SOIL
WATER, SALINITY AND OXYGENATION STATUS MONITORING DEVICES
from
INSTITUTE of AGROPHYSICS, POLISH ACADEMY of SCIENCES
The following measuring devices are intended
for the determination of:
- water content by
means of Time-Domain Reflectometry (TDR)
method, |
| - salinity (bulk
electrical conductivity) of soils by means of TDR, |
| - temperature of the
soil, |
| - soil water
capillary pressure (suction force), |
| - redox potential of
platinum electrode in the soil. |
The TDR-based solutions are
worldwide patented. There are three types of meters available:
Also adequate kinds of probes are
offered: Field Probe (FP) and Laboratory Probe (LP) respectively.
FOM
is hand-held, battery operated, microprocessor controlled
device designed for in situ field measurements of soil
moisture, temperature and salinity. It is particularly suitable
for periodic measurements at random and/or fixed locations, where
water content, temperature and salinity distribution is to be
determined by readings taken at various levels of the soil
profile.
FP is
a probe for momentary or for semipermanent installation. Through
a preaugered pilot hole it can reach any depth down to 4 m
without destroying either the soil structure or disturbing the
heat and mass transport in the soil. It can be left then intact
for as long period of time as needed.
A single probe may also be used
for momentary measurements in shallow layers of the soil profile
by walking over the field and inserting the probe in chosen sites.
For semipermanent installation,
when deeper layers are to be monitored, several FPs can be
inserted from the soil surface or horizontally through a side
wall of a soil pit. A probe installed once may be left intact in
the soil for as long as necessary and then drawn out at the end
of the experiment.
FOM/mts
- field operated meter for simultaneous measurements of the soil
moisture, temperature and salinity (bulk electrical conductivity). FOM/mts is provided with a
160 by 128 dot matrix graphic LCD to
display data and TDR trace simultaneously. Also adequate probes
are offered:
FP/m - field probe for measurements of
soil moisture,
FP/mts
- field probe for simultaneous measurements of soil moisture,
temperature and salinity.
LOM is
an IBM PC compatible aided device working under control of a
special software. It has been designated mainly to control long
term laboratory experiments which require monitoring of water,
salt and heat transport by means of periodic recording of
instantaneous soil moisture, capillary tension, temperature
and electrical conductivity profiles in chosen time intervals.
To read moisture a factory installed conversion equation for
mineral or organic soils can be chosen and/or user determined
calibration functions can be applied as well.
To switch between probes LOM is
provided with up to 16 single-pole-8-throw multiplexers. This makes it possible
to switch between up to 128 LP/ms, LP/t and LP/p probes.
LOM works with the following probes:
| LP/ms |
- Laboratory
miniProbes designed for recording
instantaneous profiles of moisture and salinity
in soil columns or in undisturbed soil cores |
| UP/ms
|
- User-made
Probes for moisture and salinity
measurement |
| LP/p |
- Laboratory
Probes (minitensiometers) for measurements of
soil water capillary pressure (suction force,
matric potential) |
| LP/t |
- Laboratory
Probes for temperature measurement |
Several LP-probes of a selected
kind or of all types can be inserted through the wall of a soil
column or a steel sampling cylinder, thus allowing for vertical
scanning of the instantaneous moisture, capillary tension (matric
potential, suction force), temperature and electrical
conductivity profiles. This makes it possible to collect a set of
corresponding water content, water potential, electric
conductivity and temperature data from drying or wetting front
transition, from which, after further processing, one can obtain
complete set of unsaturated water flow characteristics of the
soil i.e.: water retention (PF) curve, unsaturated water
conductivity (k-function), differential water capacity and
unsaturated water diffusivity as well as solute transport data.
Also heat transport coefficients (as the thermal conductivity,
thermal diffusivity, specific heat) can be determined if a heat
flux meter is installed in an experimental column.
D-LOG/mpts - is a moisture/capillary
pressure/temperature/salinity datalogger for field application
that is able to switch between up to 128 probes type of FP/mts
(or FP/m) and up to 128 tensiometers.