Appendix A
Laboratory calibration non-clay soils
This is the easiest technique, but it’s not suitable for soils that shrink or
become very hard when dry.
Equipment you will need:
ThetaProbe and meter
Soil corer (if doing a calibration for a cohesive soil rather than sand
or a substrate)
Heat-resistant beaker (
≥
500ml)
Weighing balance (accurate to < 1g)
Temperature controlled oven (for mineral soils or substrates)
Process
Notes and example
Collect a damp sample of the soil or substrate.
This sample needs to be unchanged from its in-situ
density, to be
≥
500ml, to have the correct
dimensions to fit the beaker, and to be generally
uniform in water content.
For cohesive soils this is most easily done with a
soil-corer.
Sandy soils can be poured into the beaker, but you
should take the subsequent measurements
immediately, as the water will quickly begin to drain
to the bottom of the beaker.
Compressible soils and composts often require
measurement of the in-situ density and then need to
be carefully reconstituted at that density within the
beaker.
Measure the volume occupied by the sample.
= 463.5
ml
L
s
Weigh the sample, including the beaker
.
= 743.3
g
W
w
Profile Probe User Manual
3.0a
Soil-specific calibration
z
35
