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Funded by Caring for our Country and Dept. Water land and Biodiversity Conservation Managed by ABA and MacKillop FMG

The Soil Book- Representative soils of the Upper SE

Produced from work by DWLBC and RSSA staff

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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

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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.

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2 INTERPRETING SOIL TESTS

SOIL TEST METHODS & GUIDELINES SOIL TEST METHODS & GUIDELINES SOIL TEST METHODS & GUIDELINES SOIL TEST METHODS & GUIDELINES

FOR INTERPRETATION OF SOIL FOR INTERPRETATION OF SOIL FOR INTERPRETATION OF SOIL FOR INTERPRETATION OF SOIL

RESULTSRESULTSRESULTSRESULTS

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

Moderately acidic 5.5 - 6.4 Moderately alkaline 7.6 - 8.3

Slightly acidic 6.5 - 6.9 Strongly alkaline ≥ 8.4

Neutral 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 Crops

Non-calcareous Calcareous

Pastures Potatoes Other Vegetables

Vines/apples

Very Low <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 >80

High >45 >45 >45 >100 >150

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

Low <80 <120 <150

Marginal 80 - 120 120 - 250 150 – 250

Adequate 120 - 250 >250 >250

High >250

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EXTRACTABLE SULPHUR (mg/kg) (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.

Criteria ( for permanent pastures)

Low <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 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 1.2 - 2.0 >2.0

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

High salinity >16

Use the salinity fact sheet for the tolerance of various crops and pastures

FREE LIME 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

MODERATE HIGH Calcareous VERY HIGH

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.

ION-EXCHANGE PROPERTIES 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.

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.

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.

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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 65 – 75%

Exch. Magnesium 10 – 15%

Exch. Sodium 0 – 4%

Exch. Potassium 3 – 8%

Exch. Aluminium 0 – 5%

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: <6% non sodic

6-15% sodic

>15% strongly sodic

If soils are sodic or strongly sodic and disperse, an application of gypsum should improve stability in the short term.

EXTRACTABLE TRACE ELEMENTS (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.

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) Extracted with 1:5 soil/water for one hour.

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

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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.

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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.

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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.

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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

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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.

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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.: SE051 1:50,000 sheet: 7024-4 (Keppoch)

Hundred: Beeamma Easting: 472750

Section: 31 Northing: 5957950

Sampling date: 1/2/96 Annual rainfall: 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

4 DEEP SAND

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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

Water: Moderately low.

Wind: Moderately high.

Laboratory Data

Trace Elements mg/kg (DTPA)

Exchangeable Cations

cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Mn Zn

CEC cmol

(+)/kg

Ca Mg Na K

ESP

Paddock 6.4 5.6 0 0.03 0.27 0.7 9 58 4 0.7 0.21 12 2.27 1.09 2.6 2.16 0.37 0.10 0.08 na

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: 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*

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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.

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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 1:50,000 sheet: 7025-4 (Cannawigara)

Hundred: Cannawigara Easting: 471500



Slope of a gently undulating rise, with a gradient of 2%. Soft water repellent surface.

Soil Description:


0 - 10 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

5 SAND OVER CLAY

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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.


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



cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Mn Zn

CEC cmol

(+)/kg

Ca Mg Na K

ESP

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: CEC (cation exchange capacity) is a measure of the soil's capacity to store and release major nutrient elements.



- 18 -


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.


• 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



• 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.

- 19 -

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.: SE043 1:50,000 sheet: 6925-1 (Keith)

Hundred: Stirling Easting: 446550



Lower slope of undulating rise, 3% slope. Soft surface.

Soil 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.

- 20 -


Drainage Rapidly drained. The soil is unlikely to remain wet for more than a few hours.

Fertility 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.

pH Slightly acidic in the surface, slightly alkaline in the deep subsoil.

Rooting depth 110 cm, but few roots below 70 cm.


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


Wind: Moderate, due to sandy water repellent surface.

Laboratory Data



cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Mn Zn

CEC cmol

(+)/kg

Ca Mg Na K

ESP

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




- 21 -


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.


• 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.

- 22 -

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.





Lower slope of gently undulating rises, 1% slope. Soft surface with no stones.

Soil 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 strong coarse

angular blocky structure 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

- 23 -

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:

Physical: The moderate strength of the clay subsoil restricts root densities.

Chemical: There are no apparent chemical barriers to root growth, apart from low nutrient

availability.

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


Wind: Moderate.

Laboratory Data

Trace Elements

mg/kg (EDTA)

Exchangeable

Cations cmol(+)/kg

Depth

cm

pH

H2

O

pH

CaC1

2

CO3

%

EC

1:5

dS/m

ECe

dS/m

Org.

C

%

Avail

.

P

mg/k

g

Avail

. K

mg/k

g

Cl

mg/k

g

SO4-

S

mg/k

g

Boro

n

mg/k

g Cu Fe Zn Mn

Sum

cation

cmol

(+)/kg Ca Mg Na K

Est

ESP

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 5.3 9.12 1.97 1.1 11.3

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: 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.


- 24 -


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.


• 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



• The challenge is to improve the subsurface profile. With delving, clay is dragged into and through this soil layer




into the clay layer.

- 25 -

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:





Flat on very gently undulating plain. Loose surface with no stones. Delved to 45 cm.

Soil Description:


0-12 Very dark greyish brown loose loamy sand with

fragments of clay. Abundant roots. Sharp to:

12-14 Bleached friable massive sand, following columns

to depth (~50 cm). Roots common. Abrupt to:

14-40 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:

40-54 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:

54-80 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:

80-130 Light yellowish brown hard calcareous sandy light

medium clay with coarse prismatic structure,

breaking to medium angular blocky. Very few

roots. Diffuse to:

130-160 Yellowish brown hard sandy light clay with weak

coarse prismatic structure. No roots.

Classification: Hypercalcic, Mottled-Mesonatric, Brown Sodosol; medium, non-gravelly, sandy / clayey, deep

- 26 -

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: Low.

Wind: Moderate.

Laboratory Data

Trace Elements

mg/kg (EDTA)

Exchangeable

Cations

cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC1

2

CO3

%

EC1:

5

dS/m

ECe

dS/m

Cl

mg/k

g

Org.

C

%

NO3

+

NH4

mg/k

g

Avail

.

P

mg/k

g

Avail

. K

mg/k

g

SO4-

S

mg/k

g

Reac

t Fe

mg/k

g

Boro

n

mg/k

g Cu Fe Mn Zn

Sum

cations

cmol

(+)/kg Ca Mg Na K

Est.

ESP

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.


- 27 -


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


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.




- 28 -

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.: SE122 1:50,000 sheet: 7025-2 (Tatiara)

Hundred: Tatiara Easting: 483906



Crest of low rise on gently undulating plain. Soft surface with no stones. Paddock delved to 30 cm.

Soil Description:


0-8 Very dark grey brown friable sandy loam with 10-

20% (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

- 29 -

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.


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: Low.

Wind: Moderately low, but delved clay fragments help to stabilize natural surface.

Laboratory Data

Trace Elements

mg/kg (EDTA)

Exchangeable

Cations

cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC1

2

CO3

%

EC1:

5

dS/m

ECe

dS/m

Cl

mg/k

g

Org.

C

%

NO3

+

NH4

mg/k

g

Avail

.

P

mg/k

g

Avail

. K

mg/k

g

SO4-

S

mg/k

g

Reac

t Fe

mg/k

g

Ext

Al

mg/k

g

Boro

n

mg/k

g Cu Fe Mn Zn

Sum

cation

s cmol

(+)/kg Ca Mg Na K

Est.

ESP

0-8 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 10.

7 0.2 18.8 3.55 9.19 5.07 1.01 26.9

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

85-

140 9.0 8.2 0 0.73 3.51 465 0.25 3 2 393 80.9 361 0 7.5 0.3 26

15.

3 0.2 22.2 2.45 10.1 8.63 1.03 38.9

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-

30** 5.7 4.3 0 0.03 0.55 16 1.61 3 24 54 8.9 672 4.7 0.7 0.2 255 1.9 0.1 3.6 2.38 0.81 0.32 0.1 8.8





* 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*

- 30 -


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.


• 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



• The challenge is to improve the subsurface horizons. With delving, clay is dragged into and through this soil layer



- 31 -

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:





Slope (1%) on very gently undulating plain. Soft surface with no stones. Paddock delved to 45 cm.

Soil 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

- 32 -


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.


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.


Workability: Good.

Erosion Potential

Water: Low.

Wind: Moderately low due to relatively low clay content of surface soil.

Laboratory Data

Trace Elements

mg/kg (EDTA)

Exchangeable

Cations cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC12

CO3

%

EC1:5

dS/m

ECe

dS/m

Cl

mg/kg

Org.C

%

NO3

+

NH4 mg/kg

Avail.

P

mg/kg

Avail.

K

mg/kg

SO4-S

mg/kg

React

Fe

mg/kg

Ext

Al

mg/kg

Boron

mg/kg

Cu Fe Mn Zn

Sum

cations

cmol (+)/kg Ca Mg Na K

Est.

ESP

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 6.7 0.2 15.9 9.81 4.57 0.36 1.12 2.3







# Clay under delve line

- 33 -

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:


Hundred: Pendleton Easting: 459690



Level plain, 0% slope. Soft surface with minor calcrete stones. Paddock delved to 40 cm.

Soil 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

6 SHALLOW SAND OVER CLAY ON CALCRETE

- 34 -

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.


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: Low.

Wind: Moderate if surface vegetation cover is removed and the surface is allowed to dry out.

Laboratory Data

Trace Elements mg/kg (EDTA)

Exchangeable Cations cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC 1:5

dS/m

ECe dS/m

Cl mg/kg

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4-S mg/kg

Boron mg/kg

React Fe

mg/kg Cu Fe Mn Zn

Sum cations

cmol

(+)/kg Ca Mg Na K

Est. ESP

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









- 35 -


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.


• 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.

- 36 -

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.: SE052 1:50,000 sheet: 7024-4 (Keppoch)

Hundred: Beeamma Easting: 472350



Swale between sandhills, 2% slope. Firm surface with no stones.

Soil 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 2-

10% 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

7 SHALLOW RED LOAM ON CALCRETE

- 37 -


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).


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).


Workability: The firm surface is easily worked.

Erosion Potential

Water: Low.

Wind: Low.

Laboratory Data



cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Mn Zn

CEC cmol

(+)/kg

Ca Mg Na K

ESP

Paddock 5.8 5.2 0 0.08 0.62 1.9 14 182 9 1.6 0.40 135 8.34 0.62 9.3 7.02 0.77 0.14 0.34 1.5

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: 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.




- 38 -


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.


• 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.

- 39 -

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.: SE015 1:50,000 sheet: 7025-3 (Mundulla)

Hundred: Wirrega Easting: 472450



Lower slope of low rise, adjacent to swampy flat. Firm surface, with 6% slope.

Soil 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

8 LOAM OVER CLAY

- 40 -

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.

Chemical: 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.

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.

Wind: Moderately low, depending on the degree to which the surface has been pulverized.

Laboratory Data



cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Mn Zn

CEC cmol

(+)/kg

Ca Mg Na K

ESP

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




- 41 -


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.



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.


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






- 42 -

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



Section: Racecourse Northing: 5981850


Lower slope of low rise, 3% slope. Firm surface.

Soil 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

- 43 -

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


Wind: Low.

Laboratory Data

Trace Elements mg/kg

(DTPA)


cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC12

CO3

%

EC1:5

dS/m

ECe

dS/m

Org.C

%

Avail.

P mg/kg

Avail.

K mg/kg

SO4

mg/kg

Boron

mg/kg

Cu Fe Mn Zn

CEC

cmol (+)/kg

Ca Mg Na K

ESP Cl

mg/kg

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 0.5 <0.1 27.7 4.8 12.8 7.0 1.2 25 587




- 44 -

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.


• 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.


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.

- 45 -

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.





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:


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

- 46 -

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).


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

Trace Elements mg/kg (EDTA)

Exchangeable Cations cmol(+)/kg

Depth cm

pH H2O

pH CaC12

CO3 %

EC 1:5 dS/m

ECe dS/m

Org.C %

Avail. P

mg/kg

Avail. K

mg/kg

Cl mg/kg

SO4 mg/kg

Boron mg/kg

Cu Fe Zn Mn

Sum cations

cmol

(+)/kg Ca Mg Na K

Est ESP

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




cations.


*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.

- 47 -


• 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.


• 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.

- 48 -

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.: SE078 1:50,000 sheet: 7025-3 (Mundulla)

Hundred: Wirrega Easting: 470850



Lower slope of very gently undulating plain, 100 m from watercourse. Hard setting surface

with no stones.

Soil 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

- 49 -

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.


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: Low.

Wind: Low.

Laboratory Data


(EDTA)


cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC12

CO3

%

EC 1:5

dS/m

ECe

dS/m

Org.C

%

Avail.

P mg/kg

Avail.

K mg/kg

Cl

mg/kg

SO4-S

mg/kg

Boron

mg/kg

Cu Fe Zn Mn

Sum

cations cmol

(+)/kg Ca Mg Na K

Est.

ESP

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




cations.



- 50 -


• 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.



the potential to build soil phosphorus levels with fertiliser application in addition to the immediate pasture or crop

requirement.


- 51 -

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.





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

9 CRACKING CLAY

- 52 -

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.


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.


Workability: Satisfactory, although surface may become sticky and intractable when wet.

Erosion Potential

Water: Low.

Wind: Low.

Laboratory Data

Trace Elements

mg/kg (EDTA)

Exchangeable

Cations cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC12

CO3

%

EC1:5

dS/m

ECe

dS/m

Cl

mg/kg

Org.C

%

NO3

+

NH4

mg/kg

Avail.

P

mg/kg

Avail.

K

mg/kg

SO4-S

mg/kg

React

Fe

mg/kg

Boron

mg/kg

Cu Fe Mn Zn

Sum

cations

cmol

(+)/kg Ca Mg Na K

Est.

ESP

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







- 53 -


• 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.



• 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.

- 54 -

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



Section: Racecourse Northing: 5982050


Alluvial flat, 0% slope. Self-mulching, cracking surface.

Soil 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

- 55 -

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.


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: Low.

Wind: Low.

Laboratory Data


(DTPA)


cmol(+)/kg

Depth

cm

pH

H2O

pH

CaC12

CO3

%

EC1:5

dS/m

ECe

dS/m

Org.C

%

Avail.

P

mg/kg

Avail.

K

mg/kg

SO4

mg/kg

Boron

mg/kg

Cu Fe Mn Zn

CEC

cmol

(+)/kg

Ca Mg Na K

ESP Cl

mg/kg

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 1.6 <0.1 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 1.2 <0.1 39.2 12.4 16.7 7.3 1.9 19 87




- 56 -


• 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.



• 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.

the soil book-€¦ · the ratio of exch. potassium exch. calcium + exch. magnesium can be used as...

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