SM150 User Manual 1
Appendix 1
35
Appendix 1
Soil-specific Calibration
This note provides details of 2 techniques for generating soil-
specific calibrations:
Laboratory calibration for substrates
*
and non-clay soils
Laboratory calibration for clay soils
*
We use the term substrate to refer to any artificial growing
medium.
Underlying principle
Soil moisture content (
) is proportional to the refractive index of the
soil (
) as measured by the
SM150
(see
Calibration
section).
The goal of calibration is to generate two coefficients (
a
0
,
a
1
) which can be
used in a linear equation to convert probe readings into soil moisture:
1
0
a
a
