-
3.6 HIGH IRON
The high levels of reactive iron in the surface horizon can reduce the availability of
phosphorous.
3.6.1 Management
•
•
•
Undertake phosphorus buffering index test.
These soils require regular P applications in order to overload the P fixing sites.
Banding P fertiliser will improve its availability as the P has less exposure to soil
chemicals that form low solubility P compounds
In some circumstances, foliar or liquid phosphorous products may be an option,
although this may be offset by a greater cost per unit P.
3.7 SODIC POORLY STRUCTURED SUBSOIL
Typically this soil has a hard sodic clay subsoil (B horizon) with course columnar
structure. When the sodic subsoil is relatively dry, the profile can be very slow to wet
up due to preferential drainage between the columns. However when saturated, the
columns swell and the subsoil becomes relatively impermeable and only transmits
water very slowly. The soil profile becomes imperfectly or poorly drained, and can
cause perched watertables and waterlogging of the surface and sub-surface horizons
during wetter seasons.
3.7.1 Management
•
•
•
•
•
Gypsum can be used where the sodicity is at or near the surface.
Delving, and in some case deep ripping and other soil mixing techniques, can
sometimes improve the condition of the subsoil by mixing it with the topsoil (A1
and/or A2). The sodic affect may be further reduced by working in gypsum.
Avoid trafficking and stocking when wet
Surface drainage to remove excess water.
3.8 WATERLOGGING AND PERCHED WATERTABLES
Perched watertables in wetter seasons can result in waterlogging of the surface
horizons and cause reduced crop and pasture productivity, or in severe cases total
loss. Waterlogged soils are prone to pugging by stock, causing compaction.
Trafficking of waterlogged soils also results in compaction of surface and subsurface
horizons. Waterlogging of the subsurface (A2) horizons (usually related to poorly
structured subsoils) may not be visible at the surface, but will reduce root
performance, and will lead to lateral movement of nutrients.
3.8.1 Management
•
•
•
surface drainage to remove surface water from the paddock can be beneficial.
Avoid working, stocking or trafficking when waterlogged
Activities that improve the physical condition of the subsoil may help.
- 10 -
3.9 SUBSOIL CHEMICAL CONSTRAINTS
Elevated levels of elements such as sodium, chloride and boron at depth can reach
levels at which they become toxic and affect plant productivity.
3.9.1 Management
•
•
•
•
The chemical constraints often occur at depths beyond which it is considered
feasible to manage.
Often efforts are better spent in optimising growing conditions in the soil above
where these constraints occur.
Consider using tolerant crops and varieties or, where the limitation is severe,
change land use.
In irrigated situations, some chemical constraints can be reduced by increasing
the volume of water used to leach salts beyond the rootzone
3.10 SOIL ACIDITY
When the pH of soil drops below 5.5 (when pH is measured in water), or 4.8 (when
pH is measured in calcium chloride solution), the soil is said to have become strongly
acidic. Strongly acidic soils affect plant growth in a number of ways. Soil biology,
including the Rhizobium that nodulate legumes, are inhibited. Aluminium becomes
increasingly soluble, and is toxic, directly stunting the growth of the fine root hairs of
susceptible plants. Many nutrients become less available, such as P that bonds with
the now more soluble Al and Fe. In the upper SE, strong acidity can develop in the
soil surface, and occasionally in the subsurface (A2) layer also.
3.10.1 Management
•
•
•
•
Lime is usually the most appropriate method for managing acid soils. The lime is
either applied to the surface, or cultivated into the topsoil. Working in lime greatly
enhances the speed of its effect.
Subsurface acidity requires either more lime to be applied at the surface to
maintain a pH of at least 5.5 pH(CaCl2), or for the lime to be mixed or slotted to a
greater depth.
The application of alkaline clays is effective in treating surface acidity, and can
have a residual affect for many years.
Irrigation can neutralise acid soils very rapidly.
3.11 CALCAREOUS LAYER
May include soft, finely fractionated (clayey) carbonate (or free lime). This will
produce the following impacts on the soil horizon:
• Buffers soil at an alkaline pH(water) of 8.4.
• May be associated with accumulations of other more toxic salts.
• Should be assessed if being used for clay spreading as it will induce a sustained
pH rise in the surface soil.
May include a hard calcareous layer (often fractured, allowing drainage of the
profile). As a physical barrier, this will restrict the root zone and reduce the water
- 11 -
holding capacity of the layer, although clay filled fractures often exhibit high root
densities.
3.12 COMPACTED LAYERS
Soils prone to compaction have increased bulk density and reduced porosity which
restricts root development and water transmission thereby resulting in reduced plant
available water and plant productivity. Compaction can be measured by using a
penetrometer when the soil is moist enough to allow active plant growth. Bulk density
measurements, and visual assessments of soil aggregate shape, are also good
indicators of compaction.
3.12.1 Management
•
•
•
Deep ripping can affectively treat topsoils layers.
Consider controlled traffic farming.
In grazing situations, avoid grazing when the soils are very moist. Move stock
onto more free draining soils after significant rainfall events. Consider rotational or
cell grazing.
3.13 SOIL CHEMISTRY
*Note:
The soil results in the following tables are from single point samples
and are indicative only. They may not reflect the general condition of the rest of the
paddock. Also, plant responses relating to nutrition measurements can vary between
soil types and plant species, so values are indicative only.
- 12 -
4
DEEP SAND
DEEP SAND
General Description: Thick bleached sand over a brownish sandy subsoil (colour B
horizon), becoming paler with depth
Landform:
Gently undulating dunefield.
Substrate:
Windblown siliceous sand.
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE051
Beeamma
31
1/2/96
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7024-4 (Keppoch)
472750
5957950
550 mm
Crest of dune, 4% slope. Soft surface with no stones.
Soil Description:
Depth (cm)
Description
0-7
Dark grey soft single grain sand. Gradual to:
7-15
Greyish brown loose single grain sand. Diffuse to:
15-32
Very pale brown, with dark greyish brown
inclusions, loose single grain fine sand. Diffuse to:
32-70
Pale brown loose single grain sand with strong
brown earthy lamellae. Diffuse to:
70-129
Brownish yellow and dark grey loose single grain
sand. Gradual to:
129-165
Yellow loose single grain sand.
Classification: Basic, Argic, Bleached-Orthic Tenosol; medium, non-gravelly, sandy / sandy, very deep
- 13 -
Summary of Properties
Drainage
Rapidly drained. The soil rarely remains wet for more than a few hours.
Fertility
Inherent fertility is very low, as indicated by the exchangeable cation data. There is
very little nutrient retention capacity, due to low clay and organic matter contents.
Phosphorus, sulphur, calcium, magnesium and potassium all appear to be deficient.
pH
Acidic throughout.
Rooting depth
165 cm in pit.
Barriers to root growth
Physical:
There are no physical barriers.
Chemical:
There are no chemical barriers, but low nutrient status and retention capacity are the
main reasons for sub-optimal root growth.
Water holding capacity Approximately 100 mm in the potential root zone.
Seedling emergence:
Satisfactory. Water repellence affects establishment in some seasons.
Workability:
The soft surface is easily worked.
Erosion Potential
Moderately low.
Moderately high.
Water:
Wind:
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu Fe Mn Zn
ESP
cmol(+)/kg
Ca
Mg
Na
K
2.6
2.16
0.37
0.10
0.08
na
Paddock
6.4
5.6
0
0.03
0.27
0.7
9
58
4
0.7
0.21
12
0-7
6.0
5.2
0
0.02
0.21
0.7
9
51
4
0.7
-
-
-
-
2.4
1.85
0.26
0.08
0.09
na
7-15
5.6
4.7
0
0.01
0.15
0.2
8
30
2
0.7
-
-
-
-
1.1
0.64
0.14
0.07
0.03
na
15-32
5.5
4.7
0
0.01
0.09
0.1
11
53
1
0.7
-
-
-
-
0.7
0.32
0.07
0.07
0.04
na
32-70
5.5
4.7
0
0.01
0.06
<0.1
8
36
2
0.7
-
-
-
-
0.7
0.31
0.09
0.08
0.04
na
70-110
6.3
5.4
0
0.01
0.05
<0.1
6
38
1
0.7
-
-
-
-
0.6
0.32
0.08
0.06
0.04
na
110-129
6.5
5.8
0
0.01
0.05
<0.1
5
44
2
0.6
-
-
-
-
0.8
0.45
0.14
0.08
0.06
na
129-165
6.4
5.6
0
0.01
0.06
<0.1
<4
54
1
0.6
-
-
-
-
0.7
0.33
0.11
0.06
0.07
na
Note:
2.27 1.09
Exchangeable Cations
Paddock sample bulked from 20 cores (0-10 cm) taken around the pit.
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 14 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• Due to the sandy nature of this soil it is inherently infertile with requirements for major nutrients and trace
elements in its development for agriculture. It will always be prone to leaching, with the subsequent requirement
for annual applications of phosphorus and sulphur.
• The surface of this soil is prone to the development of non-wetting. This leads to a number of problems that
include erosion risk, patchy germination and early surface drying which can severely affect the availability of
nutrients. A particular example of early surface drying is Manganese deficiency in lupins resulting in regreening
of the crop and split seed.
• A further restriction in plant root growth related to this soil is the infertility of the subsurface layers (the bleached
and pale sand layers).
Management implications:
• This soil would be improved with clay spreading and subsequent cultivation to mix the clay through the upper soil
layers.
• Clay worked in reduces the non wetting soil character and improves seedling germination with more uniform soil
wetting.
• Clay is distributed throughout the A Horizon and improves the fertility of the soil and reduces the potential for
leaching nutrients.
• With the higher clay content of the A horizon the potassium level in the soil is increased and the potential is for
the extractable phosphorus (P) level to build up with P application. This may give the opportunity when P levels
reach adequate levels to reduce P inputs, however, an annual S application would still be required particularly in
wet years.
• With the improved fertility of the soil , the potential is for higher production levels from pasture and crops such
that the trace element nutrition of the plants should be monitored with plant tissue analysis and applications
applied as necessary.
• The challenge is to improve the fertility of the subsurface horizons to promote root growth and increase the water
use efficiency.
- 15 -
5
SAND OVER CLAY
SAND OVER DISPERSIVE BROWN CLAY
General Description:
Leached siliceous sand, between 10 and 30 cm deep, sharply
overlying a yellowish mottled very firm columnar clay,
calcareous with depth.
Landform:
Flat plains, swales between
sand ridges, undulating rises
and lower slopes of calcreted
ridges. Slope range is 0 to
4%.
Substrate:
Tertiary sandy clays.
Vegetation:
Blue gum / mallee brush.
Type Site:
Site No.: SE005
Hundred:
Section:
Sampling date:
Cannawigara
8
10/12/91
1:50,000 sheet: 7025-4 (Cannawigara)
Easting:
471500
Northing:
5997150
Annual rainfall: 450 mm
Slope of a gently undulating rise, with a gradient of 2%. Soft water repellent surface.
Soil Description:
Depth (cm)
0 - 10
Description
Grey loose single grained loamy sand. Abrupt
to:
10 - 14
White loose single grained sand. Sharp to:
14 - 35
Yellowish brown, olive yellow and orange
mottled very firm sandy heavy clay with coarse
columnar structure. Gradual to:
35 - 60
Light yellowish brown, orange and olive yellow
slightly calcareous sandy heavy clay with
moderate coarse angular blocky structure.
Gradual to:
60-100
Pale olive, orange and olive yellow very highly
calcareous sandy medium clay with moderate
angular blocky structure and 20-50% soft
carbonate segregations. Gradual to:
100-130
Pale olive, orange and red slightly calcareous
medium heavy clay with strong angular blocky
structure.
Classification:
Hypercalcic, Mottled-Mesonatric, Brown Sodosol; medium, non-gravelly, sandy/clayey, deep
- 16 -
Summary of Properties
Drainage
Imperfect due to impermeable subsoil. Soil may remain wet for several weeks.
Fertility
Nutrient retention capacity is poor in topsoil, moderate in subsoil, as indicated by the
CEC values. High organic matter levels must be maintained for satisfactory surface
soil fertility. Likely deficiencies: phosphorus, nitrogen, sulphur, zinc, copper and
manganese.
pH
Acidic at surface, grading to strongly alkaline in deep subsoil.
Rooting depth
Approximately 60 cm at type site.
Barriers to root growth
Physical:
Hard, sodic clay subsoil and waterlogging above the clay retard root growth. Rapid
drying in a quick finish of the near surface sand and the very infertile subsurface
bleached sand may prevent roots from accessing subsoil moisture reserves.
Chemical:
Lack of nutrition in the very infertile bleached subsurface sand severely restricts root
development. Highly sodic, Class I carbonate layer at 60 cm typically affects root
growth.
Water holding capacity Approximately 65 mm in rootzone at type site (moderately low). Value is affected by
a) depth of sand - there are 6 mm of available water for each 100 mm of sand; b)
structure of clay - water availability varies from virtually nil to about 15 mm for each
100 mm thickness; and c) depth to a very highly calcareous layer in which little root
growth occurs.
Seedling emergence
Fair to good, depending on degree of water repellence.
Workability
Good.
Water erosion potential Low to moderate depending on slope and depth of sand. Soils with thin sandy layers
and on slopes more than 3% are most vulnerable.
Wind erosion potential Moderately low to moderate, depending on exposure and depth of sand.
Laboratory Data
Depth
cm
Ca
Mg
Na
0-10
6.6
6.1
0
0.26
3.1
1.4
53
170
-
0.9
0.5 82.6 2.0
3.3
3.8
3.4
1.0
0.15 0.24
3.9
10-14
7.1
7.0
<0.1
0.07
1.1
0.2
26
84
-
0.6
0.1 92.7 0.5
0.3
1.2
0.6
0.4
0.23 0.10
n.a.
14-35
7.8
6.9
<0.1
0.20
0.6
0.3
4
458
-
5.5
0.1 23.4 0.1
0.1
18.7
5.3
9.2
4.13 1.14 22.1
35-60
9.4
8.7
0.6
0.47
1.1
0.2
<4
405
-
8.1
0.5
8.8
0.1
0.1
19.2
4.4
9.6
5.57 0.98 29.0
60-100
9.8
8.9
32.5
1.03
7.1
<0.1
<4
478
-
11.7
0.2
3.4
0.1
0.1
18.2
2.7
9.2
7.81 1.08 42.9
100-130
9.4
8.9
0.6
1.27
6.3
<0.1
<4
498
-
12.6
0.3
4.8
0.4
0.2
21.9
2.0
10.9 8.43 1.09 38.5
Note:
Exchangeable Cations
ESP
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu Fe Mn Zn
cmol(+)/kg
K
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 17 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• Due to the sandy nature of this soil it is inherently infertile and will always be prone to leaching, with the
subsequent requirement for annual applications of phosphorus and sulphur.
• The surface of this soil is non-wetting. This leads to a number of problems that include erosion risk, patchy
germination and early surface drying which can severely affect the availability of nutrients. A particular example
is Manganese deficiency in lupins resulting in regreening of the crop and split seed.
• Further restrictions in plant root growth related to this soil are the infertility of the subsurface layer (the bleached
sand layer), and the hardness, density and low permeability of the clay subsoil.
• The clay subsoil (B horizon) only transmits water slowly, leading to prolonged waterlogging on the top of the
clay.
• High sodicity in the B horizon, a carbonate layer and toxic levels of boron at 60 cm significantly affects
root growth.
Management implications:
• The topsoil (A horizon) would be improved with clay added during delving or clay spreading
(depending on depth to clay) and subsequent cultivation.
• Clay is distributed throughout the A horizon and improves the fertility of the soil and reduces the potential for
leaching nutrients. Clay brought to the surface and worked in reduces the non-wetting soil character and improves
seedling germination with more uniform soil wetting. With the higher clay content of the A horizon the
potassium level in the soil is increased and the potential is for the extractable phosphorus (P) level to build up with
P application. This may give the opportunity when P levels reach adequate levels to reduce P inputs, however, an
annual sulphur application would still be required particularly in wet years.
• With the improved fertility of the soil, the potential is for higher production levels from pasture and crops such
that the trace element nutrition of the plants should be monitored with plant tissue analysis and applications
applied as necessary.
• The challenge is to improve the subsurface layers. With delving, clay is dragged into and through this soil layer
but it is defined largely in the rip or delve line. Ideally the entire bleached area of the subsurface soil would have
clay and organic matter mixed through it, greatly improving its fertility and potential to retain nutrients.
• Delving may also improve drainage where the surface of the clay B horizon is penetrated and incorporating sand
into the clay layer. Delving may also remove the tops of the clay columns and the silcrete capping which would
improve water infiltration potential.
- 18 -
SAND OVER FRIABLE SANDY CLAY LOAM
General Description: Thick bleached sand overlying a friable brown, yellow and red sandy
clay loam, calcareous with depth
Landform:
Undulating rises in relict
coastal dune - corridor
systems.
Substrate:
Calcreted calcarenite.
Vegetation:
Pink gum.
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE043
Stirling
380
08/11/95
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
6925-1 (Keith)
446550
6007300
470 mm
Lower slope of undulating rise, 3% slope. Soft surface.
Soil Description:
Depth (cm)
Description
0-13
Soft dark grey loamy sand. Abrupt to:
13-30
Soft brown light loamy sand. Sharp to:
30-45
Soft bleached sand. Sharp to:
45-70
Firm orange and brown sandy clay loam with weak
coarse columnar breaking to weak polyhedral
structure. Abrupt to:
70-110
Firm orange and yellow sandy clay loam with
weak polyhedral structure and 10-20% calcrete
fragments.
Classification: Bleached, Hypocalcic, Yellow Chromosol; thick, non-gravelly, sandy / clay loamy, deep.
- 19 -
Summary of Properties
Drainage
Rapidly drained. The soil is unlikely to remain wet for more than a few hours.
Fertility
pH
Natural fertility is moderate despite the low clay content of the surface. The CEC
values indicate that surface soil fertility is mainly due to its favourable organic matter
levels. Data indicate that phosphorus, potassium and sulphur levels are adequate, but
magnesium and calcium levels in the soil are marginal.
Slightly acidic in the surface, slightly alkaline in the deep subsoil.
Rooting depth
110 cm, but few roots below 70 cm.
Barriers to root growth
Physical:
None apparent.
Chemical:
None apparent.
Water holding capacity Approximately 100 mm in root zone (moderate).
Seedling emergence
Fair to good depending on degree of water repellence (strong at sampling site).
Workability
Good.
Erosion Potential
Water:
Moderately low.
Wind:
Moderate, due to sandy water repellent surface.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu Fe Mn Zn
Exchangeable Cations
ESP
cmol(+)/kg
Ca
Mg
Na
K
0-13
6.4
5.4
0
0.07
0.49
1.3
34
304
10
0.5
-
-
-
-
4.4
2.93
0.71
0.09
0.59
na
13-30
6.6
5.9
0
0.04
0.22
0.5
35
131
10
0.4
-
-
-
-
3.0
2.43
0.59
0.02
0.23
na
30-45
6.4
5.6
0
0.02
0.13
0.1
22
61
6
0.1
-
-
-
-
1.4
0.77
0.36
0.02
0.08
na
45-70
7.0
6.1
0
0.05
0.19
0.3
10
187
9
1.0
-
-
-
-
8.2
6.17
1.67
0.14
0.59
1.7
70-110
7.4
6.7
0
0.09
0.72
0.2
<4
162
25
0.9
-
-
-
-
10.5
7.70
1.89
0.16
0.37
1.5
Note:
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 20 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• The non-wetting nature of the sandy surface impedes germination of crops and pastures.
• The adequate levels of extractable phosphorus and potassium indicate the potential of this soil type, however the
low CEC indicate that the soil could be overworked.
• With continuous cropping of this soil type there is the potential that organic matter will decline with resulting
nutrient decline.
Management implications:
• Delving this soil type so that clay is distributed throughout the A Horizon improves the fertility of the soil and
reduces the potential for leaching nutrients.
• Clay brought to the surface, and worked in, reduces the non wetting soil character and improves seedling
germination with more uniform soil wetting.
- 21 -
THICK BLEACHED SAND OVER BROWN CLAY
General Description:
Thick bleached sand with an organically darkened surface,
abruptly overlying a brown, yellow and red mottled clay with
variable ironstone gravel, becoming sandier with depth
Landform:
Gently undulating rises.
Substrate:
Clayey sands to sandy clays
of Tertiary age.
Vegetation:
Blue gum (Eucalyptus
leucoxylon) and hill gum (E.
fasciculosa) woodland.
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE079
Cannawigara
1
21/09/04
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-4 (Cannawigara)
473350
5993150
450 mm
Lower slope of gently undulating rises, 1% slope. Soft surface with no stones.
Soil Description:
Depth (cm)
Description
0-15
Brown soft single grain light loamy sand. Gradual
to:
15-55
Very pale brown (bleached) soft single grain
sand. Sharp to:
55-75
Strong brown, yellowish brown and red mottled
hard sandy medium clay with weak coarse
columnar (breaking to strong medium angular
blocky) structure, and 2-10% ironstone nodules.
Gradual to:
75-115
Yellowish brown, red and strong brown hard
fine sandy medium clay with str ong coarse
angular blocky structur e and 2-10% ironstone
nodules. Diffuse to:
115-150
Brownish yellow, light olive brown, light grey
and red hard sandy medium clay with moderate
coarse prismatic (breaking to medium angular
blocky) structure and 2-10% fine carbonate
segregations. Diffuse to:
150-200
Yellowish brown, pale yellow and light red firm
sandy clay loam with weak coarse structure
and 2-10% fine carbonate segregations.
Classification:
Hypocalcic, Mottled-Subnatric, Brown Sodosol; thick, non-gravelly, sandy / clayey, very deep
- 22 -
Summary of Properties
Drainage:
Well drained. Water perches on top of the clayey subsoil for a few days following
heavy or prolonged rainfall. This is unlikely to present problems for annual plants due
to the thickness of the topsoil.
Fertility:
Inherent fertility is low, as indicated by the low clay content of the surface soil and
the exchangeable cation data. Phosphorus levels are low, but this is expected as the
sampling site is in an area not used for cropping or improved pastures. These soils are
susceptible to deficiencies of potassium, copper, zinc and manganese, as well as
phosphorus and nitrogen.
pH:
Neutral at surface, alkaline with depth. Note that elevated surface pH is due to lime
dust from adjacent clay pit.
Rooting depth:
Few annual plant roots below 70 cm.
Barriers to root growth:
The moderate strength of the clay subsoil restricts root densities.
There are no apparent chemical barriers to root growth, apart from low nutrient
availability.
Physical:
Chemical:
Water holding capacity: Approximately 60 mm in potential root zone.
Seedling emergence:
Fair, due to the susceptibility of the surface to water repellence.
Workability:
Satisfactory. Sandy surfaces are easily worked over a range of moisture conditions.
Erosion Potential
Water:
Wind:
Moderately low.
Moderate.
Laboratory Data
Depth
cm
pH pH CO3 EC ECe Org. Avail Avail Cl SO4- Boro Trace Elements
H2 CaC1 %
1:5 dS/m C
.
. K mg/k S
n
mg/kg (EDTA)
O
dS/m
%
P mg/k g mg/k mg/k
2
Cu Fe Zn Mn
mg/k g
g
g
g
Sum
Exchangeable
Est
cation Cations cmol(+)/kg ESP
cmol
(+)/kg Ca Mg Na K
0-15
8.2
7.4
0.5
0.06 0.35 1.61
10
74
13
5.8
0.9 0.55 49 0.70 10.3
4.5
3.4 0.77 0.11 0.2 2.5
15-55
7.7
7.2
0
0.03 0.28 0.16
3
32
2
2.1
0.4 0.08 19 0.05 3.09
1.2
0.76 0.27 0.08 0.08 na
55-75
7.0
6.1
0
0.11 0.59 0.41
3
367
44
23
1.6 0.19 38 0.11 0.91 16.7 5.47 8.55 1.67 0.97 10.0
75-115
7.0
6.2
0
0.11 1.12 0.23
1
412
191
11
2.1 0.15 18 0.14 1.99 17.5
115-150 8.9
7.9
0.5
0.28 1.84 0.13
3
299
160
18
3.2 0.15 22 0.35 1.31 16.6 6.14 7.63 2.08 0.75 12.5
150-200 9.0
7.9
0.5
0.28 1.78 0.10
3
281
168
25
4.3 0.21 18 0.26 2.04 16.0 4.35 8.4 2.54 0.7 15.9
Note:
5.3 9.12 1.97 1.1 11.3
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a measure of the
soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is estimated by dividing the exchangeable sodium value by the sum of
cations.
Very low- may indicate deficiency and/or other limitations *
- 23 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• Due to the sandy nature of this soil it is inherently infertile with requirements for major nutrients and trace
elements in its development for agriculture. It will always be prone to leaching, with the subsequent requirement
for annual applications of phosphorus and sulphur.
• The surface of this soil is prone to the development of non-wetting. This leads to a number of problems that
include erosion risk, patchy germination and early surface drying which can severely affect the availability of
nutrients. A particular example of early surface drying is Manganese deficiency in lupins resulting in regreening
of the crop and split seed.
• Further restrictions in plant root growth related to this soil are the infertility of the subsurface profile (the bleached
sand layer), and the hardness, density and low permeability of the clay subsoil.
• The clay subsoil (B horizon) only transmits water slowly, leading to prolonged waterlogging on the top
of the clay, however with the depth of the topsoil this will only seldom be a problem. It does represent a
source of stored water which would be available to plants if their roots could access it through such a
depth of infertile soil.
Management implications:
• This soil would be improved with clay added during delving or clay spreading (depending on depth to
clay) and subsequent cultivation to mix the clay through the upper profile.
• Clay is distributed throughout the A Horizon and improves the fertility of the soil and reduces the potential for
leaching nutrients. Clay brought to the surface and worked in reduces the non wetting soil character and improves
seedling germination with more uniform soil wetting. With the higher clay content of the A horizon the potassium
level in the soil is increased and the potential is for the extractable phosphorus (P) level to build up with P
application. This may give the opportunity when P levels reach adequate levels to reduce P inputs, however, an
annual sulphur application would still be required particularly in wet years.
• With the improved fertility of the soil , the potential is for higher production levels from pasture and crops such
that the trace element nutrition of the plants should be monitored with plant tissue analysis and applications
applied as necessary.
• The challenge is to improve the subsurface profile. With delving, clay is dragged into and through this soil layer
but it is defined largely in the rip or delve line. Ideally the entire bleached area of the subsurface soil would have
clay and organic matter mixed through it, greatly improving its fertility and potential to retain nutrients.
• Delving may also improve drainage where the surface of the clay B horizon is penetrated and incorporating sand
into the clay layer.
- 24 -
SAND OVER POORLY STRUCTURED CLAY
General Description: Medium thickness grey sand with a bleached subsurface layer, over a
coarsely structured dispersive brown mottled clay, calcareous with
depth
Landform:
Very gently undulating plain.
Substrate:
Tertiary age sandy clay
capped by fine windblown
carbonate.
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE131
Cannawigara
37
22/02/07
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-4 (Cannawigara)
475300
5993170
450 mm
Flat on very gently undulating plain. Loose surface with no stones. Delved to 45 cm.
Soil Description:
Depth (cm)
Description
0-12
Very dark greyish brown loose loamy sand with
fragments of clay. Abundant roots. Sharp to:
Bleached friable massive sand, following columns
to depth (~50 cm). Roots common. Abrupt to:
Yellowish brown and brown mottled sandy light
medium clay with very coarse columnar structure,
breaking to coarse angular blocky. Thin siliceous
pan on surface of columns. Roots common to
many. Gradual to:
Light yellowish brown and yellowish brown
mottled slightly calcareous sandy light medium
clay with very coarse prismatic structure, breaking
to weak coarse angular blocky. Roots few to
common. Abrupt to:
Yellow with yellowish brown mottles firm very
highly calcareous sandy medium clay with
medium angular blocky structure and more than
50% fine carbonate. Very few roots. Clear to:
Light yellowish brown hard calcareous sandy light
medium clay with coarse prismatic structure,
breaking to medium angular blocky. Very few
roots. Diffuse to:
Yellowish brown hard sandy light clay with weak
coarse prismatic structure. No roots.
12-14
14-40
40-54
54-80
80-130
130-160
Classification:
Hypercalcic, Mottled-Mesonatric, Brown Sodosol; medium, non-gravelly, sandy / clayey, deep
- 25 -
Summary of Properties
Drainage:
Imperfectly drained. Water is likely to perch on top of the clay subsoil for several
weeks following heavy or prolonged rainfall. There are strong preferential drainage
pathways along the sandy edges of soil columns
Fertility:
Inherent fertility is low due to low clay content of surface. Surface fertility has been
improved by delving (50% increase in sum of cations compared with similar undelved
soils). Surface nutrient status is adequate for most crops and pastures. The bleached
subsurface sandy layer is highly leached and nutrient deficient, particularly in
potassium, zinc and manganese. This layer has a very low capacity to retain soluble
nutrients, including phosphorus.
pH:
Neutral at the surface, alkaline in the subsoil, and strongly alkaline at depth.
Rooting depth:
Few roots below 54 cm in the sampling pit
Barriers to root growth:
Physical:
The hard and very coarsely structured subsoil clay is a significant barrier, made worse
by the silcrete capping. Roots are largely confined to the aggregate surfaces.
Waterlogging above the clay restricts root abundance in the subsurface, and
preferential drainage increases leaching losses of nutrients and water.
Chemical:
Root growth is restricted by the very low fertility of the bleached subsurface layer,
high sodicity and pH from 40 cm, and elevated salinity / chloride and boron
concentrations from 54 cm.
Water holding capacity: Approximately 60 mm total available water in the potential rootzone.
Seedling emergence:
Satisfactory provided that delving has controlled water repellence.
Workability:
Good. Sandy soils are easily worked.
Erosion Potential
Water:
Wind:
Low.
Moderate.
Laboratory Data
Depth pH pH CO3 EC1: ECe Cl Org. NO3 Avail Avail SO4- Reac Boro Trace Elements
cm H2O CaC1 %
5 dS/m mg/k C
+
.
.K
S t Fe n
mg/kg (EDTA)
dS/m
g
% NH4 P mg/k mg/k mg/k mg/k
2
mg/k mg/k g
g
g
g Cu Fe Mn Zn
g
g
Sum Exchangeable Est.
cations
Cations
ESP
cmol
cmol(+)/kg
(+)/kg Ca Mg Na K
0-12
6.8
5.9
0
0.10 1.15
87
1.64
20
64
174
8.2
994
1.6 4.4 377 5.0 4.0
6.9
4.9 1.1 0.4 0.5 6.1
12-14
6.8
6.0
0
0.03 0.30
10
0.23
2
13
38
2.6
194
0.4 1.5 91 0.9 0.2
1.4
0.9 0.2 0.1 0.1 8.9
14-40
8.2
7.1
0
0.14 1.51
65
0.28
3
2
185 19.8 730
3.0 1.1 75 1.5 0.5 15.6 4.1 7.9 3.1 0.6 19.5
40-54
9.4
8.5
1
0.34 1.86 160 0.16
4
2
311 34.3 645
9.2 1.3 49 2.2 0.3 23.5 6.4 10.5 5.8 0.9 24.7
54-80
9.6
8.7
31
0.60 3.36 484 0.21
4
2
350 74.2 489 11.1 1.2 22 1.1 0.2 31.6 9.7 12.4 8.6 0.9 27.1
80-130 9.7
8.8
2
0.65 3.93 655 0.09
3
2
414 104 586 13.1 1.4 29 6.0 0.4 31.3 5.6 13.2 11.3 1.2 36.1
130-160 8.9
7.8
0
0.72 5.10 773 0.07
3
2
350 108 436 11.6 1.4 38 18.4 0.3 25.1 2.0 12.6 9.6 0.9 38.3
Note:
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a
measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC,
in this case estimated by the sum of cations.
Very low- may indicate deficiency and/or other limitations *
- 26 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints
• The surface of this soil has been improved through clay added during delving and subsequent cultivation. The
surface is slightly sodic due to the clay and has a tendency to seal. This sealing can be overcome with further
cultivation and incorporation of the clay into the sub-surface layers.
• The main restrictions related to this soil are the infertility of the subsurface layers (the bleached sand layer), and
the hardness, density and low permeability of the clay subsoil.
• The clay subsoil (B horizon) only transmits water slowly, leading to prolonged waterlogging on the top of the
clay.
• Due to the sandy nature of this soil it will always be prone to leaching, with the subsequent requirement for annual
applications of phosphorus and sulphur. With the higher clay content of the A horizon following delving, the
potential is for the extractable phosphorus (P) level to build up with P application. This may give the opportunity
when P levels reach adequate levels to reduce P inputs, however, an annual S application would still be required
particularly in wet years.
• With the improved fertility of the soil after delving the potential is for higher production levels from pasture and
crops such that the trace element nutrition of the plants should be monitored with plant tissue analysis and
applications applied as necessary.
Management implications
• Delving this soil type so that clay is distributed throughout the A Horizon improves the fertility of the soil and
reduces the potential for leaching nutrients. Clay brought to the surface and worked in reduces the non wetting soil
character and improves seedling germination with more uniform soil wetting.
• The challenge is to improve the subsurface horizons. With delving clay is dragged into and through this soil layer
but it is defined largely in the rip or delve line (as indicated by the low potassium and sum of cations 12 – 14 cm
despite the delving undertaken). Ideally the entire bleached area of the subsurface soil would have clay and
organic matter mixed through it, greatly improving its fertility and potential to retain nutrients.
• Delving may also improve drainage where the surface of the clay B horizon is penetrated and incorporating sand
into the clay layer. Delving may also remove the tops of the clay columns and the silcrete capping which would
improve water infiltration potential.
- 27 -
THIN SANDY LOAM OVER HARD YELLOW CLAY
General Description: Delved thin sandy loam with a narrow bleached band over brownish
yellow very hard, very coarsely structured light clay.
Landform:
Gently undulating plains
with low sand dunes.
Substrate:
Tertiary age clay mantled by
fine carbonates.
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE122
Tatiara
453
30/10/06
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-2 (Tatiara)
483906
5986400
450 mm
Crest of low rise on gently undulating plain. Soft surface with no stones. Paddock delved to 30 cm.
Soil Description:
Depth (cm)
Description
0-8
Very dark grey brown friable sandy loam with 1020% (delved) clay fragments. Abundant roots.
Clear to:
8-15
Light yellowish brown (bleached) soft single grain
sand. Few roots. Sharp to:
15-55
Brownish yellow very hard sandy light clay with
very coarse columnar, breaking to coarse angular
blocky, structure. Few roots (roots common on
column faces). Gradual to:
8-30
Delved zone - mix of upper three horizons along
delve line. Roots common in sand, few in clay.
55-85
Brownish yellow very hard light medium clay with
coarse angular blocky structure and 20-50%
carbonate veins. No roots. Diffuse to:
85-140
Pale yellow and light grey hard light clay with
very coarse weak prismatic structure. No roots.
Classification:
Calcic, Hypernatric, Yellow Sodosol; medium, non-gravelly, loamy / clayey, deep
- 28 -
Summary of Properties
Drainage:
Imperfectly drained. Water is likely to perch on top of the poorly structured clay for
several weeks.
Fertility:
Inherent fertility is moderately low, as indicated by the exchangeable cation data, but
delving has improved cation status of near surface soil. Levels of tested nutrient
elements are adequate, although trace element concentrations are marginal- tissue
testing required for confirmation.
pH:
Slightly acidic at the surface, strongly alkaline in the subsoil, acidic with depth.
Rooting depth:
55 cm in sampling pit.
Barriers to root growth:
Physical:
The coarsely structured clay restricts root growth with low root densities inside the
clay columns. The platy pans within the calcreted limestone presents a severe barrier
to root penetration.
Chemical:
High pH and sodicity from 55 cm restrict deeper root penetration.
Water holding capacity: Approximately 70 mm total available water in the potential root zone.
Seedling emergence:
Satisfactory.
Workability:
Good.
Erosion Potential
Water:
Wind:
Low.
Moderately low, but delved clay fragments help to stabilize natural surface.
Laboratory Data
Depth pH pH CO3 EC1: ECe Cl Org. NO3 Avail Avail SO4- Reac Ext Boro Trace Elements Sum
Exchangeable Est.
cm H2O CaC1 %
5 dS/m mg/k C
+
.
. K S t Fe Al
n mg/kg (EDTA) cation
Cations
ESP
dS/m
g
% NH4 P mg/k mg/k mg/k mg/k mg/k
s cmol
cmol(+)/kg
2
mg/k mg/k g
g
g
g
g Cu Fe Mn Zn (+)/kg Ca Mg Na K
g
g
6.3
5.5
0
0.11 1.26 53 1.47
8
22
286 28.7 774
0
1.0 0.7 129 5.5 0.6
9.2 5.96 2.15 0.35 0.72 3.8
8-15 7.0
6.0
0
0.05 0.61 14 0.36
2
6
29
5.2 253
0
0.4 0.2 88 1.2 0.2
1.7 0.83 0.49 0.26 0.07 15.8
15-55 8.6
7.6
0
0.30 1.49 118 0.30
2
2
378 31.6 522
0
5.1 0.2 29
55-85 9.5
8.7
7
0.76 3.31 333 0.21
2
2
366 80.3 422
0
7.8 0.3 13 1.3 0.2 24.6 6.82 9.54 7.21 1.04 29.3
9.0
8.2
0
0.73 3.51 465 0.25
3
2
393 80.9 361
0
7.5 0.3 26
8-30* 6.8
5.6
0
0.11 0.76 43 0.79
6
3
337 23.9 896
0
2.5 0.1 74 3.6 0.2 19.8 7.97 9.64 1.26 0.94 6.4
8- 5.7
30**
4.3
0
0.03 0.55 16 1.61
3
24
54
0-8
85140
8.9 672 4.7
10.
0.2 18.8 3.55 9.19 5.07 1.01 26.9
7
15.
0.2 22.2 2.45 10.1 8.63 1.03 38.9
3
0.7 0.2 255 1.9 0.1
3.6 2.38 0.81 0.32 0.1 8.8
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a
measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC,
in this case estimated by the sum of cations.
* Clay lumps sampled from within the zone altered by delving.
** Sand sampled from within the zone altered by delving.
Very low- may indicate deficiency and/or other limitations
High reading- may indicate toxicity and/or other limitations*
*
Note:
- 29 -
Management of this soil type
Constraints:
• Prior to delving this soil would have been acidic in the topsoil (A horizon) with a low cation exchange capacity
that indicates low inherent fertility.
• The sandy surface would have developed some water repellence. This has been modified by delving.
• The major problem with this soil type is the relatively shallow depth of the topsoil and the very hard sodic subsoil
layer that restricts root development and in wet years is subject to waterlogging.
• An increase in salinity and sodicity from 55cm limits root development.
Management implications:
•
•
•
•
•
•
•
•
The high cation exchange capacity and extractable potassium levels indicate the inherent fertility of this soil and
the potential to build soil phosphorus levels with fertiliser application in addition to the immediate crop or pasture
requirement.
Surface water drainage alleviates the potential for crop losses on this highly productive soil type.
Delving may also improve drainage where the surface of the clay B horizon is penetrated and
incorporating sand into the clay layer. Delving may also remove the tops of the clay columns and the
silcrete capping which would improve water infiltration potential.
Clay is distributed throughout the A horizon and improves the fertility of the soil and reduces the potential for
leaching nutrients.
Clay brought to the surface and worked in reduces the non-wetting soil character and improves seedling
germination with more uniform soil wetting.
With the higher clay content of the A horizon the potassium level in the soil is increased and the potential is for
the extractable phosphorus (P) level to build up with P application. This may give the opportunity when P levels
reach adequate levels to reduce P inputs, however, an annual sulphur application would still be required
particularly in wet years.
With the improved fertility of the soil, the potential is for higher production levels from pasture and crops such
that the trace element nutrition of the plants should be monitored with plant tissue analysis and applications
applied as necessary.
The challenge is to improve the subsurface horizons. With delving, clay is dragged into and through this soil layer
but it is defined largely in the rip or delve line. Ideally the entire bleached area of the subsurface soil would have
clay and organic matter mixed through it, greatly improving its fertility and potential to retain nutrients.
- 30 -
BLEACHED SAND OVER CLAY
General Description:
Delved sandy loam with a bleached sandy subsurface layer over a
moderately well structured reddish clay, calcareous with depth
Landform:
Very gently undulating plain.
Substrate:
Tertiary age sandy clay
loam.
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE124
Cannawigara
2
30/10/06
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-4 (Cannawigara)
473121
5994380
450 mm
Slope (1%) on very gently undulating plain. Soft surface with no stones. Paddock delved to 45 cm.
Soil Description:
Depth (cm)
Description
0-12
Very dark greyish brown soft sandy loam.
Clay fragments common. Abundant roots.
Clear to:
12-30
Yellowish brown (bleached) friable sand. Very
few roots. Sharp to:
30-60
Yellowish red firm to hard light clay with weak
medium angular blocky structure. Very few roots
(however, roots common under delve line).
Diffuse to:
12-44
Delved zone - mix of upper three horizons along
the line of delve tine. Many roots.
60-105
Brownish yellow and yellowish brown mottled
hard light clay with weak coarse prismatic
structure and 20-50% carbonate veins. Very few
roots. Gradual to:
105-120
Brownish yellow and red mottled massive firm
sandy clay loam. No roots.
Classification:
Bleached, Calcic, Red Chromosol; thick, non-gravelly, loamy / clayey, deep
- 31 -
Summary of Properties
Drainage:
Moderately well drained. Water is likely to perch on top of the clay subsoil for up to a
week at a time following heavy or prolonged rainfall.
Fertility:
Inherent fertility is moderately low, as indicated by the exchangeable cation data, but
delving has improved cation status of near surface soil (compare original subsurface
layer 12-30 cm with delved sand layer 12-44 cm). Soil test data indicate that
phosphate levels are low, but concentrations of other nutrient elements are adequate.
pH:
Under natural conditions, slightly acidic at the surface, but now slightly alkaline at the
surface due to delving and / or past liming, alkaline in the subsoil.
Rooting depth:
60 cm in sampling pit, with a very few roots to 105 cm.
Barriers to root growth:
Physical:
The clay subsoil restricts root growth to some extent, but is naturally moderately well
structured. Delving has improved root growth by disrupting the sharp break between
topsoil and subsoil, and breaking up the clay.
Chemical:
No apparent barriers apart from very low subsurface nutrient retention capacity.
Water holding capacity: Approximately 90 mm total available water in potential rootzone.
Seedling emergence:
Satisfactory.
Workability:
Good.
Erosion Potential
Water:
Wind:
Low.
Moderately low due to relatively low clay content of surface soil.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe
Cl Org.C NO3 Avail. Avail. SO4-S React Ext Boron
Trace Elements
Sum
Exchangeable
Est.
H2O CaC12 % dS/m dS/m mg/kg %
+
P
K mg/kg Fe
Al mg/kg
mg/kg (EDTA)
cations Cations cmol(+)/kg ESP
NH4 mg/kg mg/kg
mg/kg mg/kg
cmol
Cu Fe Mn Zn (+)/kg Ca Mg Na K
mg/kg
0-12
7.4
6.4
0
0.06
0.48
11
1.20
5
12
213
7.5
276
0
1.2
2.7
83 15.4 2.0
5.3
3.93 0.83 0.09 0.49 1.7
12-30
5.9
5.1
0
0.02
0.21
7
0.13
4
8
65
4.6
201
0.6
0.5
2.1
62
4.2 0.9
1.4
0.97 0.2 0.06 0.15 na
30-60
7.6
6.5
0
0.05
0.38
11
0.49
6
2
475
4.8
490
0
2.4
0.1
18
6.8 0.4
15.1
8.69 4.85 0.29 1.25 1.9
60-105
8.5
8.2
9
0.19
0.55
21
0.28
4
2
351
8.5
604
0
4.0
0.1
7
1.3 0.3
20.0
13.3 5.31 0.54 0.91 2.7
105-120
8.7
8.4
3
0.13
0.42
11
0.12
2
2
172
5.9
505
0
2.2
0.1
6
2.7 0.3
12.4
9.3 2.32 0.33 0.45 2.7
12-44*
7.3
6.6
0
0.13
1.11
22
0.60
21
4
445
32.8
493
0
2.6
2.4
41
6.7 1.0
13.1
8.56 3.17 0.28 1.13 2.1
12-44**
6.5
5.4
0
0.04
0.36
6
0.93
6
12
90
8.9
253
0.5
0.7
6.8
97 10.2 2.2
3.2
2.48 0.44 0.08 0.2 2.5
44-60#
8.3
7.5
0
0.13
0.64
24
0.43
7
2
423
17.7
604
0
3.0
0.4
19
15.9
9.81 4.57 0.36 1.12 2.3
Note:
6.7 0.2
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a
measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC,
in this case estimated by the sum of cations.
* Clay lumps sampled from within the zone altered by delving.
** Sand sampled from within the zone altered by delving.
#
Clay under delve line
- 32 -
6
SHALLOW SAND OVER CLAY ON CALCRETE
SHALLOW SAND OVER CLAY ON CALCRETE
General Description: Delved grey sand with a bleached subsurface over weakly structured
brown clay subsoil, over calcreted lagoonal sediments.
Landform:
Level plain.
Substrate:
Calcreted limestone of the
Padthaway Formation
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE119
Pendleton
49
06/11/06
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-4 (Cannawigara)
459690
6001255
460 mm
Level plain, 0% slope. Soft surface with minor calcrete stones. Paddock delved to 40 cm.
Soil Description:
Depth (cm)
Description
0-15
Very dark grey brown single grain clayey sand
with 10-20% small clay fragments and 2-10%
calcrete fragments. Many roots. Clear to:
15-25
Very pale brown (bleached) single grain sand.
Few roots. Abrupt to:
25-38
Strong brown friable weakly subangular blocky
light medium clay. Roots common. Sharp to:
38-64
White calcreted limestone. An occasional root
present. Diffuse to:
64-115
White calcreted limestone. An occasional root
present. Diffuse to:
115-150
Massive light grey medium clay with brownish
yellow mottle. Interspersed with up to 50% soft
carbonate. No roots.
Note:
Clay delving has caused mixing of the first three,
(and occasionally part of the fourth) layers where
the delve tine has passed.
Classification:
Eutrophic, Petrocalcic, Brown Sodosol; medium, slightly gravelly, sandy / clayey, shallow
- 33 -
Summary of Properties
Drainage:
Well drained. No part of the profile is likely to remain wet for more than a day or so.
Fertility:
Clay delving has improved the fertility of the soil surface, with cation data indicating
moderate inherent fertility – natural fertility of this soil is low. Fertility has also been
improved in the second layer along the delve line. Phosphorus levels are low, but
most other nutrients appear adequate for pasture growth. Surface levels of cobalt,
molybdenum and nickel were 1007, 154 and 2118 parts per billion respectively.
pH:
Alkaline throughout – surface alkalinity attributable to irrigation water
Rooting depth:
64 cm in the sampling pit. Root zones of soils formed over limestone are usually
variable due to the dissolution of the limestone. Deeper solution holes (up to 100 cm)
evident during excavation. Very low root numbers in small clay filled holes in
calcreted limestone.
Barriers to root growth:
Physical:
The cemented platy pan of calcreted limestone restricts root penetration.
Chemical:
High pH and high carbonate of limestone prevents most roots from accessing these
horizons. The soil is moderately saline, becoming highly saline below 25 cm. The soil
is strongly sodic, particularly in the third layer.
Water holding capacity: Total available water:
Estimate 30-60 mm
Readily available water (RAW): Estimate 15-30 mm.
The influence of the limestone layer on water availability is unknown.
Seedling emergence:
Good. The clay spread at the surface through the delving process has improved the
surface condition and reduced water repellence.
Workability:
Good.
Erosion Potential
Water:
Wind:
Low.
Moderate if surface vegetation cover is removed and the surface is allowed to dry out.
Laboratory Data
Depth
cm
pH
pH
H2O CaC12
CO3
%
EC
ECe
Cl Org.C Avail. Avail. SO4-S Boron React
1:5 dS/m mg/kg
%
P
K mg/kg mg/kg Fe
dS/m
mg/kg mg/kg
mg/kg
Trace Elements
mg/kg (EDTA)
Cu
Fe
Mn
Sum Exchangeable Cations Est.
cations
cmol(+)/kg
ESP
cmol
Zn (+)/kg Ca Mg Na
K
0-15
8.6
8.1
1
0.44
4.57
385
1.77
15
166
32.5
1.7
326
2.65 132 16.9 3.35
13.9
6.7 4.82 2.0 0.41 14.4
15-25
8.3
8.0
0
0.25
3.59
235
0.18
2
44
18.2
0.4
149
1.12 45 0.92 52.0
3.8
2.2 0.72 0.8 0.08 21.0
25-38
7.7
7.3
0
1.16
10.25 1395
0.94
2
307
98.3
1.1
902
1.55 91 2.95 0.76
25.1
12.1 5.22 6.84 0.94 27.2
38-64
8.5
8.1
79
2.01
14.03 2528
0.69
2
84
131
0.7
133
1.54 21 1.74 0.63
25.7
17.5 1.62 6.29 0.22 24.5
64-115
8.6
8.1
81
1.05
8.58
1259
0.37
2
136
22.2
0.6
224
1.53 20 1.88 0.59
19.7
16.1 1.36 1.89 0.35
9.6
115-150
9.1
8.2
6
0.25
1.39
198
0.14
2
271
11.2
0.5
376
1.68 23 3.13 0.7
27.6
16.9 8.59 1.39 0.74
5.0
15-40*
8.8
8.2
2
0.88
7.40
839
0.91
3
293
62.6
1.2
921
1.95 213 3.43 1.28
23.0
10.5 6.35 5.36 0.82 23.3
15-40**
8.9
8.2
1
0.43
5.43
469
0.68
4
65
27.6
0.5
266
5.45 145 6.07 5.1
9.5
6.0 1.57 1.69 0.16 17.9
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a
measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC,
in this case estimated by the sum of cations.
*
Clay lumps sampled from within the zone altered by delving.
**
Sand sampled from within the zone altered by delving.
Very low- may indicate deficiency and/or other limitations
High reading- may indicate toxicity and/or other limitations*
*
Note:
- 34 -
Management of this soil type
Constraints:
• Prior to irrigation and delving the sandy texture of this soil would indicate low inherent fertility and
possible moderate non wetting evident.
• The pH of the A horizon would have been acidic.
• The calcrete layer at 38 cm is a major barrier to root growth.
• With irrigation the pH of the soil has become alkaline throughout with high pH over 8.3 indicating an
emerging salinity problem associated with saline irrigation water.
• Despite the improvement of the potential fertility with delving the extractable phosphorus levels
indicate that there will be a continued response to phosphorus fertilizer applications.
• With increasing pH as a result of irrigation trace elements, particularly manganese, may become
limiting.
Management implications
• Delving has improved the potential for building up the general nutrition of the soil.
•
To increase productivity and so use irrigation water more efficiently the phosphorus inputs should be
evaluated.
• Under the current irrigation regime there is an elevated salinity level which could normally (November)
be a problem so early in the irrigation system. This is most likely due the lack of rain in the preceding
winter that would normally leach the salt build up from the previous irrigation season. A heavier
application of water may help leach salts if they become limiting in the crop being irrigated.
- 35 -
7
SHALLOW RED LOAM ON CALCRETE
SHALLOW GRADATIONAL SANDY LOAM OVER CALCRETE
General Description: Sandy loam grading to a weakly structured red sandy clay loam, more clayey
with depth over calcrete within 50 cm
Landform:
Gently undulating dunefield.
Substrate:
Calcreted clay.
Vegetation:
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE052
Beeamma
22
1/2/96
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7024-4 (Keppoch)
472350
5957300
550 mm
Swale between sandhills, 2% slope. Firm surface with no stones.
Soil Description:
Depth (cm)
Description
0-8
Brown friable sandy loam with weak polyhedral
structure and 2-10% carbonate nodules (6-20
mm). Clear to:
8-26
Yellowish red friable massive light sandy clay
loam with minor carbonate nodules. Gradual to:
26-32
Yellowish red firm massive sandy clay loam.
Abrupt to:
32-34
Very strongly cemented massive calcrete pan.
Clear to:
34-83
Firm massive highly calcareous sandy clay loam
with 20-50% fine carbonate segregations and 210% calcrete nodules (20-60 mm). Diffuse to:
83-102
Yellowish brown firm massive highly calcareous
sandy light clay with 20-50% fine carbonate
segregations and 2-10% calcrete nodules (20-60
mm).
Classification:
Haplic, Petrocalcic, Red Kandosol; thin, slightly gravelly, loamy / clayey, shallow
- 36 -
Summary of Properties
Drainage
Well drained. Soil rarely remains wet for more than a few days.
Fertility
Inherent fertility is moderately low, as indicated by the exchangeable cation data.
However, favourable organic carbon levels help provide nutrient retention capacity.
Magnesium concentrations are low, in absolute terms and in relation to calcium.
Phosphorus concentrations are also low.
pH
Acidic at the surface, alkaline with depth.
Rooting depth
102 cm in pit, but few roots below 32 cm (pan).
Barriers to root growth
Physical:
The calcrete pan at shallow depth prevents most roots from growing deeper.
Chemical:
There are no chemical barriers, although nutrient availability in the high carbonate
layer below the calcrete restricts any roots which penetrate the calcrete.
Water holding capacity Approximately 50 mm in the root zone (above the calcrete).
Seedling emergence:
Satisfactory.
Workability:
The firm surface is easily worked.
Erosion Potential
Water:
Low.
Wind:
Low.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu Fe Mn Zn
ESP
cmol(+)/kg
Ca
Mg
Na
K
9.3
7.02
0.77
0.14
0.34
1.5
Paddock
5.8
5.2
0
0.08
0.62
1.9
14
182
9
1.6
0-8
6.5
6.1
0
0.10
0.70
2.8
28
200
9
1.7
-
-
-
-
13.0
10.39 1.06
0.18
0.40
1.4
8-26
6.5
6.0
0
0.05
0.43
0.7
5
73
5
1.4
-
-
-
-
8.9
8.08
0.79
0.10
0.18
1.2
26-32
7.5
6.9
0.1
0.05
0.29
0.4
<4
59
3
1.3
-
-
-
-
6.8
6.19
0.59
0.11
0.11
1.6
32-34
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
34-72
8.7
7.9
54.1
0.10
0.35
0.5
<4
56
6
0.8
-
-
-
-
3.3
4.71
0.50
0.13
0.10
na
72-83
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
83-102
8.6
7.9
26.9
0.11
0.29
0.3
<4
95
5
1.0
-
-
-
-
10.0
9.85
0.95
0.12
0.17
1.2
Note:
0.40 135 8.34 0.62
Exchangeable Cations
Paddock sample bulked from 20 cores (0-10 cm) taken around the pit.
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations
*
High reading- may indicate toxicity and/or other limitations*
- 37 -
Management of this soil type
Constraints:
• The only problem with this soil type is the relatively shallow depth of the topsoil and the very hard
calcrete layer that restricts root development.
Management implications:
• The high cation exchange capacity and extractable potassium levels indicate the inherent fertility of this
soil and the potential to build soil phosphorus levels with fertiliser application ni addition to the
immediate crop or pasture requirements.
- 38 -
8
LOAM OVER CLAY
SANDY LOAM OVER POORLY STRUCTURED BROWN CLAY
General Description: Medium thickness loamy sand to sandy loam with a compact bleached
subsurface layer, overlying a red, brown and yellow mottled tough
clay, calcareous with depth.
Landform:
Gently undulating low rises
Substrate:
Heavy clay with soft
carbonate (lime)
accumulations
Vegetation:
Eucalyptus leucoxylon (blue
gum) woodland
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE015
Wirrega
595
17/03/93
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-3 (Mundulla)
472450
5976450
510 mm
Lower slope of low rise, adjacent to swampy flat. Firm surface, with 6% slope.
Soil Description:
Depth (cm)
Description
0-15
Dark reddish brown massive light sandy loam.
Clear to:
15-23
Pinkish grey massive light sandy loam. Sharp to:
23-45
Red, brown and orange mottled very firm heavy
clay with strong coarse columnar structure. Gradual
to:
45-55
Orange and dark brown mottled firm medium clay
with strong coarse prismatic structure. Clear to:
55-85
Dark brown and pale yellow firm highly calcareous
medium clay with strong coarse prismatic structure
(Class I carbonate layer). Diffuse to:
85-120
Pale olive and yellowish brown mottled very firm
heavy clay with strong very coarse prismatic
structure and soft calcareous segregations.
Classification: Hypercalcic, Mottled-Mesonatric, Brown Sodosol; medium, non-gravelly, loamy/clayey, deep
- 39 -
Summary of Properties
Drainage
Imperfect due to slowly permeable subsoil. Water lies on top of the clay layer,
saturating the lower part of the topsoil for weeks at a time during winter.
Fertility
Moderately high inherent fertility, as indicated by the CEC value of the subsoil which
has a reasonable capacity to store and release major plant nutrients. The light topsoil
however has a much lower capacity, with most nutrient storage attributable to the
organic matter. At the type site (not a farmed paddock), phosphorus is very low
(natural levels), and subsoil zinc is also low.
pH
Mildly acidic at the surface, becoming strongly alkaline with depth.
Rooting depth
55 cm in pit (native grass roots).
Barriers to root growth
Physical:
The tough clay subsoil impedes root development. The bleached subsurface layer
when saturated in winter restricts root growth, and forms a physical barrier when it
becomes hard and dense on drying in spring time.
The Class I carbonate layer (from 55 cm) impedes root growth. Subsoil zinc
deficiency may also be a problem. Low levels of other nutrients are readily corrected
by fertilizer applications.
Chemical:
Water holding capacity 75 mm in root zone (moderate), but a portion of this is effectively unavailable due to
sub-optimal root densities.
Seedling emergence
Fair to good depending on the condition of the surface. Reduced organic matter levels
will cause the surface to set hard, restricting seedling emergence.
Workability
Fair to good, depending on organic matter levels. Excessive cultivation or stock
trampling will destroy organic matter and induce a hard setting condition.
Erosion Potential
Water:
Moderately low to moderate, depending on the slope. The soil is highly erodible, so
even gentle slopes are susceptible.
Moderately low, depending on the degree to which the surface has been pulverized.
Wind:
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu
Fe
Mn
Zn
Exchangeable Cations
ESP
cmol(+)/kg
Ca
Mg
Na
K
0-15
6.3
6.0
0
0.08
0.54
2.2
5
341
-
1.2
0.2
33
3.9
0.3
10.8
8.07
1.59
0.12
0.57
7.1
15-23
5.9
5.1
0
0.02
0.17
0.3
3
238
-
0.4
0.1
27
0.3
0.1
3.2
2.53
0.80
0.11
0.25
na
23-45
6.7
5.9
0
0.11
0.46
0.7
<4
1026
-
3.9
0.4
28
0.6
0.1
31.1
13.1
12.2
1.79
2.73
20.9
45-55
8.3
7.8
1
0.39
1.36
0.5
<4
1290
-
7.9
0.4
11
1.7
0.1
36.8
12.7
15.3
3.06
3.14
24.8
55-85
8.9
8.1
27
0.42
2.17
0.4
<4
921
-
8.5
0.4
7
0.7
0.3
23.9
7.74
11.9
2.62
1.98
25.6
85-120
9.2
8.4
19
0.65
2.84
0.3
<4
701
-
12.1
0.3
6
0.5
0.3
22.7
4.21
13.7
4.63
1.68
39.9
Note:
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 40 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• The only problem with this soil type is the relatively shallow depth of the topsoil and the very hard sodic subsoil
layer that restricts root development and in wet years may be subject to waterlogging.
• An increase in salinity from 45cm is associated with increasing boron levels.
Management implications:
• The high cation exchange capacity and extractable potassium levels indicate the inherent fertility of this soil and
the potential to build soil phosphorus levels with fertiliser application with requirements for major nutrients and
trace elements in its development for agriculture.
• Surface water drainage alleviates the potential for crop losses on this productive soil type.
• Delving this soil type so that clay is distributed throughout the A Horizon improves the fertility of the soil and
reduces the potential for leaching nutrients. Clay brought to the surface and worked in, reduces the non wetting
soil character and improves seedling germination with more uniform soil wetting.
• The challenge is to improve the subsurface layers. With delving clay is dragged into and through the soil profile
but it is defined largely in the rip or delve line. Ideally the entire bleached area of the subsurface soil would have
clay and organic matter mixed through it, greatly improving its fertility and potential to retain nutrients.
• Delving may also improve drainage where the surface of the clay B horizon is penetrated and incorporating sand
into the clay layer. Delving may also remove the tops of the clay columns and the silcrete capping which would
improve water infiltration potential.
- 41 -
IRONSTONE SANDY LOAM OVER RED ALKALINE CLAY
General Description: Hard setting medium thickness massive sandy loam to sandy clay
loam with ironstone gravel, sharply overlying a reddish mottled
coarsely structured clay, calcareous with depth.
Landform:
Gentle slopes running down
to the flats of the Tatiara and
Nalang Creeks. Slopes range
from 1% to 4%
Substrate:
Tertiary sandy clays,
ferruginised in places
Vegetation:
Open woodland of
Eucalyptus leucoxylon and
Casuarina spp
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE002
Tatiara
Racecourse
23/01/91
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-2 (Tatiara)
480400
5981850
500 mm
Lower slope of low rise, 3% slope. Firm surface.
Soil Description:
Depth (cm)
Description
0-12
Dark reddish brown massive light sandy clay
loam, with 5% ironstone gravel. Clear to:
12-27
Pink massive light sandy loam with up to 50%
ironstone gravel. Abrupt to:
27-45
Red and dark brown heavy clay with strong
angular blocky structure. Gradual to:
45-70
Red, brown and brownish yellow heavy clay with
strong angular blocky structure. Gradual to:
70-150
Yellowish grey highly calcareous medium clay
(Class I carbonate layer).
Classification:
Ferric, Mottled-Subnatric, Red Sodosol; medium, slightly gravelly, loamy / clayey, very
deep
- 42 -
Summary of Properties
Drainage
Moderately well to imperfectly drained. Soil may remain wet for a week to several
weeks due to its slowly permeable subsoil.
Fertility
Natural fertility is high as indicated by the CEC values, although the 12-27 cm layer is
strongly leached. Provided that organic matter levels are maintained, nutrient
deficiencies other than nitrogen, phosphorus and possibly zinc should not be a
problem.
pH
Neutral to slightly alkaline at the surface, strongly alkaline with depth.
Rooting depth
70 cm at pit site.
Barriers to root growth
Physical:
The poorly structured gravelly layer (12-27 cm) and the hard sodic clay subsoil
restrict root development. Waterlogging in the gravelly layer is likely, preventing root
growth. This layer, having a very low moisture storage capacity will dry out rapidly in
spring-time and may prevent surface roots from extending into the moisture reserves
in the clay.
Chemical:
Class I carbonate layers typically impede root growth.
Water holding capacity 110 mm in rootzone at type site. Some of this is effectively unavailable due to low
root density in the subsoil.
Seedling emergence
Fair, due to the tendency of the poorly structured surface soil to seal over.
Workability
Fair. Hard setting surface pulverises when too dry and puddles when too wet.
Erosion Potential
Water:
Wind:
Moderately low.
Low.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu
Fe
Mn
Zn
Exchangeable Cations
ESP
Cl
mg/kg
cmol(+)/kg
Ca
Mg
Na
K
0-12
7.7
7.5
0.6
0.16
-
1.9
19
340
-
1.5
0.3 11.2 3.8
0.5
12.1
10.4
0.9
0.1
0.8
1
55
12-27
7.6
7.4
<0.1
0.08
-
0.6
3
22
-
0.9
0.1 10.7 0.8 <0.1
6.1
5.1
0.5
0.1
0.3
2
8
27-45
8.1
7.8
0.4
0.37
-
1.1
<2
360
-
7.0
0.5 25.9 1.0
1.2
30.4
13.3
12.3
4.3
1.2
14
81
45-70
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
70-150
9.4
8.7
23.4
0.81
-
0.3
<2
380
-
8.8
0.2
4.2
27.7
4.8
12.8
7.0
1.2
25
587
Note:
-
0.5 <0.1
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 43 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• The major problem with this soil type is the shallow depth of the topsoil and the infertile subsurface
layer that restricts root development. This restricts the available water that can finish crops and pastures
in a dry spring.
• In wet years this soil type is subject to waterlogging due to the hard sodic clay subsoil.
Management implications:
• The challenge is to improve the subsurface profile. This soil may be improved with clay delving and
subsequent cultivation to mix the clay through the upper profile.
• Surface water drainage is desirable to maximise crop production in wet years. This encourages root growth during
the winter and early spring so that there is maximum root development throughout the soil when the soil dries out
later in spring.
• Delving may also improve drainage where the surface of the clay B horizon is penetrated and incorporating sand
into the clay layer.
• The levels of extractable phosphorus are marginal and crops would respond to phosphorus applications. The
elevated levels of extractable potassium indicate there is potential to build up the phosphorus nutrition of this soil
type with fertiliser application.
• The trace element status particularly for copper and zinc should be monitored with plant tissue analysis to ensure
potential crop yields are realised.
- 44 -
HARD LOAMY SAND OVER DISPERSIVE RED CLAY
General Description:
Thin hard sandy topsoil over a coarsely structured, dispersive
red or brown mottled clay, calcareous with depth, grading to
Tertiary sandy clay
Landform:
Slopes of gently undulating
rises.
Substrate:
Fine to medium grained
Tertiary sediments, capped
by fine carbonate.
Vegetation:
Blue gum (Eucalyptus
leucoxylon) woodland.
Type Site:
Site No.: SE077
Hundred:
Tatiara
Section:
335
Sampling date: 21/09/04
1:50,000 sheet: 7025-2 (Tatiara)
Easting:
492700
Northing:
5983150
Annual rainfall: 450 mm
Upper slope of gentle rise, 2% slope. Hard setting surface with minor ironstone fragments and
clods of subsoil brought up by recent delving.
Soil Description:
Depth (cm)
Description
0-8
Brown soft (cultivated) massive loamy sand with
clods (to 2 cm) of subsoil clay. Sharp to:
8-30
Strong brown and brown mottled hard sandy
medium clay with strong very coarse prismatic
structure. Gradual to:
30-55
Light yellowish brown and strong brown mottled
firm sandy medium heavy clay with moderate
coarse subangular blocky structure. Clear to:
55-90
Light yellowish brown and reddish yellow firm
highly calcareous sandy medium clay with weak
coarse structure and 20-50% fine carbonate
segregations. Diffuse to:
90-130
Light yellowish brown and reddish yellow hard
moderately calcareous sandy medium clay with
weak coarse structure and 20-50% fine carbonate
segregations.
Classification:
Hypercalcic, Mottled-Mesonatric, Brown Sodosol; thin, non-gravelly, sandy / clayey, moderate
- 45 -
Summary of Properties
Drainage:
Imperfectly drained. Water perches on the surface of the subsoil clay, saturating the
lower topsoil and upper subsoil for periods of up to several weeks following heavy or
prolonged rainfall.
Fertility:
.The shallow clayey subsoil has high nutrient retention capacity. Test results indicate
possible deficiencies of copper, zinc and manganese. Regular phosphorus and
nitrogen applications are essential.
pH:
Slightly acidic at the surface, strongly alkaline with depth.
Rooting depth:
90 cm in pit, but roots below 55 cm are confined to macropores (old root channels).
Barriers to root growth:
Physical:
The hard, coarsely structured, dispersive subsoil confines most root growth to the
surfaces of the aggregates, resulting in poor root distribution patterns.
Chemical:
High pH and sodicity impede root growth below 30 cm.
Water holding capacity: Approximately 60 mm in the root zone, but not all available due to poor root
distribution in clay subsoil.
Seedling emergence:
Fair, due to tendency for surface to seal over. Water repellence may be a problem in
some seasons.
Workability:
Satisfactory.
Erosion Potential
Water:
Moderate. Soils with thin sandy surfaces and slowly permeable subsoil clays are
highly erodible. Even gentle slopes are vulnerable to sheet and rill erosion.
Wind:
Moderately low to moderate, depending on sandiness of surface
Laboratory Data
Depth
cm
pH
pH
H2O CaC12
CO3 EC 1:5 ECe Org.C Avail. Avail. Cl
SO4 Boron Trace Elements mg/kg Sum Exchangeable Cations Est
%
dS/m dS/m
%
P
K mg/kg mg/kg mg/kg
(EDTA)
cations
cmol(+)/kg
ESP
mg/kg mg/kg
cmol
Cu Fe Zn Mn (+)/kg Ca Mg Na
K
0-8
6.3
5.4
0
0.05
0.53
1.14
56
134
9
6.1
1.1
0.85 198 1.06 3.64
7.3
4.54 2.16 0.23 0.36
3.2
8-30
7.5
6.8
0
0.18
1.40
0.38
7
189
29
27
2.7
0.53
73
0.1 2.84
17.3
5.64 8.34 2.83 0.5
16.3
30-55
9.6
8.5
1
0.60
2.39
0.18
5
354
210
66
6.7
0.42
23
0.25 3.82
24.9
6.02 11.3 6.64 0.92 26.6
55-90
9.3
8.5
24
0.89
3.66
0.25
6
386
406
99
5.7
0.37
9
0.28 1.55
28.3
9.86 10.5 7.04 0.99 24.8
90-130
9.6
8.6
12
0.82
3.98
0.12
2
323
520
62
5.6
0.47
14
0.46 0.35
23.3
6.99 9.17 6.31 0.85 27.1
Note:
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a measure of the
soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is estimated by dividing the exchangeable sodium value by the sum of
cations.
Very low- may indicate deficiency and/or other limitations *
High reading- may indicate toxicity and/or other limitations*
*Note: Soil results are from a single point sample and are indicative only. They may not reflect the general
condition of the rest of the paddock. Also, plant responses relating to nutrition measurements can vary between
soil types and plant species, so values are indicative only.
- 46 -
Management of this soil type
Constraints:
• The major problem with this soil type is the shallow depth of the A horizon (topsoil) and the very hard sodic
subsoil layer that restricts root development.
• High pH and salinity at around 35 cm suggests a limitation that is further exacerbated with a carbonate layer from
55 cm that typically affects root development.
Management implications:
• The high cation exchange capacity and extractable potassium levels indicate the potential to build soil phosphorus
levels with fertiliser application in addition to immediate pasture or crop requirements.
• The trace element status for copper, zinc and manganese should be monitored with plant tissue analysis to ensure
potential crop yields are realised.
• Surface water drainage is desirable to maximise crop production in wet years.
- 47 -
SANDY LOAM OVER GREY BROWN CLAY
General Description:
Hard setting sandy to silty loam over a well structured grey
brown clay, calcareous with depth.
Landform:
Flats of ancient alluvial
plains.
Substrate:
Clayey sediments of Tertiary
age, mantled by fine
carbonates.
Vegetation:
Red gum (Eucalyptus
camaldulensis) woodland.
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE078
Wirrega
9
21/09/04
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-3 (Mundulla)
470850
5982650
450 mm
Lower slope of very gently undulating plain, 100 m from watercourse. Hard setting surface
with no stones.
Soil Description:
Depth (cm)
Description
0-8
Dark brown friable massive sandy loam. Abrupt
to:
8-15
Brown friable massive sandy clay loam. Abrupt
to:
15-40
Strong brown and dark greyish brown mottled
firm medium heavy clay with strong medium
polyhedral structure. Gradual to:
40-65
Light olive brown, brownish yellow and reddish
yellow hard medium heavy clay with strong
medium subangular blocky structure. Clear to:
65-95
Light yellowish brown and greyish brown very
hard, weakly structured and highly calcareous
heavy clay with 10-20% fine carbonate
segregations. Gradual to:
95-125
Light yellowish brown very hard highly
calcareous heavy clay with strong medium
angular blocky structure and more than 50% fine
carbonate segregations. Gradual to:
125-140
Pale olive and reddish yellow very hard highly
calcareous medium clay with strong coarse
angular blocky structure and more than
50% fine carbonate segregations.
Classification:
Hypercalcic, Mottled-Subnatric, Brown Sodosol; thin, non-gravelly, loamy / clayey, deep
- 48 -
Summary of Properties
Drainage:
Moderately well drained. Part of the profile remains saturated for a week or so
following heavy or prolonged rainfall.
Fertility:
Inherent fertility is moderately high, as indicated by the exchangeable cation data.
Concentrations of all measured nutrient elements are adequate.
pH:
Neutral at the surface, strongly alkaline with depth.
Rooting depth:
125 cm in pit, but few roots below 65 cm.
Barriers to root growth:
Physical:
The moderate strength of the clay subsoil restricts root densities to some extent.
Chemical:
High pH, boron levels and sodicity from 65 cm restrict root densities.
Water holding capacity: Approximately 90 mm in potential root zone.
Seedling emergence:
Fair, due to tendency for surface to seal and set hard if it dries out after initial rains.
Workability:
Fair. Surface tends to set hard and shatter when too dry, and puddles when wet.
Erosion Potential
Water:
Wind:
Low.
Low.
Laboratory Data
Depth
cm
pH
pH
H2O CaC12
CO3 EC 1:5 ECe Org.C Avail. Avail. Cl SO4-S Boron Trace Elements mg/kg Sum Exchangeable Cations Est.
%
dS/m dS/m
%
P
K mg/kg mg/kg mg/kg
(EDTA)
cations
cmol(+)/kg
ESP
mg/kg mg/kg
cmol
Cu Fe Zn Mn (+)/kg Ca Mg Na
K
0-8
6.8
6.7
0
0.17
0.71
3.48
133
797
26
16
1.6
2.46 367 5.36 16.8
14.1
8.47 3.11 0.49 2.03
3.4
8-15
6.5
6.1
0
0.20
1.16
1.64
53
806
48
19
2.2
1.69 250 2.08 39.7
17.2
10.0 4.5 0.64 2.04
3.7
15-40
8.7
7.6
0
0.28
1.49
0.70
13
1184
213
22
4.2
1.41
87
0.51 58.7
34.0
15.5 12.8 2.57 3.14
7.6
40-65
8.8
8.0
1
0.48
2.02
0.51
8
959
351
21
6.2
1.35
50
0.49 58.2
31.3
11.7 13.6 3.61 2.47 11.5
65-95
9.3
8.3
28
0.61
3.04
0.28
6
830
408
25
9.8
0.71
15
0.44 5.80
35.4
11.7 14.9 6.69 2.18 18.9
95-125
9.3
8.4
27
0.63
2.79
0.20
4
778
411
34
14.6
0.72
15
0.44 1.12
35.1
9.09 14.9 9.23 1.93 26.3
125-140
9.4
8.4
48
0.74
3.06
0.18
6
643
375
45
12.1
0.41
13
0.3 1.40
30.3
9.52 11.1 8.06 1.67 26.6
Note:
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a measure of the
soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is estimated by dividing the exchangeable sodium value by the sum of
cations.
Very low- may indicate deficiency and/or other limitations
*
High reading- may indicate toxicity and/or other limitations*
- 49 -
Management of this soil type
Constraints:
• The only problem with this soil type is the relatively shallow depth of the topsoil and the very hard sodic subsoil
layer that restricts root development and in wet years may be subject to waterlogging.
• An increase in salinity from 40cm that at around 65cm limits root development is further exacerbated with
increasing boron levels.
Management implications:
• The high cation exchange capacity and extractable potassium levels indicate the inherent fertility of this soil and
the potential to build soil phosphorus levels with fertiliser application in addition to the immediate pasture or crop
requirement.
• Surface water drainage alleviates the potential for crop losses on this highly productive soil type.
- 50 -
9
CRACKING CLAY
DARK CLAY LOAM OVER HEAVY CLAY
General Description: Dark clay loam over moderately structured dark brown medium heavy
clay, becoming calcareous and more coarsely structured with depth.
Landform:
Gently undulating rises.
Substrate:
Fine to medium grained
Tertiary sediments.
Vegetation:
Grey box, blue gum, bull
oak.
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE130
Tatiara
358
22/02/07
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-2 (Tatiara)
490900
5972830
450 mm
Midslope of gently undulating rise, 2% slope. Hard setting surface with no stones.
Soil Description:
Depth (cm)
Description
0-11
Very dark brown friable clay loam with moderate
platy structure. Surface sealing evident. Abundant
roots. Gradual to:
11-35
Dark brown firm medium heavy clay with strong
moderate subangular blocky structure. Many
roots. Gradual to:
35-60
Brown firm medium heavy clay with weak
moderate subangular blocky structure. Roots
common. Gradual to:
60-80
Pale brown firm moderately calcareous light
medium clay with weak coarse prismatic structure
and 10-20% carbonate veins. Few roots. Diffuse
to:
80-110
Very pale brown and reddish brown firm highly
calcareous light medium clay with weak, very
coarse lenticular, breaking to weak coarse angular
blocky, structure and 10-20% carbonate veins.
Very few roots. Diffuse to:
110-150
Very pale brown and reddish brown firm
moderately calcareous light medium clay with
moderate very coarse lenticular structure. No roots.
Classification:
Vertic, Calcic, Brown Dermosol; medium, non-gravelly, clay loamy / clayey, deep
- 51 -
Summary of Properties
Drainage:
Moderately well to imperfectly drained. Water is likely to perch on top of the clay
subsoil for a week to several weeks following heavy or prolonged rainfall.
Fertility:
Inherent fertility is high, as indicated by the exchangeable cation data and the high
extractable potassium. Phosphorus levels can accumulate with applications to become
adequate for most crops and pastures, although zinc, copper and manganese levels in
crops and pastures should be checked by plant tissue testing. High reactive iron
content in the surface indicates potential for phosphate fixation.
pH:
Slightly acidic to neutral at the surface, alkaline in the subsoil, and strongly alkaline
associated with salinity at depth.
Rooting depth:
80 cm in the sampling pit, but few roots below 60 cm.
Barriers to root growth:
Physical:
The coarseness of the clay aggregates will restrict root abundance in the subsoil.
Chemical:
High sodicity and boron levels from 60 cm, and high pH and salinity from 80 cm
significantly restrict root abundance. Severity of these deep subsoil constraints is
related to restricted drainage.
Water holding capacity: Approximately 80 mm total available water in the potential rootzone.
Seedling emergence:
Satisfactory.
Workability:
Satisfactory, although surface may become sticky and intractable when wet.
Erosion Potential
Water:
Low.
Wind:
Low.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe
Cl Org.C NO3 Avail. Avail. SO4-S React Boron
Trace Elements
Sum
Exchangeable
Est.
H2O CaC12 % dS/m dS/m mg/kg %
+
P
K mg/kg Fe mg/kg
mg/kg (EDTA)
cations Cations cmol(+)/kg ESP
NH4 mg/kg mg/kg
mg/kg
cmol
Cu Fe Mn Zn (+)/kg Ca Mg Na K
mg/kg
0-11
6.7
5.6
0
0.09
0.79
42
2.05
16
44
333
12.2
1246
1.9
1.3 215 53.3 0.6
16.6
11.7 3.31 0.77 0.85 4.6
11-35
8.0
6.8
0
0.13
1.38
73
0.66
6
5
154
17.7
1051
2.9
2.4 125 37.8 3.1
24.8
12.3 8.71 3.37 0.41 13.6
35-60
9.1
8.4
1
0.49
2.27
330
0.36
6
3
217
78
705
10.0
1.7
55 75.0 0.8
33.6
11.7 13.3 8.07 0.62 24.0
60-80
9.2
8.6
12
0.88
3.78
733
0.18
6
2
289
190
555
17.7
1.2
16
2.9 0.5
40.4
10.9 16.4 12.2 0.86 30.2
80-110
9.3
8.7
6
0.84
6.38
1189
0.15
6
2
305
231
505
18.7
0.9
17
3.0 0.2
40.0
10.3 16.3 12.5 0.83 31.2
110-150
9.2
8.7
14
1.08
6.29
1480
0.13
4
2
304
225
489
17.7
1.2
17
1.8 0.1
43.1
11.8 16.2 14.1 0.9 32.8
Note:
Sum of cations, in a neutral to alkaline soil, approximates the CEC (cation exchange capacity), a
measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC,
in this case estimated by the sum of cations.
Very low- may indicate deficiency and/or other limitations
*
High reading- may indicate toxicity and/or other limitations*
- 52 -
Management of this soil type
Constraints:
• The major physical problem associated with this soil type is waterlogging in above average rainfall
years.
• At this site salinity and boron become a potential problem at approximately 35cm.
While the exchangeable sodium percentage is relatively high and there is potential for structural problems
affecting workability, the high organic matter ameliorates the problem.
Management implications
• Surface water drainage alleviates the potential for crop losses on this highly productive soil type.
• With continued cultivation and reduction in organic matter, gypsum applications may be required to
address the structural decline.
• Trace element nutrition, particularly zinc should be monitored.
- 53 -
DARK GREY CRACKING CLAY
General Description: Dark grey to black self-mulching and cracking clay
Landform:
Elevated very gently
undulating plains and low
lying alluvial flats. Crabholes
(gilgai) are common.
Substrate:
Pleistocene clays
(Blanchetown Clay
equivalent)
Vegetation:
Open woodland of bulloak
and box
Type Site:
Site No.:
Hundred:
Section:
Sampling date:
SE003
Tatiara
Racecourse
23/01/91
1:50,000 sheet:
Easting:
Northing:
Annual rainfall:
7025-2 (Tatiara)
480350
5982050
500 mm
Alluvial flat, 0% slope. Self-mulching, cracking surface.
Soil Description:
Depth (cm)
Description
0-2
Very dark grey strongly granular medium clay
(self-mulching). Abrupt to:
2-20
Dark grey moderately subangular blocky medium
clay. Gradual to:
20-40
Grey moderately subangular blocky medium heavy
clay. Gradual to:
40-60
Dark grey moderately angular blocky moderately
calcareous heavy clay. Gradual to:
60-100
Brownish grey strongly angular blocky,
moderately calcareous heavy clay. Gradual to:
100-150
Light grey strongly angular blocky highly
calcareous medium clay (Class I carbonate layer).
Classification: Epicalcareous-Endohypersodic, Self-mulching, Grey Vertosol; non-gravelly, medium fine /
very fine, deep
- 54 -
Summary of Properties
Drainage
Imperfectly drained. Soil may remain wet for some weeks, due to its high clay content
and low lying position.
Fertility
Natural fertility is very high, as indicated by the CEC values throughout the soil. The
only likely deficiency (apart from phosphorus - highly deficient at time of sampling and nitrogen) is zinc, which is low at the type site and is commonly deficient on clay
soils.
pH
Slightly alkaline at surface, strongly alkaline with depth.
Rooting depth
100 cm in pit.
Barriers to root growth
Physical:
No physical limitations apart from possible damage to roots from cracking.
Waterlogging will retard root growth in wet years.
Chemical:
Class I carbonate layer and excessive boron from 100 cm limit root growth.
Water holding capacity 150 to 200 mm in root zone (very high).
Seedling emergence
Good, provided that self-mulching surface is maintained.
Workability
Fair. Soil becomes sticky and boggy when wet.
Erosion Potential
Water:
Wind:
Low.
Low.
Laboratory Data
Depth
cm
pH
pH
CO3 EC1:5 ECe Org.C Avail. Avail. SO4 Boron Trace Elements mg/kg CEC
H2O CaC12 %
dS/m dS/m
%
P
K mg/kg mg/kg
(DTPA)
cmol
mg/kg mg/kg
(+)/kg
Cu Fe Mn Zn
Exchangeable Cations
ESP
Cl
mg/kg
cmol(+)/kg
Ca
Mg
Na
K
0-20
7.9
7.8
<0.1
0.19
-
1.7
9
550
-
3.1
0.5 14.9 3.1
0.3
36.0
25.3
8.1
0.5
2.0
1
78
20-40
8.2
7.9
3.3
0.21
-
0.8
4
420
-
4.6
0.6 13.3 3.8 <0.1
36.9
22.4
11.5
1.5
1.7
4
83
40-60
8.9
8.3
10.1
0.32
-
0.3
<2
440
-
10.4
0.7
9.1
38.2
16.9
15.1
4.4
1.8
12
74
60-100
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
-
100-150
9.1
8.4
21.1
0.39
-
0.2
3
450
-
23.7
0.6
8.8
39.2
12.4
16.7
7.3
1.9
19
87
Note:
1.6 <0.1
-
-
1.2 <0.1
CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.
ESP (exchangeable sodium percentage) is derived by dividing the exchangeable sodium value by the CEC.
Very low- may indicate deficiency and/or other limitations *
- 55 -
High reading- may indicate toxicity and/or other limitations*
Management of this soil type
Constraints:
• The major physical problem associated with this soil type is waterlogging in above average rainfall
years.
• At this site boron toxicity may become a potential problem associated with carbonate and elevated pH
at approximately 40cm.
• Low extractable phosphorus would limit plant production.
Management implications:
• Surface water drainage alleviates the potential for crop losses on this highly productive soil type.
• This site would be highly responsive to applied phosphorus due to the low soil P status and have the potential for
high levels of accumulated phosphorus in response to fertilizer application in addition to immediate crop or
pasture requirements.
• Trace element nutrition should be monitored. Zinc levels are low and depending on the crop grown and the
particular susceptibility of that crop the pH can induce manganese, iron and zinc deficiencies but copper should
also be monitored.
- 56 -