Download Here is a list of soil tests

Soil testing
Soil property
Field tests which provide
information
Off-site tests which provide
information
Colour
Observation
Colour charts
Depth
Tape measure or ruler to
measure horizons in exposed
profile or auger core
Texture
Field texture assessment
Structure
Observation
Aggregate stability
Test in water and gypsum
Organic matter
content
Observation
Colour
Drainage & aeration
Texture/structure
Compaction
Colour
Water in a hole (time to drain
away)
Leaching
Texture
Horizon
Colour
Waterlogging
Texture
Horizon
Colour
Erodability
Texture /Structure
Organic matter content
Aggregate stability
Water holding
capacity
Estimate from texture
RAW
Water infiltration
Infiltration rate
Particle analysis
Organic Carbon content
Weigh and dry, reweigh
Acidity or alkalinity
pH colorimetric kit
pH meter or Ca Cl2 test
Fertility
Parent material
Texture
Organic matter content
Individual nutrient levels assayed
Salinity
Cation Exchange Capacity CEC
Electrical Conductivity EC
Nutrient availability
pH
Nutrient balance
Susceptibility to
compaction
Structure
Texture
Presence of
compaction
Screwdriver test
Bulk density
Soil contamination,
toxicity
Bulk density
Specific chemical tests
Additional soil tests
Carbonate testing
As you saw in the first section on Soil classification, the Gradational group in the Northcote
System is subdivided according to whether the soil is calcareous or not.
Calcareous means that a form of calcium carbonate is present. This may come from some
sort of limestone parent material or it may be injected into the rocks after they form and be
present in the soil as nodules.
The test for the presence of calcareous deposits is simple. A few mm of dilute acid (such as
HCl Hydrochloric acid) is dripped onto a sample of the soil and if effervescence occurs
(fizzing and bubbling) it indicates the presence of CaCO3, with CO2 being driven off as a gas.
Remember that acid will burn. Use cautiously, wear gloves, protect eyes from splash, and
place the soil sample in a saucer or similar container that will not itself react with the acid.
Dispose of the tested sample in a safe place.
Salinity
When the Ec is low it means general nutrient levels are low. If the Ec is high then the soil
may be saline, containing sodium chloride salt, or it may contain soluble salts other than
sodium chloride. This can be the result of overfertilising.
Sodicity
Sodic soils have sodium ions attached to the clay particle.
When the soils are wet this causes the particles to move away from each other, so the soil
disperses. You have seen this in the aggregate stability test (see 1618C).
Dispersion is caused by an interaction between the sodium ions and the particular type of
clay. The sodium displaces other useful ions such as K+, Ca++, NH4+, Zn++, Cu++ etc and then
destroys the soil structure.
When the water evaporates, the individual particles of soil settle into a compacted
impenetrable mass, causing waterlogging, poor infiltration and hard-setting crusts.
Gypsum can help ameliorate these soils, but is not economical for large areas.
Understanding off-site soil test results
The following figures indicate generally acceptable levels for various soil tests.
These figures are guidelines only and interpretations will vary depending upon soil type, soil
history, sampling methods and requirements of particular plant species.
Generally acceptable levels for various soil tests
Off-site soil test
pH (CaCl2 test)
Organic Carbon
Total Nitrogen N
Available Sulphur S
Phosphorus P
Cation Exchange Capacity CEC
Sodium levels
Aluminium levels
Calcium; Magnesium
Ca:Mg
Chloride levels and Electrical
Conductivity EC
Purpose
pH between 5-7 ideal for most
plants
7 = neutral
Estimate of this indicates %
Organic matter in soil
Meaning of results
PH can be adjusted to suit plant
requirements
%C x factor dependent on
method used = % OM
Aim for 2% OM
Major nutrients required
200-300 kg N/ha is considered
adequate
5-10 mg S/kg soil
20-35 mg P/kg soil is
considered a medium level
The higher the clay and/or
Desirable ranges for % cations:
organic matter content of the
Ca
65-80%
soil, the higher is the colloid
Mg
10-15%
level and the CEC.
K
1-5 %
Al
< 5%
Na
< 5%
If Na is more than 6% the soil becomes dispersive and should
respond to gypsum.
If Al is more than 5% toxicity starts to affect growth of sensitive
plant species. Apply lime to raise pH above 5, the point where Al
is no longer available as a cation.
This ratio should be 2:1. Higher Magnesium levels can cause a
dispersive effect similar to Sodium.
These are measures of salinity. There is a risk of salinity if Cl levels
> 300mg/kg soil, or if EC is more than 2 dS/m.