Product Manual

10
Protection of IRROMETERS
Growers find that they protect their investment by protecting the instruments. The purposes of
protection are:
1. To prevent accidental damage to the instruments resulting from field operation.
2. To facilitate taking readings by keeping the gauge crystal clean.
3. To inhibit the growth of algae by keeping out of sunlight.
4. To provide a measure of frost protection. In areas where temperatures drop only a few degrees
below freezing for short periods, protection makes it possible to keep the instruments in the
ground all through the winter. In this case, mineral wool, straw or other insulation should be
packed around the instrument.
5. To minimize temperature fluctuations
which have a slight effect on gauge
readings.
With tree crops or in other permanent
installations where furrow or flood irrigation is
used, sections of steel, concrete or PVC pipe,
or wood boxes are recommended. The cover
may either be a waterproof fertilizer sack or a
wood lid.
When used is pastures, IRROMETERS should be
protected with a heavy concrete or steel pipe and
the instruments installed at an angle so that the tips
extend beyond the protective covering.
Wherever IRROMETERS are installed, it is
advisable to mark them plainly with a flag or stake to
minimize the danger of accidental damage and to
locate them easily when taking readings.
Starting Irrigations
It is impossible to give specific instructions as to when to start irrigations for all crops, all soils, all
climatic conditions and all methods of irrigation. You will learn the best time to start irrigations for your
particular crop and local conditions by following your charts after a few irrigation cycles. If you have
not used IRROMETER control the following suggestions are offered as a starting point.
For most crops, a rule-of-thumb recommendation is to start irrigations at a gauge reading of about 50
(except with drip or low volume irrigation – see below).
In order to do this properly, you will need to allow a reserve of soil moisture as a safety factor, as few
growers can wait until the last minute to irrigate. The following are typical of adjustments in irrigation
treatments.
In hot, dry climates, irrigations start at the following readings for most crops:
10-35 in sandy soils / 35-50 in medium soils / 50-60 in fine textured soils
In cool humid climates – coastal areas, for example – it is often safe to delay irrigations until readings
are 10 to 15 points higher in each case.
The concept of drip irrigation is to apply low volumes of water very frequently to maintain
readily available water to the plant. To accomplish this, the IRROMETER located 12"-18" from
the water source should be maintained at or near field capacity (3-20 reading on the gauge).
This will assure outward and downward water movement in the soil as in a blotting action.
IT IS IMPORTANT when the emitter wets the entire root zone of a newly planted tree or plant that soil
not be saturated (0-5 reading) for extended periods.