• TABLE OF CONTENTS
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 Copyright
 Front Cover
 Title Page
 Table of Contents
 Acknowledgement
 Introduction
 Experimental methods
 Results and discussion
 Summary and conclusions
 Literature cited
 Back Cover






Group Title: Bulletin - University of Florida. Agricultural Experiment Station - no. 762
Title: Management of wet savanna forest soils for pine production
CITATION PAGE IMAGE ZOOMABLE PAGE TEXT
Full Citation
STANDARD VIEW MARC VIEW
Permanent Link: http://ufdc.ufl.edu/UF00027525/00001
 Material Information
Title: Management of wet savanna forest soils for pine production
Series Title: Bulletin University of Florida. Agricultural Experiment Station
Physical Description: 22 p. : ill., charts ; 23 cm.
Language: English
Creator: Pritchett, William L
Smith, W. H
Publisher: Agricultural Experiment Stations, Institute of Food and Agricultural Sciences, University of Florida
Place of Publication: Gainesville Fla
Publication Date: 1974
 Subjects
Subject: Forest soils -- Southern States   ( lcsh )
Soil management -- Southern States   ( lcsh )
Pine -- Soils -- Southern States   ( lcsh )
Genre: government publication (state, provincial, terriorial, dependent)   ( marcgt )
bibliography   ( marcgt )
non-fiction   ( marcgt )
 Notes
Bibliography: Bibliography: p. 22.
Statement of Responsibility: W.L. Pritchett and W.H. Smith.
General Note: Cover title.
Funding: Bulletin (University of Florida. Agricultural Experiment Station) ;
 Record Information
Bibliographic ID: UF00027525
Volume ID: VID00001
Source Institution: Marston Science Library, George A. Smathers Libraries, University of Florida
Holding Location: Florida Agricultural Experiment Station, Florida Cooperative Extension Service, Florida Department of Agriculture and Consumer Services, and the Engineering and Industrial Experiment Station; Institute for Food and Agricultural Services (IFAS), University of Florida
Rights Management: All rights reserved, Board of Trustees of the University of Florida
Resource Identifier: aleph - 000929857
oclc - 18432878
notis - AEP0659

Table of Contents
    Copyright
        Copyright
    Front Cover
        Front Cover 1
        Front Cover 2
    Title Page
        Title Page
    Table of Contents
        Table of Contents
    Acknowledgement
        Table of Contents
    Introduction
        Page 1
    Experimental methods
        Page 2
        Page 3
        Page 4
        Page 5
        Page 6
    Results and discussion
        Page 7
        Page 8
        Page 9
        Page 10
        Page 11
        Page 12
        Page 13
        Page 14
        Page 15
        Page 16
        Page 17
        Page 18
    Summary and conclusions
        Page 19
        Page 20
        Page 21
    Literature cited
        Page 22
    Back Cover
        Page 23
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





BULLETIN 762 TECHNICALA) '


MANAGEMENT OF

WET SAVANNA FOREST SOILS
FOR PINE PRODUCTION




W. L. PRITCHETT AND W. H. SMITH






AGRICULTURAL EXPERIMENT STATIONS
INSTITUTE OF FOOD AND AGRICULTURAL SCIENCES
J. W. SITES, DEAN FOR RESEARCH
UNIVERSITY OF FLORIDA, GAINESVILLE


II


FEBRUARY 1974




















Cover: Eleven-year old slash pine plantation on wet savanna soil in
phosphorus source experiment. (Foreground) Unfertilized check plot. (Back-
ground) Fertilized with 35 pounds per acre each of N, P, and K at planting.













MANAGEMENT OF WET SAVANNA FOREST


SOILS FOR PINE PRODUCTION





By


W. L. Pritchett

and


W. H. Smith


Dr. Pritchett is Professor of Soils (Soil Chemist), Department of Soil
Science, and Dr. Smith is Associate Professor of Forestry (Associate Forester),
Department of Forest Resources and Conservation, University of Florida
Agricultural Experiment Station, Gainesville.


This public document was promulgated at an annual
cost of $1,398.00 or a cost of 280 per copy to provide re-
search results and management guidelines to forest land
owners and scientists interested in forest soil management
problems.



















Contents


Page


Introduction


Experimental Methods ....

Results and Discussions -.

Summary and Conclusions


Literature Cited ...-.. ... .--- ---..- --- ------------------ 22
















Acknowledgment

The authors are grateful to the St. Joe Paper Company and Gulf
Timberlands on whose properties the experiments were located, to the Gulf
County Agricultural Extension Director for assistance in installations,
and to the CRIFF program for financing part of the costs.



















Contents


Page


Introduction


Experimental Methods ....

Results and Discussions -.

Summary and Conclusions


Literature Cited ...-.. ... .--- ---..- --- ------------------ 22
















Acknowledgment

The authors are grateful to the St. Joe Paper Company and Gulf
Timberlands on whose properties the experiments were located, to the Gulf
County Agricultural Extension Director for assistance in installations,
and to the CRIFF program for financing part of the costs.







Introduction
Pine production in Florida, as well as in much of the lower
coastal plain of the southeastern United States, is largely con-
fined to the Flatlands Coastal Plain Province, as described by
Hodgkins (3). This province is predominantly occupied by the
flatwoods region-a region characterized by flat to undulating
topography, high fluctuating water tables, and generally coarse,
sandy topsoils, except where broken by lakes, sinkholes, and
depressions that are typical of limestone country recently
emerged from the sea. In Florida, soils of the flatwoods region
(mostly Spodosols) comprise more than 40% of the total land
area (9) and an even larger percentage of the commercial
forestlands of the state. Although considerably less extensive
than the flatwoods, the region of wet savanna soils, with which
this report deals, are of interest because they are used exten-
sively for forest production, and their management problems
are distinct from others in the Flatlands Coastal Plains physio-
graphic province.
The wet savanna coastal lowlands occupy approximately
1.1 million acres in the state (9), and during the early part of
this century, when wildfires were frequent, they supported a
thriving stand of longleaf pine (Pinus palustris). During that
period the soil water table was apparently lower than during
recent years because of higher transpirational losses by the
forest cover. Apparently the groundwater table gradually rose
following the harvest of this original stand of timber, resulting
in a reduction in soil volume available to tree rooting. High
water tables during extended periods of the year retarded the
reestablishment of vigorous stands. The absence of fully stocked
conditions is now the principal cause of many of the manage-
ment problems of the area.
Present vegetation is typically wiregrass (Aristida stricta),
pitcher plants (Sarracenia spp.), St. Johns wort (Hypericum
aspalanthoides), and slash pine (Pinus elliottii var. elliottii
Engelm). These hydromorphic soils generally belong to the
Ochraquult and Umbraquult (Humic Gley and Low Humic
Gley) great soil groups of the order Ultisol and include such
series as Bladen, Leaf, Plummer, Rains, Rutlege, and Weston
(9). These poorly drained acid soils, which geologically were
deposited in slack water flats, generally have a finer textured,
thicker, and darker surface layer than the better drained soils
of the flatwoods region. Although their nutrient content is
often higher than that of the typical flatwoods (total phosphorus
concentrations in these soils range from 60 to 120 ppm) they







are the most responsive to fertilizers, especially phosphorus, of
all forest soils of the Coastal Plain Province (5).
Fertilization is rapidly becoming an accepted management
practice for pine forests of the Southeast. It was estimated
that more than 250,000 acres of pine land were fertilized by
1973 (8). Most of this acreage was in the Flatlands Coastal
Plain Province.
Mechanical preparation is a standard management practice
to hasten reforestation of clear-cut sites to be planted to south-
ern pine (7). Bedding (ridging) is a particularly popular step
in the site preparation sequence in both the flatwoods and wet
savanna regions. Apparently bedding is a more effective method
for keeping excess water away from seedling roots than is
ditch drainage. Because of the poor internal drainage and near
level topography of the wet savanna region, ditching is an un-
economical practice on most of these soils.
In this bulletin results of several field experiments designed
to study soil management problems of the wet savanna are re-
ported. Emphasis is placed on fertilization and site preparation
because of their importance in reestablishing vigorous pine
stands in this area.
Experimental Methods
Many experiments on forest fertilization and site prepara-
tion have been installed on soils of the wet savanna region,
particularly by CRIFF Cooperators.' Four were selected as
representative of the group for discussion here. They were in-
stalled 3, 5, 10, and 19 years ago on soils of the Bladen-Rains-
Plummer complex in west Florida. Slash pine seedlings were
planted in all cases. Treatments were applied near time of
planting without subsequent applications, except as noted. Tree
heights and diameters were measured at approximately two-
year intervals and soil and tissue samples collected periodically
for chemical analyses.
Techniques employed in each of the four experiments were
as follows.
1. Site Preparation-Fertilization: Three methods of site
preparation formed whole plots, and 10 fertilizer treatments
were applied to sub-plots in a split-plot factorial experiment
with three replications. The 90 sub-plots were each approxi-
mately 0.6 acres in size and represented a total experimental
'CRIFF (Cooperative Research in Forest Fertilization) is a research
program at the University of Florida that is partially supported by
industry.







area of about 60 acres on Rains loamy fine sand. The three
methods of site preparation were: (a) "control", which was a
minimum preparation of clear-cutting of timber and burning;
(b) "disced" in which a single pass with a tandem disc plow
followed clear-cutting and burning; and (c) ridging by a single
pass with a 3-disc Rome bedding plow after treatment "b".
Tops of beds were approximately 8 inches above mean ground
level. Sites were prepared a year prior to planting of slash pine
(Figures 1-4).
Ten fertilizer treatments consisted of all combinations of
three levels of nitrogen (0, 20, and 80 pounds N per acre) and
three levels of phosphorus (0, 20, and 80 pounds P per acre)
plus a tenth treatment of 80 pounds each of N, P, and potas-
sium (K). Fertilizer sources were ammonium nitrate, concen-
trated superphosphate, and potassium chloride. All materials
were applied in 4-foot bands down the rows of trees, resulting
in a band concentration 2.5 times the per-acre rate given above.
Fertilizers were applied in May, about 4 months after seedlings
were planted.
Soil samples to a depth of 8 inches were collected with a
soil tube from the tree rows immediately prior to fertilization,
and current-year needle samples were collected in January, 1972.


r ., .
*N,_ >-v


Figure 1. Residual stand of cut-over pine on wet savanna soil in Gulf County,
Florida. Note dense ground cover of wire grass.































Figure 2. Minimal site preparation of a wet savanna soil by burning after
removal of residual timber in site preparation-fertilization ex-
periment.










: w5' -b o
... .. .. *.- ,.











Figure 3. Site preparation of a wet savanna soil by discing, following re-
moval of residual timber and burning, in site preparation-fertili-
zation experiment.
zation experiment.





























Figure 4. Bedding of a wet savanna soil following removal of residual timber
and burning in site preparation-fertilization experiment.

2. Fertilizing Seeded Pine on Beds: A Plummer fine sand
site was burned, stumped, and bedded on 8.5-foot centers in June
1964. Slash pine seeds treated with rodent repellent and fungi-
cide were aerially sown at a rate of 1.0 pound per acre in
October 1964. Germination was good in furrows, as well as on
ridges, resulting in approximately 3,500 stems per acre after
2 years.
Three randomized complete blocks of 13 treatments each
were established in June 1966. The treatments consisted of
combinations of four rates of ammonium nitrate (0, 20, 40, and
80 pounds N per acre), three rates of rock phosphate (17.5,
35, and 70 pounds P per acre), and a non-fertilized control.
Fertilizers were surface applied in 4-foot bands down the ridges.
In 1971, 27 trees were selected systematically at approxi-
mately 11-foot intervals on the three center beds of each plot
and measured for heights and diameters. All other trees were
removed to leave a stand density of 576 trees per acre. Tree
volume was calculated from the equation: V = -0.0852 +
0.1454D 0.05839D2 + 0.003102D2H, where D is diameter at
breast high and H is total height. The resultant volumes were
projected to cubic-feet per acre.







3. Phosphate Sources: Three randomized complete blocks of
10 treatments each were installed in May 1962 on slash pine
planted 4 months previously. In this experiment, timber was
clear-cut on a Bladen fine sandy loam and burned prior to
planting 6 feet apart in 10-foot rows. Fertilizer materials were
surface applied in 4-foot bands down the row of trees at per-
acre rates of 17.5 and 35 pounds P from ordinary superphos-
phate and 35, 70, 140, and 280 pounds P from rock phosphate.
In addition, the following plots were included: a control plot;
a plot treated with N, P, and K (35 pounds per acre of each
element from ammonium nitrate, ordinary superphosphate, and
potassium chloride) ; a plot receiving calcium sulfate; and a
plot treated with calcium carbonate. The latter two materials
were applied at rates equivalent to the amounts of sulfur and
calcium contained in the high rate of ordinary superphosphate
and rock phosphate, respectively.
4. Reapplication of Fertilizers: On an area where an at-
tempt to grow clover had failed, four 1/2-acre plots were planted
to slash pine at 6 x 10 ft spacings in 1953.2 One ton per acre
of "mill waste" liming material was applied to all plots and
disced (but not bedded) prior to planting. Two plots were
treated with 1 ton of 2-12-12 fertilizer per acre, and the re-
maining two plots were left unfertilized.
Tree growth response to the fertilizers was evident from the
first year, and by 1967 trees in fertilized soil were more than
twice the height and contained about eight times the wood vol-
ume of unfertilized trees. Fourteen years after the initial treat-
ment, an experiment was installed to determine if a delayed
fertilizer application would promote growth of stagnant trees
in the original control plots and further stimulate tree growth
in areas fertilized in 1953. Each of the four original plots was
divided into two 14-acre plots; one of the sub-plots in each
whole plot was randomly selected and treated with 400 pounds
ammonium polyphosphate (15-60-0) per acre. This material sup-
plied the same amount of P as the original treatment (but
slightly more N). Soil and tissue tests had indicated that the
initial growth response was primarily due to the P contained in
the mixed fertilizer (Figure 5).
Ten trees in each plot were selected from the array of diam-
eter classes present to represent the population in each plot and
'The initial treatments and plantings to clover and finally to slash
pine were done by Mr. John Haynie, Apiculturist, and Mr. Cubie Laird,
Gulf County Extension Director, Florida Agricultural Extension Service,
respectively, and Mr. Henry Maige, Forester, St. Joe Paper Company.


























Figure 5. Twelve-year old slash pine plantation prior to reapplication of
fertilizer. (Left) Unfertilized plot; (Right) Fertilized with one ton
2-12-12 at planting.
destructively sampled in December 1968 as described elsewhere
(2). Dry weight of tree components, nutrient concentrations,
and total nutrient uptake were determined by standard pro-
cedures.

Results and Discussion
Although growth response data were collected at regular
intervals since the installation of all experiments, emphasis
will be given to the most recent measurements in each instance.
Site Preparation-Fertilization: The analysis of variance of
height data summarized in Table 1 indicated that bedding this
wet savanna soil resulted in significantly taller trees than those
in the control or disced plots. In fact, trees in bedded plots con-
tinued to make greater annual growth after 3 years than trees
in either the control or disced plots. The mean third-year in-
crement in bedded plots was nearly 3 feet, while increments in
the latter plots were each about 1.6 feet.
Effects of fertilizer treatments on tree height were highly
significant, with the greatest response to P. Trees fertilized
with 20 pounds P per acre were about 60% taller than trees
that received no P fertilizer and were almost as tall as those
that received 80 pounds P per acre. On non-bedded plots, the
addition of N without P generally suppressed tree growth but
increased tree growth when applied in conjunction with P. In







Table 1. Mean heights
experiment.
Nutrient Applied
N P K
-lb/acre--


of 3-year-old trees in site preparation-fertilization

Site Preparation Avg.
Control Disced Bedded


- ft -


-ft-

3.8
3.8
3.5

5.6
5.7
6.1

5.8
6.0


80 80 0 5.2 6.1 7.6 6.3

80 80 80 6.5 6.1 7.6 6.7


4.5 4.9 6.7


bedded plots, N had little influence on tree growth regardless
of added P. This apparently resulted from the increased miner-
alization and release of soil N in the beds, as explained later.
Potassium had little effect on tree growth except in the control
(minimally prepared) plots where tree growth appeared to be
increased by K fertilizer. In spite of these trends, the inter-
action of site preparation X fertilizers was not sufficiently high
to be statistically significant. This apparently resulted from the
fact that the strong response to P was little affected by the de-
gree of site preparation used.
It is likely that the superior growth of trees in bedded plots
resulted from better aeration in the rooting zone, as well as
from the concentration of topsoil organic matter and nutrients
in the beds and a possible enhancement of nutrient availability
by accelerated decomposition. Analyses of soil samples, taken
to a depth of 8 inches in the tree rows, one year after site prep-
aration, illustrate the increase in total N and extractable bases
(K, Ca, Mg) associated with the increase of organic matter in
the bedded plots (Table 2). The increased levels of these nu-
trients in the bedded rows help explain the lack of response to

















Table 2. Some properties of soil (0-8 inches) sampled 1 year after site preparation and before fertilization.
Site Soil NH,OAc(pH 4.8)-extractable Organic Total CEC
Preparation pH Ca Mg P K Al Matter N
-ppm % % meq/100lg


5.0 25 17 0.2 13 196
4.5 32 23 0.2 12 187
4.3 41 32 0.2 15 207


3.09
3.13
4.41


5.88
5.48
7.24


Unprepared
Disced
Bedded







N and K in bedded plots in contrast to the consistent response
to P in all plots and the response to N and K where other prep-
aration was done.
Fertilizing Seeded Pine on Beds: Statistical analyses of
measurements made after 5 years (Table 3) indicated that only
P had significant effect on tree growth on this bedded and seeded
site. Without the addition of rock phosphate, trees made very
poor growth, but the lowest rate of P was almost as effective as
higher rates at this early stage of growth. For example, mean
height of control-plot trees was 10.5 feet as compared to 15.2,
15.0, and 15.9 feet where 17.5, 35, and 70 pounds P per acre
were applied. Based on these data, the first 17.5 pounds P per
acre applied as rock phosphate increased tree height over con-
trol trees by 45%, but application of additional units resulted
in little additional response by the end of the fifth year. How-
ever, the heavier application rates may prove superior to the
low rate before the end of the rotation period.

Table 3. Mean volumes per acre of 5-year-old seeded slash pine on beds.
N Applied Phosphorus Applied, Ib/acre Avg.
Ib/acre 0 17.5 35 70
cu ft/acr-
0 50 125 124 128 126
20 133 114 175 141
40 122 123 136 127
80 130 138 153 141

Avg. 50 128 125 148


Phosphate Sources: After 10 years, trees that received
either super or rock phosphate at planting time continued to
produce significantly greater height, diameter, and volume in-
crement than trees in control plots or in plots that received
CaCOs or CaS04 (Table 4). Although superphosphate resulted
in greater growth responses than rock phosphate during the
first 6 or 7 years, rock phosphate appeared to effect the most
sustained response (Figure 6). For example, height growth
increment during the ninth year was 22% and diameter incre-
ment 48% greater for trees fertilized with 35 pounds P per acre
from rock phosphate than those fertilized with the same rate of
P from superphosphate (Table 4). The greatest volume growth













4- 35 lb P/acre OSP + NK P/acre

20 OSP





10 -L -35 lb P/acre GRP
I0


SControl-



0 2 4 6 8 10

Tree age, years
Figure 6. Heights of slash pine fertilized at planting with 35 pounds P per
acre from ordinary superphosphate (OSP) or ground rock phos-
phate (GRP) or superphosphate plus 35 pounds per acre of N
and K.

was produced by 140 pounds P per acre from 1000 pounds of
rock phosphate.
Nitrogen and potassium applied with superphosphate in-
creased growth rate above that obtained from superphosphate
alone, as shown in the cover photograph.
Analyses of current-year needle samples, collected at the
end of the seventh growth season, indicated that not only were
the control trees extremely P deficient (0.05% P), but the trees
in the superphosphate plots also contained less P than required
for optimum growth. Mean concentrations of P were 0.054%
and 0.065% where 17.5 and 35 pounds P per acre were applied
as superphosphate. Only in plots that received rock phosphate
were the P levels above the critical response range of 0.085%
(5). For example, in plots that received 280 pounds P per acre
from rock phosphate, the needle P levels averaged 0.098% (4).
Thus after 10 years only rock phosphate appeared to release
adequate phosphorus to meet the tree requirements.












Table 4. Mean tree heights, volumes, and
P

P Source Rate
ib/acre


Control
Superphosphate
Superphosphate
Superphos- +40 NK**
Rock phosphate
Rock phosphate
Rock phosphate
Rock phosphate
CaSO, (equiv. to 3)
CaCO, (equiv. to 8)


0
17.5
35
35
35
70
140
280
0
0


annual increments of 10-year-old slash pine in phosphate source experiment.
1972 Measurements 1971 Increments
Heights Volumes* Heights Diameters Volumes*
ft cu ft/acre ft in cu ft/acre


8.8
25.5
28.6
32.3
29.2
30.5
31.7
31.5
9.9
9.8


37a
541b
914e
1177e
908e
937c
1174e
1022d
54a
4a


0.18
0.19
0.21
0.29
0.31
0.30
0.42
0.47
0.19
0.18


13
109b
205e
235c
232e
231c
324d
286d
12.
11a


* Means with the same superscript are not significantly different.
** 40 Ib/acre of N and K applied as NHINO0 and KgSO,.


1.
2.
3.
4.
to 5.
6.
7.
8.
9.
10.







Reapplication of Fertilizers: Phosphate fertilizer can be
used to effectively increase growth of pole-sized pine on wet
savanna soils. The value of the fertilizer was illustrated by
periodic measurements of height and diameter of all trees in
net plots. The most recent of these data are summarized in
Table 5. Measurements indicated that trees in control plots
(never fertilized) were stagnant. Furthermore, they exhibited
visual symptoms of severe P deficiency; i.e., sparse crown, short
needles, and early abscission, which resulted in crowns com-
posed of only one year's complement of needles. The P concen-
tration in current needles of 15-year old stagnant trees was
less than 0.06%. The site index at 25 years is about 40 feet (1),
and the height, diameter, and volume increments during the
18th year were 1.2 feet, 0.2 inches, and 96 cubic feet per acre,
respectively.
Trees in plots fertilized at time of planting in 1953, but not
refertilized in 1967, continued to make good growth. The height,
diameter, and volume increments on these plots during 1971
were 1.8 feet, 0.3 inches, and 414 cubic feet per acre, respec-
tively. The site index at 25 years of these plots averaged about
65 feet (1), an increase of approximately 25 feet in site index
resulting from application of a ton of 2-12-12 fertilizer per acre.
Stagnant trees in control plots (originally unfertilized) that
were fertilized at 14 years of age showed a marked increase in
growth rate during the last 5 years (Figure 7). For example,
the 1971 height increment of these trees was 2.8 feet, as com-
pared to 1.2 feet for unfertilized trees, and a volume increment
of 284 cubic feet as compared to 96 cubic feet per acre. How-
ever, the current volume increment of trees fertilized only at
planting was still about twice that of trees fertilized only at 14
years of age (Table 5). This apparently resulted from the much
larger volume base of the former trees.

Table 5. Mean heights and diameters and 5-year volume increments
in refertilization experiment.
Fertilized 1972 Measurements 1967-1972
Volume
1953 1967 Heights Diameters Increment
ft in cu ft/acre

no no 29.8 4.00 446
no yes 38.2 5.05 1035
yes no 55.7 7.20 2020
yes yes 60.2 7.85 2158








60 I I I I
FERTILIZED AT PLANTING AND 14 YEARS .,v

V
AT PLANTING ONLY



O-I











7 11 15 19
REE A T 14 YEARS ONLYYEARS



















'8). Heavy applications of P (such as 105 pounds per acre) at
.-r1O .^0I "O
--

/Yi NEVER FERTILIZED
20 -




711 15 19

TREE AGE, YEARS
Figure 7. Mean heights of trees fertilized at planting and/or after 14 years.

Trees fertilized at planting and again at 14 years of age
increased their rate of growth over that of trees fertilized only
at planting, but the increase in growth was rather small (Figure
'8). Heavy applications of P (such as 105 pounds per acre) at
planting time apparently influence slash pine growth for the
entire rotation period on these wet savanna soils. This long
term effect probably occurred as a result of internal recycling
within the trees of the P absorbed early in stand development,
since soil analyses showed little readily available P. The equiv-
alent rate of P applied late in the rotation will significantly
increase growth rate of stagnant trees, but it is doubtful that
these latter trees will ever attain the volume of trees fertilized
at planting time, during a 25-year rotation.
The effect of vigorous growth of fertilized trees on the
ground water table of this wet savanna soil is illustrated by a
series of measurements made in the unfertilized and fertilized
plots. During a relatively dry period in November, the water
table in unfertilized plots averaged 15 inches below the surface,








while the water table in fertilized plots was at 32 inches. The
lower water table under rapidly growing trees probably in-
creases the volume of soil for root exploitation, and thus results
in greater nutrient supply.
For a better understanding of the disposition of applied
nutrients in the wet savanna. pine ecosystem, a biomass and
nutrient uptake study was made when the trees were 15 years
old. In a previous report (2), it was pointed out that (a) bark
thickness on upper stem was decreased by fertilization; (b)
absolute and Girard form quotients were not significantly af-
fected by the fertilizer treatment; (c) specific gravity was
slightly reduced, but increased volume as a result of fertiliza-
tion more than made up for this loss; and (d) pulping was
improved by fertilizer use.
Height Diameter
(ft) (in)





12.0 1.5









SI-
8.0 1.0




4.o0 -0.5





none 1953 1967 1953 &
only only 1967


Year Fertilizer Applied
Figure 8. 1967-1972 height and diameter increments of 19-year-old trees
fertilized at planting and/or after 14 years. (Solid bars refer
to height.)













Table 6. Mean nutrient concentrations in above-ground components and litter of fertilized
and non-fertilized 15-year-old slash pine on a wet savanna.


Element


Nitrogen, %
Phosphorus, %
Potassium, %
SCalcium, %
Magnesium, %
Aluminum, ppm
Copper, ppm
Iron, ppm
Manganese, ppm
Zinc, ppm


Non-Fertilized Trees Fertilized Trees
Bark Bolewood Branches Foliage Litter Bark Bolewood Branches Foliage Litter
oi 02

0.21 0.10 0.24 1.16 0.65 0.19 0.11 0.19 0.92 0.45 0.56
0.011 0.006 0.015 0.055 0.013 0.015 0.006 0.018 0.069 0.030 0.020
0.04 0.05 0.08 0.31 0.03 0.06 0.05 0.10 0.32 0.04 0.04
0.18 0.09 0.30 0.25 0.64 0.19 0.06 0.28 0.26 0.66 1.15
0.02 0.02 0.05 0.20 0.05 0.03 0.02 0.05 0.12 0.07 0.05
196 75 90 225 3270 365 75 103 318 533 4312
5.4 1.5 2.7 3.2 2.3 4.2 2.3 2.5 3.7 2.0 3.3
24 9 42 31 1290 16 4 37 97 176 1140
5.6 6.7 17.9 51 22 2.5 2.1 9.5 38 15 33
12 8.7 14 8 4 8.3 2.6 4.9 14 26 24







Nutrient concentrations (Table 6) varied considerably
among tree components. The greatest concentrations of most
elements were in the foliage. A notable exception was the high
level of Ca found in branches. Nutrient concentrations were
also influenced by age and position of component tissue on the
tree. It was interesting that concentrations did not differ
greatly between the fertilized and non-fertilized trees. Phos-
phorus levels, which were low in all components, were increased
by fertilization. However, concentrations of some non-limiting
elements were higher in control trees than in fertilized trees,
probably reflecting the dilution effect from more rapid growth
of the latter.
Concentrations of N, P, and K were less in litter samples
than in green foliage from the same plots (Table 6). A con-
siderable portion of these mobile elements was translocated
from the foliage before needle cast: Ca, Al, and Fe (and all
heavy metals which are immobile) tended to accumulate in the
litter layer during decomposition. Movement down into the
mineral soil was apparently slow.
Biomass in fertilized plots was 5.5 times more than the bio-
mass in control plots; but, more importantly, fertilized trees
produced 6.6 times more dry weight of bolewood than control
trees (Table 7). That is, the fertilized trees contained a greater
proportion of bolewood relative to bark, needles, and branches
than did the unfertilized trees. Litter made up to 19.4% and
17.4% of the total above-ground biomass in non-fertilized and
fertilized plots, respectively. Since there was approximately
3 times as much litter as tree foliage in these plots, decompo-
sition rates were slower than deposition,' thus resulting in an
accumulation of surface litter. Nutrients immobilized in this
litter should accentuate a deficiency.
Total N uptake was about 4 times as great in the fertilized
plots as in unfertilized plots. This increased uptake was about
6 times the 40 pounds of N added in the fertilizer. Apparently
the additional N contained in the fertilized trees was derived
either from increased mineralization of organic N or from
greater symbiotic or non-symbiotic fixation of N in the ferti-
lized plots or both. Much of this N was contained in the bole-
wood. For example, there was 4 times more N in needles, but
7 times more N in bolewood of fertilized trees than of unferti-
lized trees.
Although 240 pounds of P205 per acre (105 pounds P) were
applied at time of planting 15 years previously, only 21.7 pounds
of P were found in the tree components, and only 30.1 pounds










Table 7. Dry weight and total nutrient content in above-ground components and litter of
fertilized and non-fertilized 15-year-old slash pine on a wet savanna.


Non-Fertilized Trees
Element Bark Bolewood Branches Foliage Litter
Ib per acre
Nitrogen 11.6 17.1 10.1 38.0 47.4
Phosphorus 0.6 1.0 0.6 1.8 0.7
Potassium 2.3 9.3 3.2 10.2 2.2
Calcium 10.0 15.4 12.4 8.3 46.7
Magnesium 1.4 4.0 1.9 6.5 3.9
Aluminum 1.1 1.3 0.4 0.7 23.8
Copper 0.03 0.03 0.01 0.01 0.02
Iron 0.13 0.16 0.17 0.10 9.49
Manganese 0.03 0.12 0.07 0.07 0.16
Zinc 0.07 0.15 0.06 0.06 0.18
Dry Wt. 5,640 17,270 4,120 3,260 7,300


Total


124.2
4.7
27.2
92.8
17.7
27.3
0.12
10.05
0.55
0.52
37,590


Fertilized Trees
Bark Bolewood Branches Foliage Litter Total
lb per acre
40.7 122.7 38.3 106.3 182.9 491
3.2 6.8 3.7 8.0 8.4 30
12.4 53.4 19.6 36.8 14.2 136
41.6 72.7 58.4 29.6 340.8 543
6.7 17.0 9.9 13.6 19.5 67
7.9 8.5 2.1 3.7 101.8 124
0.09 0.26 0.05 0.04 0.09 0.53
0.35 0.47 0.76 1.12 27.2 30
0.05 0.24 0.20 0.44 0.92 1.85
0.18 0.30 0.10 0.16 0.88 1.62
21,670 113,360 20,580 11,590 35,340 171,004







P were found in tree components plus litter of fertilized plots.
The above-ground biomass contained only 4.7 pounds P in un-
fertilized plots. If the unmeasured additional P in the root
biomass was about 25% of the total P in the tree biomass, then
the P in the total tree and litter biomass was 37.3 pounds in the
fertilized plots and 5.4 pounds in the unfertilized plots. Further-
more, if the 5.4 pounds P derived from the soil in the control
plots is subtracted from the 37.3 pounds in fertilized plots, this
gives a total of 31.9 pounds that can be considered as derived
from the 105 pounds of fertilizer P, which accounts for 30.4%
of the applied P. This does not necessarily mean that the other
59.6% has been irreversibly lost to the system. A high per-
centage of this residual P was undoubtedly fixed by the clay
minerals or existed as iron and aluminum phosphates of re-
duced availability. Another significant fraction was held in
organic combinations in the soil A1 horizon and will become
available through the mineralization of these compounds (4).

Summary and Conclusions
The wet savanna soils of the Southeastern Flatlands Coastal
Plain Province generally support a sparse stand of slow-growing
pine along with a wiregrass cover. A high water table for rela-
tively long periods of the growing season and the low native
fertility of the soil were blamed for the low productivity of these
sites. Ditch drains did not appear to be a practical and eco-
nomically feasible solution to the water problem on many of
these soils. The flat topography and poor internal drainage, due
to fine textured sub-soils, rendered surface drains effective for
only short distances. On the other hand, results of a series of
experiments showed that management practices which affected
root-zone moisture and nutrient levels in these soils, converted
them from essentially unproductive to highly productive forest-
land. Apparently, functioning of this ecosystem was controlled
by excess water and deficient nutrients. Other conclusions drawn
from results of these tests are the following:
(a) Discing as a means of site preparation did not appear
to be particularly beneficial to pine growth on these soils. Re-
duction in the competition for moisture by lesser vegetation on
these wet sites was not a critical factor. In fact, a vigorously
growing ground cover helped lower the water table by increas-
ing transpiration per unit land area.
(b) Bedding, or ridging, resulted in improved tree growth
during the early years of plantation development. After three
years, trees in bedded plots were 50% taller than trees in un-
































































Figure 9. Most wet savanna sites can be made highly productive by increas-
ing the level of soil available phosphorus by fertilizers and/or
bedding.








bedded plots. Growth improvement apparently resulted from
better aeration in the seedling root zone as well as the improved
nutrition by concentrating the soil organic material and in-
creasing its mineralization in the bed environment. Availability
of several nutrients was increased in the beds; the importance
of this was demonstrated by the absence of a N fertilizer re-
sponse on the bedded sites. If the benefits are derived primarily
from increased nutrient mineralization from a limited nutrient
capital, it is likely the growth rate on the beds will slow to that
of trees on unbedded sites, as soon as the soil organic matter in
the beds is oxidized back to the same level as that of the un-
bedded soil. This means that bedding, changes the rate of nu-
trient release but not the total released. On the other hand, early
tree growth on beds appears to be sufficiently improved over
that of unbedded trees to eventually make a significant differ-
ence in watertable levels.
(c) Fertilization resulted in a growth response which was
similar to that obtained from bedding or ditch drainage.
(d) These soils were deficient in available P, and growth
response to phosphate fertilizers was noted within a year after
application even when surface applied. Nitrogen applied alone
did not result in increased tree growth, but when applied in
combination with phosphates it resulted in increased growth
over that obtained from P alone.
(e) Fertilizers should normally be applied at time of plan-
tation establishment, because unfertilized trees grow poorly and
may never reach merchantable size. Such stagnant stands can
be rejuvenated by the surface application of a nitrogen-phos-
phate fertilizer, such as diammonium phosphate. Applications
of 250 to 300 pounds per acre of the latter material, made 5 to
10 years prior to harvest, proved beneficial.
(f) Soils of the wet savannas generally have a high capacity
to fix P. Consequently, slowly soluble forms such as ground
rock phosphate are desirable. A partially-acidulated, pelletized
rock phosphate has advantages for use on these soils, but it is
not generally available as yet. It should be applied at rates
between 300 and 500 pounds per acre. If a soluble phosphate
such as concentrated superphosphate or diammonium phosphate
is used, a reapplication at about 10-year intervals may be re-
quired to sustain good growth. Fixation can be reduced by band
placement of the fertilizer (4). Applications of 20 to 40
pounds P per acre may be adequate under these conditions.
According to a recent survey (8), forestland can be ferti-
lized for about $12-18 per acre. Fertilization of these sites has









a marked effect on timber production and is economically fea-
sible. Other values not evaluated to date could include an
improvement in species composition and diversity in systems
constrained by severe nutrient deficiencies. Also, forage quality
and quantity should be greatly improved, thus increasing the
site carrying capacity for animals.


Literature Cited

1. Barnes, R. L. 1955. Growth and yield of slash pine plantations in
Florida. University of Florida, School of Forest Resources and
Conservation, Rpt. No. 3, 23 pp.
2. Gooding, J. W., and W. H. Smith. 1972. Effects of fertilization on
stem, wood properties, and pulping characteristics of slash pine
(Pinus elliottii var. elliottii Engelm.). In: Proc. Symposium on
the Effect of Growth Acceleration on the Properties of Wood.
pp. E-1 to E-18. USDA Forest Products Laboratory, Madison,
Wisconsin.
3. Hodgkins, E. J. 1965. Southeastern forest habitat regions based on
physiography. Auburn University Agricultural Experiment Sta-
tion, Forest Dept. No. 2, 10 pp.
4. Humphreys, F. R., and W. L. Pritchett. 1971. Phosphorus adsorption
and movement in some sandy forest soils. Soil Sci. Soc. Amer.
Proc. 35(3): 495-500.
5. Pritchett, W. L., and W. H. Smith. 1968. Fertilizing slash pine on
sandy soils of the Lower Coastal Plain. In: C. T. Youngberg and
C. B. Davey (Ed) Proc. 3rd N. A. Forest Soil Conf., Oregon
State University Press.
6. Pritchett, W. L. 1969. Slash pine growth during the seven to ten years
after fertilizing young plantations. Soil and Crop Sci. Soc. of
Fla. Proc. 29: 34-44.
7. Pritchett, W. L. 1969. Site preparation and soil amendments. Proc.
SE Sec. SAF, Birmingham, Alabama.
8. Pritchett, W. L., and W. H. Smith. 1973. Operational fertilization in
the U. S. Southeast. Proc. 4th N. A. Forest Soils Conf. (in press).
9. Smith, F. B., R. G. Leighty, R. E. Caldwell, V. W. Carlisle, L. G.
Thompson, and T. C. Matthews. 1967. Principal soil areas of
Florida. Florida Agricultural Experiment Stations, Bull. 717. 66 pp.

























Institute of Food and Agricultural Sciences



TEACHING I FAS
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