• TABLE OF CONTENTS
HIDE
 Historic note
 Introduction
 For youn, non-bearing trees
 For bearing trees
 Nutrional sprays for bearing...














Group Title: Sub-Tropical Experiment Station - mimeographed report ; no. 7
Title: Fertilizing orange and grapefruit trees on rockdale soils of Dade county, Florida
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067812/00001
 Material Information
Title: Fertilizing orange and grapefruit trees on rockdale soils of Dade county, Florida
Series Title: Mimeographed report
Physical Description: 4 leaves : ; 28 cm.
Language: English
Creator: Lynch, S. J ( S. John )
Fifield, W. M ( Willard Merwin ), 1908-
Ruehle, George D
Sub-Tropical Experiment Station
Publisher: University of Florida, Sub-Tropical Experiment Station
Place of Publication: Homestead Fla
Publication Date: 1940, 1946
 Subjects
Subject: Oranges -- Fertilizers -- Florida   ( lcsh )
Grapefruit -- Fertilizers -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: S.J. Lynch and W.M. Fifield; rev. by Geo. D. Ruehle.
General Note: "October 1940; Revised ... October 1946."
Funding: Mimeographed report (Sub-Tropical Experiment Station) ;
 Record Information
Bibliographic ID: UF00067812
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71834232

Table of Contents
    Historic note
        Copyright
    Introduction
        Page 1
    For youn, non-bearing trees
        Page 2
    For bearing trees
        Page 2
        Page 3
    Nutrional sprays for bearing trees
        Page 4
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







University of Florida
SUB-TQOPICAL 1EPE2IMESTR STATION
Homestead, Florida

FERTILIZING ORANGE AND GRAPEFRUIT TREES ON
ROCKDALE SOILS OF DADE COUNTY, FLORIDA
By
S. J. Lynch and W. M. Fifield / /

Revised by
Geo. D. Ruehle /
October 1946
1976
Rockdale soils of both the sandy phase, near Miami, and of tleU', clay phase,
near Homestead, naturally have a very high pH due to their hih,. in carbonate
content. Readings of pH 7.2 to 8.0 are common and sometimes reach^.Y-ICfAils
of this type iron, manganese, copper and zinc generally become immobiliie`--QtUfaf
quickly even though applied in appreciable amounts with the fertilizer. In fac, J4
iron exists in these soils in relatively large amounts but is practically all
fixed in the form of insoluble oxides. Magnesium is also immobilized and relative-
ly large amounts of water soluble magnesium must be applied if magnesium deficiency
symptoms (foliage bronzing) are to be corrected.

These soils tend to fix phosphorus rapidly and hold it in forms unavailable to
plants. This is particularly true when the parent rock is broken up in the process
of scarification. It is very important, therefore, to apply phosphates generously
and frequently to young trees plante& in freshly scarified soil. Nitrates leach
out rapidly during periods of heavy rainfall and potash is also leached, although
less rapidly than nitrates.

The following recommendations are not issued as being final or complete but have
given satisfactory results and apparently meet most general requirements. Sug-
gestions for fertilizing Tahiti (Persian) limes are somewhat different and are
covered in a separate report.

Regardless of how well the fertilizer program is planned and conducted, maximum
yields of first grade fruit cannot be expected, unless other fundamentals for suc-
cessful fruit production also are provided. Insufficient soil moisture is a major
limiting factor in growth. Proper preparation of the soil prior to planting, in-
cluding scarification and preparation of the hole, has been found very important.
The selection of varieties and rootstocks should be given careful consideration.
Insect and disease control is likewise essential.

It is recognized that individual groves may differ in their response to a given
fertilizer program, and doubtless the practices listed below will require modifi-
cation for certain conditions. The amount and frequency of irrigation often
necessitates a modification in fertilizer procedure. Trees appreciably injured
by cold or storms cannot always be treated as normal trees of the same age. New
materials are constantly being developed for fertilizer purposes, and undoubtedly
some of them will give as satisfactory results as those mentioned below. In the
event experiments make changes in the general program advisable, it will be re-
vised accordingly,


October 1940


Mimeographed Report No. 7







2 -

For young, non-bearing trees (first 4 or 5 years)

About 21 days after planting, approximately one-half pound per tree of a mixture
analyzing about 4% nitrogen (N), 9% phosphoric acid (P203), 3% potash (K20),
1.5% magnesium (MgO) and 1% manganese (MnO) (4-9-3-1.5-1) is applied, The nitro-
gen is derived 25 to 40% from organic sources and the magnesium from Sulpomag or
from sulfate of potash-magnesia. The fertilizer is broadcasted uniformly over an
area beginning 6 to 8 inches from the trunk of the tree and extending to the edge
of the watering basin, The application is repeated every 60 days during the
spring and summer months. As the tree becomes established the roots spread beyond
the watering basin and the fertilized area is widened accordingly, One pound per
tree is applied in the fall (October or November).

The 2d year, 2 pounds per tree of the sane mixture is applied at each of three
periods--spring (March or April), summer (June or July), and fall (October or
November). If some of the trees show indications of losing their full green
color in mid-summer, 1/8 pound of Uramon or 1/4 pound of sulfate of ammonia or
sulfate of potash may be applied per tree to replace nitrogen leached by summer
rains. In the 2d year. spraying with a nutritional spray containing zinc and
copper should be begun and continued annually thereafter until the trees come into
bearing. For this purpose 3 lbs. of zinc sulfate and 3 lbs. of copper sulfate (or
its equivalent in one of the neutral coppers) plus sufficient hydrated lime for
neutralization (3 lbs. if copper sulfate is used and 1.5 lbs. if a neutral copper
is used) for each 100 gallons of water should be used. This mixture is applied
just before the spring flush of growth appears for greatest effectiveness. Manga-
nese may be omitted from the fertilizer at the beginning of the 2d year, but if
this is done, 2 lbs. of manganese sulfate should be added to the nutritional spray
with extra lime (1 lb.) added to the mixture for neutralization.

The 3d year from 3 to 4 lbs. per tree of the same mixture is applied at each
application. As the trees grow larger, the fertilizer is spread further from the
tree, extending it slightly beyond the spread of the foliage.

During the 4th and 5th years, as the trees are coming into bearing, the practice
is changed somewhat. Three applications a year-are continued, using 4 to 6 lbs.
per tree the 4th year and 5 to 8 lbs, the 5th year. In the spring application
in these years, the use of the 4-9-3-1.5 formula is continued. In the summer an
analysis of about 4-8-8-1.5 (25 to 40% organic), and in the fall, one approximating
4-8-5-1.5 (25 to 30% organic) is used. Many growers include 100 lbs. of manganese
sulfate per ton in these mixtures, but it is somewhat cheaper and more effective
to apply the manganese with the annual application of nutritional spray.


For bearing trees (5 years and older)

In January or February, about three weeks before the bloom, each tree is given
about 1.5 lbs. (depending upon the size of the tree) of nitrate of potash, 1 lb.
of sulfate of ammonia or 1/2 lb. of Uranon. The size of this application is
gradually increased as the trees grow. Thus, an average 10-year-old tree receives
2.5 to 3 Ibs. of nitrate of potash, 2 lbs. of sulfate of ammonia or 1 lb. or Uramon.







2 -

For young, non-bearing trees (first 4 or 5 years)

About 21 days after planting, approximately one-half pound per tree of a mixture
analyzing about 4% nitrogen (N), 9% phosphoric acid (P203), 3% potash (K20),
1.5% magnesium (MgO) and 1% manganese (MnO) (4-9-3-1.5-1) is applied, The nitro-
gen is derived 25 to 40% from organic sources and the magnesium from Sulpomag or
from sulfate of potash-magnesia. The fertilizer is broadcasted uniformly over an
area beginning 6 to 8 inches from the trunk of the tree and extending to the edge
of the watering basin, The application is repeated every 60 days during the
spring and summer months. As the tree becomes established the roots spread beyond
the watering basin and the fertilized area is widened accordingly, One pound per
tree is applied in the fall (October or November).

The 2d year, 2 pounds per tree of the sane mixture is applied at each of three
periods--spring (March or April), summer (June or July), and fall (October or
November). If some of the trees show indications of losing their full green
color in mid-summer, 1/8 pound of Uramon or 1/4 pound of sulfate of ammonia or
sulfate of potash may be applied per tree to replace nitrogen leached by summer
rains. In the 2d year. spraying with a nutritional spray containing zinc and
copper should be begun and continued annually thereafter until the trees come into
bearing. For this purpose 3 lbs. of zinc sulfate and 3 lbs. of copper sulfate (or
its equivalent in one of the neutral coppers) plus sufficient hydrated lime for
neutralization (3 lbs. if copper sulfate is used and 1.5 lbs. if a neutral copper
is used) for each 100 gallons of water should be used. This mixture is applied
just before the spring flush of growth appears for greatest effectiveness. Manga-
nese may be omitted from the fertilizer at the beginning of the 2d year, but if
this is done, 2 lbs. of manganese sulfate should be added to the nutritional spray
with extra lime (1 lb.) added to the mixture for neutralization.

The 3d year from 3 to 4 lbs. per tree of the same mixture is applied at each
application. As the trees grow larger, the fertilizer is spread further from the
tree, extending it slightly beyond the spread of the foliage.

During the 4th and 5th years, as the trees are coming into bearing, the practice
is changed somewhat. Three applications a year-are continued, using 4 to 6 lbs.
per tree the 4th year and 5 to 8 lbs, the 5th year. In the spring application
in these years, the use of the 4-9-3-1.5 formula is continued. In the summer an
analysis of about 4-8-8-1.5 (25 to 40% organic), and in the fall, one approximating
4-8-5-1.5 (25 to 30% organic) is used. Many growers include 100 lbs. of manganese
sulfate per ton in these mixtures, but it is somewhat cheaper and more effective
to apply the manganese with the annual application of nutritional spray.


For bearing trees (5 years and older)

In January or February, about three weeks before the bloom, each tree is given
about 1.5 lbs. (depending upon the size of the tree) of nitrate of potash, 1 lb.
of sulfate of ammonia or 1/2 lb. of Uranon. The size of this application is
gradually increased as the trees grow. Thus, an average 10-year-old tree receives
2.5 to 3 Ibs. of nitrate of potash, 2 lbs. of sulfate of ammonia or 1 lb. or Uramon.





- 3 -


In March or April, about 3 weeks after the main flush of bloom, a mixed fertilizer
analyzing about 4-7-3-3 (or 4-7-5-3 if nitrate of potash is not used in January),
with about 25% of the nitrogen from organic sources, is applied. The magnesium
is increased to 3% for bearing trees, since the requirements for this element
increases as fruit is produced. The mixture is distributed at rates of 6 to 10
lbs. per tree, depending upon the size of the tree. The amount of fertilizer re-
quired is often roughly estimated at about 1 lb..of a standard mixed fertilizer to
each foot of treespread diameter.

In June or July, 6 to 10 lbs. per tree of a 4-8-8-3 mixture (nitrogen 25 to 40%
from organic sources) is applied.

In October or early November, 6 to 10 lbs. of a 4-8-5-3 mixture per tree is applied.
For grapefruit trees that have a tendency to produce thick skinned fruit, the same
quantities per tree of a 3-8-~-3 or a 4-8-8-3 mixture is used instead. The nitro-
gen in these formulas is ordinarily derived about 30 to 40% from organic sources.

The fertilizer is broadcasted evenly in a 4- to 5-foot band about half inside and
half outside the outer edge of the foliage. While fertilizer was formerly applied
by hand in a ring around the trees, it is applied now in many commercial groves
from trunk to trunk by means of mechanical spreaders. With many of these, the
distribution of fertilizer is much better in the middles than under the trees, and
the fertilizer is somewhat less efficient than where it is spread carefully by
hand. In old groves this is not a serious objection to the use of mechanical
spreaders.

The soil preferably should be moist at the time of application. It is not neces-
sary to work the fertilizer into the soil, but care should be used to see that a
heavy mulch does not prevent its working into the soil after a rain or an irriga-
tion. During seasons of heavy rainfall, if and when the foliage shows signs of
nitrogen deficiency, an application of 1 or 2 lbs. of sulfate of ammonia or nitrate
of potash or an equivalent amount of Uramon is often made to replace the nitrogen
leached from the soil.

In the fertilizers commonly used in Dade County, phosphoric acid is usually de-
rived from superphosphate. Triple superphosphate and other sources also have
proved satisfactory. The potash may be derived from muriate or sulfate of potash,
from Sulpomag or from sulfate of potash-magnesia.

The inorganic nitrogen sources sulfate of ammonia, nitrate of potash or ammonium
nitrate, and the organic sources cottonseed meal, castor pomace, fish meal, tankage,
urea (Uramon), milorganite, Peruvian guano, sheep manure, goat manure and dried
blood have all given satisfactory results in several different combinations. Cal-
cium cyananid has some objections as a fertilizer. In moist soil its nitrogen
changes rather readily to ammonium carbonate but if applied to dry soil certain
temporary intermediate products are formed which may be harmful to crops. How-
ever, considerable amounts of calcium cyanamid are used satisfactorily in mixed
fertilizers, the physical condition of the cyanamid making it especially desirable.






-4-

Nutrional sprays for bearing trees

Annual applications of zinc, manganese and copper should be continued. Since
these materials do not give satisfactory results when applied to Rockdale soil
either in the fertilizer or as a separate application, they should be applied as
sprays. It is recommended that the zinc and manganese be applied as a dormant
spray combined with lime-sulfur and wettable sulfur if rust mites are present.
Copper is applied with wettable sulfur as a post-bloom spray to supply nutritional
copper and control melanose. Zinc and manganese may be applied with the copper
in the post-bloom spray, although the results are somewhat better if these are
applied prior to the spring flush of growth.

Scale insects and other pests may be expected to increase considerably following
the application of nutritional sprays, and the grower should be prepared to take
proper measures to control such pests. For details of pest control the reader is
referred to the Better Fruit Program Spray and Dust Schedule, copies of which are
obtainable from the Florida Citrus Commission, Lakeland, Florida.




University of Florida Home Page
© 2004 - 2010 University of Florida George A. Smathers Libraries.
All rights reserved.

Acceptable Use, Copyright, and Disclaimer Statement
Last updated October 10, 2010 - - mvs