Drip
irrigation is an ideal watering system for plants, flowers, vegetables
and shrubs. Because the water is applied directly to the plants'
root zone , there is no waste. Another benefit of using a drip system
is that the ground between emitters usually remains too dry for
weeds to grow (except when rainfall occurs). In
saline soils, a drip system removes salts from the plants' root
zone, thereby increasing plant growth. A fertilizer injector also
can be installed to take care of other plant needs. Greenhouse plants,
hanging baskets of plants, pottedplants ab\nd gardens can benefit
from a drip system. When combined with a timed controller, the plants
will be watered on a regular basis, eliminating the worry that they
will become dry or even die if left unattended.
TYPES
OF SYSTEMS-
There are numerous types of drip irrigation systems available. They
range from a leaky pipe to permanently installed emitters.
The
simplest system consists of a hose that drips water from strategically-placed
holes on each side.
A more
advanced drip system consists of a 3/4 inch or larger pipe with
half-inch laterals. The large pipe is referred to as the main line
because it is connected to the main water source; the half inch
laterals are sometimes called sub-mains. Any device that drips water
at the point of attachment is an emitter. These are directly installed
into the laterals by means of a special punch tool. If the emitter
is punched directly into the pipe, it may run next to the plant
being watered. However, spaghetti tubing may be attached to the
emitter or punched directly into the lateral with the tube extended
to the plant being watered. This tubing, which is only 1/4-inch
in diameter, is flexible. By cutting the tube on a diagonal, a pointed
end is created which makes the connection easier
INSTALLATION
The Filter-
Unless a filter is utilized to remove particles from the water prior
to reaching the drip system, the emitters will become plugged. When
using domestic water, install a basic filter to remove the flakes
common with metal pipe usage. All additional pipes and fittings
should be plastic.
Filters
require periodic cleaning to remove trapped particles. A screen
filter is easily cleaned by unscrewing the filter body and flushing
the screen with water.
If
ditch, pond, or other non-filtered water is used, a more extensive
filtration system is necessary. Check with an irrigation specialist
for information on filtration systems.
The
Pressure Regulator-
Drip irrigation systems require a pressure regulator. Those who
plan to enlarge the drip system in the future should purchase an
adjustable regulator.
Main
Lines and Lateral-
The main line of the irrigation system directs water to the laterals
which extend to the plants. These lines can be buried or laid on
top of the ground. If possible, it is best to bury the pipes to
eliminate leaky fittings due to the expansion and contraction caused
by temperature changes common to exposed pipes.
Rigid
polyvinyl chloride (PVC) or flexible black polyethylene pipe can
be used. When working with PVC, be sure to use fittings, primer
and glue specifcally designed for this type of pipe. Do not use
an excessive amount of primer and glue as it may damage the pipe
or block the system. Any burrs found on the cut PVC pipe should
be removed.
Barbed
insert fittings are used with black polyethylene systems. Clamps
should be used at each joint to prevent separation.
To
prevent punctures, buried pipe is placed on a bed of sand. If left
on the surface, remove any sharp objects found beneath the pipes.
A back-flow
prevention device should be installed to prevent back siphoning
of fertilizers, pesticides, and other toxic materials into the drinking
water. Check with local health or government officials to determine
the type of back-flow prevention device that is necessary. A drip
system equipped with a fertilizer injector may require a more extensive
backflow prevention device. Fertilizer injectors should always be
installed upstream in relation to the filter, so that particles
cannot plug emitters.
Emitters:
Different types of emitters are available with a water flow capacity
ranging from 1/2 gallon to 8 gallons per hour. The type of emitter
chosen
