SM150T User Manual 1.0
48
provides two dielectric values,
w
and
m
,
at two known water contents,
w
and
m
For the wet
soil
Substituting Vw = 0.349 gives
√𝜀
𝑤
= 3.83 = 𝑎
0
+ 𝑎
1
. 𝜃
for
𝜃
𝑤
=
(743.3−627.2)
463.5
= 0.25
For the moist
soil
Substituting Vm = 0.180 gives
√𝜀
𝑚
= 2.84 = 𝑎
0
+ 𝑎
1
. 𝜃
f
or
𝜃
𝑚
=
(693.2−627.2)
463.5
= 0.14
Calculate
a
1
Then
𝑎
1
=
√𝜀
𝑤
− √𝜀
𝑚
𝜃
𝑤
−𝜃
𝑚
= 9.0
a
1
= 9.00
Calculate
a
0
and
𝑎
0
= √𝜀
𝑤
− (𝑎
1
. 𝜃
𝑤
) =
1.58
a
0
= 1.58
Result
a
1
= 9.00
a
0
= 1.58
In this example this soil is now calibrated.
You can now use these two numbers in place of the standard mineral or
organic calibration factors to convert SM150T readings into volumetric water
content
θ
using:
1
0
a
a
on page 42
