Citation
Microirrigation of young blueberries in Florida

Material Information

Title:
Microirrigation of young blueberries in Florida
Series Title:
Florida Cooperative Extension Service bulletin 301
Creator:
Haman, D. Z. (Dorota Z.)
Smajstrla, Allen G.
Zazueta, Fedro S.
Lyrene, Paul M.
Pritchard, Robert T.
Affiliation:
University of Florida -- Florida Cooperative Extension Service -- Institute of Food and Agricultural Sciences
Place of Publication:
Gainesville, Fla.
Publisher:
Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida
Publication Date:
Language:
English
Physical Description:
8 p. : ill. ; 28 cm.

Subjects

Subjects / Keywords:
Agriculture ( LCSH )
Farm life ( LCSH )
Farming ( LCSH )
University of Florida. ( LCSH )
Agriculture -- Florida ( LCSH )
Farm life -- Florida ( LCSH )
Blueberries -- Irrigation -- Florida ( LCSH )
Irrigation engineering -- Florida ( LCSH )
Microirrigation -- Florida ( LCSH )
Spatial Coverage:
North America -- United States of America -- Florida

Notes

Funding:
Florida Historical Agriculture and Rural Life

Record Information

Source Institution:
Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location:
Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management:
All rights reserved, Board of Trustees of the University of Florida
Resource Identifier:
AKJ3747 ( NOTIS )
020314656 ( ALEPH )
32486100 ( OCLC )

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Copyright 2005, Board of Trustees, University
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C.1 UNIVERSITY OF

FLORIDA

Florida Cooperative Extension Service


Marston Science
Library

APR 2 019

University of Florida


Microirrigation of Young Blueberries in Florida1 J

Dorota Z. Haman, Allen G. Smajstrla, Fedro S. Zazueta, Paul M. Lyrene, Robert T. Pritchard2


BLUEBERRY PRODUCTION IN FLORIDA

Blueberry production shows great promise as a
fruit crop in Florida. Although blueberries are grown
in many other states, Florida's climate allows fruit to
reach maturity earlier, avoiding competition with
growers in other states. The unique market window
brings very high prices to blueberry growers. This
advantage has been increased by the recent
introduction of earlier-yielding highbush varieties.

Currently, about 2,100 acres of blueberries are
grown in Florida. This acreage is expected to expand
with new early-yielding blueberry varieties, and
existing growers expanding their acreage. Presently,
the blueberry acreage is evenly divided between
rabbiteye and highbush varieties. However, for the
last 10 years, new plantations have been almost
exclusively planted to highbush varieties.

Newly developed early ripening highbush varieties
are of the greatest interest to Florida growers. These
varieties are lower yielding and much more difficult to
grow than rabbiteye varieties, but the early ripening >,
fruit brings high prices since it is the only blueberitf
available at this time. Before May 20, the average
price is approximately five dollars per pound. After
June 1, the average price drops to around one dollar
per pound. Highbush plants are more difficult to
establish and have a shorter life expectancy than the
rabbiteye varieties. They are also much more
sensitive to water stress and require frequent


irrigation to grow and produce even when well
established.

Rabbiteye blueberries are native to Florida. They
are relatively easy to grow and they are the highest
yielding variety under Florida's climatic conditions.
The plants are more vigorous, longer living, higher
yielding, but later ripening than the highbush variety.
However, the rabbiteyes experience some problems
with fruit setting, thus yields do not always reach the
expected levels. If the pollination problems can be
solved, it is very likely that rabbiteyes will again
account for a significant percentage of new plantings
since they are much easier to grow, and once
established, live longer and produce much better.
During the establishment period the plants respond
very well to irrigation, however, once well established,
they are less sensitive to water stress than highbush
varieties. In addition, rabbiteye blueberries can be
mechanically harvested which significantly decreases
production cost.

The recommendations presented in this
publication were developed based on a three year
experiment on water requirements for establishment
of young blueberry plants which was conducted at the
University of Florida. The project was partially
funded by the St. John's River and the Southwest
Florida Water Management Districts. Both native
rabbiteye and newly developed early-yielding highbush
varieties were studied. Two-year old, container-grown
plants were transplanted to the field at the beginning


1. This document is Bulletin 301, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida.
Publication date: October 1994.
2. Dorota Z. Haman, Associate Professor, Allen G. Smajstrla, Professor, Fedro S. Zazueta, Professor, Agricultural Engineering Department; Paul
M. Lyrene, Professor, Horticultural Science Department; Robert T. Pritchard, Graduate Research Assistant, Agricultural Engineering
Department, Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida, Gainesville FL 32611.
The Institute of Food and Agricultural Sciences is an equal opportunity/affirmative action employer authorized to provide research,
educational information and other services only to individuals and institutions that function without regard to race, color, sex, age, handicap,
or national origin. For information on obtaining other extension publications, contact your county Cooperative Extension Service office.
Florida Cooperative Extension Service / Institute of Food and Agricultural Sciences / University of Florida / John T. Woeste, Dean


Bulletin 301
October 1994








Microirrigation of Young Blueberries in Florida


of 1991. The experiment ended in
December 1993. Total water use
evapotranspirationn), irrigation
requirements, crop yield, and
vegetative plant growth were evaluated
during the three years after
transplanting.

IRRIGATION SCHEDULING OF
YOUNG BLUEBERRIES

To avoid drought stress, irrigation
and rain must be adequate to provide
water for plant transpiration and
evaporation from the soil and plant
surfaces. The term which describes
the amount of water used in this
processes is called evapotranspiration
(ET). For young plants, ET is a
fraction of reference
evapotranspiration (ETo) which is
defined as the evapotranspiration rate
from an extensive, short grass cover,
completely shading the ground, and
not subjected to water stress. ETo is
a function of climatic conditions and
can be calculated from an energy
balance at the crop canopy level. The
most accurate method of calculating
ETo is the Penman method which is
based on radiation, temperature,
humidity, and wind velocity. Long-
term average values of ETo for
Florida are available from IFAS
extension service (Extension Bulletin
205).

Evapotranspiration of young
blueberries


The evapotranspiration of young 3 Jul
blueberry plants during the first three
years after transplanting was presented Ag
in the IFAS Extension Bulletin "Water Sep
Use in Establishment of Young Oct
Blueberry Plants". The amount of Nov
water used by the plants is a direct
function of ETo and depends on Dec
plants' age, planting density, and the
blueberry species highbushh or rabbiteye). In this
publication, a density of 1000 plants/acre was
assumed. Estimates of water use, in gallons per acre,
in inches over the entire production area, and in
gallons per plant during the first three years after


Table 1. Water requirements of young blueberries during the first three years of
establishment based on long term average weather data.

Rabbiteye Highbush
Year Month gaal in_ gal gal in ga
acre acre acre plant
Apr 5550 .26 6 6940 .26 7
May 22120 .81 22 7900 .29 8
Jun 30850 1.14 31 16240 .60 16
Jul 37660 1.39 38 19650 .72 20


1 Aug
Sep


32440
27120


16220
13560


Oct 23760 .88 24 11400 .42 11
Nov 16090 59 16 10300 38 10
Dec 6210 .23 6 6210 .23 6
Jan 6610 24 7 7720 .28 8
Feb 8810 .32 9 9610 .35 10
Mar 12900 48 13 9680 36 10
Apr 27750 1.02 28 12490 .46 12
May 36350 1.34 36 15800 .58 16
Jun 38970 1.44 39 19490 .72 19
2
Jul 40930 1.51 41 24560 .90 25
Aug 35380 1.30 35 26540 .98 27
Seo 28350 1.04 28 23420 .86 23


19960
12230


.74
.45


19000
11580


Dec 7170 .26 7 6210 .23 6
Jan 7720 .28 8 3300 .20 3
Feb 6400 .24 6 4800 .24 5
Mar 7530 .28 7 7530 .28 8


27750 1.02 28 23590 .87 24
56890 2.10 57 39510 1.46 40
61700 2.27 62 43840 1.61 44
68770 2.53 69 49120 1 81 49
60450 2.23 60 42760 1.57 43
57940 2.13 58 43140 1 59 43
29460 1.09 29 29460 1.09 29
14160 .52 14 22520 .83 23
13860 .51 14 21980 .81 22


transplanting, are presented in Table 1. These
amounts of water must be supplied to the plant to
provide moisture conditions for optimum plant
growth. If density of planting is different from 1000


Page 2








Microirrigation of Young Blueberries in Florida


of 1991. The experiment ended in
December 1993. Total water use
evapotranspirationn), irrigation
requirements, crop yield, and
vegetative plant growth were evaluated
during the three years after
transplanting.

IRRIGATION SCHEDULING OF
YOUNG BLUEBERRIES

To avoid drought stress, irrigation
and rain must be adequate to provide
water for plant transpiration and
evaporation from the soil and plant
surfaces. The term which describes
the amount of water used in this
processes is called evapotranspiration
(ET). For young plants, ET is a
fraction of reference
evapotranspiration (ETo) which is
defined as the evapotranspiration rate
from an extensive, short grass cover,
completely shading the ground, and
not subjected to water stress. ETo is
a function of climatic conditions and
can be calculated from an energy
balance at the crop canopy level. The
most accurate method of calculating
ETo is the Penman method which is
based on radiation, temperature,
humidity, and wind velocity. Long-
term average values of ETo for
Florida are available from IFAS
extension service (Extension Bulletin
205).

Evapotranspiration of young
blueberries


The evapotranspiration of young 3 Jul
blueberry plants during the first three
years after transplanting was presented Ag
in the IFAS Extension Bulletin "Water Sep
Use in Establishment of Young Oct
Blueberry Plants". The amount of Nov
water used by the plants is a direct
function of ETo and depends on Dec
plants' age, planting density, and the
blueberry species highbushh or rabbiteye). In this
publication, a density of 1000 plants/acre was
assumed. Estimates of water use, in gallons per acre,
in inches over the entire production area, and in
gallons per plant during the first three years after


Table 1. Water requirements of young blueberries during the first three years of
establishment based on long term average weather data.

Rabbiteye Highbush
Year Month gaal in_ gal gal in ga
acre acre acre plant
Apr 5550 .26 6 6940 .26 7
May 22120 .81 22 7900 .29 8
Jun 30850 1.14 31 16240 .60 16
Jul 37660 1.39 38 19650 .72 20


1 Aug
Sep


32440
27120


16220
13560


Oct 23760 .88 24 11400 .42 11
Nov 16090 59 16 10300 38 10
Dec 6210 .23 6 6210 .23 6
Jan 6610 24 7 7720 .28 8
Feb 8810 .32 9 9610 .35 10
Mar 12900 48 13 9680 36 10
Apr 27750 1.02 28 12490 .46 12
May 36350 1.34 36 15800 .58 16
Jun 38970 1.44 39 19490 .72 19
2
Jul 40930 1.51 41 24560 .90 25
Aug 35380 1.30 35 26540 .98 27
Seo 28350 1.04 28 23420 .86 23


19960
12230


.74
.45


19000
11580


Dec 7170 .26 7 6210 .23 6
Jan 7720 .28 8 3300 .20 3
Feb 6400 .24 6 4800 .24 5
Mar 7530 .28 7 7530 .28 8


27750 1.02 28 23590 .87 24
56890 2.10 57 39510 1.46 40
61700 2.27 62 43840 1.61 44
68770 2.53 69 49120 1 81 49
60450 2.23 60 42760 1.57 43
57940 2.13 58 43140 1 59 43
29460 1.09 29 29460 1.09 29
14160 .52 14 22520 .83 23
13860 .51 14 21980 .81 22


transplanting, are presented in Table 1. These
amounts of water must be supplied to the plant to
provide moisture conditions for optimum plant
growth. If density of planting is different from 1000


Page 2







Microirrigation of Young Blueberries in Florida

plants per acre, the gallons per plant can be
multiplied by the number of plants to calculate the
amount of water which must be applied per acre.

Effective Rainfall

In arid climates all water required for plant
growth must be applied through an irrigation system.
In humid climates rainfall will contribute to the water
supply, decreasing the amount of water which must be
provided by irrigation.

The root zone of a blueberry plant is very
shallow, especially for the highbush species. The
roots of a highbush plant can uptake water from only
the upper 1 foot of the soil profile. The rabbiteye
species has a deeper root system which allows the
plants to utilize 2 feet of the soil profile.

In Florida's humid climate, part of the water used
by the plant is supplied by rainfall. The annual
rainfall in Florida is about 50-60 inches, however,
most of this water is not available to the plant due to
uneven distribution of rainfall throughout the year
and very low water storage (water holding capacity) of
Florida sandy soils. On average, only .75 in of water
is available to the plant from each foot of the soil
profile. Usually, an irrigation is scheduled when
approximately one third of this water has been used.
This means that at the time of irrigation there is
room for only about 0.25 inch of water per foot of
root depth.

Timing of rain is critical to its effectiveness. If
rain occurs just before an irrigation would normally
be scheduled, the maximum amount of rain which
would be effective (stored in the root zone and
available for plant use) is 0.25 in/foot. Any additional
amount of rain will be lost to deep percolation and
will not be available to the plant. If the rainfall
occurs directly after irrigation and the root zone is
already filled with water, most or all of the rainfall
will be lost to deep percolation. As a result, for
efficient water use, blueberries require frequent,-small
applications of water through an irrigation system and
only a fraction of rainfall can be effective.

Irrigation scheduling

Irrigation scheduling must take under
consideration the total water requirements of the
plants, the amount of water which can be stored in
the root zone for plant use, and the constraints of the
irrigation system. The size of an irrigation system and


Page 3


its layout will have an impact on the minimum time
the system can be operated. For example, for many
larger systems, it is not practical to schedule irrigation
events shorter than 1/2 hour.

A microirrigation system applies water to a
portion of the field leaving a significant amount of
land dry. However, it is important to realize that the
amount which the plant needs per month is the
amount listed in Table 1 regardless of the percentage
of wetted area. The total amount which can be
applied during a single irrigation event without
significant losses to deep percolation depends on the
wetted area of the emitter and the allowable
depletion in the root zone. Therefore, more frequent
irrigations will be required if the wetted area is
reduced, while less frequent irrigations will be
permitted if the wetted area is larger.

The wetted surface area of the emitter and the
depth of the root zone determines the wetted volume
of soil for each plant. For the highbush varieties, it
was assumed that the root depth did not change
significantly during the first three years of
establishment and that it was equal to 1 foot. Since
the rabbiteye varieties have a deeper root system, a
gradual increase in root depth over three years was
considered in the calculations. It was assumed that
the root depth changed from 1 foot to 1.5 and 2 feet
in the first, second, and third year, respectively.
Based on the depletion level between irrigations, the
amount of water necessary to bring the soil volume to
field capacity (maximum water content) at each
irrigation was calculated.

Table 1 was developed for a production system
with a plant density of 1000 plants/acre. The
irrigation system is microsprinklers with a flow rate of
10 gal/hr. A deflector should be used to limit the
wetted diameter to 4, 5, or 6 ft for 1, 2, or 3-year-old
plants, respectively. These diameter changes can be
made by adjusting the height of the stake which
supports the emitter.

In development of Table 2 it was assumed that
the flow rate from each emitter is 10 gal/hr and there
is 1 emitter for every two plants. To minimize the
losses to deep percolation the duration of irrigation
events must be carefully monitored. It is assumed
that the duration of the irrigation events will change
with the development of the root system and the
change of wetted diameter of the emitter.







Microirrigation of Young Blueberries in Florida

plants per acre, the gallons per plant can be
multiplied by the number of plants to calculate the
amount of water which must be applied per acre.

Effective Rainfall

In arid climates all water required for plant
growth must be applied through an irrigation system.
In humid climates rainfall will contribute to the water
supply, decreasing the amount of water which must be
provided by irrigation.

The root zone of a blueberry plant is very
shallow, especially for the highbush species. The
roots of a highbush plant can uptake water from only
the upper 1 foot of the soil profile. The rabbiteye
species has a deeper root system which allows the
plants to utilize 2 feet of the soil profile.

In Florida's humid climate, part of the water used
by the plant is supplied by rainfall. The annual
rainfall in Florida is about 50-60 inches, however,
most of this water is not available to the plant due to
uneven distribution of rainfall throughout the year
and very low water storage (water holding capacity) of
Florida sandy soils. On average, only .75 in of water
is available to the plant from each foot of the soil
profile. Usually, an irrigation is scheduled when
approximately one third of this water has been used.
This means that at the time of irrigation there is
room for only about 0.25 inch of water per foot of
root depth.

Timing of rain is critical to its effectiveness. If
rain occurs just before an irrigation would normally
be scheduled, the maximum amount of rain which
would be effective (stored in the root zone and
available for plant use) is 0.25 in/foot. Any additional
amount of rain will be lost to deep percolation and
will not be available to the plant. If the rainfall
occurs directly after irrigation and the root zone is
already filled with water, most or all of the rainfall
will be lost to deep percolation. As a result, for
efficient water use, blueberries require frequent,-small
applications of water through an irrigation system and
only a fraction of rainfall can be effective.

Irrigation scheduling

Irrigation scheduling must take under
consideration the total water requirements of the
plants, the amount of water which can be stored in
the root zone for plant use, and the constraints of the
irrigation system. The size of an irrigation system and


Page 3


its layout will have an impact on the minimum time
the system can be operated. For example, for many
larger systems, it is not practical to schedule irrigation
events shorter than 1/2 hour.

A microirrigation system applies water to a
portion of the field leaving a significant amount of
land dry. However, it is important to realize that the
amount which the plant needs per month is the
amount listed in Table 1 regardless of the percentage
of wetted area. The total amount which can be
applied during a single irrigation event without
significant losses to deep percolation depends on the
wetted area of the emitter and the allowable
depletion in the root zone. Therefore, more frequent
irrigations will be required if the wetted area is
reduced, while less frequent irrigations will be
permitted if the wetted area is larger.

The wetted surface area of the emitter and the
depth of the root zone determines the wetted volume
of soil for each plant. For the highbush varieties, it
was assumed that the root depth did not change
significantly during the first three years of
establishment and that it was equal to 1 foot. Since
the rabbiteye varieties have a deeper root system, a
gradual increase in root depth over three years was
considered in the calculations. It was assumed that
the root depth changed from 1 foot to 1.5 and 2 feet
in the first, second, and third year, respectively.
Based on the depletion level between irrigations, the
amount of water necessary to bring the soil volume to
field capacity (maximum water content) at each
irrigation was calculated.

Table 1 was developed for a production system
with a plant density of 1000 plants/acre. The
irrigation system is microsprinklers with a flow rate of
10 gal/hr. A deflector should be used to limit the
wetted diameter to 4, 5, or 6 ft for 1, 2, or 3-year-old
plants, respectively. These diameter changes can be
made by adjusting the height of the stake which
supports the emitter.

In development of Table 2 it was assumed that
the flow rate from each emitter is 10 gal/hr and there
is 1 emitter for every two plants. To minimize the
losses to deep percolation the duration of irrigation
events must be carefully monitored. It is assumed
that the duration of the irrigation events will change
with the development of the root system and the
change of wetted diameter of the emitter.








Microirrigation of Young Blueberries in Florida


Table 2. Approximate numbers of days between irrigations during the first three
years after transplanting under no-rain conditions.**
Year one Year two Year three
rabbit- high- rabbit- high- rabbit- high-
eye bush eye bush eye bush
4 ft WD* 5 ft WD 6ftWD
Jan 10 10 10 7 14 12
Feb 10 10 7 4 14 9
Mar 10 10 6 4 14 9
Apr 5 4 3 3 4 2
May 2 3 2 3 2 1
Jun 1 2 2 2 2 1
Jul 1 1 2 2 2 1
Aug 1 2 2 1 2 1
Sep 1 2 3 2 2 1
n I


Table 3. Recommended maximum duration
of irrigation events in minutes for highbush
and rabbiteye blueberries during the first
three years of establishment.*

Year 1 Year 2 Year 3
4ft 5ft 6ft
WD** WD** WD**

High- 15 20 30
bush
Rabbit- 15 30 60
eye

*microsprinkler flow rate 10 gal/hr.
**WD wetted diameter of the micro-
sprinkler.


Irrigation adjustment after rainfall


cI 1 24 2 4
Rainfall between irrigation events
Nov 2 3 6 4 9 2 will contribute to the water supply in
Dec 5 4 10 7 9 3 the root zone and delay the next
irrigation event. The length of delay
*WD wetted diameter of the microsprinkler. irrigation event. The effectiveness of thel
**root zone depths assumed 1, 1.5, and 2 ft in for years 1, 2, and 3, depends on the effectiveness of the
respectively for rabbiteye and a constant depth of 1 ft highbush varieties rain which in turn depends on the
dutingalltlfmeyears. amount and timing of the rain. A .25
inch rainfall per foot of root zone
depth just before the scheduled
The root system for both varieties was assumed to irrigation is all available to the plant. The same
be approximately 1 foot deep at the time of amount of rain just after an irrigation event is lost to
transplanting. Since tfie root depth for the highbuhighbuslHtpqaqtii olation since there is no room for additional
varieties remains quite shallow, only lateral growth in water in the root zone.
consecutive years is taken under consideration in
calculating root volume of the plant. For all three The following tables give guidelines on adjusting
years the depth of root zone was assumed to be 1 the irrigation schedule depending on when rain
foot. occurred, and the amount of rainfall. Assuming


For the rabbiteye varieties the increase in root
depth during the first three years of plant growth was
large enough that this increase is reflected in
scheduling the irrigation events. The depth of the
root zone was assumed 1 foot, 1.5 feet and 2 ft for
years 1, 2, and 3, respectively. Recommended
maximum durations of irrigation events for the system
described above are presented in Table 3. If the
irrigation system does not permit 15 min water
applications, the system should be run for as short a
period of time as possible.

If the conditions of a specific production system
are different, these numbers must be adjusted.


Florida's sandy soils, the allowable depletion between
irrigations was assumed to be .25 in/ft.

Table 4 was developed for both highbush and
rabbiteye varieties during the first year after
transplanting. A 1 ft root depth and a .25 inch
allowable water depletion in the root zone were
assumed. Since the root depth for highbush varieties
was assumed to be constant, Table 4 should be used
during all three years for these varieties of blueberry.
Table 5 was developed for the second year of
establishment of rabbiteye varieties with a 1.5 ft root
depth and a 0.38 inch allowable water depletion. And
finally, Table 6 was developed for the last year of
establishment of rabbiteye blueberries with a 2 ft root
depth and 0.50 inch allowable water depletion.


Page 4








Microirrigation of Young Blueberries in Florida Page 5

These tables should not be used without adjustment if soil and plant conditions are different from the above
assumptions.


Table 4. Number of days an irrigation should be delayed for highbush varieties during all three years and for rabbiteye varieties
in the first year.

Normal Irrigation Rain Depth
Interval (days) (inches) 1 2 3 4 5 6 7
1 2 3 4 5 6 7

.10 1 2 2 2 2 2 2

7 .20 1 2 3 4 5 5 5

.25 or more 1 2 3 4 5 6 7

.10 1 2 2 2 2 2

6 .20 1 2 3 4 4 4

.25 or more 1 2 3 4 5 6

.10 1 2 2 2 2

5 .20 1 2 3 4 4

.25 or more 1 2 3 4 5

.10 1 1 1 1

4 .20 1 2 3 3

.25 or more 1 2 3 4

.10 1 1 1

3 .20 1 2 2

.25 or more 1 2 3

.10 0 0

2 .20 1 1

.25 or more 1 2

.10 0

1 .20 0
.25 or more 1








Microirrigation of Young Blueberries in Florida Page 6

Table 5. Number of days an irrigation should be delayed during the second year for rabbiteye varieties.

Normal Irrigation Rain Depth
Interval (days) (inches) 1 2 3 4 5 6 7
1 2 3 4 5 6 7

.10 1 1 1 1 1 1 1

.20 1 2 3 3 3 3 3
7
.30 1 2 3 4 5 5 5
.38 or more 1 2 3 4 5 6 7

.10 1 1 1 1 1 1
.20 1 2 3 3 3 3
6
.30 1 2 3 4 4 4
.38 or more 1 2 3 4 5 6

.10 1 1 1 1 1
.20 1 2 2 2 2
5
.30 1 2 3 4 4

.38 or more 1 2 3 4 5
.10 1 1 1 1
.20 1 2 2 2
4
.30 1 2 3 3
.38 or more 1 2 3 4

.10 0 0 0
.20 1 1 1
3
.30 1 2 2
.38 or more 1 2 3
10 0 0
.20 1 1
2
30 1 1
38 or more 1 2

.10 0
.20 0
.30 0
.38 or more 1








Microirrigation of Young Blueberries in Florida Page 7

Table 6. Number of days an irrigation should be delayed during the third year for rabbiteye varieties.

Normal Irrigation Rain Depth
Interval (days) (inches)
1 2 3 4 5 6 7
.10 1 1 1 1 1 1 1
.20 1 2 2 2 2 2 2
7 .30 1 2 3 4 4 4 4
.40 1 2 3 4 5 5 5
.50 or more 1 2 3 4 5 #6 7
.10 1 1 1 1 1 1
.20 1 2 2 2 2 2
6 .30 1 2 3 3 3 3
.40 1 2 3 4 4 4
.50 or more 1 2 3 4 5 6
.10 1 1 1 1 1
.20 1 2 2 2 2
5 .30 1 2 3 3 3
.40 1 2 3 4 4
.50 or more 1 2 3 4 5
.10 0 0 0 0
.20 1 1 1 1
4 .30 1 2 2 2
.40 1 2 3 3
.50 or more 1 2 3 4
.10 0 0 0
.20 1 1 1
3 .30 1 1 1
.40 1 2 2
.50 or more 1 2 3
.10 0 0
.20 0 0
2 .30 1 1
.40 1 1
.50 or more 1 2
.10 0
.20 0
1 .30 0
.40 0
.50 or more 1








Microirrigation of Young Blueberries in Florida


Example


How many days should irrigation be delayed for
rabbiteye blueberries during April of the second year
of establishment if there is a .30 inch rainfall 2 days
after irrigation?

From Table 2, rabbiteye blueberries in the second
year of establishment require an irrigation every 3
days in April under no-rain conditions. From Table
5, a rain event of .30 inch 2 days after irrigation
allows for an additional two days before scheduling
the next irrigation. This means that the next
irrigation event will be scheduled 3 days after the
rain, for a total irrigation interval of 5 days.


The recommendations presented in this
publication were based on three-year experiment on
water requirements for establishment of young
blueberry plants which was conducted at the
University of Florida. The project was partially
funded by the St. John's River and the Southwest
Florida Water Management Districts. Based on the
results from this project and long term average
weather data, a general schedule of irrigation events
was developed for the first three years of blueberry
establishment. A series of tables adjusting the timing
of irrigation events due to rainfall was also developed
and presented.


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SUMMARY