Download soil ph variations and lychee growth

NANZ: SOIL pH AND LYCHEE
275
SOIL PH VARIATIONS AND LYCHEE GROWTH
Robert A. Nanz
Florida Chemists and Engineers, Inc.
Orlando
Agricultural chemistry is coming more and
more to the fore.
Soil pH findings take on
greater significance.
The chemistry of the
soil and its pH is related to yields and growth
of plants.
Soil pH governs both leaching and avail
ability of nutrients.
Potassium, ammoniacal
nitrogen, magnesium and calcium leach quick
er from strongly acid soils than from slightly
acid to neutral soils. Volk and Gammon (1)
state that this is especially true in sandy soils
low in humus.
Liming is needed in low
humus soils. Between 5.5 and 6.0, they state,
is the most desirable pH range under Florida
conditions unless special needs must be con
sidered.
Lychees do not appear to have
special requirements.
Above 6.0, copper, zinc, boron and man
ganese become less available in most soils.
Residual phosphorus becomes less available
at higher pHs.
To change the pH one unit, various soils
may need anywhere between 1000 to 5000
pounds of lime per acre, depending on the
soil type.
Groff (2) states that in native China most
lychee trees are on dykes and at waters edge.
They are in an acid peaty soil. The liquid
night soil fertilization must leach rapidly. Its
residual effect may yield a pH around 5.5.
In the appendix to Dr. Groffs book (2),
Coville believes that lychee growth is best in
an acid medium. The mycorrhizal fungi on
the roots were beneficially developed in an
acid soil. Poorer growth resulted from pot
culture in loam, manure and sand, wherein
no fungi growths developed.
The report in 1943 by Dr. Groff (3) states
the lychee is more plastic (adjustable) in its
relation to soils than to climate.
Clay-like
acid soils in South China are seen. They are
heavily fertilized with animal and vegetable
wastes.
Large trees seen in the Everglade
area of Florida never bore fruit, possibly due
to lack of phosphate, potash and other essential
nutrients. Or possibly too high a pH, making
these nutrients unavailable.
In the Ridge
area of Florida, on citrus soils, lyqhees do
nicely.
Referring to growth in the Miami-Home
stead area of Florida, Groff (4) states that
soil conditions are not as ideal as those in the
Ridge and West Coast area. But early growth
in an acid "produced" condition, may eventuate
a mature tree able to tolerate alkaline condi
tions there.
Lynch (5) confirms the lychee's adapta
bility with a recent review of growth and
good yield in the Miami area. Their pH is in
the 7.5 to 7.8 range. The soil is sandy and
has very little loam.
Fertilization 4 to 5
times a year is needed to keep supplying
nitrogen steadily. Such applications may drop
the pH somewhat.
Young trees in this limestone area need
rich feeding, Lynch reported in 1953 (6).
Reports to the Florida Lychee Growers As
sociation,
in
1954,
by
Lynch further con
firm the need for this heavy feeding program
(7). In this area, sludge and manures are
recommended for both young and bearing
trees.
Young, (8), suggests maintaining a pH of
5.5 - 6.5. This range reduces toxicities such
as copper, especially on old citrus soils.
The excellent Lychee bulletin by Cobin
(9) revised by Ledin reviews these reports
and stresses the adaptability of the lychee.
We may find that where more alkaline condi
tions are found heavier feeding is needed.
This will come from more studies on the
fertilizer demand of the tree.
Straw mulch is suggested for maintaining
a neutral to acid media for the lychee roots.
Decaying mulch acidifies the roots' feeding
area.
Methods
A number of lychee growers were con
tacted. They were asked to supply informa
tion on pH levels from various parts of their
groves. They were asked to state which were
areas of best growth.
Groves were visited also.
Samples were
drawn and the pH determined by electrical
potential (pH meter) in our laboratory. Some
FLORIDA STATE HORTICULTURAL SOCIETY, 1955
276
of the reported pHs were determined by
the grove owners colorimetrically.
Expres
sions on growth and degree or yield were
obtained directly from the grower.
These pH findings and their relation to
growth and yield (when expressed) are given
Geneva, in the planning of this study and the
help in obtaining data and samples.
We
further appreciate the help of Jim Pinkerton,
South Merritt Island, Dr. S. John Lynch,
South Miami, and Dr. Frank Gardner, Orlando,
in supplying grove data.
in the table.
Pf ftTTPB
TABLE I
A*A««
inflation
Uitohell.
C.o!
lucky
Acres,
H. Simpson
Area of Grove
Relationship of t>H to Rated Growth and Yield
Yield
Growth
largo
Well Drained
6.5
Good
Good
Geneva
Low
Slope
Ridge
4.8
5.1
5.4
6.1
Medium
Medium
Best
Medium
Best
4.4
5.2
Poor
Best
Smaller
Larger
7.5
Medium
Good
5.7
Good
Smallest
Medium
Large at
Pinkerton So.Merritt
Orchard
ES
Island
University
of Miami.
Richmond
Horth West
South East
Hot
Speoified
1 -
7.0"
6.5"
Experimental
Farm
Experimental Orlando
Parm.U.S.D.A.
Hort.Pield
Hortto.
Bast
South
6*0
n
Station
5.5"
Due to the various ages of trees surveyed,
yields varied accordingly.
Only a general
relationship could be gleaned on this and the
tree's size or growth.
An approximate relationship of such growth
and size, weighted by the knowledge of the
tree's yield when known, is shown in this bar
graph.
It must be stressed that this graph
shows a rating of combined growth and yield
when known and is not based on exact figures.
However, it serves to show at what pH best
performances are seen.
Results
We see that best performance on the part
of most trees is in the range of pH 5.0 to 5.5.
Greater acidity has an inhibiting effect on
growth and yield.
Over pH 6.0 calls for
special feeding to get adequate nutrient's con
tribution for good growth and yield.
Conclusions
Best availability of nutrients from the soil,
for the lychee's best growth and best yield,
is found in. soils of pH 5.0 to 5.5.
Acknowledgments
We acknowledge the inspiration and cooper
ation of Mr. and Mrs. Henry A. Simpson, of
J
5.0:
4.51
4.0"
Ratings on Growth.
Tree Size.
Weighted on Yield Where Known.
LITERATURE CITED
1. Volk, G. M. and Gammon, Nathan, Jr., 1951.
Soil Reaction
(pH), Circular S-39.
University
of
Florida Agricultural Experiment Stations, Gainesville.
2. Groff, G. Weidman, 1921.
The Lychee and Lungan, Orange Judd Co., New York. 58-61. Also Coville,
Frederick
V.
151-152.
3. Groff, G. Weidman, 1943.
Some Ecological Fac
tors Involved in Successful Lychee Culture.
Proc.
Fla. State Hort. Soc. 56,
134-155.
4. Groff, G. Weidman, 1948.
the History of the "Brewster"
State Hort. Soc.
61.
285-289.
Additional Notes on
Lychee.
Proc. Fla.
5. Lynch, S. John, 1955.
University of Miami, Ex
perimental Farm, South Miami, Personal Communica
tion.
6. Lynch, S. John, and Roy Nelson, 1953.
Care of
Young Lychee Trees.
Florida Grower, Jan. 1953, 14.
7. Lynch,
Lychee
S.
Growers
John.
Assoc.
1954.
8. Young, T. W. 1954.
Growers
Assoc.
11,
and
14,
and
Proceedings
31-37.
Proceedings Florida Lychee
30.
9. Cobin, M.
The Lytfhee in Florida.
tural Experiment Station Bulletin 546,
gust
1954
by
R.
Bruce
Florida
Ledin.
Fla. Agricul
Revised Au