2017-05-30
TRIME
®
-PICO IPH Version 2_0
Page 19
Figure 4 :
Comparison of neutron probe and TRIME-T3 for water content determinations an illitic clay.
Some materials, especially very clayey soils and soils with high organic contents, can afford ma-
terial specific calibrations due to their different dielectric behaviour.
A limiting factor in TDR measuring is the electrical conductivity. For the TRIME-PICO IPH tube
probe, the pore water conductivity should not exceed 15 dS/m. Note that bulk soil electrical
conductivity is a combination of the pore water electrical conductivity and the surface conductiv-
ity of the soil matrix. Due to the tortuous nature of the conductivity path in the soil (soil type
dependent), the bulk soil conductivity is much lower than the electrical conductivity of the pore
water and it is dependent on water content.
7.4
Summary
The TRIME-PICO IPH tube probe is a promising new tool for determining water content profiles
with the TDR method. Fast, routine and non destructive measurements of water content without
the use of hazardous radioactive materials are possible. A measuring accuracy of
2 vol.-% is
possible, provided that soil and access tube are in close contact and pore water conductivity
doesn’t exceed 15 dS/m.
