IRRIGATION
From page 15
they are to water.
Properly positioned, therefore, driplines deliver a
measurable amount of water
directly to the base of each
plant, with no loss of water
through misting and spray or,
if the flow is slow enough,
through run-off.
The only maintenance
necessary in a dripline system
is a periodic check to see that
the delivery holes are not
blocked.
Even plantings of annual
crops, particularly of larger
plants spaced some distance
apart, such as tomatoes, can
be irrigated using driplines,
with the added advantage
that the system will benefit
plants (such as tomatoes) that
are prone to leaf mould and
mildew if they have their
leaves wetted.
A further advantage of
dripline irrigation is that it can
be achieved using very low
water pressure. In some cases
the pressure
achieved merely by
mounting a tank on a
tank stand will be
sufficient. Thus,
dripline irrigation
becomes possible for
smallholders without
electricity or who
Microjet irrigation in an orchard
cannot afford booster
sprayers, pumps become
pumps.
essential because the
The moment some kind of
pressures required are very
spray is involved, either in the much higher.
form of microjets, rotary
Microjets, like driplines, can
impact sprayers, or cannon
be used to water individual
plants. They will usually be in
a permanent irrigation system
and the little spray heads can
be found in various spray
configurations and spray
o
angles, from 90 (for corners
o
of beds,) 180 (for watering
on only one side of a path)
o
and 360 (for watering in the
middle of a bed).
If your water supply is in any
way contaminated, with fine
sand or plant material
(including algae) it is essential
to install an inline sieve or
filter in the system to save
yourself from spending hours
unblocking clogged microjet
heads.
A further disadvantage of
microjet irrigation is the
considerable amount of water
that is lost in spray mist,
particularly when the system
is run on a windy day.
Plus, of course, the fact that
the entire plant, and bed, is
soaked is disadvantageous to
plants that prefer their leaves
and stems to remain dry.
Rotary sprayers come in many
types, from pop-ups typically
found in permanent garden
irrigation systems where the
pressure in the pipework
causes the sprinkler head to
pop up out of a hole in the
ground to do its job and
which, on completion of its
task, falls back into its hole. In
this way pop-ups are great
when laid in a lawn as they
allow mowers to do their job
unhindered by either having
to move pipework or
sprinklers or having to work
around protruding irrigation
Continued on page 17
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