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Copyright 2005, Board of Trustees, University
GULF COAST RESEARCH AND EDUCATION CENTER
IFAS, UNIVERSITY OF FLORIDA
5007 60th Street East
Bradenton, Florida 34203
Bradenton GCREC Research Report BRA1985-18 May 19C5
GUIDELINES FOR THE CHOICE AND USE OF CAPILLARY MAT, SPAGHETTI
TUBE AND TRICKLE IRRIGATION SYSTEMS FOR FLORICULTURAL CROPS
B. K. Harbaugh and C. D. Stanley
Water resources in Florida are being used at a much higher rate than
ever before primarily due to population increases and expanded agricultural
and industrial activity. This increased demand on water supplies and more
frequent problems with salt water intrusion into wells, and with periods of
drought, have prompted state agencies to mandate water conservation for all
water users. For these reasons, irrigation management practices are
changing, and must continue to change to insure survival of the
floricultural industry. Irrigation systems which utilize overhead sprinklers
are the most common types used for floricultural crops. However, these
systems can be an inefficient users of water due to evaporation and
irrigation of walkways and the space between pots. Due to the unique and
intensive culture of floricultural crops, several water-conserving systems
are available for producers including capillary mat, spaghetti tube and
trickle irrigation. The advantages and disadvantages of these irrigation
systems are discussed as well as management guidelines for their successful
Capillary Mat Irrigation Systems
Capillary mats function to uniformly distribute water over a bench for
subirrigation of potted crops. The mat itself is constructed from natural or
synthetic fibers formed into a mat 1/8 to 1/4 inch thick. Water (often
supplied to the mat by trickle irrigation tubing) moves through the mat and
into the pots' soil mix by capillary action, thus maintaining the soil mix
at container capacity. A plastic sheet is placed under the mat to prevent
loss from water moving through the mat. Further water conservation can be
achieved with the use of mat overlays to prevent evaporation from the mat
area between pots.
1) Water savings When managed properly (for example, using plastic
mat overlays), savings compared to overhead irrigation approach 90-95% for
the final spacing of a 6-inch pot crop since the plant uses water only as
needed with negligible loss to conveyence and non-cropped areas.
2) Reduction of pumping costs.
3) Adaptable for many crop species and pot sizes grown in the same
4) The system is easily automated and provides uniform water
5) Eliminates "tangle syndrome" common to spaghetti tube systems when
used with close pot spacings or small pot production.
6) Since plant foliage is not wetted by the system, there is a
reduction in foliage and flower disease potential and the need for frequent
reapplication of pesticides.
7) When used with controlled release fertilizers, fertilization costs
are lower and the need to inject fertilizer is reduced.
8) This system is exempt from mandated water use reductions during
declared regional water shortages.
1) High initial investment costs compared to overhead systems.
2) Excessively succulent growth can occur on some plant species.
3) Problems with design, water quality control and engineering may be
4) Cannot be used for frost protection, washing plant foliage, or to
5) Plants must be overhead irrigated once or twice to establish
capillarity in 'the pots.
6) Algae and weed growth must be controlled to prevent deterioration of
the mat material, unless mat overlays are used.
7) Lacks flexibility to adjust fertilizer within a crop cycle since
injection of fertilizer into the mat is not advised because of the tendency
to induce rootigrowth into the mat and increase algae problems.
1) The bench must be constructed without depressions (resulting in
standing water) or high spots (resulting in dry areas). A crowned bench or
one sloping 1-2 inches across the bed can alleviate these problems.
2) Since pots must be watered in initially to establish capillarity,
some method of overhead irrigation must be available.
3) An opaque polyethylene film should be used over the mat to inhibit
algae and weed growth on the mat and reduce evaporation from the mat area
between pots. Film types available include solid film requiring holes to be
cut where pots are placed, and films with pre-cut pin holes or slits. The
latter types prevent root penetration into the mat.
4) The mat should be kept moist at all times often requiring water
application to the mat 3-6 times daily. Clocks, controllers or computers
can be used to automate water application as conditions require.
5) Controlled release fertilizer should be used in conjunction with
capillary mat irrigation. Plants can be "toned" at the end of the
production cycle if needed by injecting soluble fertilizer through the
overhead system used to establish capillarity. In more arid climates with
low humidity or with long-term crops, salts may accumulate on the soil
surface requiring leaching every 6-8 weeks.
6) For outside production with automated systems9 care must be taken
to avoid over-irrigation during periods of significant rainfall.
7) Do not use a soil mix with large pore spaces, or one that is
extremely light. The pots must be heavy enough to push into the mat so ths
water can move into and through the media by capillarity action. Large air
spaces under pots caused by.footed plastic pots or large pore spaces in the
media (as caused by undecomposed bark or other aerating media components)
will result in problems.
8) Quality pots with flat bottoms and clean cut drainage holes should
9) If pots are moved or the soil mix becomes dry for any reason, the
pots must be overhead irrigated to re-establish capillarity.
Spaghetti Tube Irrigation Systems
Spaghetti tube systems utilize small diameter polyethylene tubing to
supply water to individual pots. This small tubing is connected to larger
diameter (1/2 or 3/4 inch) polyethylene tubing. Drip or spray type emitters
connected to the ends of the small diameter tubing are used to keep the
tubes in the pots and control water application patterns.
1) Water savings Since water is applied to each pot individually,
water savings comparable to capillary mat systems can be expected (90-95%
reduction compared to overhead systems).
2) Reduction of pumping costs.
3) Uniform distribution of water.
4) Fertilizers can be injected through the system and since only the
pots.are receiving.irrigation, less total fertilizer is required compared
5) The foliage is kept dry, thus reducing disease potential and the
need to reapply pesticides.
6) Easily automated.
7) This system is exempt from mandated water use reductions during
declared regional water shortages.
1).High initial investment and installation costs.
2) Increased maintainance requirements.
3) Different management skills required (water quality control,
4) Not useful for frost protection, washing foliage, or rooting plants
compared to overhead irrigation.
5) "Tangle syndrome" occurs when many tubes are used with closely
spaced pots or with small pot production (< 10 cm).
1) Give strict attention to manufacturers' specifications concerning
design limitations to insure equal water distribution to each pot. Submain
supply lines that are too long or that are irrigating too many pots, and
improper water pressure are factors to consider which affect water
2) Water quality can cause serious problems with this system.
a) Problem: particulate matter (sand, organic matter, algae, etc.)
in water, especially when surface water is used.
Solution: use of proper filtration system, such as sand, screen,
sock, or ring types, manually or automatically cleaned.
b) Problem: Bacteria which metabolize iron and sulfur present in the
water may plug tubes and emitters.
Solution: Periodic chlorination of the system.
c) Problems Precipitation of soluble salts from injected fertilizer
or naturally occurring minerals can plug tubes and emitters.
Solution: i) Avoid using liquid fertilizers which may form
insoluble precipitates in the system (such as calcium and phosphate which
form insoluble calcium phosphates).
ii) Adjust the pH of the irrigation water to keep
specific ions in solution.
iii) Use larger diameter tubing (0.06 to 0.076 inches) or
large pore emitters or spray stakes. One must remember, however, that doing
this will decrease the maximum number of pots irrigated from a particular
3) For production using pots 4 inches or less in diameter, consider
using a capillary mat system since the time to place spaghetti tubes in pots
and the tendency of the tubes to become tangled makes the system less
practical than when larger pot sizes are used.
Trickle Irrigation Systems
Trickle irrigation utilizes polyethylene tubing placed in the crop's
root zone to convey and distribute only that water needed by the crop for
growth. This system is most suited for cut flower crops or as a distribution
system for capillary mat systems (see capillary mat section). Water is
emitted from the tubing either through emission ports spaced at desired
distances (usually 4 to 12 inches), or from micropores spaced continuously
along the tubing (ooze tubes).
1) Efficient use of water When properly managed, application
efficiency can approach 95%. Compared to reported water use with overhead
systems for cut chrysanthemums, trickle irrigation can reduce irrigation
requirement by 60-90%.
2) This system is exempt from mandated.water use reductions during
declared regional water shortages.
3) Reduced purchasing or pumping costs for water Since water usage is
considerably less and trickle systems operate at low pressure levels, lower
investment and operating costs are required for pumping stations compared to
those for overhead systems.
4) Reduced use of fertilizer When fertilizer is injected through the
trickle irrigation system, it is placed only in the cropped area. When
fertilizer is applied through overhead systems, fertilizer is distributed
over the entire area, increasing fertilizer use and potential of groundwater
5) Causes no disruption in production and harvesting operations -
Trickle irrigation allows more flexibility for scheduling production and
harvesting operations when compared to overhead irrigation since irrigation
and these operations can occur simultaneously.
6) Effects on pest management The foliage of the crop is never wettod
with trickle irrigation. This can benefit disease control since high
humidity environments and splashing water promote fungal and bacterial
diseases. Pesticide use may be reduced with integrated pest management (IPM)
since applied chemicals are not washed off the plant foliage as occurs with
overhead irrigation. Also, weed growth is reduced is the non-cropped areas
since no irrigation is taking place in these areas.
7) Potential for chemigation (the injection of fumigants a- .
through the trickle tubes) is promising. This may prove to be an efficient
and safe method for applying chemicals without affecting desirable predators
8) Easily automated
1) Cannot be used for frost protection, establishing unrooted cuttings,
washing of foliage, and field preparation (fumigation and bed preparation).
2) Using a deep well water source, the total fixed and operating costs
of this system are generally higher compared to overhead sprinkler.
3) Different design and management skills are required to operate the
system efficiently (i.e., filtration, chlorination, rodent damage, water
4) Extremely dry driveways and walkways can lead to vehicular traffic
problems and sandblasting of the plants during high winds on sandy soils.
1) Proper design and operation of this system is a necessity. Follow
manufacturer's specifications to insure that the design will meet the needs
of your operation. Shortcuts in design or lack of proper management can
prove to be disastrous with respect to water distribution, and ultimately,
crop production. Care should be taken to work with a reputable irrigation
supplier who has experience in design and operation of trickle systems and
is willing to assist if problems arise after installation.
2) Poor water quality can cause serious distribution problems by
reducing flow rates or plugging emitting orifices. These problems include:
a) particulate matter (sand, organic matter, algae, etc.) in water,
especially when surface water is used; b) algae and iron- or sulfur-
metabolizing bacteria which can proliferate within the tube or emitting
orifices; and, c) precipitation of soluble salts from injected fertilizers
or naturally occurring minerals in the water. The solutions to these
problems are identical to similar problems encountered with water quality
for the previously-discussed spaghetti tubs system (see section 2 under
anao.c:.int Guidelines for spaghetti tube systems).
3) Selection of number of tubes per bed depends primarily on the
species of crop grown. For example, for cut chrysanthemums, it is
recommended that one tube be used for each two rows in the bed or bench,
while for a single row crop such as gypsophila, only one tube in the bed is
needed. Choice of in-line spacing of the emitting orfices along the tubing
depends on soil characteristics such as water holding capacity or the
propensity of water move to laterally from the tube. Since sandy soils are
limited in both these characteristics, it is recommended that in-line
spacings of 4-12 inches be used on these soils,
4) It is essential that the soil moisture in the bed be maintained at
field capacity prior to irrigation from the trickle system to insure propr
water movement in the bed. This often necessitates the use of an alternate
irrigation system (such as subirrigation or overhead) for bed preparation
and plant establishment.
5) The amount of water applied per day depends on the plant species,
growth stage, and climate. Frequency of application depends primarily on the
soil characteristics discussed above. For example, cut chrysanthemums grown
on sandy soils may require 3 to 6 applications per day to insure an adequate
water supply to the crop. The multiple applications (of lesser volume) do
not increase the total amount of water applied per day, but simply are used
to prevent water from moving beyond the root zone.
6) In the past growers have depended on their irrigation systems for
functions other than irrigation. Since trickle irrigation cannot serve these
functions, alternate irrigation systems must be considered for management
practices such as frost protection, bed preparation, fumigation and
transplant establishment, and to avoid sandblasting of the crop and problems
with vehicular movement.
7) It is highly recommended that the system be automated to take full
advantage of this system. Since multiple applications per day are often
required, automation using clocks, controllers, or computers can reduce
labor input substantially and utilize water resources more efficiently.
When contemplating an irrigation system for a new operation or change
from an existing system, producers must aquaint themselves with as much
information as possible about the system to be aware of its total impact on
production practices and costs. System design, effect of the irrigation
system on other management practices (fertilization, pest control, quality
control, harvesting, frost protection, plant establishment, labor
management, etc.), and economical justifications must be analyzed carefully
to insure that successful and profitable production will result. Quality and
availability of the water supply may ultimately dictate the choice,
requiring the producer to become proficient in management of water-
conserving irrigation systems.
Systems discussed in this paper currently are exempted from water use
restrictions during periods of declared water shortages when reductions in
permitted water use are mandated (including agricultural use) by the South
Florida and Southwest Florida Water Management Districts. This advantage is
insurance that during these periods, no disruption in normal production
practices will occur when a producer uses these systems.
All systems discussed have been and are currently being used
successfully by floricultural producers. These growers have gained expertise
in the operation of these systems, as well as the crop management skills
required for profitable production. Producers interested in using the
systems discussed in this paper should utilize the experiences of their
colleagues as well as information from reputable commercial irrigation
specialists and extension personnel of the University of Florida, IFAS.