• TABLE OF CONTENTS
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 Historic note
 Introduction
 Procedure
 Results and discussion
 Conclusion














Group Title: Sub-Tropical Experiment Station - mimeographed report ; no. SUB65-1
Title: Efficiencies of phospate fertilizers
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00067804/00001
 Material Information
Title: Efficiencies of phospate fertilizers
Series Title: Mimeographed report
Physical Description: 6 leaves : ; 28 cm.
Language: English
Creator: Orth, Paul G
Sub-Tropical Experiment Station
Publisher: University of Florida, Sub-Tropical Experiment Station
Place of Publication: Homestead Fla
Publication Date: 1964
 Subjects
Subject: Fertilizers -- Analysis -- Florida   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
non-fiction   ( marcgt )
 Notes
Statement of Responsibility: Paul G. Orth.
General Note: "August, 1964."
Funding: Mimeographed report (Sub-Tropical Experiment Station) ;
 Record Information
Bibliographic ID: UF00067804
Volume ID: VID00001
Source Institution: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: oclc - 71816670

Table of Contents
    Historic note
        Copyright
    Introduction
        Page 1
    Procedure
        Page 1
    Results and discussion
        Page 2
        Page 3
        Page 4
        Page 5
    Conclusion
        Page 6
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





u '-; / ,.-
Mimeographed Report No. SUB65-1 August, 1964


University of Florida
SUB-TROPICAL EXPERIMENT STATION
Homestead, Florida



EFFICIENCIES OF PHOSPHATE FERTILIZERS
S:1 By
Paul G. Orth


Introduction

Phosphorus fertilization of the calcareous Rockdale soil presents several problems.
Calcium carbonate is dominant in this soil. After phosphate fertilizer is added,
the availability of the phosphorus decreases rapidly. Decreased availability gen-
erally results in decreased uptake by plants. Low temperatures may also reduce
phosphorus uptake. Typically, cool periods occur during the winter growing season,
and phosphorus uptake is adversely affected.

A large, available supply of phosphate is necessary to meet the high requirements
of rapidly growing tomato plants. Since the concentration of phosphate ions in the
soil solution is low, uptake must be over long periods of time and replenishment
must be rapid. Quick replenishment of solution phosphate is greatly dependent on
the quantity and solubility of the phosphorus compounds in the soil and the amount
of surface in contact with the soil solution.

Dalton* has presented background material indicating the possible disadvantages of
the use of ammoniated superphosphate on calcareous Dade County soils. Some growers
have obtained good response to dilute phosphoric acid sprays applied to tomato
plant foliage. Field experiments during the 1963-64 season were designed to indi-
cate differences in several phosphorus carriers as to their efficiency in supplying
phosphorus to tomatoes during early stages of growth.


Procedure

Three experiments are discussed in this report. Experiments A and B compared
several phosphorus carriers and were very similar to each other. Experiment A con-
sisted of single row plots, 35 feet long. There were four replications, and the
phosphorus treatments were applied at two side-dressings. Plots were 17.5 feet
long in experiment B, there were three replications, and only one side-dressing
included the phosphorus treatment.

As a sub-experiment, a two-replicate trial of dilute phosphoric acid spray was in-
cluded on the buffer rows in experiment A. Four foliar sprays were applied during
the second and third weeks after emergence of the plants. Treatments are listed
in Table 1.




*J. D. Dalton, Chemistry of ammoniating superphosphate and its subsequent use in
Dade County soils--a paper presented at the twenty-third annual
meeting of the Soil and Crop Science Society of Florida, October
22, 1963, Winter Park, Florida.





u '-; / ,.-
Mimeographed Report No. SUB65-1 August, 1964


University of Florida
SUB-TROPICAL EXPERIMENT STATION
Homestead, Florida



EFFICIENCIES OF PHOSPHATE FERTILIZERS
S:1 By
Paul G. Orth


Introduction

Phosphorus fertilization of the calcareous Rockdale soil presents several problems.
Calcium carbonate is dominant in this soil. After phosphate fertilizer is added,
the availability of the phosphorus decreases rapidly. Decreased availability gen-
erally results in decreased uptake by plants. Low temperatures may also reduce
phosphorus uptake. Typically, cool periods occur during the winter growing season,
and phosphorus uptake is adversely affected.

A large, available supply of phosphate is necessary to meet the high requirements
of rapidly growing tomato plants. Since the concentration of phosphate ions in the
soil solution is low, uptake must be over long periods of time and replenishment
must be rapid. Quick replenishment of solution phosphate is greatly dependent on
the quantity and solubility of the phosphorus compounds in the soil and the amount
of surface in contact with the soil solution.

Dalton* has presented background material indicating the possible disadvantages of
the use of ammoniated superphosphate on calcareous Dade County soils. Some growers
have obtained good response to dilute phosphoric acid sprays applied to tomato
plant foliage. Field experiments during the 1963-64 season were designed to indi-
cate differences in several phosphorus carriers as to their efficiency in supplying
phosphorus to tomatoes during early stages of growth.


Procedure

Three experiments are discussed in this report. Experiments A and B compared
several phosphorus carriers and were very similar to each other. Experiment A con-
sisted of single row plots, 35 feet long. There were four replications, and the
phosphorus treatments were applied at two side-dressings. Plots were 17.5 feet
long in experiment B, there were three replications, and only one side-dressing
included the phosphorus treatment.

As a sub-experiment, a two-replicate trial of dilute phosphoric acid spray was in-
cluded on the buffer rows in experiment A. Four foliar sprays were applied during
the second and third weeks after emergence of the plants. Treatments are listed
in Table 1.




*J. D. Dalton, Chemistry of ammoniating superphosphate and its subsequent use in
Dade County soils--a paper presented at the twenty-third annual
meeting of the Soil and Crop Science Society of Florida, October
22, 1963, Winter Park, Florida.






-2 -


A placement experiment carried out at the same time as experiments A and B gives
information useful in evaluating the latter experiments. The placement experiment
explored the application of some phosphate fertilizer proximate to the seed. The
preplanting fertilization method was the same as in experiments A and B. Either no
phosphorus or 80 pounds of P205 per acre was applied at this time. At planting,
concentrated superphosphate (0-45-0) and tomato seeds were placed, by hand, in the
same shallow furrow. There were three rates of concentrated superphosphate and
three replications of each treatment. Plots were single rows, 35 feet long, loca-
ted adjacent to experiment B and planted the same day. No phosphorus was applied
after the seed was planted. The treatments are outlined in Table 2.

In all experiments the initial fertilizer application was made by hand in a three
inch strip in the center of the prepared seeding area. Tractor mounted tines were
used to work the fertilizer into the soil in a 4 to 6 inch band. Seeding date was
January 9, 1964. The Homestead tomato variety was grown. Three plant samplings
were made to obtain plant weight and nitrogen, phosphorus, potassium and calcium
content.


Results and Discussion

Initial plant growth appeared normal in all experiments. Before the second samp-
ling the effects of potato virus Y infection were beginning to appear. The infec-
tion was so severe by the third sampling that further observations were unwarranted.
Better plant growth was achieved in experiment B and the placement experiment than
in experiment A. Plant growth and phosphorus uptake showed response to treatment.
These data are recorded in Tabls 3 6.

Single superphosphate (SS) and phosphoric acid plus spray (PA + S) produced the
best growth in experiments A and B. Differences among other materials were small
and not always consistent. Ammonium polyphosphate (AP) produced poorer growth than
ammoniated superphosphate (AS) in experiment A but better growth in experiment B.
The superphosphate ammoniated to a lower degree (AS 5) gave slightly better growth.

Generally, high phosphorus concentration was associated with good growth (2 SS) and
low phosphorus concentration with poor growth (6 AS 8). However, striking excep-
tions were 7 PA and 8 AP where high phosphorus concentration was associated with
poor to fair growth. Further experiments are necessary to explain this response.
It may reflect a residual effect on growth of plants deficient in phosphorus the
first week or two of growth. (The first sampling was three weeks after emergence.)

Phosphoric acid did not give as good a response as expected. Phosphoric acid is
completely water soluble and its efficiency as a fertilizer would be expected to
be as great as any of the materials used. However, it ranked with treatments
which produced the least growth. Placement may have been a problem. Seventy-five
percent acid was applied directly to the soil. Being a liquid and in concentrated
form may have prevented good mixing and an adequate supply being near the seed. A
small amount of phosphorus applied to the foliage in a phosphoric acid spray when
the plants were small was enough to overcome the factor which retarded growth.

In the placement experiment the first sampling is of the greatest interest. All
the phosphorus was applied at seeding, and information about initial response was
the most important. The first sampling showed a strong positive relationship








- 3-


Table 1. Treatments in phosphorus carrier comparison experiments.


Treatment Rate (Ib/acre) initially
No. Symbol Material and at each side-dressing
P205 N K20 MgO MnO

1 SS Single superphosphate (0-20-0) 40 40 60 20 10
2 SS 80 40 60 20 10
3 AS 5 Ammoniated superphosphate (5-16-0) 40 40 60 20 10
4 AS 5 80 40 60 20 10
5 AS 8 (8-16-0) 40 40 60 20 10
6 AS 8 80 40 60 20 10
7 PA 75% Phosphoric acid (0-56-0) 80 40 60 20 10
8 AP Ammonium polyphosphate (15-60-0) 80 40 60 20 10
9 PA + S 75% Phosphoric acid (0-56-0) 80* 40 60 20 10


* 9% of the initial
dilution of 1:500


application was applied as four foliar sprays at a
(by volume)


Table 2. Treatments in phosphorus placement experiment.


Fertilizer applied (Ib/acre)
Treatment Pre-plant With seed
Number N P205* K20 MgO MnO P205**


I 40 0 60 20 10 0
II 40 0 60 20 10 23
III 40 0 60 20 10 93
IV 40 80 60 20 10 0
V 40 80 60 20 10 23
VI 40 80 60 20 10 93


from 0-20-0
from 0-45-0






-4-


Table 3. Tomato plant growth as affected by five phosphorus carriers.


Treatment
Designation


Average dry plant weight (grams/plant)
Experiment A Experiment B


I. Higher rates of phosphorus


2/25
.930
.590
.440
.280
.320


4/7
31.8
26.8
21.7
13.5
13.0


2/6
.086
.060
.062
.062
.070


2/20
.750
.540
.490
.420
.590


II. Half rates of three materials


.650
.490
.410


24.8
14.6
13.3


.078
.065
.056


.610
.530
.460


III. Buffer rows


.037 .340 13.7
.062 .940 38.9


Table 4. Percent phosphorus in tomato plants fertilized
with five different phosphorus carriers.


Treatment
Designation


Percent Phosphorus
Experiment A Experiment B


I. Higher rates of phosphorus


2/7 2/25
1.19 .94
.80 .73
.69 .80
.97 1.09
1.30 1.24


2/6 2/20
.99 .87
.68 .63
.54 .56
.99 1.02
1.15 1.09


II. Half rates of three materials


III. Buffer rows


1.02
.70


1.00


2 SS
4 AS
6 AS
7 PA
8 AP


2/7
.061
.046
.037
.035
.039


3/19
12.03
9.20
11.71
5.63
10.55


.054
.038
.042


7 PA
9 PA + S


9.55
8.53
8.51


7 PA
9 PA + S


----[ ............


|







-5-


Table 5. Tomato plant growth response to two methods
of placement and six rates of application
of phosphorus.


Treatment Average dry plant weight (grams/plant)
number 2/6 2/20 3/20


I .012 -- -
II .061 .49 6.9
III .079 .77 9.0
IV .067 .95 10.5
V .078 .80 9.9
VI .106 1.18 10.6
















Table 6. Phosphorus uptake response to two methods
of placement and six rates of application.


Treatment Percent phosphorus in plants
Number 2/6 2/20

I .13 --
II .80 .74
III 1.05 .93
IV .83 .81
V 1.10 .85
VI 1.22 .85







- 6-


between percent phosphorus and growth. Only one treatment, VI, clearly exceeded
the performance of the best treatment, 2 SS, in experiments A and B. This could
be attributed to the larger amount of phosphorus applied as well as to placement.

Treatment II, with all the phosphate placed near the seed, compared favorably
with treatment 1 SS which received almost twice as much phosphorus at planting
but placed farther from the seed.



Conclusions


Under the conditions of these experiments, single superphosphate was a better
source of phosphorus for normal fertilization of young tomato plants than was
ammoniated superphosphate, ammonium polyphosphate, or phosphoric acid. Insurance
against the possibility of phosphorus deficiency can be obtained by placing some
phosphate fertilizer less than k inch from the seed and by spraying the seedlings
with dilute (0.15%) phosphoric acid.








# # #


200 copies
August 1964




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