• TABLE OF CONTENTS
HIDE
 Copyright
 Introduction
 Lateral movement of irrigation...
 Number of emitters per plant to...
 Soil moisture measurement as a...
 Using trickle irrigation for the...
 Frost protection and the importance...
 Types of pumps and filters to be...
 Installations of trickle irrigation...
 Effects on grove weed growth
 Comparative costs of trickle...














Group Title: Homestead AREC research report - University of Florida Agricultural Research and Education Center ; SB74-4
Title: Use of trickle irrigation on tropical fruit tree growing on Rockdale solids
CITATION PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067825/00001
 Material Information
Title: Use of trickle irrigation on tropical fruit tree growing on Rockdale solids a progress report
Series Title: Homestead AREC research report
Physical Description: 5 leaves : ; 28 cm.
Language: English
Creator: Malo, Simâon E
Agricultural Research and Education Center, Homestead
Publisher: University of Florida, Agricultural Research and Education Center
Place of Publication: Homestead Fla
Publication Date: 1974
 Subjects
Subject: Tropical fruit -- Irrigation -- Florida   ( lcsh )
Microirrigation -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: S.E. Milo.
General Note: "May 13, 1973"
 Record Information
Bibliographic ID: UF00067825
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 72464694

Table of Contents
    Copyright
        Copyright
    Introduction
        Page 1
    Lateral movement of irrigation water in trenched and untrenched groves from the emitter or point of application
        Page 1
    Number of emitters per plant to use and placement
        Page 1
    Soil moisture measurement as a guide to water application
        Page 2
    Using trickle irrigation for the application of soluble or liquid fertilizer and chelates
        Page 3
    Frost protection and the importance of a good herbicide program
        Page 4
    Types of pumps and filters to be used
        Page 4
    Installations of trickle irrigation on mature groves planted without trenching
        Page 4
    Effects on grove weed growth
        Page 5
    Comparative costs of trickle irrigation
        Page 5
Full Text





HISTORIC NOTE


The publications in this collection do
not reflect current scientific knowledge
or recommendations. These texts
represent the historic publishing
record of the Institute for Food and
Agricultural Sciences and should be
used only to trace the historic work of
the Institute and its staff. Current IFAS
research may be found on the
Electronic Data Information Source
(EDIS)

site maintained by the Florida
Cooperative Extension Service.






Copyright 2005, Board of Trustees, University
of Florida






Homestead AREC Research Report SB74-4


Use of Trickle Irrigation on Tropical Fruit Trees
Growing on Rockdale Soils A Progress Report


S. E. Malo
Associate Horticulturist
University of Florida
Institute of Food and Agricultural Sciences
Agricultural Research and Education Center
Homestead


Introduction

Trickle irrigation consists of maintaining a constant moisture in the soil by means
of a slow, prolonged delivery of water from specially designed and constructed emit-
ters. The system usually works at a pressure of 15 psi or lower, uses relatively
small pumps and narrow gauge underground PVC pipe and above ground polyethylene hose.
The initial investment cost compared with sprinkler irrigation is very low. Low
costs also apply to maintenance and operation of the system. Experiments were begun
early in 1971 to determine the performance of this method of irrigation on tropical
fruit crops growing in shallow "Rockdale" soils and under the climatic conditions of
the Homestead area. This progress report is a summary of the information gained after
3 years of testing this system at the Agricultural Research and Education Center.
Since many specific points have been raised regarding the application of this new
method of irrigation to Rockdale soils we will discuss our progress under a variety
of headings.

1. Lateral movement of irrigation water in trenched and untrenched groves from the
emitter or point of application.

In deep trenched Rockdale soils (16-20 inches) water moves by capillary action 5 feet
or more laterally on both sides of the emitter (10 feet of distance); however, in
untrenched groves because of the shallow soils (8-12 inches), lateral movement is
approximately 2V 3.0 feet in radius. The extent of capillary movement depends on
the initial soil moisture, maximum movement occurring in soils which are very moist,
decreasing to a minimum in a very dry soil. This is one of the reasons why once it
is started, trickle irrigation should be continued, maintaining a high degree of soil
moisture. Once the soil dries out it may take several days of operating the system
for the soil to reach the degree of wetness that it had before, unless a good rain
occurs.

2. Number of emitters per plant to use and placement.

The number of emitters used depends on the size and age of the plant. One emitter
for young plants appears sufficient. For trees already in production in trenched
groves one emitter for every 8 feet of trench is sufficient since, as stated before,
total lateral water movement in trenched soil is 10 feet or more. The number of
emitters for large trees (20-30 years old) in untrenched groves has not been deter-
mined with precision. At present there is no reason to believe that emitters should
be positioned closer than 5 feet in the lateral polyethylene hose. Very large trees
planted at 30-35 feet spacing may require additional emitters in spur-laterals or
placed in circular laterals around the tree. The location of the emitters with re-
spect to the trunk does not appear to be important. No damage or increase in soil-
borne disease has been observed when emitters were located very close to the trunk.


May 13, 1974






Homestead AREC Research Report SB74-4


Use of Trickle Irrigation on Tropical Fruit Trees
Growing on Rockdale Soils A Progress Report


S. E. Malo
Associate Horticulturist
University of Florida
Institute of Food and Agricultural Sciences
Agricultural Research and Education Center
Homestead


Introduction

Trickle irrigation consists of maintaining a constant moisture in the soil by means
of a slow, prolonged delivery of water from specially designed and constructed emit-
ters. The system usually works at a pressure of 15 psi or lower, uses relatively
small pumps and narrow gauge underground PVC pipe and above ground polyethylene hose.
The initial investment cost compared with sprinkler irrigation is very low. Low
costs also apply to maintenance and operation of the system. Experiments were begun
early in 1971 to determine the performance of this method of irrigation on tropical
fruit crops growing in shallow "Rockdale" soils and under the climatic conditions of
the Homestead area. This progress report is a summary of the information gained after
3 years of testing this system at the Agricultural Research and Education Center.
Since many specific points have been raised regarding the application of this new
method of irrigation to Rockdale soils we will discuss our progress under a variety
of headings.

1. Lateral movement of irrigation water in trenched and untrenched groves from the
emitter or point of application.

In deep trenched Rockdale soils (16-20 inches) water moves by capillary action 5 feet
or more laterally on both sides of the emitter (10 feet of distance); however, in
untrenched groves because of the shallow soils (8-12 inches), lateral movement is
approximately 2V 3.0 feet in radius. The extent of capillary movement depends on
the initial soil moisture, maximum movement occurring in soils which are very moist,
decreasing to a minimum in a very dry soil. This is one of the reasons why once it
is started, trickle irrigation should be continued, maintaining a high degree of soil
moisture. Once the soil dries out it may take several days of operating the system
for the soil to reach the degree of wetness that it had before, unless a good rain
occurs.

2. Number of emitters per plant to use and placement.

The number of emitters used depends on the size and age of the plant. One emitter
for young plants appears sufficient. For trees already in production in trenched
groves one emitter for every 8 feet of trench is sufficient since, as stated before,
total lateral water movement in trenched soil is 10 feet or more. The number of
emitters for large trees (20-30 years old) in untrenched groves has not been deter-
mined with precision. At present there is no reason to believe that emitters should
be positioned closer than 5 feet in the lateral polyethylene hose. Very large trees
planted at 30-35 feet spacing may require additional emitters in spur-laterals or
placed in circular laterals around the tree. The location of the emitters with re-
spect to the trunk does not appear to be important. No damage or increase in soil-
borne disease has been observed when emitters were located very close to the trunk.


May 13, 1974






Homestead AREC Research Report SB74-4


Use of Trickle Irrigation on Tropical Fruit Trees
Growing on Rockdale Soils A Progress Report


S. E. Malo
Associate Horticulturist
University of Florida
Institute of Food and Agricultural Sciences
Agricultural Research and Education Center
Homestead


Introduction

Trickle irrigation consists of maintaining a constant moisture in the soil by means
of a slow, prolonged delivery of water from specially designed and constructed emit-
ters. The system usually works at a pressure of 15 psi or lower, uses relatively
small pumps and narrow gauge underground PVC pipe and above ground polyethylene hose.
The initial investment cost compared with sprinkler irrigation is very low. Low
costs also apply to maintenance and operation of the system. Experiments were begun
early in 1971 to determine the performance of this method of irrigation on tropical
fruit crops growing in shallow "Rockdale" soils and under the climatic conditions of
the Homestead area. This progress report is a summary of the information gained after
3 years of testing this system at the Agricultural Research and Education Center.
Since many specific points have been raised regarding the application of this new
method of irrigation to Rockdale soils we will discuss our progress under a variety
of headings.

1. Lateral movement of irrigation water in trenched and untrenched groves from the
emitter or point of application.

In deep trenched Rockdale soils (16-20 inches) water moves by capillary action 5 feet
or more laterally on both sides of the emitter (10 feet of distance); however, in
untrenched groves because of the shallow soils (8-12 inches), lateral movement is
approximately 2V 3.0 feet in radius. The extent of capillary movement depends on
the initial soil moisture, maximum movement occurring in soils which are very moist,
decreasing to a minimum in a very dry soil. This is one of the reasons why once it
is started, trickle irrigation should be continued, maintaining a high degree of soil
moisture. Once the soil dries out it may take several days of operating the system
for the soil to reach the degree of wetness that it had before, unless a good rain
occurs.

2. Number of emitters per plant to use and placement.

The number of emitters used depends on the size and age of the plant. One emitter
for young plants appears sufficient. For trees already in production in trenched
groves one emitter for every 8 feet of trench is sufficient since, as stated before,
total lateral water movement in trenched soil is 10 feet or more. The number of
emitters for large trees (20-30 years old) in untrenched groves has not been deter-
mined with precision. At present there is no reason to believe that emitters should
be positioned closer than 5 feet in the lateral polyethylene hose. Very large trees
planted at 30-35 feet spacing may require additional emitters in spur-laterals or
placed in circular laterals around the tree. The location of the emitters with re-
spect to the trunk does not appear to be important. No damage or increase in soil-
borne disease has been observed when emitters were located very close to the trunk.


May 13, 1974





A *


3. Soil moisture measurement as a guide to water application.

There are many ways of estimating rates of irrigation needed by fruit trees; however
none are as meaningful as the measurement of actual soil moisture. The most practical
te manner for a grower to determine this with precision is by using a tensiometerr".
These instruments operate by measuring soil moisture tension a dry soil draws water
from the instrument creating a negative pressure which is recorded in a calibrated
scale or dial. At least two tensiometers have been used in Rockdale soils effective-
ly. One utilizes a mercury column for showing a reading, the other one uses a
manometer dial. Both translate moisture stress to centibars of negative pressure,
however, the first will give an erroneous reading if the column of mercury is dis-
rupted by jarring or bumping. The "Irrometer" type belongs in the second category
and works effectively in Rockdale soils if the grower has a clear understanding of
its principle of operation and follows directions carefully. Studies and records
kept by the author for several years have indicated that this instrument is quite
sensitive to fluctuation in soil moisture tension under local conditions. Used in
pairs, one station for each 5 acres (depending on soil uniformity), Irrometers are
a great help in estimating the total daily irrigation regime. One Irrometer should
be installed to provide a moisture reading of the bottom of the trench (usually 18"),
the other next to it, should monitor moisture inthe upper portion (6"-12") of the
soil. Moisture tension readings higher than 35 or 45 centibars (zero indicates
saturation) indicates a soil dry enough to cause severe stress and damage to roots.
Due to the relative small amount of soil available for root growth in the Homestead
area, plants remove the usable moisture very quickly, consequently daily inspection
of irrometers is necessary to increase or decrease the period of water flow of the
emitters according to the soil moisture condition. The amount 6f irrigation should
follow very closely the tensiometer readings, regardless of whether or not trees show
signs of water stress. Avocado and mango trees do not exhibit obvious wilting symp-
toms, such as citrus, thus monitoring the soil moisture tension is the best way of
S estimating how much to irrigate.

4. Water emitters for the Homestead area.

Emitters are perhaps the single most important piece of equipment in trickle irri-
gation. They have to be designed in such a way that clogging is minimal. There are
many types of emitters manufactured in several countries, but generally those made in
Israel are the most advanced. However, Israeli emitters are also the most expensive
and difficult to obtain due to the worldwide demand for trickle irrigation and the
present scarcity of plastics. We have tested most of the available emitters at the
Agricultural Research and Education Center in Homestead and find very few which don't
work properly. The majority work quite adequatelywith our local water, particularly
if certain steps of preventive maintenance are taken. Consult with your local exten-
sion agent for more specific information on the virtues and possible problems of each
type of emitter which are commercially available in our area.

5. Problems encountered with emitters in our area.

Emitters should never be covered with soil because if this happens they will soon be
surrounded by roots which will reduce their performance. Next emitters should be
away from direct sunlight because growth of algae around the area df discharge will
eventually decrease water output. Shading will inhibit growth of algae, thus it is
advisable to use a light mulch around recently planted trees. A thick mulch is un-
desirable because it may be harmful to the young tree and it will encourage surface
root growth around the emitters, reducing their discharge.

Another serious problem is associated fortunately with only isolated wells. Theater
from these wells has a high iron content which tends to clog emitters rendering them
inoperable. At present there is no way of predicting the proper location of a well
in order to avoid this problem. There is also no proven way to control or minimize







the accumulation of iron precipitates in the emitters. Some wetting agents added to
the water have shown initial promise in cleaning emitters and maintaining their
operation at full capability. At this time we are not ready to recommend any products
since we must assess their long range effect, if any, on plants. Young avocado and
Tahiti lime trees have shown no deleterious effect after the use of wetting agents
for over a year.

Accumulation of calcium carbonate around the discharge area of emitters has not proven
to be as much of a problem as anticipated. Here again some of the wetting agents
under investigation have done a very adequate job of preventing the build up of a
deposit when used weekly in conjunction with a liquid fertilizer and chelate appli-
cation. The growth and build up of algae in emitters exposed to sunlight has been
prevented by the occasional use of blue stone (copper sulfate: 3-15 ppm. See:
"Trickle Irrigation" Research Report No. SB73-2 by S. E. Malo).

One rather unexpected problem stems from the fact that birds are attracted to the
emitters for drinking water particularly during the dry winter and spring months.
In the process of drinking most birds linger around long enough to leave droppings
containing seeds of noxious weeds which germinate readily on the moist soil. Weeds
such as lantana (Lantana camera var: aculeata), Brazilian pepper or Florida holly
(Schinus terebinthifoliBs, Jasmine vines (Jasminun dichotomum and J. fluminense) etc.
are commonly found associated with emitters. This problem appears to be especially
serious with robins which have a predilection for the red fruits of the Brazilian
pepper which are very abundant during this time of the year. Application of Paraquat
when the plants are 3-5 inches tall will control these weeds.

Damage by rodents has been isolated and minimal. However, there have been cases
where either rato or rabbits have gnawed on polyethylene laterals. This damage is
easily found and is corrected by cutting off the affected area and rejoining with a
plastic union.

6. Using trickle irrigation for the application of soluble or liquid fertilizer and
chelates.

Any chemical which can be dissolved in water can be either injected or absorbed into
the system and discharged through the emitters. Both nitrogen and potassium are ef-
fectively applied in this manner from such readily soluble sources as urea, ammonium
nitrate and potassium nitrate.

The same applies to chelates.df iron, manganese or zinc, as long as they are dissolved
or come in liquid form. Soluble forms of phosphorus are not as readily obtainable
and our experience with them is rather limited. Phosphoric acid is expensive, diffi-
cult to use and dangerous if not handled properly by trained personnel.

A method of fertilizer application which is particularly suited to the small grower
with a few acres consists of placing a valve in the intake side of the pump to let
its suction absorb the fertilizer or chelate solution very slowly into the system.
The emitters will discharge the fertilizer in the proliferation of roots around the
emitters where absorption is presumably very rapid with a minimum of leaching and
other losses. Six year old avocado trees fertilized weekly in this manner for a
period of 3 years are at present very vigorous and productive. The rates of ferti-
lizer have been drastically reduced by applying it weekly but we still don't have
precise information on optimum rates of fertilizer for different crops and varieties.
At present we have found that the method works satisfactorily and that we can reduce
the annual fertilizer rate by applying it in this manner. Since we have had satis-
factory results in the mechanics of application, we did not feel the need for using
a separate injection pump for metering and injecting the fertilizer solution intofthe
system. Distribution appears not to be a problem if the fertilizer is absorbed over
a period of 4-5 hours.







The accumulation of precipitates in the polyethylene laterals has not been a severe
problem so far, although materials such as potassium nitrate and some chelates
usually leave a precipitate which could eventually clog emitters. We use a wetting
A agent in conjunction with the fertilizer solution to facilitate the flow of small
particles through the emitters and prevent accumulations which could be potentially
troublesome later.

At this point, we should caution growers that this type of "fertigation" should be
approached carefully because of the potential danger in clogging emitters. A certain
amount of experimenting with small amounts of soluble fertilizer is necessary before
starting regular applications. Having the proper type of filter is very important
because it is an insurance against particles and other impurities often found in
commercial fertilizers.

7. Frost protection and the importance of a good herbicide program.

Trickle irrigation does not provide frost protection in the manner nor to the degree
that sprinkler irrigation does. This is very important particularly with young plants
for which frost protection should be provided by heating devices or other means.
However, one manner of minimizing the danger of frost damage is by keeping the ground
clean and free of weeds with herbicides during the critical winter months. Mulch and
trash should be removed to expose the ground around young plants. It is a well known
fact in the Homestead area that bare ground radiates enough accumulated heat to give
young plants some protection. The success of this protection depends, of course, on
the severity and the duration of the temperature drop, but it is important in the
usual ranges recorded in the Homestead area (26-320F).

8. Types of pumps and filters to be used.

SElectrical pumps are definitely the most versatile types and are the ones we recommend
Among their merits are: need little maintenance, start instantly, are economical to
operate, can be automated by the use of time clocks, and they work continuously with-
out the need of refueling.

The filters to be used should be the best available type for our conditions. Our
experience has shown that those consisting of nylon and stainless steel sieves of
different meshes work very adequately. The finest sieve is usually a nylon cloth of
160 mesh which removes practically all particles of sand. It should be stressed here
that good filters are an insurance against failure of the system which will happen if
a large portion of emitters are stopped up. It is very laborious and expensive to
clean emitters once they have become clogged in the field.

9. Installations of trickle irrigation on mature groves planted without trenching.

Prior to 1960 most groves were not planted by the system of cross-trenching. Despite
some initial doubts trickle irrigation has worked very adequately in these untrenched
old groves. It does appear, however, that more emitters per tree are required than
in trenched groves because the lateral movement of water is not as extensive as in
the trenches. The number of emitters depends on the fruit tree to be irrigated. In
some instances it may even be necessary to use two laterals, one on each side of the
row of trees with a separation of approximately 6 feet between each other. This type
of arrangement works very well, particularly in old groves adjacent to housing de-
velopments where the neighbors may object to other types of irrigation. In this re-
gard we could also add that trickle irrigation is ideally adapted to the dooryard
S grower, or to the suburbanite with a few acres of trees who is surrounded by expensive
homes.
J







The accumulation of precipitates in the polyethylene laterals has not been a severe
problem so far, although materials such as potassium nitrate and some chelates
usually leave a precipitate which could eventually clog emitters. We use a wetting
A agent in conjunction with the fertilizer solution to facilitate the flow of small
particles through the emitters and prevent accumulations which could be potentially
troublesome later.

At this point, we should caution growers that this type of "fertigation" should be
approached carefully because of the potential danger in clogging emitters. A certain
amount of experimenting with small amounts of soluble fertilizer is necessary before
starting regular applications. Having the proper type of filter is very important
because it is an insurance against particles and other impurities often found in
commercial fertilizers.

7. Frost protection and the importance of a good herbicide program.

Trickle irrigation does not provide frost protection in the manner nor to the degree
that sprinkler irrigation does. This is very important particularly with young plants
for which frost protection should be provided by heating devices or other means.
However, one manner of minimizing the danger of frost damage is by keeping the ground
clean and free of weeds with herbicides during the critical winter months. Mulch and
trash should be removed to expose the ground around young plants. It is a well known
fact in the Homestead area that bare ground radiates enough accumulated heat to give
young plants some protection. The success of this protection depends, of course, on
the severity and the duration of the temperature drop, but it is important in the
usual ranges recorded in the Homestead area (26-320F).

8. Types of pumps and filters to be used.

SElectrical pumps are definitely the most versatile types and are the ones we recommend
Among their merits are: need little maintenance, start instantly, are economical to
operate, can be automated by the use of time clocks, and they work continuously with-
out the need of refueling.

The filters to be used should be the best available type for our conditions. Our
experience has shown that those consisting of nylon and stainless steel sieves of
different meshes work very adequately. The finest sieve is usually a nylon cloth of
160 mesh which removes practically all particles of sand. It should be stressed here
that good filters are an insurance against failure of the system which will happen if
a large portion of emitters are stopped up. It is very laborious and expensive to
clean emitters once they have become clogged in the field.

9. Installations of trickle irrigation on mature groves planted without trenching.

Prior to 1960 most groves were not planted by the system of cross-trenching. Despite
some initial doubts trickle irrigation has worked very adequately in these untrenched
old groves. It does appear, however, that more emitters per tree are required than
in trenched groves because the lateral movement of water is not as extensive as in
the trenches. The number of emitters depends on the fruit tree to be irrigated. In
some instances it may even be necessary to use two laterals, one on each side of the
row of trees with a separation of approximately 6 feet between each other. This type
of arrangement works very well, particularly in old groves adjacent to housing de-
velopments where the neighbors may object to other types of irrigation. In this re-
gard we could also add that trickle irrigation is ideally adapted to the dooryard
S grower, or to the suburbanite with a few acres of trees who is surrounded by expensive
homes.
J







The accumulation of precipitates in the polyethylene laterals has not been a severe
problem so far, although materials such as potassium nitrate and some chelates
usually leave a precipitate which could eventually clog emitters. We use a wetting
A agent in conjunction with the fertilizer solution to facilitate the flow of small
particles through the emitters and prevent accumulations which could be potentially
troublesome later.

At this point, we should caution growers that this type of "fertigation" should be
approached carefully because of the potential danger in clogging emitters. A certain
amount of experimenting with small amounts of soluble fertilizer is necessary before
starting regular applications. Having the proper type of filter is very important
because it is an insurance against particles and other impurities often found in
commercial fertilizers.

7. Frost protection and the importance of a good herbicide program.

Trickle irrigation does not provide frost protection in the manner nor to the degree
that sprinkler irrigation does. This is very important particularly with young plants
for which frost protection should be provided by heating devices or other means.
However, one manner of minimizing the danger of frost damage is by keeping the ground
clean and free of weeds with herbicides during the critical winter months. Mulch and
trash should be removed to expose the ground around young plants. It is a well known
fact in the Homestead area that bare ground radiates enough accumulated heat to give
young plants some protection. The success of this protection depends, of course, on
the severity and the duration of the temperature drop, but it is important in the
usual ranges recorded in the Homestead area (26-320F).

8. Types of pumps and filters to be used.

SElectrical pumps are definitely the most versatile types and are the ones we recommend
Among their merits are: need little maintenance, start instantly, are economical to
operate, can be automated by the use of time clocks, and they work continuously with-
out the need of refueling.

The filters to be used should be the best available type for our conditions. Our
experience has shown that those consisting of nylon and stainless steel sieves of
different meshes work very adequately. The finest sieve is usually a nylon cloth of
160 mesh which removes practically all particles of sand. It should be stressed here
that good filters are an insurance against failure of the system which will happen if
a large portion of emitters are stopped up. It is very laborious and expensive to
clean emitters once they have become clogged in the field.

9. Installations of trickle irrigation on mature groves planted without trenching.

Prior to 1960 most groves were not planted by the system of cross-trenching. Despite
some initial doubts trickle irrigation has worked very adequately in these untrenched
old groves. It does appear, however, that more emitters per tree are required than
in trenched groves because the lateral movement of water is not as extensive as in
the trenches. The number of emitters depends on the fruit tree to be irrigated. In
some instances it may even be necessary to use two laterals, one on each side of the
row of trees with a separation of approximately 6 feet between each other. This type
of arrangement works very well, particularly in old groves adjacent to housing de-
velopments where the neighbors may object to other types of irrigation. In this re-
gard we could also add that trickle irrigation is ideally adapted to the dooryard
S grower, or to the suburbanite with a few acres of trees who is surrounded by expensive
homes.
J










10. Effect on grove weed growth.

Observations indicate that weed growth throughout the grove is not encouraged with
trickle irrigation as is the case with sprinkler irrigation. Weed growth during the
winter and spring months is limited to the area wetted by the emitter. This has
permitted either the elimination of the January herbicide treatment or a change from
a blanket into a spot application. Whatever weed growth occurs in the middles during
the dry months can be easily suppressed by mowing.

11. Comparative costs of trickle irrigation.

Depending on the acreage involved the type of equipment and labor used, and whether
or not the grower makes his own installation, initial costs range between $250.00
to $400.00/acre. The cost of operating an installation depends on the area irrigated
and the amount of daily irrigation applied and fluctuates between $1.00 and $2.50
per month per acre. Large installations need some labor for a certain amount of
supervision and trouble shooting but small installations are almost trouble free if
well made. Susceptibility to vandalism is perhaps the greatest handicap at present
and one that could prove costly at times. Polyethylene laterals are easy to cut off
and take away. Since electrical pumps are usually small they can be easily carried
away if the PVC connections are sawed off. The best insurance against theft is to
locate this equipment in such a way that it is hidden from passersby.










10. Effect on grove weed growth.

Observations indicate that weed growth throughout the grove is not encouraged with
trickle irrigation as is the case with sprinkler irrigation. Weed growth during the
winter and spring months is limited to the area wetted by the emitter. This has
permitted either the elimination of the January herbicide treatment or a change from
a blanket into a spot application. Whatever weed growth occurs in the middles during
the dry months can be easily suppressed by mowing.

11. Comparative costs of trickle irrigation.

Depending on the acreage involved the type of equipment and labor used, and whether
or not the grower makes his own installation, initial costs range between $250.00
to $400.00/acre. The cost of operating an installation depends on the area irrigated
and the amount of daily irrigation applied and fluctuates between $1.00 and $2.50
per month per acre. Large installations need some labor for a certain amount of
supervision and trouble shooting but small installations are almost trouble free if
well made. Susceptibility to vandalism is perhaps the greatest handicap at present
and one that could prove costly at times. Polyethylene laterals are easy to cut off
and take away. Since electrical pumps are usually small they can be easily carried
away if the PVC connections are sawed off. The best insurance against theft is to
locate this equipment in such a way that it is hidden from passersby.




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