1. Soil Testing Methods
Chapter 8

2. Three approaches Observations in the field On‑site measurements
Laboratory measurements
Soil Analysis Ch 8

3. Field Observations
Field observations of properties which can be observed after digging a soil pit
Semi‑quantitative assessments of properties rather than direct measurements.
Soil Analysis Ch 8

4. Field Measurements
On‑site measurements using equipment inserted into soil, without significant disturbance of the soil.
This approach applies particularly to soil water studies.
Soil Analysis Ch 8

5. Laboratory Analysis
Measurements made in the laboratory on soil samples taken from the field.
Sub-sampling down to an analytical sample also occurs
Soil Analysis Ch 8

6. Soil Survey Reports what kinds of soil exist in an area
described in terms of location, profile characteristics, relationship to each other, suitability for various uses, and needs for particular kinds of management
two major parts in a soil survey report:
the soil map
the narrative
Soil Analysis Ch 8

7. SALIS NSW soil survey database Soil And Land Information Service
run by Dept of Natural Resources
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8. Field Analysis of Soils
How can we Analyse Soil in the Field?

9. Field investigation soil pits expose the soil profile and horizons
allow field testing of parameters that would be destroyed by cores
in-situ testing devices
semi-quantitative assessments
field data minimises sampling error
does not guarantee reliable or even consistent data
soils have very poor homogeneity
Soil Analysis Ch 8

10. Soil Pit
from
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11. Choosing Sites for Soil Pits
Avoid
areas close to gateways, paths and tracks
headlands of arable fields (the outer 10 m)
sites where straw or fertiliser have been stored
sites used for localised burning of crop residues or hedge trimmings
old field boundaries where a hedge or bank has been removed and the land levelled
Soil Analysis Ch 8

12. Choosing Sites for Soil Pits
soil varies spatially (from one place to another)
some properties vary in time
eg nutrient levels, moisture
others are more permanent
horizon depth, texture, stone content and ion exchange capacity
Soil Analysis Ch 8

13. Is it just digging holes?
How do we Sample Soil?
Is it just digging holes?

14. Sampling questions How many samples do I take?
Do we composite lots of sub samples?
How deep do we take the samples?
Do we replicate the sampling?
What quality control do we need?
What tools do I need?
How do we transport, store and prepare the samples?
Soil Analysis Ch 8

15. Information we need to know
Why are we analysing the soil?
Surveys, chemical analysis etc.
How large is the area of interest?
Large areas require lots of sampling
Do we now the soil profile at all?
If we don’t, how deep do we sample?
What are we analysing the soil for?
Physical, chemical or biological parameters
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16. Amount of sample depends upon; Time constraints Topography
Cost factors
Reasons for sampling
There are no specific guidelines
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17. Soil Sampling undisturbed stratification:
remove a core with all horizon information retained, eg with auger
disturbed stratification
no attempt to keep the vertical connection between horizons, eg with a shovel
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18. Soil Sampling How many samples do we take?
At least 20 single samples per m2 must be taken with an earth boring tool (or spade) and combined to a mixed sample.
To what depth do we sample?
The usual sampling depth is up to 20 cm in arable land or 10cm in pasture. Undisturbed soil samples are obtained with a cutting cylinder with minimum capacity of 100cm3 .
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19. How do we sample? test lot diagonal line cross line random
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20. Sampling using Augers
pressed and rotated into the soil to take samples from depth increments of between 15 and 20cm.
samples are 'disturbed' to varying degrees
observations that can be made on the samples will be restricted
colour, texture, stones, roots and horizon depth can be recorded
soil structure cannot
special coring equipment is required to obtain 'undisturbed' samples
Soil Analysis Ch 8

21. Sampling for lab testing
normal sampling depth for horticultural and tree crops is 0-15 cm
deep sampling down to cm may be necessary to better assess soil salinity, acidity, S, and mineral N status
sampling depth must be recorded
protocols relevant to important crop and soil tests should be followed
usually involves making a composite from around 15 to 30 sub-samples from the area in question
Soil Analysis Ch 8

22. Transportation, preparation and storage of samples
Now that you have your soil samples, what do you do with them?

23. Laboratory Preparation of Samples
should be kept cool or cold between during transport
may be air-dried remote from the laboratory (max. 40C) when moisture content is not required
breaking up any large cores or peds on a clean surface
remove rocks by hand or sieving
retain a representative portion in a sealed polyethylene bag or 'moisture container' for moisture determination
sample size reduction: coning and quartering or riffler
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24. Laboratory Preparation of Samples
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25. Laboratory Preparation of Samples
Next spread the soil samples on drying trays (if applicable) and air-dry at up to 40C.
When the soil is thoroughly air-dry, mix, roll, and/or grind.
Retain the <2mm fraction, preferably in an air-tight plastic or inert container, for subsequent laboratory analyses.
Soil Analysis Ch 8

26. Laboratory Preparation of Samples
When required, determine the weight percentage (oven-dry basis) of the residual >2-20 mm size fraction.
When fine grinding is specified, take a representative sub-sample (usually around 30g) from the <2 mm portion.
Pass the entire sub-sample through the required mill and store in a small air-tight container.
Soil Analysis Ch 8

27. Coning & quartering
Soil Analysis Ch 8

28. Riffling
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