Product Manual

7
main tube and pull straight up. Always avoid a lever or a “crow bar” action. It puts a strain on the
ceramic tip connection.
Specify instruments of suitable lengths. There should be a minimum clearance of about 1 inch
between the bottom of the gauge and the soil. This allows the gauge diaphragm to expand and
contract freely with temperature fluctuations. Also, not more than about six inches of the main tube
should project above ground to avoid damage.
In some cases, it is desirable to install the IRROMETERS at an angle. This allows the tip to be placed
at specific depths without having too much of the IRROMETER body exposed above ground. In
orchards, this helps to keep the exposed portion of the instrument under the canopy which offers
better protection. Instrument bodies can even be bent to certain angles to make such installation
easier. Consult factory for details. Always set the instrument so the gauge is in a downward position.
After installation, fill the reservoir with IRROMETER Fluid, and release any air that may have
accumulated below the reservoir.
(See section on “SERVICING.”)
Installation of instruments invariably disturbs the normal soil structure and root system to some extent,
yet in most soils IRROMETERS give an accurate indication of soil moisture content a few hours after
installation. In rocky soils or when an oversize hole is drilled, it may take an irrigation to settle the soil
normally around the ceramic tip and insure precise readings. De-airing the instruments thoroughly
during the first 3-6 days after installation insures maximum sensitivity and accuracy.
IRROMETER Charts
Just as a thermostat in your home
guides you in maintaining the desired
temperature, the IRROMETER
guides you in maintaining desired
soil moisture content. And just as you
need to know when and how much
fuel is needed to keep a safe reserve
on hand to meet varying climatic
conditions, it is necessary to know
when and how much to irrigate to
maintain soil moisture content within
the desired range. This requires
planning irrigations in advance based
on seasonal use in the past.
The IRROMETER charts provide the
simplest method of keeping records
for this purpose. Special pocket size
chart forms are included with each
IRROMETER Service Unit.
Readings are plotted directly in the
field. The resulting curves give a
picture of the rapidly fluctuating soil
moisture conditions throughout the
root zone, in each section, that can
be visualized in no other way. “Rate
of change” may be the best indicator of WHEN to irrigate. That is, if the reading increases 10-15
centibars (kPa) in just a few days, the soil is drying rapidly. Thus the charts provide a complete original
record with an absolute minimum of clerical work. Projecting the seasonal curves for each section
makes it easy for the grower
, or executive in charge of larger operations, to plan irrigations in advance.
PROJECTED
READING
DETERMINES
IRRIGATION
IN ADVANCE
TODAY’S
READINGS