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Group Title: Agronomy research report - University of Florida Institute of Food and Agricultural Sciences ; AY-95-02
Title: Comparison of Zn nutritionals spray treatments for citrus leaf Zn adsorption and absorption
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 Material Information
Title: Comparison of Zn nutritionals spray treatments for citrus leaf Zn adsorption and absorption
Series Title: Agronomy research report
Physical Description: 20 leaves : ill. ; 28 cm.
Language: English
Creator: Gallaher, Raymond N
University of Florida -- Agronomy Dept
Publisher: Department of Agronomy, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1995?]
 Subjects
Subject: Citrus -- Diseases and pests -- Control -- Florida   ( lcsh )
Foliar diagnosis   ( lcsh )
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non-fiction   ( marcgt )
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Bibliography: Includes bibliographical references (leaves 7-8).
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        Page 4
        Page 5
        Page 6
        Page 7
        Page 8
        Page 11
        Page 12
        Figure 1
        Figure 2
        Figure 3
        Page 13
        Page 14
        Page 15
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Copyright 2005, Board of Trustees, University
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9c- 0 2-
Agronomy Research Report AY-95-02


ijhr'st : Scien:
L irary
JAN 0 3 1026
1:--. r..esit^ O? n ^ -


Comparison of Zn Nutritionals Spray
Treatments for Citrus Leaf Zn Adsorption and
Absorption



R. N. Gallaher


Professor of Agronomy, Institute of Food and
Agricultural Sciences, University of Florida,
Gainesville 32611







Agronomy Research Report AY-95-02


Comparison of Zn Nutritionals Spray Treatments for Citrus Leaf Zn
Adsorption and Absorption

R. N. Gallaher
Professor of Agronomy, Institute of Food and Agricultural Sciences,
University of Florida, Gainesville 32611


INTRODUCTION

Leaf analysis for diagnosis of nutritional status of citrus is
an old practice (Reitz et al. 1952; Reuther et al. 1954; Smith et
al. 1949; Smith et al. 1966). Sufficiency level standards have
been established for most plant nutrients (Jones et al. 1991; Koo,
et al. 1984) (Table 1). However, for the tissue test to be
meaningful, growers and researchers must follow established methods
for leaf collection, decontamination and analysis (Jones et al.
1991; Koo et al. 1994; Obreza, et al., 1992; Futch and Gallaher,
1994).

Previous recommendations state that analysis of leaves sprayed
with nutritional elements must be thoroughly washed with detergent
solution and rinsed in distilled water prior to drying (Smith et
al. 1966). It has also been reported that leaves sprayed with Cu,
Zn, or Mn should not be analyzed for these elements even if washed,
as it is impossible to eliminate interference from surface
contamination (Koo et al. 1984; Smith et al. 1966; Obreza et al.
1992). On the other hand, another study showed that washing citrus
leaves previously sprayed with Zn nutritional was effective in
removing adsorbed Zn from the leaf surface (Futch and Gallaher,
1994). Form their study it appeared that be best decontamination
treatment was to first wash with a detergent solution followed by
HC1 acid wash and rinse with deionized water. While detergent
solution was effective in removal of highly soluble compounds like
basic ZnSO4, the addition of dilute HC1 was required to dissolve and
remove the highly insoluble ZnO (Futch and Gallaher, 1994).

The objectives of this study were: 1. To assess the
adsorption and absorption of Zn by 3 to 6 months old valencia
orange tree leaves using three Zn compounds (ZnO, basic ZnSO4, and
ZnNH4PO4). 2. To conduct electron microscope scans of the top and
bottom surfaces of citrus leaves with and without wash treatment
for Zn adsorption, distribution and/or contamination. 3. To
observe the changes in Zn and other nutrient status from the day of
nutritional spray application until 42 days after treatment
application.







MATERIALS AND METHODS


Twenty potted Valencia citrus (Citrus sinensis) trees on sour
orange (Citrus aurantium) rootstock were obtained from Holmberg
Farms Inc. (13430 Hobson-Simmons Road, Lithia, Florida 33547, phone
# 813-689-3601) two weeks prior to the beginning of the experiment
(Also received 2 'Satsuma Mandarin', 2 'Duncan Grapefruit', and 2
'Nagami Kumquat'). The price was $16.50 per tree with no cost for
shipping. The trees had been under a commercial citrus nursery
production program for 2 1/2-years and were well maintained. By
request the trees had not been sprayed with any Zn nutritional for
the past few months so as to eliminate excessive absorption of Zn
in the leaves. The trees were grown in 7 gallon containers and
were approximately 5 feet tall from the bottom of the container to
the top of the trees.

Prior to experimentation all leaves were washed with 0.1%
Liqui-nox detergent, rinsed with deionized water, and washed with
3% by volume HCl and rinsed with deionized water. This wash was
conducted to remove surface contamination prior to implementing Zn
nutritional spray treatments. Trees were secured by a plastic bag
around the base of the tree and over the pot to ensure that roots
would not fall out of the pot and to ensure that no potting
material would fall into the wash liquid. Trees were turned upside
down and immersed into 20 gallon plastic cans containing the wash
liquid. Tree tops were moved vigorously back and forth for about
2 minutes to allow for removal of contaminants adsorbed on the leaf
surface. A sample of 20 leaves per tree were taken just before and
just after washing to determine the degree of leaf surface Zn and
other nutrient contamination and the success of washing prior to
experimental spraying of Zn nutritional.

Each tree was sprayed on 20 April 1994 with 500 ml of
deionized water containing either 0.360 g of ZnO (5 lb Zn/acre),
0.262 g basic ZnSO4 (2.5 lb Zn/acre), 0.39 g ZnNH4PO4 (2.5. lb
Zn/acre) or 0.78 g ZnNH4PO4 (5 Ib Zn/acre) and control trees
without any Zn in the deionized water. Zinc oxide was 99% pure and
the product contained 79.54% Zn. Basic ZnSO4 contained 54.6% Zn and
ZnNH4PO4 contained 36.7% Zn. An electric, hand held Wagner 120
power paint sprayer was used to spray each tree. All possible
efforts were taken to assure an even and complete coverage of both
the upper and under sides of the leaves. Rate per acre of Zn were
based upon IFAS Bulletin 536D (Koo et al., 1984) that recommended
a rate of 5 lbs. Zn per acre. Treatment trees were assumed to
cover 5.5 square feet (2 ft. 4 in. X 2 ft. 4 in.) or 0.000126 acre.

Trees remained outside during the study period. Rainfall was
recorded daily. Rainfall occurred during the course of the study
as follows: 1.25" 24 April, light shower 27 April, 0.70" 11 May,
1.50" 12 May, and 0.20" 20 May. Trees were placed into a
randomized complete block design which consisted of five trees of







equal size in each replication. Trees were watered as needed with
each tree receiving the same amount of water each time.

Each leaf sampling date consisted of 12 leaves (3 to 6-months
old) collected at random per tree. Leaves were collected weekly
beginning 7 days after spraying and until 42 days after spraying
(7, 14, 21, 28, 35, 42). When the 12 leaves were collected they
were immediately washed as follows: hand washed with 0.1% Liqui-
nox detergent, rinsed with deionized water, hand washed in 3% by
volume HC1 and rinsed with deionized water. Leaves were washed
thoroughly by rubbing each leaf between the fingers using 500 ml of
0.1% Liqui-nox detergent. Each wash time was approximately 2 to 3
minutes per 12 leaves, leaves were rinsed once by rubbing each
leaf with fingers in clean deionized water (500 ml each rinse) for
about 30 seconds per each 12 leaves. Leaves were hand washed
thoroughly by rubbing each leaf between the fingers using 500 ml of
3% HC1 by volume for about 2 to 3 minutes per 12 leaves. Leaves
were rinsed using 500 ml of deionized water (Futch and Gallaher,
1994). An additional set of 12 leaves per tree was collected as
standards and analyzed without any wash treatment.

Detergent solution: 0.1% Liqui-Nox, phosphate free analytical
grade detergent. Measure 0.5 ml of Liqui-Nox/500 ml deionized
water for wash solution.

Three percent HC1 solution: 3% HC1 by volume = 15.0 ml of
concentrated HCl/500 ml of deionized water-HCl each time per wash.

Leaves were washed within 8 hours after collection. Leaves
were cut into small pieces 5 mm or smaller in width with hand held
scissors. The scissors were reined and cleaned between sets of
leaves to avoid any contamination. Leaves were placed in small
paper bags and dried in a forced air oven at 70 C for 48 hours.

After forced air drying, the leaf samples were transferred to
sterile, air tight plastic storage bags. Before weighing samples,
bags were opened and each leaf sample was redried at 70 C prior to
analysis of material for Zn, Fe, Cu, Mn, Ca, Mg, K, P and N
concentrations.

Plant Mineral Analysis

Plant samples were weighed (1.00 g) and placed into 50 ml
pyrex beakers. Beakers were placed in a Thermolyne muffle furnace
at 480 C for approximately 6 hours for dry ashing of the samples.
Cool ash contents were hydrated with 20 ml deionized water, mixed
with 2 ml of concentrated HC1 and gently heated to dryness on a hot
plate. This water/acid treatment was repeated a second time and
brought to a vigorous boil on the hotplate, removed and allowed to
cool to room temperature. This solution was transferred to 100 ml
volumetric flask and brought to volume with deionized water for a
solution strength of 0.1 N HC1. Solutions were analyzed in the IFAS







Extension Soil Testing Lab, University of Florida, for P
(colorimetry), K (flame emission spectrophotometry) and Zn, Fe, Cu,
Mn, Ca and Mg (atomic absorption spectrophotometry) on a Perkin-
Elmer Atomic Absorption Spectrophotometer.

Leaf N Analysis

A 0.100 g of ground leaf sample and two glass boiling beads
were placed in a 100 ml Pyrex test-tube under a hood with 3.2 g of
prepared catalyst (9:1 K2SO4:CuSO4) and 10 ml of concentrated H2SO4,
mixed, placed into an aluminum digester block and digested at 370
C for 210 minutes (Gallaher, et al., 1975). Tubes were capped with
small funnels which allowed gases to escape while preserving
refluxing action. Cool, digested solutions were mixed with
approximately 25 ml of deionized water and allowed to cool.
Solutions were mixed again with deionized water and brought to 75
ml volume, transferred to square Nalgene storage bottles, sealed,
mixed and stored.

Nitrogen was analyzed on a Technicon Autoanalyzer II
(manifold, colorimeter) linked to an automatic Technicon Sampler
IV, and Alpkem Corporation Proportioning Pump III and a strip chart
recorder. A standard laboratory control plant sample was used as
a check with each 39 samples.

Data was tabulated, organized and ASCII files prepared using
Quattro Pro 4.0 (1985) spreadsheet. The ANOVA for a split plot and
mean separation was by use of MSTAT 4.0 (1985) statistical
software. The manuscript was prepared using WordPerfect 5.1 (1990)
word processing software.

Six citrus trees were used in an excessive Zn nutritional
application observation test. This test was desired to determine
if tree leaves were harmed should a grower accidentally apply an
overdose of one of the nutritional during spray treatment. Two
trees were used for duplication of the observation and each of the
three Zn nutritional were applied at the rate of 7.5 lb Zn/acre
equivalent. Therefore, rates per tree will be 0.54 g ZnO, 0786 g
basic ZnSO4, and 1.179 g ZnNH4PO4.

Electron Microscope Analysis

Leaves were collected from control and washed leaves of the
five treatments 10 days after spray treatments were initiated.
Leaves were washed or left unwashed according to procedures
outlined earlier. Stiff cardboard was used on each side of each
flattened leaf in a sandwich fashion and held tightly in place with
large rubber bands. These leaves were then frozen and freeze dried
in order to minimize destruction of the leaf surfaces. Each leaf
was prepared for top and bottom surface viewing to determine the
degree of leaf coating of Zn nutritional as well as cleaning by







the wash treatment. The author personally conducted the electron
microscope analysis utilizing facilities, support personnel and
equipment from Dr. Gregory W. Erdos' lab, University of Florida
(Personal communication, Dr. Gregory W. Erdos, Electron Microscopy,
Microbiology and Cell Science, Bldg 981, Room 1052, P.O. Box
110700, Gainesville, FL 32611-0700). Leaves were prepared in such
a fashion that duplicate electron microscope scans were made for
each leaf surface per washed and unwashed treatment.

RESULTS AND DISCUSSION

Total rainfall and intensity for some events were not as great
as in a previous study (Futch and Gallaher, 1994). The
distribution of rainfall did not appear to have any significant
effect on Zn absorption in this study.

Zinc concentrations indicated that nutritional were effective
in increasing Zn inside citrus leaves (Table 2 and Figures 1, 2 and
3). Large quantities of Zn was removed by the wash treatment
(Table 2). Washed leaves showed that ZnO caused Zn concentration
to steadily increase until 35 to 42 days after treatment (Figure
1). However, for the other Zn nutritional Zn concentration
increased until about 21 days after treatment and then remained
constant or began a slight decline up to 42 days after treatment.
The control treatment showed a slight but steady decrease in Zn
concentration over the 42 day period (Figure 1). Unwashed leaves
showed a steady decline in Zn for all treatments until about 28
days after treatment then appeared to become stable (Figure 2).
The high variability resulted in no differences between basic ZnSO4
and the two rates of ZnNH4PO4 (Table 1), but the trend between the
2.5 lb Zn/acre of each and the control was in favor of the basic
ZnSO4 (Figure 3).

Control leaves contained Zn concentrations in the low to
sufficient range for healthy citrus (Table 1). All Zn nutritional
resulted in leaf Zn concentrations increasing to well within the
optimum or sufficient range except for ZnO. The 5 lb Zn/acre from
ZnO resulted in high levels of Zn in leaves by 35 days after spray
treatment (Table 1 and Figures 1). At 42 days after spray
treatment the trend was for the Basic ZnSO4 to retain greater Zn in
leaves compared to an equal amount of Zn from ZnNH4PO4 (Figure 3).
Zinc concentration from the 2.5 lb basic ZnSO4 at 42 days after
spraying was in the mid range of optimum or sufficient (Tables 1
and 2 and Figure 3).

The effectiveness of the wash treatment in removal of Zn
contamination on the external surface of citrus leaves was
confirmed by electron microscope analysis. Leaf surfaces that were
washed were found to be over 99% free of any foreign matter.
Unwashed leaves sprayed with ZnO were found to have the ZnO
compound imbedded in many of the stomata. Other compounds were not







found to be imbedded in the stomata to the same degree as was ZnO.
This may explain why the Zn was continually absorbed into the leaf
from the ZnO treatment more than the other Zn nutritional. The
highly insoluble ZnO would be in the respiration/transpiration
water stream while imbedded in the stomata. On the other hand this
plugging of the stomata likely interfered in the normal opening and
closing of the stomata.

While electron micrographs showed that all compounds appeared
to be fairly well distributed over the leaf surfaces the ZnO was
found to be in much greater quantities. This raised the question
of whether the ZnO product may have contained some kind of sticker
agent to help it be retained on the leaf surface compared to the
other Zn nutritional. On the other hand, the more soluble basic
ZnSO4 and ZnNH4PO4 could more readily wash off leaf surfaces by
rainfall or from excessive water during the spray treatment.

Unwashed leaves were found to be moderately contaminated with
Fe and highly contaminated with Cu (Tables 3 and 4). When
comparing standard citrus leaf concentrations (Table 1) with washed
leaves, washed leaves were found to contain optimum or sufficient
concentrations of Mn, Ca, Mg and K (Tables 5, 6, 7, and 8). Iron
was the only element that appeared to be low in leaf concentration
(Table 3). Leaf P concentration was in the optimum (sufficient) to
high range and leaf N concentration was in the high to excessively
high range (Tables 9 and 10).

SUMMARY AND CONCLUSIONS

Under the conditions of this study ZnO sprayed at a rate of 5
lb Zn/acre on 3 to 6 month old citrus leaves resulted in the
greatest adsorption and absorption compared to other Zn
nutritional in the study. Zinc levels in the leaves reached the
high range, far above the sufficiency level. Electron micrographs
showed some stomata were plugged with ZnO which likely accounted
for the steady increase in absorption of Zn over the 42 days of the
study. The author questions whether the ZnO product may have
contained some type of sticker agent because of the high levels of
Zn adsorbed on the surfaces of leaves. Basic ZnSO4 at the rate of
2.5 lb Zn/acre brought the Zn concentration in the leaves up to
what appeared to be a relatively steady concentration in the
sufficiency (optimum) range. Basic ZnSO4 at 2.5 lb Zn/acre tended
to be superior in Zn absorption compared to ZnNH4PO4 at the 2.5 Ib
Zn/acre rate and tended to be equal or better than ZnNH4PO4 at 5 lb
Zn/acre. Electron micrographs confirmed that leaf surfaces were
almost completely free from Zn nutritional sprays when washed with
detergent solution, followed by acid wash with dilute HC1 and
rinsed with deionized water.







LITERATURE CITED


CA-CRICKET Graph"t. 1990. User's Guide for CA-CRICKET Graph for
Microsoft Windows. Computer Associates, Software Superior Designs,
10505 Sorrento Valley Road, San Diego, CA 92121-1698.

Gallaher, R.N., C.O. Weldon, and J.G. Futral. 1975. An aluminum
block digester for plant and soil analysis. Soil Science Society
of America Proceedings. 39:803-806.

Futch, S.H., and R.N. Gallaher. 1994. Citrus leaf wash comparison
of zinc nutritional and nutrient uptake analysis. Agronomy
Research Report. AY-94-06. Agronomy Department, Inst. Food and
Agr. Sci., Univ. of Florida, Gainesville.

Jones Jr., J.B., B. Wolf, and H.A. Mills. 1991. Plant Analysis
Handbook. Micro-Macro Publishing, Inc. Athens, Georgia.

Koo, R.C.J., J.I. Stewart, C.A. Anderson, D.V. Calvert, and H.K.
Wustscher. 1984. Recommended fertilizer and nutritional sprays
for citrus. In R.C.J. Koo (ed). Florida Agricultural Experiment
Station Bulletin 536D, 33 p.

MSTAT 4.0 1985. Users Guide to MSTAT, Version 4.0. Michigan
State University, Lansing, Michigan.

Obreza, T.A., A.K. Alva, E.A. Hanlon, and R.E. rouse. 1992.
Citrus grove leaf-tissue and soil testing: sampling, analysis, and
interpretation. Florida Agricultural Experiment Station Fact Sheet
SL115, 4 p.

QUATTRO PRO 4.0 1987. Manual for QUATTRO PRO 4.0, Getting
Started. Borland Int., Inc., 1800 Green Hills Road, P.O. Box
660001, Scotts Valley, CA 95067-0001.

Reitz, H.J., and W.T. Long. 1952. Mineral composition of citrus
leaves from the Indian River area of Florida. Proceedings of the
Florida State Horticultural Society 65:32-38.

Reuther, W., and P.F. Smith. 1954. Leaf analysis of citrus.
Chapter 7. In N.F. Childers (Ed) Mineral Nutrition of Fruit Crops.
Horticultural Publications, Rutgers University, New Brunswick,
N.J., Somerset Press, Somerville, N.J.

Smith, P.F., W. Reuther, and A.W. Specht. 1949. The influence of
rootstock on the mineral composition of Valencia orange leaves.
Plant Physiology 24(3):455-461.

Smith, P.F. 1966. Leaf analysis of citrus. Chapter 7 & 8. In
N.F. Childers, (Ed.) Fruit Nutrition. Horticultural Publications,
Rutgers University, New Burnswick, N.J., Somerset Press,










Somerville, N. J.


WordPerfect Version 5.1. 1990.
Computers and PC Networks. Wo
Technology Way, Orem, Utah 84057.


WordPerfect for IBM Personal
rdPerfect Corporation, 1555 N.


ACKNOWLEDGEMENTS

The author acknowledges the technical assistance of Mr. Jim
Chichester and Mr. Howard Palmer of the University of Florida and
Mr. William C. Duckhardt, Griffin Corporation for his support in
completing this project.





Table .1.
month-old


Leaf analysis standards for citrus based on 4 to 6-
spring-cycle leaves from nonfruiting terminals.


Source: Recommended Fertilizers and Nutritional Sprays for
Citrus. 1984. Koo et al.
Crop Orange, navel and Valencia
Number 30 leaves
Plant Part Nonfruiting, nonflushing shoots
Time Most recently fully developed

ELEMENT LOW SUFFICIENT HIGH
N % 2.20-2.39 2.40-2.69 2.70-2.8

P % 0.09-0.11 0.12-0.16 0.17-0.3

K % 0.40-0.69 0.70-1.09 1.10-2.3

Ca % 1.00-1.49 1.50-2.59 >2.5
Mg % 0.16-0.25 0.26-0.69 0.70-1.1

S % 0.14-0.19 0.20-0.39 0.40-0.6

B ppm 21-30 31-100 101-260
Cu ppm 3-4 5-16 >17
Fe ppm 36-59 60-120 >120
Mn ppm 16-24 25-200 201-300

Mo ppm 0.06-0.09 0.1-3.9 >4

Zn ppm 16-24 25-100 101-300

Source: Plant Analysis Handbook. 1991. Jones et al.


Element

N (%)

P (%)

K (%)
Ca (%)

Mg (%)
Cl (%)

Mn (ppm)

Zn (ppm)

Cu (ppm)
Fe (ppm)

B (ppm)

Mo (ppm)


Deficient

<2.2

<.09

<.7
<1.5
<.20
?<

<17

<17
<3

<35

<20

<.05


Low

2.2-2.4

.09-.11

.70-.11

1.5-2.9
.20-.29
?1

18-24
18-24

3-4
36-59

21-35

.06-.09


Optimum

2.5-2.7

.12-.16

1.2-1.7
3.0-4.9
.30-.49

.05-.10

25-100
25-100

5-16

60-120

36-100

.10-1.0


High
2.8-3.0

.17-.29

1.8-2.3
5.0-6.9

.50-.70

.11-.20

101-300

101-300

17-20
121-200

101-200

2.0-5.0


Excess

>3.0
>.30

>2.4
>7.0
>.80

>.20

>500

>300
>20

>200

>250

>5.0





Table 2. Zinc concentration in 3 to 6 month old leaves of 3-year
old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnSO4 ZnNH4PO4-1 ZnNH4PO4-2 Average


---------- Pretreated-0 days (Zn, ppm)
no 37 38 31 36
yes 35 40 34 36
Average 36a 39a 32a 36a
CV=12.08%


no 55bx
yes 47ax
Average 51
CV=74.29% LSD=199


no 45bx
yes 52ax
Average 49
CV=55.50% LSD=136


no 62bx
yes 31bx
Average 47
CV=58.62% LSD=143


no
yes
Average
CV=40.30%


32bx
33bx
33
LSD=79


no 25bx
yes 40bx
Average 33
CV=33.80% LSD=65


32bx
27bx
30


7 days
990ax
79ay
534


14 days
843ax
132ay
487


21 days
810ax
190ay
500


28 days
611ax
198ay
404


35 days
605ax
220ay
413


42 days
620ax
228ay
424


after treatment (Zn,
106bx ll4bx
64ax 55ax
85 84


after treatment (Zn,
132bx 108bx
88ax 63ax
104 85


after treatment (Zn,
98ax 98ax
69abx 51abx


after treatment (Zn,
66bx 70bx
89bx 63bx
77 66


after treatment (Zn,
79bx 63bx
71bx 51bx
75 57


after treatment (Zn,
62bx 66bx
55bx 37bx
58 52


-----------------
40 36x
47 38x
44a


ppm)----------
203bx 294
61ax 61
132


ppm)----------
155bx 254
61ay 79
108


ppm)------------
145ax 242
64abx 81
105


ppm)----------
76bx 171
65bx 89
70


ppm) ----
69bx 168
52bx 87
60


ppm)----------
73bx 171
73bx 78
58


CV=45.24% LSD=84.7
Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.


no
yes
Average





Figure 1. Zn concentration in washed

valiencia citrus leaves from application of

Zn nutritional


8.83x 0.1x^2 r^2 0.99
5.1x 0.15x'2 + 0.001x^3 r"2 0.83
2.6x 0.078x^2 + 0.0004x^3 r^2 0.78
- n e f. *


Control
ZnO-5 Ib Zn/a
ZnS04-2.5 Ib Zn/a
ZnNH4P04-2.5 Ib Zn/a
ZnNH4P04-5 Ib Zn/a


28


Days After Treatment


300


y 33
y 35.
y 37
1 (


E
a.

CF
0

LM
C

C
c


0
0
O

N


250


200


150


100


50


0 7


35


42




Figure 2. Zn concentration in unwashed
valiencia citrus leaves from application of
Zn nutritional
1000

900 -

E 800 -
CL
0 700

.2 600 -
EeI
500 n on Control
0) y 1033- 2x 0.88x^2 + 0.016x^3 r^2 0.95 a ZnO-5 Ib Zn/a
0 400 -y 62 + 10x 0.56x'2 + 0.0075x'3 r^2 0.80 O ZnS04-2.5 Ib Zn/a
ZnNH4P04-2.5 Ib Znja
0 -y 92 + 5.x 0.35x^2 0.005x^3 r^2 0.98NH4P4- b Zn/a
0 300 y 2.: ZnNH4PO4-5 Ib Znla
C
N 200
100 _A___

0 I
7 14 21 28 35 42


Days After Treatment




Figure 3. Zn concentration in washed
valiencia citrus leaves from application of
selected Zn nutritional
120 -
110 ZnS04-2.5 Ib Zn/a
y = 38 + 2.12x 0.05x^2 r^2 = 0.75 ZnNH4PO4-2.5 Ib Zn/a
E 100 y = 40 + 0.41x 0.017x^2 r^2 = 0.36 o Control
a.
90

.2 80

5 70
C
U 60
C
00
o 50 0

N 40
30 o

20
0 7 14 21 28 35 42


Days After Treatment





Table 3. Copper concentration in 3 to 6 month old leaves of 3-year
old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnSO4 ZnNH4PO4-1 ZnNH4PO4-2 Average

---------- Pretreated-0 days (Cu, ppm)-----------------
no 45 26 37 16 22 29x
yes 17 15 16 24 14 17y
Average 31a 21a 26a 20a 18a
CV=60.61% LSD=9.5

---------- 7 days after treatment -(Cu, ppm) -----------
no 12 12 12 22 10 13x
yes 14 11 13 20 11 14x
Average 13a 12a 12a 21a 10a
CV=16.49%


no 14
yes 11
Average 12a
CV=27.46% LSD=2.4


no 13
yes 10
Average 1la
CV=15.43% LSD=1.3


no
yes
Average
CV=14.83%


no
yes
Average
CV=16.27%


no
yes
Average
CV=31.15%


12
10
1la


1la


14 days after treatment (Cu, ppm)------------
12 11 25 10 14x
10 9 18 8 1ly
lla 10a 21a 9a


21 days after treatment (Cu,
13 14 22
10 10 17
12a 12a 20a


28 days after treatment (Cu,
12 11 21
11 13 21
12a 12a 21a


35 days after treatment (Cu,
8 12 19
10 10 21
9a lla 20a


ppm)----------
10 14x
9 1ly
10a


ppm)----------
11 13x
9 13x
10a


ppm)------------
9 12.x
8 12x


42 days after treatment (Cu, ppm) ------------
7 12 23 9 13x
10 12 19 9 12x
8a 12a 21a 9a


13
13a


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 4. Iron concentration in 3 to 6 month old leaves of 3-year
old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnSO4 ZnNH4PO4-1 ZnNH4PO4-2 Average

---------- Pretreated-0 days (Fe, ppm)--------------
no 47 43 64 94 89 67x
yes 20 19 41 38 14 26y
Average 33a 31a 53a 65a 52a
CV=60.53% LSD=19.1

---------- 7 days after treatment (Fe, ppm)------------
no 68 75 60 65 60 66x
yes 53 50 48 45 43 48y
Average 60a 63a 54a 55a 51a
CV=15.66% LSD=6.0


no 63
yes 48
Average 55a
CV=26.74% LSD=2.9


no 65
yes 45
Average 55a
CV=17.71% LSD=6.2


no 75
yes 50
Average 63a
CV=19.43% LSD=7.3


no 68
yes 50
Average 59a
CV=21.93% LSD=7.6


no 80
yes 48
Average 64a
CV=22.1q5 =LSD=8.4


14 days after treatment (Fe, ppm) -----------
63 58 60 45 58x
45 43 33 35 41y
54a 50a 46a 41a


21 days after treatment (Fe, ppm) ----------
65 63 53 53 60x
53 46 38 45 45y
59a 54a 45a 49a


28 days after treatment (Fe, ppm) -----------
58 60 63 48 61x
53 58 50 48 52y
55a 59a 56a 48a


35 days
63
52
57a


42 days
59
53
56a


after treatment (Fe, ppm) -----------
58 50 57 59x
40 45 35 44y
49a 48a 46a


after treatment (Fe, ppm) ------------
65 63 58 65x
53 48 38 48y
59a 55a 48a


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 5. Manganese concentration in 3 to 6 month old leaves of
3-year. old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnS04 ZnNH4PO4-1 ZnNH4PO4-2 Average


---------- Pretreated-0 days (Mn, ppm)
no 56 60 47 60
yes 40 60 28 50
Average 48a 60a 37a 55a
CV=44.76%

---------- 7 days after treatment (Mn,
no 64 45 43 42
yes 64 40 41 44
Average 64a 43a 42a 43a
CV=7.80%


no
yes
Average
CV=18.58%


no
yes
Average
CV=7.77%


no
yes
Average
CV=10.35%


no
yes
Average
CV=14.65%


77
59
68a



69
69
69a
LSD=3.0


79
78
78a


63
69a


14 days after treatment (Mn,
45 45 43
44 41 43
44a 43a 43a


21 days after treatment (Mn,
49 52 50
50 46 44
49b 49b 47b


28 days after treatment (Mn,
49 46 49
49 48 46
49a 47a 48a


35 days after treatment (Mn,
46 47 48
46 52 42
46a 49a 45a


-----------------
50 55x
42 44x
46a


ppm)------------
59 50x
62 50x
60a


ppm)----------
56 53x


61
59a


49x


ppm)------------
73 59x
68 55y
70a


ppm)------------
72 59x
80 60x
76a


ppm)----------


63
68a


58.x
53x


--------- 42 days after treatment (Mn, ppm) -----------
no 73 45 55 42 66 56x
yes 64 48 43 43 72 54x
Average 69a 46a 49a 43a 69a
CV=11.78%
Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 6. Calcium concentration in 3 to 6 month old leaves of
3-year old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnS04 ZnNH4P04-1 ZnNH4P04-2 Average


no
yes
Average
CV=15.51%


no
yes
Average
CV=8.53%


no
yes
Average
CV=12.37%


no
yes
Average
CV=8.26%


no
yes
Average
CV=9.94%


no
yes
Average
CV=8.12%


no
yes
Average
CV=9.68%


---------- Pretreated-0 days


2.18
1.98
2.08a


2.30
2.50
2.40a


---------- 7 days
1.57 2.01
1.75 1.92
1.66a 1.96a


1.96
1.66
1.81a


1.85
1.78
1.81


2.12
2.28
2.20a


2.26
1.85
2.05a


2.11
1.92
2.02a


14 days
2.01
1.90
1.95a


21 days
2.21
2.29
2.25a


28 days
2.29
2.32
2.30a


35 days
2.06
2.06
2.06a


42 days
2.15
2.37
2.26a


2.33
2.43
2.38a


(Ca, %)
2.35
2.20
2.28a


after treatment (Ca,
2.10 2.00
1.99 1.96


2.04a


1.98a


after treatment (Ca,
2.27 2.20
1.93 2.04
2.10a 2.12a


after treatment (Ca,
2.56 2.37
2.36 2.28
2.46a 2.33a


after treatment (Ca,
2.63 2.48
2.66 2.18
2.65a 2.33a


after treatment (Ca,
2.55 2.30
2.41 2.31
2.48a 2.31a


after treatment (Ca,
2.43 2.32
2.60 2.40
2.52a 2.36a


1.95
2.20
2.08a


1.85
1.83
1.84a


1.82
1.95
1.88a


2.26
2.14
2.20a


2.33
2.39
2.36a


2.28
2.22
2.25a


2.12
2.53
2.32a


2.22x
2.26x


1.90x
1.89x


2.05x
1.90x


2.25x
2.17x


2.37x
2.37x


2 .29x
2.17x


2.32x
2.36x


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 7. Magnesium concentration in 3 to 6 month old leaves of
3-year. old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnS04 ZnNH4P04-1 ZnNH4PO4-2 Average


---------- Pretreated-0 days


no
yes
Average
CV=12.09%


no
yes
Average
CV=3.42%


no
yes
Average
CV=13.37%


no
yes
Average
CV=6.80%


no
yes
Average
CV=8.82%


no
yes
Average
CV=7.23%


no
yes
Average
CV=9.68%


0.38
0.38
0.38a


----------
0.33
0.34
0.33a


0.35
0.32
0.34a


0.36
0.37
0.36a


0.35
0.38
0.36a


0.33
0.33
0.33a


0.33
0.31
0.32a


0.43
0.35
0.39a


7 days
0.39
0.37
0.38a


14 days
0.36
0.35
0.35a


21 days
0.40
0.40
0.40a


28 days
0.42
0.40
0.41a


35 days
0.36
0.39
0.37a


42 days
0.38
0.41
0.39a


0.38
0.40
0.39a


(Mg, %)
0.35
0.35
0.35a


after treatment (Mg,
0.40 0.32
0.40 0.33
0.40a 0.32a


after treatment (Mg,
0.42 0.34
0.41 0.31
0.41a 0.33a


after treatment (Mg,
0.45 0.35
0.41 0.36
0.43a 0.35a


after treatment (Mg,
0.43 0.32
0.43 0.35
0.43a 0.33a


after treatment (Mg,
0.39 0.30
0.41 0.30
0.40a 0.30a


after treatment (Mg,
0.42 0.33
0.46 0.32
0.44a 0.33a


0.40
0.45
0.43a


0.39x
0.39x


0.40 0.37x
0.40 0.37x
0.40a


0.39
0.32
0.37a


0.37x
0.34x


S---------------
0.45 0.40x
0.42 0.39x
0.43a


%) -----------
0.45 0.39x
0.43 0.40x
0.44a


%) ----------
0.39 0.35x
0.39 0.36x
0.39a


0.40
0.43
0.41a


0.37x
0.39x


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnS04=source
of 2.5 pound Zn/acre; ZnNH4PO4-l=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 8. Potassium concentration in 3 to 6 month old leaves of
3-year.old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnSO4 ZnNH4P04-1 ZnNH4PO4-2 Average


no
yes
Average
CV=16.52%


1.83
1.50
1.66a


Pretreated-0 days (K, %)------------------
1.60 1.78 1.70 1.95 1.78x
1.58 1.65 1.58 1.68 1.60x
1.59a 1.71a 1.64a 1.81a


no
yes
Average
CV=6.69%


no
yes
Average
CV=8.55%


no
yes
Average
CV=6.80%


no
yes
Average
CV=8.82%


no
yes
Average
CV=8.07%


no
yes
Average
CV=9.25%


--------- 7 days


1.78
1.73
1.75a


1.70
1.64
1.68a


1.81
1.82
1.81a


1.56
1.65
1.60a


1.36
1.58
1.47a


1.38
1.46
1.42a


1.46
1.55
1.50a


14 days
1.52
1.40
1.46a


21 days
1.58
1.64
1.61a


28 days
1.47
1.40
1.44a


35 days
1.37
1.44
1.40a


42 days
1.35
1.28
1.32a


after treatment (K,
1.73 1.51
1.78 1.62
1.76a 1.57a


after treatment (K,
1.72 1534
1.86 1.62
1.79a 1.57a


after treatment (K,
1.76 1.65
1.88 1.64
1.82a 1.64a


after treatment (K,
1.59 1.48
1.67 1.47
1.63a 1.48a


after treatment (K,
1.45 1.25
1.60 1.22
1.52a 1.24a


after treatment (K,
1.46 1.39
1.43 1.35


1.44a


1.37a


1.75
1.76
1.75a


1.73
1.70
1.71a


1.70
1.76
1.73a


1.39
1.45
1.42a


1.29
1.33
1.31a


1.32
1.27
1.29a


1.65x
1.69x


1.64x
1.65x


1.70x
1.75x


1.50x
1.53x


1..34x
1.43x


1.38x
1.36x


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 9. Phosphorus concentration in 3 to 6 month old leaves of
3-year -old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnSO4 ZnNH4P04-1 ZnNH4P04-2 Average


---------- Pretreated-0 days
no 0.25 0.28 0.25
yes 0.23 0.25 0.28
Average 0.24a 0.26a 0.26a
CV=12.16%


(P, %)
0.25
0.25
0.25a


0.28
0.30
0.29a


0.26x
0.26x


no
yes
Average
CV=4.73%


no
yes
Average
CV=5.15%


no
yes
Average
CV=5.54%


no
yes
Average
CV=8.82%


no
yes
Average
CV=4.29%


no
yes
Average
CV=5.88%


---------- 7 days


0.21
0.21
0.21a


0.21
0.20
0.20a
LSD=0.007


0.18
0.18
0.18a


0.16
0.16
0.16a


0.14by
0.16abx
0.15
LSD=0.015


0.14
0.15
0.14a


0.19
0.20
0.19a


14 days
0.20
0.18
0.19a


21 days
0.19
0.18
0.18a


28 days
0.17
0.18
0.17a


35 days
0.16ax
0.17ax
0.16


42 days
0.16
0.16
0.16a


after treatment (P,
0.20 0.20
0.21 0.21
0.20a 0.21a


after treatment (P,
0.20 0.21
0.20 0.20
0.20a 0.21a


after treatment (P,
0.17 0.19
0.17 0.19
0.17a 0.19a


after treatment (P,
0.16 0.17
0.17 0.16
0.16a 0.16a


after treatment (P,
0.15bx 0.15bx
0.16abx 0.15bx
0.16 0.15


after treatment (P,
0.15 0.15
0.14 0.15
0.15a 0.15a


0.24
0.23
0.24a


0.24
0.22
0.23a


0.21
0.23
0.22a


0.19
0.19
0.19a


0.16ax
0.16abx
0.16


0.17
0.16
0.16a


0.21x
0.21x


0.21x
0.20y


0.19x
0.19x


0.17x
0.17x


0..15
0.16


0.15x
0.15x


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-1=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.





Table 10. Nitrogen concentration in 3 to 6 month old leaves of
3-year-old valencia orange trees.

Leaf Zn Treatment
Wash Control ZnO ZnS04 ZnNH4PO4-1 ZnNH4P04-2 Average


no
yes
Average
CV=5.16%


no
yes
Average
CV=6.65%


no
yes
Average
CV=6.82%


no
yes
Average
CV=5.62%


no
yes
Average
CV=4.49%


no
yes
Average
CV=4.71%


3.58ax
3.55abx
3.57
LSD=0.27


3.33
3.00
3.17a


3.35
3.35
3.35a


3.49
3.63
3.56a
LSD=0.14


3.26
3.40
3.33a
LSD=0. 104


3.71
3.74
3.73a


7 days
3.14bx
3.28bx
3.21


14 days
3.15
3.01
3.08a


21 days
3.64
3.76
3.70a


28 days
3.85
4.13
3.99a


35 days
3.74
3.74
3.74a


42 days
3.80
3.87
3.83a


after treatment (N, %)
3.69ax 3.45ay
3.40by 3.78ax
3.55 3.62


after treatment (N,
3.20 3.31
3.17 3.29
3.18a 3.30a


after treatment (N,
3.20 3.52
3.27 3.76
3.23a 3.64a


after treatment (N,
3.61 3.69
3.81 3.73
3.71a 3.71a


after treatment (N,
3.25 3.36
3.52 3.40
3.38a 3.38a


after treatment (N,
3.44 3.62
3.60 3.75
3.52a 3.68a


3.47ax
3.51abx
3.49


3.47
3.50


%)--------------
3.21 3.24x
3.09 3.11x
3.11a


%)--------------
3.59 3.46x
3.72 3.57x
3.66a


3.59
3.78
3.68a


3.65y
3.81x


---------------
3.06 3.33y
3.49 3.51x
3.28a


3.58
3.68
3.63a


3 ..63x
3.73x


Control=no Zn applied; ZnO=source of 5 pound Zn/acre; ZnSO4=source
of 2.5 pound Zn/acre; ZnNH4PO4-l=source of 2.5 pound Zn/acre;
ZnNH4PO4-2=source of 5 pound Zn/acre. Values among Zn treatments
within a wash treatment not followed by the same letter (a,b,c,d)
and values between wash treatments not followed by the same letter
(x,y) are significantly different according to LSD.




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