• TABLE OF CONTENTS
HIDE
 Cover
 Table of Contents
 Introduction
 Relative availability to plants...
 Rate and manner of applying copper...
 Responses to residual copper
 Field experiments with copper oxide...
 Conclusions






Title: Copper oxide as a source of fertilizer copper for plants growing on Everglades organic soils
CITATION THUMBNAILS PAGE IMAGE ZOOMABLE
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027588/00001
 Material Information
Title: Copper oxide as a source of fertilizer copper for plants growing on Everglades organic soils
Physical Description: Book
Language: English
Creator: Forsee, W. T. Jr.
Erwin, T. C.
Kretschmer, Albert E. Jr.
Publisher: University of Florida Agricultural Experiment Station
Place of Publication: Gainesville, Fla.
Publication Date: 1954
Copyright Date: 1954
 Notes
General Note: Bulletin - Florida Agricultural Experiment Station ; 552
 Record Information
Bibliographic ID: UF00027588
Volume ID: VID00001
Source Institution: University of Florida
Holding Location: University of Florida
Rights Management: All rights reserved by the source institution and holding location.
Resource Identifier: electronic_aleph - 003246782
electronic_oclc - 60384829

Table of Contents
    Cover
        Page 1
    Table of Contents
        Page 2
    Introduction
        Page 3
    Relative availability to plants of copper as the oxide and the sulfate
        Page 4
    Rate and manner of applying copper oxide
        Page 5
        Page 6
        Page 7
        Page 8
    Responses to residual copper
        Page 9
        Page 10
        Page 11
    Field experiments with copper oxide and copper sulfate
        Page 12
        Page 13
        Page 14
        Page 15
    Conclusions
        Page 16
Full Text



Bulletin 552


October 1954


UNIVERSITY OF FLORIDA
AGRICULTURAL EXPERIMENT STATIONS
WILLARD M. FIFIELD, Director
GAINESVILLE, FLORIDA
(A Contribution from the Everglades Experiment Station)




Copper Oxide as a Source of Fertilizer

Copper for Plants Growing on

Everglades Organic Soils


W. T. FORSEE, JR., T. C. ERWIN and
ALBERT E. KRETSCHMER, JR.


Fig. 1.-Response of shallu growing on Everglades peat soil to applica-
tions of 50 pounds per acre of copper oxide, No. 3 (right), and copper sulfate,
No. 1 (left). Middle jar, No. 2, is the check treatment.


Single copies free to Florida residents upon request to
AGRICULTURAL EXPERIMENT STATION
GAINESVILLE, FLORIDA


f;













CONTENTS
PAGE

INTRODUCTION ................ ..--........... .... ----- ----. 3

RELATIVE AVAILABILITY TO PLANTS OF COPPER AS THE OXIDE AND
THE SULFATE .....--........... ..------ -------- -....- ------... ........... 4

RATE AND MANNER OF APPLYING COPPER OXIDE .................................... 5

RESPONSES TO RESIDUAL COPPER ..............----------. ........-----.........-.. 9

FIELD EXPERIMENTS WITH COPPER OXIDE AND COPPER SULFATE ................ 12

CONCLUSIONS .........-------------.. ..............--..... ...--.....--.... 16

LITERATURE CITED .. ......--.---........-... ----... --........ ----. ....... .. 16










TABLE 1.-GROWTH RESPONSE TO SOIL APPLICATIONS OF Two FORMS OF
COPPER AS MEASURED BY HEIGHT OF SHALLU PLANTS.


Treatment Copper Application Rate, Average Height of
Number Source Pounds per Acret Plants, Inches


1 no copper 14.2

2 sulfate* 50 26.5

3 oxide** 50 29.7

4 oxide** 100 29.4

5 f oxide** 500 30.0

L.S.D. (19:1) 3.3

L.S.D. (99:1) 4.8

Copper sulfate (blue vitriol), snow form, 25.5 percent copper.
** Copper oxide, 79.6 percent copper.
t Calculated on the basis of volume of soil in each jar as related to the volume of
1 acre X 6 inches.










Copper Oxide as a Source of Fertilizer

Copper for Plants Growing on

Everglades Organic Soils'

W. T. FORSEE, JR., T. C. ERWIN and
ALBERT E. KRETSCHMER, JR.

INTRODUCTION
Most of the early plantings of vegetable, forage and other
crops on the virgin peat soils of the Florida Everglades resulted
in partial to complete failure until the need for copper was dem-
onstrated in experiments conducted in 1927 by Allison and
others (1). These experiments initiated the use of large ap-
plications of copper to peat and muck soils in the Everglades
and to other organic soils in Florida. Because of these and
subsequent discoveries (2) relative to the needs for copper,
large acreages of the Everglades organic soils have been planted
to vegetable, pasture, forage, grain, sugar cane and fiber crops,
some of which have produced phenomenal yields.
Until recently copper sulfate (blue vitriol), commercial source
of soluble copper, had been used almost universally for soil
applications of copper. The heavy copper requirements of peat
and muck soils, along with shortages of copper sulfate created
by increased industrial uses during recent years, have stimulated
interest in other sources of copper that can be utilized by plants.
Experiments were initiated in 1948 at the Everglades Station
to study the effectiveness of finely ground copper oxide 1 as a
source of copper as a plant nutrient. In all experiments copper
sulfate was used as the standard for comparison because its
effectiveness already had been determined by experimental and
commercial use over a period of approximately 20 years.

These investigations were supported in part by a grant-in-aid from
Calumet Division, Calumet and Hecla. Inc. The authors are indebted to
Dr. W. S. Fraser, supervisor of agricultural research, for his interest dur-
ing progress of the investigations and suggestions during preparation of the
manuscript.
1 Copper oxide, 79.6 percent Cu, is a highly cupric mixture of copper
oxides, particle size 92 percent less than 20 microns. This is a commercial
form of copper oxide which is available as a 50 or 75 percent grade.







Florida Agricultural Experiment Stations


RELATIVE AVAILABILITY TO PLANTS OF COPPER
AS THE OXIDE AND THE SULFATE
Initial experiments were conducted to determine the avail-
ability to plants of copper oxide added to organic soils. Virgin
Everglades peaty muck soil with a pH of 5.5 was placed in two-
gallon glazed earthenware pots in the greenhouse. All jars were
uniformly treated with 800 pounds per acre of 20 percent super-
phosphate and 60 percent muriate of potash and 50, 15 and 10
pounds per acre, respectively, of manganese sulfate, zinc sul-
fate and borax. Copper sulfate and copper oxide treatments,
Table 1, were made in triplicate by intimately mixing the
materials with the entire soil volume. The jars were seeded
to shallu, Sorghum sp., immediately after treatment. All water
used to maintain moisture was distilled and passed through an
ion exchanger to remove contaminating copper.





( (S~


J 4N

Fig. 2.-Growth response of shallu to soil applications of copper sulfate,
No. 2 (middle), and copper oxide, No. 4 (right), applied at rates equivalent
to six pounds actual copper per acre. Left, No. 1, is the check.

Plants growing on soils that were not treated with copper
began to show evidence of copper deficiency soon after germi-
nation. The copper sulfate and copper oxide treatments pro-







Copper Oxide as a Source of Fertilizer Copper


duced normal growth. Fig. 1 shows a comparison in growth
of plants from the copper sulfate and copper oxide treatments
applied at the rate of 50 pounds per acre with plants that re-
ceived no copper. It is evident that growth response to the oxide
was as good as that to the sulfate. However, the amount of
copper applied in the form of the oxide was approximately
three times as much as that applied as the sulfate because of
the differences in copper composition. The height of each plant
in each jar was measured and the averages according to treat-
ment are recorded in Table 1. Growth differences between
plants from the copper treatments and the no-copper treatment
were highly significant. The heights of the plants on all the
copper oxide treatments were equal or slightly superior to those
on the sulfate treatment.
These results indicate that copper oxide (79 percent Cu) ap-
plied at the rate of 50 pounds per acre is as effective as copper
sulfate (25 percent Cu) applied at the same rate in preventing
copper deficiency in shallu growing on virgin Everglades soil.
The growth response to the oxide was as good as or slightly
superior to that of the sulfate.

RATE AND MANNER OF APPLYING COPPER OXIDE
Since the copper content of the oxide used in the experiment
previously described was approximately three times that of the
sulfate, a test was designed to determine the relative effective-
ness of the two materials when applied at equal rates calcu-
lated according to their actual copper contents. Also, since
much of the copper used commercially is applied as an in-
gredient in mixed fertilizers, treatments were made both as
separate applications and mixed with an 0-8-24 fertilizer con-
taining 3.0, 1.5 and 0.4 percent, respectively, of MnO, ZnO and
B.O:. This was done to determine if interactions might be set
up between or among a complex group of elements under such
conditions and thus alter the availability of the applied copper.
The soil and experimental procedures were similar to those
used in the tests previously described. Treatments were made
in triplicate, with applications ranging from 0 to 100 pounds
per acre of copper sulfate or the copper equivalent as the oxide
(Table 2). Shallu was seeded immediately after treatment.
Copper deficiency symptoms were evident on the plants from
the check treatment soon after germination. Figure 2 indi-
cates the response in growth to copper sulfate at 25 pounds







Florida Agricultural Experiment Stations


per acre and copper oxide at 8 pounds per acre compared to
the check treatment which received no copper. No differences
in growth response between copper sources and methods of ap-
plication were observed during the experiment. The shallu was
harvested 36 days after seeding and whole plant samples were
saved for analysis. Average yields and copper analyses for each
treatment are recorded in Table 2.

TABLE 2.-RESPONSE OF SHALLU TO SOIL APPLICATIONS OF COPPER
COMPOUNDS AS INDICATED BY YIELD AND COPPER CONTENTS.
Yield of
Treat- Rate per Acre,* Approx. Cop- Shallu Tops, Cu Content
ment Source and Method** per Equivalent, Gis. Dry ppm Dry
Number of Treatment Lbs. per Acre Wt. per Jar Wt.

1 Check 0 5.4 7.0
2 25 lbs. sulfate 6 31.0 6.2
applied separately
3 25 lbs. sulfate mixed 6 30.5 6.6
in fertilizer
4 8 lbs. oxide applied 6 29.7 8.2
separately
5 8 lbs. oxide mixed in 6 29.3 9.9
fertilizer
6 50 lbs. sulfate 12 26.9 9.5
applied separately
7 50 lbs. sulfate mixed 12 28.0 10.7
in fertilizer
8 16 lbs. oxide applied 12 29.8 10.4
separately
9 16 lbs. oxide mixed 12 29.8 10.6
in fertilizer
10 100 Ibs. sulfate 24 29.2 11.7
Applied separately
11 1 32 lbs. oxide applied 24 27.6 11.7
S separately

L.S.D. (19:1) 2.3 1.9
L.S.D. (99:1) 3.2 2.6
Calculated on the basis of volume of soil. In metallic copper content 25 pounds of
the sulfate and S pounds of the oxide are approximately equivalent to 6 pounds copper
per acre.
** Separately indicates applying the copper source and mixing with the soil in a
separate operation from that of applying the mixed fertilizer (0-8-24 mixture containing
approximately 200, 60 and 20 pounds manganese sulfate, zinc sulfate and borax, respec-
tively, per ton).

All copper-treated plants significantly outyielded the check
plants. Variations between copper treatments were small. Yield
responses with respect to treatment rates and sources are re-
corded in Table 3. The very slight average yield increase from
applications of the oxide over the sulfate was not significant.
Yield response with respect to treatment methods and rates
are recorded in Table 4. Average yields from the copper applied
separately and in the mixed fertilizer were the same. This







Copper Oxide as a Source of Fertilizer Copper


TABLE 3.-INFLUENCE OF DIFFERENT APPLICATION RATES OF COPPER OXIDE
AND COPPER SULFATE ON YIELD OF SHALLU.

Copper Equivalent Yield of Shallu, Grams, Dry Weight per Jar
Pounds per Acre Sulfate Oxide | Average

0 5.4
6 30.7 29.5 30.1
12 27.5 29.8 28.7
24 29.2 27.6 28.4

Weighted Average .... 29.1 29.2

indicates that no change in availability of copper from either
source had occurred as a result of mixing with commonly used
fertilizer ingredients.

TABLE 4.-INFLUENCE OF METHOD OF APPLICATION OF COPPER AT VARIOUS
RATES ON YIELD OF SHALLU.

Copper Equivalent Yield of Shallu, Grams, Dry Weight per Jar
Pounds per Acre Applied Mixed in
SSeparately Fertilizer Average

0 5.4
6 30.3 29.9 30.1
12 28.4 28.9 28.7

Average ....................... 29.4 29.4

Copper contents of the shallu treated with 50 pounds per acre
of copper sulfate or its equivalent in copper oxide (12 pounds
copper per acre) were significantly higher than copper contents
of shallu from the check treatment and the 6-pound copper
level derived from the sulfate (Table 2). The higher levels of
copper application, treatments 10 and 11, resulted in increased
copper content of the plant, but these increases in most cases
were not significant. Copper analyses with respect to rate of
application and source are recorded in Table 5. The increase
in average copper content of plants resulting from applica-
tions of copper at the 12-pound rate compared to the 6-pound
rate was significant. Plants from the oxide source treatments
averaged 9.7 ppm copper compared to 8.3 ppm from the sulfate-
treated plots, but this difference was not significant. This in-
crease reflected in the average was derived almost entirely
from the difference at the lower (6-pounds copper per acre)
treatment level. At the 6-pound rate the copper oxide treat-







Florida Agricultural Experiment Stations


ments significantly raised the copper content of the plants above
that of the check plants, while the copper sulfate did not.
Copper contents of shallu plants with respect to rate and method
of application are recorded in Table 6. Although average copper
contents were slightly higher from copper treatments made
with the mixed fertilizer, the differences were not significant
and indicate no decided trend.

TABLE 5.-INFLUENCE OF APPLICATION RATES OF COPPER OXIDE AND COPPER
SULFATE ON COPPER CONTENT OF SHALLU.

Copper Equivalent Copper Content of Shallu, ppm
Pounds per Acre Sulfate Oxide Average*
0 7.0
6 6.4 9.0 7.7
12 10.1 10.5 10.3
24 11.7 11.7 11.7
Weighted Average ... 8.9 10.1
Differences statistically significant, L.S.D. (19:1) = 1.4.

These results indicate equal growth response to soil applica-
tions of copper oxide and copper sulfate, with no effect on avail-
ability resulting from mixing the copper sources with fertilizers
commonly used on Everglades peat and muck soils. There was
a trend toward slightly higher copper contents of the shallu plants
grown on copper oxide-treated soils, especially at the lower
rates of copper application. This may be due to the fact that
the sulfate is not so finely divided as the oxide and, therefore,
tends to be localized in the soil; while the oxide, because of its
fineness, is easy to distribute uniformly.

Fig. 3.-Growth response of pepper plants to soil applications of copper
sulfate and copper oxide. Left to right: No copper; 25 pounds sulfate
(6 pounds Cu); 8 pounds oxide (6 pounds Cu); 50 pounds sulfate (12 pounds
Cu); and 16 pounds oxide (12 pounds Cu), all expressed on the basis of per-
acre application rates.












I -iji Hi








Copper Oxide as a Source of Fertilizer Copper


TABLE 6.-INFLUENCE OF METHOD OF APPLICATION OF COPPER AT VARIOUS
RATES ON COPPER CONTENT OF SHALLU.

Copper Equivalent Copper Content of Shallu, ppm
Pounds per Acre Applied Mixed in
SSeparately Fertilizer Average*
0 7.0
6 7.2 8.2 7.7
12 10.0 10.6 10.3

Average ................. 8.6 9.4
Differences statistically significant, L.S.D. (19:1) 1.4.

RESPONSES TO RESIDUAL COPPER

To check further the growth response with other crops, the
potted soils used in the previous tests were fertilized with phos-
phate and potash and used for another experiment utilizing
the residual copper levels remaining from the preceding treat-
ments.
Treatments 3, 5, 7 and 9 (see Table 2), along with extra jars
of treatment 1, were planted to green peppers. Observations
made 75 days after seeding showed a tremendous response to
copper treatments from both sources and at all levels. Photo-
graphs were made 115 days after seeding, Figure 3. Maximum
growth response was obtained from copper applied as either
sulfate or oxide at the rate of 12 pounds per acre of elemental
copper equivalent. At the lower rate of application, 6 pounds
copper equivalent per acre, the growth response to the oxide

Fig. 4.-Growth response of Pangola grass to soil applications of copper
sulfate and copper oxide. Left to right: No copper; 25 pounds sulfate
(6 pounds Cu); 8 pounds oxide (6 pounds Cu); 50 pounds sulfate (12 pounds
Cu); and 16 pounds oxide (12 pounds Cu), all expressed on the basis of
per acre application rates.











1si !^




...22







Florida Agricultural Experiment Stations


may have been slightly superior, see Figure 3. Copper de-
ficiency symptoms of the pepper plants and growth response
to soil applications of copper were identical to those reported
previously (2, 3, 4). The plants were not carried through the
fruiting stage, hence no yield records were obtained.
Treatments 1, 2, 4, 6, 8, 10 and 11, representing levels rang-
ing from 0 to 24 pounds copper per acre applied as the sulfate
and oxide (see Table 2), were planted to cuttings of Pangola
grass, Digitaria decumbens. This grass had been determined
from previous experiments to be very sensitive to copper de-
ficiencies and had shown marked response to applications of
this element on Everglades soils. After about three months
the grass had become well established and formed good sods
on the soils in the jars. All were then clipped to a height of
approximately two inches and thus adjusted to the same height
for future growth and yield measurements. The relative growth
after 30 days as a result of the various copper treatments and
levels is indicated in Figure 4. The poor growth on the check
treatment is quite evident, with little if any noticeable differ-
ences between the rates and sources of copper treatment.
The grasses were harvested after 40 days by clipping at
an approximate height of two inches above the soil line. Yields
of this first clipping are recorded in Table 7, along with those
of a second clipping made 28 days later. For both clippings
all the copper treatments resulted in statistically larger dry
weight yields than the check plants. There were no statis-
tically significant differences between the oxide and sulfate
sources at the same rate of copper treatment. There was a
tendency toward increased yields as a result of copper treat-
ments up to a level of 12 pounds per acre of elemental copper
equivalent. Total yields from the two cuttings arranged ac-
cording to treatment levels and copper sources are recorded in
Table 8. Although the differences are not statistically signifi-
cant, it is interesting to note that the over-all average for the
oxide is slightly larger than that for the sulfate. This difference
is due primarily to increased response to the oxide at the lowest
treatment level, 6 pounds copper equivalent per acre. Also,
average yields at the 12- and 24-pound copper levels are higher
than those at the 6-pound level.
Copper analyses of Pangola grass clippings from each treat-
ment are recorded in Table 7. The copper contents increased
with increasing copper applications from 4 to 5 ppm at the









TABLE 7.-RESPONSE OF PANGOLA GRASS IN GREENHOUSE EXPERIMENTS TO RESIDUAL COPPER FROM PREVIOUS APPLICATIONS
OF THE OXIDE AND SULFATE, AS INDICATED BY YIELD AND COPPER CONTENTS.


Treat-
ment
No.


1


Application Approximate
Rate Copper
Lbs./Acre Equivalent
Lbs./Acre

0


L.S.D. (19:1)

L.S.D. (99:1)


Copper
Source


no
copper

sulfate

oxide

sulfate

oxide

sulfate

oxide


Cu, ppm Dry Weight


Average Yield of Pangola Grass
Grams, Dry Weight per Jar
First Second
Clipping Clipping Total

10.3 5.8 16.0


17.4 19.7 37.1

22.4 25.6 48.0

23.6 28.5 52.0

27.7 19.9 47.6

25.6 22.7 48.3

27.3 25.8 53.2


7.1 6.6 11.4

9.9 8.8 16.1


Second
Clipping

5.1


8.6

7.7

9.5

11.9

12.5

12.1


3.9

not sig.


SAnalyses made on one composite sample from each Ireatment.


First
Clipping

4.1


6.9

7.8

11.5

13.0

11.2

12.8








Florida Agricultural Experiment Stations


TABLE 8.-INFLUENCE OF APPLICATION RATES OF COPPER OXIDE AND COPPER
SULFATE ON YIELD OF PANGOLA GRASS.


Copper Equivalent
Pounds per Acre


0
6
12
24


Average


Yield of Pangola Grass, 2 Cuttings, Grams,
Dry Weight per Jar
Sulfate ] Oxide Average

16.0
37.1 48.0 42.6
52.0 47.6 49.8
48.3 53.2 50.7

45.8 49.6


lowest treatment rate to 12 to 13 ppm at the highest treatment
rate. Average copper analyses of samples from the second
clipping arranged according to treatment rates and sources are
recorded in Table 9. These data indicate no difference between
the sulfate and oxide sources with respect to availability in
the soil, as expressed by copper contents of plants. The data
indicate that the copper content of Pangola grass may be in-
creased by soil applications of either the sulfate or oxide form
of this element.

TABLE 9.-INFLUENCE OF APPLICATION RATES OF COPPER OXIDE AND COPPER
SULFATE ON COPPER CONTENT OF PANGOLA GRASS.


Copper Equivalent
Pounds per Acre

0
6
12
24


Average


Copper Content of Pangola
Second Cutting, ppm
Sulfate Oxide


8.6 7.7
9.5 11.9
12.5 12.1

10.2 10.6


FIELD EXPERIMENTS WITH COPPER OXIDE AND
COPPER SULFATE

Large field plots were initiated in the summer of 1951 on a
40-acre block of virgin Everglades peaty muck soil. Copper
treatments were made according to a randomized block, split-
plot design in which copper rates constituted the main treat-
ment variables and the subtreatments were the sources, oxide
and sulfate. Two experiments were set up: one with St. Augus-
tine grass, Stenotaphrum secundatum, and one with Pangola
grass, Digitaria decumbens. In previously conducted small plot


Grass,

Average

5.1
8.1
10.7
12.3







Copper Oxide as a Source of Fertilizer Copper


experiments (5) St. Augustine grass gave a growth response to
soil applications of copper sulfate but maintained a sod where
no copper had been applied. Pangola grass, however, died out
completely after a few months on Everglades peaty muck soils
not treated with copper. Figure 5 shows the growth response
of Pangola grass to applications of copper sulfate at the rate
of 50 pounds per acre. The photograph was taken 42 days
after planting with vegetative cuttings. Eight months after
planting the Pangola grass was no longer evident on the no-
copper plots. Because of the previous observations with respect
to the differences in response of these two grasses to applica-
tions of copper, treatments on the St. Augustine grass experi-
ment consisted of 0. 12 and 24 pounds per acre of copper applied
as the sulfate and the oxide, whereas the no-copper treatment
was not included in the Pangola grass experiment. The respec-
tive copper treatments were made in the over-all mixed fertilizer
application which consisted of a 500-pound-per-acre application
of an 0-8-24 mixture containing 200, 60 and 40 pounds per ton,
respectively, of manganese sulfate, zinc sulfate and borax. The
grasses were planted as vegetative cuttings during August. In




rI jr

















Fig. 5.-Pangola grass growing on Everglades peaty muck soil to which
had been applied 50 pounds per acre of copper sulfate (3, background) and
no copper (2, foreground).







14 Florida Agricultural Experiment Stations

November the St. Augustine grass plots were seeded to winter
grasses, half of each plot to rye grass and half to Southland
oats.
Copper deficiency symptoms became evident on the oats grow-
ing on the no-copper plots during the early stages of growth
and became increasingly severe with the advance in stage of
maturity. The deficiency symptoms included chlorosis, retarded
growth and necrosis of the younger leaf tips and meristems.
Similar symptoms on rye grass were less severe. Growth was
uniformly good on all the copper treatments, regardless of rate
and source. The chlorosis of plants on the plots which did not
receive any copper is very evident in the aerial photograph
(Figure 6). Four of the five replicates of the no-copper treat-

Fig. 6.-Aerial view of copper plots planted to winter pasture grasses.
Light horizontal strips are the no-copper treatments passing alternately
through the strips of rye grass, oats, and rye grass and oats (left to right).
Chlorosis as indicated by the light areas was more severe on the oats.








Copper Oxide as a Source of Fertilizer Copper


ments are shown in the lighter strips appearing in a horizontal
direction across the photograph. The absence of visible differ-
ences between treatments including copper as either the sul-
fate or the oxide is an indication that both are effective as
sources for this element as a fertilizer.

TABLE 10.-EFFECTS OF SOURCE AND RATE OF SOIL APPLICATIONS OF COPPER
ON AVERAGE YIELDS AND COPPER CONTENTS OF OATS.


Copper Source and
Rate per Acre

No copper ....... . .....
Oxide @ 16 lbs. ...................
Sulfate @ 50 lbs. .............
Oxide @ 32 lbs. ...............
Sulfate @ 100 lbs ............

L.S.D (19:1) ......................


Approximate
Copper Yield, Lbs. Cu Content
Equivalent, Dry Wt. ppm
Lbs. per Acre Per Acre Dry Wt.

0 i 257 2.3
12 499 3.8
12 i 496 3.2
24 736 3.7
24 585 3.7

258 0.9


Yields of Southland oats were taken 63 days after seeding.
The yield data are recorded in Table 10, along with the results
of copper analyses on plant samples collected at the time of
harvest. Applications of 24 pounds of copper from either source
significantly increased yield over that of the check. There were
no significant yield differences between any of the copper treat-
ments, regardless of rate or source. Copper contents of oats
from all copper treatments were significantly higher than the
check but there were no differences between any of the copper
treatments.
TABLE 11.-EFFECTS OF RATES OF SOIL APPLICATIONS OF COPPER OXIDE AND
COPPER SULFATE ON AVERAGE COPPER CONTENTS OF ST. AUGUSTINE GRASS
AND PANGOLA GRASS.
Application Ratel Copper Contents, ppm. Oven-Dry
Lbs. Copper I
Equivalent I St. Augustine Grass Pangola Grass
per Acre Oxide Sulfate Average*1 Oxide Sulfate IAverage*

0 5.0 5.7 5.4
12 6.4 7.6 7.0 5.0 5.6 5.3
24 6.4 7.5 6.9 5.4 6.7 6.0

Average* ...... 6.4 7.6 5.2 6.2
Differences between averages with respect to copper sources or rates were not statis-
tically significant.

Pangola and St. Augustine grass became well established
on the plots during the summer of 1952 and the area was used
for grazing cattle during the late summer and fall. Attempts







Florida Agricultural Experiment Stations


to obtain yield data from cages were not successful because of
the grazing animals. Samples for analysis were collected from
all the plots during late fall. Average results of copper analyses
are recorded in Table 11. There were no differences between
copper contents for St. Augustine grass or Pangola grass due
to rate or source of copper. These results indicate that copper
oxide is equally as effective as copper sulfate in satisfying the
copper nutritional requirements of pasture grasses growing on
Everglades organic soils.

CONCLUSIONS

These experiments indicate that finely ground copper oxide
as a soil corrective for copper deficiencies in crops growing on
Everglades organic soils is as efficient as copper sulfate when
applied on the basis of equivalent amounts of elemental copper.
Furthermore, both forms may be applied with equal effect,
either as separate applications or mixed in the fertilizer. Maxi-
mum growth and yield responses with the indicator plants used
in these experiments under both greenhouse and field condi-
tions were obtained with soil applications of the copper com-
pounds equivalent to 12 pounds per acre of elemental copper.

LITERATURE CITED

1. ALLISON, R. V., O. C. BRYAN and J. H. HUNTER. The stimulation of
plant response on the raw peat soils of the Florida Everglades
through the use of copper sulfate and other chemicals. Fla. Agr.
Exp. Sta. Bul. 190. 1927.
2. FORSEE, W. T., JR. Recent plant responses to some of the micro elements
on Everglades peat. Soil Science Soc. Fla. Proc. 2, 53-58. 1940.
3. FORSEE, W. T., JR. Fertilizer requirements of vegetable crops growing
on the organic soils of the Florida Everglades. Veg. Grower's Assoc.
of Amer. Ann. Rept. 70-82. 1952.
4. FORSEE, W. T., JR. Minor element deficiencies and field corrections es-
tablished by research in Florida vegetables. Proc. Fla. State Hort.
Soc. 65, 154-159. 1952.
5. FORSEE, W. T., JR., ROY A. BAIR, C. C. SEALE and T. C. ERWIN. Soil
fertility investigations under field and greenhouse conditions. Fla.
Agr. Exp. Sta. Ann. Rept., p. 170. 1946.




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