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Title: Tung oil industry in Florida
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Title: Tung oil industry in Florida
Physical Description: Book
Language: English
Creator: Hadsell, Duane W.
Publisher: State of Florida, Dept. of Agriculture,
Place of Publication: Tallahassee, Fla.
Publication Date: 1957
Copyright Date: 1957
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Subject: Tung oil
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General Note: State of Florida, Department of Agriculture ; bulletin 11
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Bibliographic ID: UF00088973
Volume ID: VID00001
Source Institution: University of Florida
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Table of Contents
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        Front Cover
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Full Text
Bulletin No. 11 Apnrl 17

Tung Oil Industry

In Florida


By DUANE W. HADSELL
STATE OF FLORIDA
DEPARTMENT OF AGRICULTURE :IG
Nathan Mayo, Commissioner
Tallahassee


22 ..






Bulletin No. 11 April 1957


Tung Oil Industry


In Florida





By DUANE W. HADSELL
(Revised Edition)







STATE OF FLORIDA
DEPARTMENT OF AGRICULTURE
Nathan Mayo, Commissioner
Tallahassee


Bulletin No. 11


April 1957






2 DEPARTMENT OF AGRICULTURE


PREFACE



This bulletin presents an outline of the Tung
Industry in Florida and related factors affecting
it. The data covers orchard location, establish-
ment, culture, operation, fertilization, insects and
diseases, harvesting, marketing, costs, returns and
profits .. with a discussion of market supply and
demand, competition and stability of the industry.

The author, Mr. D. W. Hadsell (B.S.A. Cor-
nell), was formerly connected with the largest
tung grove development in Florida; with the
U. S. Department of Agriculture as Investigator
in Marketing and Food Products Inspection; with
the Federal Land Bank as Land Bank Appraiser;
and is a member of the American Society of
Farm Managers and Rural Appraisers. He is at
present a chemist with the Florida Department of
Agriculture.
-NATHAN MAYO
State Commissioner of Agriculture




COVER SHOT: This beautiful shot of the tung blos-
soms in color was made possible through the courtesy
of Charles J. Belden, photographer in St. Petersburg.






TUNG OIL INDUSTRY IN FLORIDA 3


CONTENTS


Page

PREFACE . . . . . . 2
WHAT IS TUNG. . . .. . . 4
WHERE GROWN . . . . . 4
SITES . . . . . . 5
SSOILS FOR TUNG . . . . . 6
TOPOGRAPHY . . . . . 6
LAND PREPARATION . . . . 6
PLANTING PLANS . . . . . 7
PLANTING STOCK . . . . 8
PLANTING THE ORCHARD.. . . . 8
TRAINING AND PRUNING TUNG . . . 8
CULTIVATION AND COVERCROPS . . . 10
FERTILIZATION . . . . 12
FERTILIZER RATES AND RECOMMENDATIONS 13
FERTILIZERS . . . . 15
FERTILIZATION AND COVERCROPS . . . 17
INSECTS AND DISEASES .. . . . 18
HARVESTING THE CROP ... . . 18
THE MARKET SUPPLY AND DEMAND 19
SUBSTITUTES AND SYNTHETICS .. . 21
DRYING OILS AND SYNTHETICS . . . 22
TUNG AND THE DRYING-OIL OUTLOOK . . 23
TUNG OIL MARKET. . . . . 24
MARKETING THE CROP . . . . 25
TABLES AND STATISTICS . . . 25
PRODUCTION . . . . . 28
ORCHARD COSTS AND RETURNS . . . 30
ORCHARD PROFITS.... . . 30
STABILITY OF TUNG INDUSTRY . . . 31
APPENDIX . . . . 33






4 DEPARTMENT OF AGRICULTURE


TUNG IN A NUT SHELL
By D. W. HADSELL


What Is Tung
Tung, a tree grown commercially in China for 40 centuries,
was first planted in Tallahassee, Florida, in 1906 and now covers
an area of some 40,000 acres in this state. The tree bears fruits
containing nut-like seeds from which Tung Oil, the world's finest
quick-drying paint oil, is extracted in six modern tung mills in
Florida. It is now well established in Southern States industry,
with a production of 23 million pounds of tung oil in 1950.
With a mature spread and height of over 35 feet, large dark-
green heart-shaped leaves, a showy pinkish-white bloom coming
out ahead of the April foliage- it matures its crop in the Fall,
which is harvested mostly by hand-pickup after drying for a few
weeks on the ground. These fruits called "tung nuts" are then
sacked and placed in tree crotches or drying sheds to further dry
down to 12 or 15 percent moisture before they are sold or hauled
to the mill for oil extraction.
During the past 49 years in Florida, Tung has become adapted,
improved, and its culture highly perfected. Its production per
acre has been more than doubled, and the oil content of the nuts
materially increased. Unfavorable factors of production have been
determined and controlled . and entry into this industry today
can be profitable, and stable under good management, with a
probable period of 30 to 40 years profitable returns.


Where Grown
The adapted Tung Belt is a strip of high, rolling land, 50 to
100 miles in width, stretching from eastern Texas to the Atlantic
Coast of Florida. Productive tung is possible only in a favorable
climatic range. An optimum of about 50 to 55 inches of annual
rainfall, uniformly warm days and nights during the growing sea-
son, a dormant period or chilling requirement, of from 350 to
400 hours per season at 45 degrees or lower, averaging 5 to 15
days below freezing during the Winter- these conditions most
favorable for tung production may be best found in the Florida
Tung Belt. (1, 2, 11) The leading areas of tung growing in Florida
in order of crop volume produced in 1949, are the following
counties: Jefferson, Leon, Jackson, Alachua, Walton, Levy, Brad-






TUNG OIL INDUSTRY IN FLORIDA 5

ford, Calhoun and Gadsden. Only the uplands in these counties
are adapted to tung . and in general stretch from East to West
along the northern halves of the counties. (15, 16, 17)


A snowfall of tung blossoms.


Sites

Good sites for tung orchards are available in these counties,
conveniently located in respect to highways, utilities, railroads,
shopping centers . and populated with available and experienced
labor. Tung mills are in operation in this area at Altha, Capps,
Compass Lake, Gainesville, Lloyd, and Monticello, Florida, to
buv and adequately handle the tung crop. Such sites with suitable
soil and terrain may be selected as . old farms with more or
less improvements and cleared land for orchard planting . or
as virgin land commonly in second-growth timber, some of it
marketable as pulpwood and logs. The best sites and soils have






6 DEPARTMENT OF AGRICULTURE

been selling for around 80 to 100 dollars an acre, more or less,
and may be in tracts with an additional 40 percent of pasture,
timber, and swamp land of lower value.

Soils for Tung
The proper choice of an adapted soil and topography is a vital
prerequisite for successful tung production. A deep sandy soil is
very undesirable, being subject to leaching and drought losses
and requiring heavier and costly fertilization. Low, flat land should
never be planted to tung, being subject to poor drainage and heavy
frosts. The best soil types- the Ruston, Red Bay, Orangeburg,
Norfolk, Magnolia, Marlboro, Greenville, Faceville, Tifton and
Carnegie Soil Series- are in general well-drained upland soils
with relatively sandy surface and sub-surface; . and with a
sandy-clay loam . to sandy clay, friable and uniformly-colored
red or yellow sub-soil. These soils are deeply permeable to root
growth, well-drained and relatively high in their base exchange
or absorption capacity for fertilizer, plant food and moisture. A
heavy humus content in such soils is the most effective natural
factor, assuring h e a vy crop production. Appendix References
(1, 2, 4, 11, 13, 18).

Topography
Frost damage to the early Spring bloom and late Fall imma-
ture growth is the greatest hazard to crop production in thrifty
orchards. Suitable topography . with high sloping land from
which cold frosty air, being heavier, runs off down the slope into
adequate bottom areas, basins, or drainage runs . provides good
air drainage . the best protection against frost damage. Such
topography also assures good soil drainage and aeration, both
necessary for thrifty growth and heavy production. Tung is in-
tolerant of wet feet and poor soil aeration.

Land Preparation
Woodland should be thoroughly cleared, all stumps, brush, and
trash removed. Cleared land, or old-field land, is then thoroughly
plowed and disced. All orchards on the desirable hilly sites, with
slopes of 3 per cent or over, should be terraced to control erosion
and root damage. Well-built terraces are necessary to conduct
excess surface-water around the slopes at a surveyed decline, into
adequate carefully-designed sodded outlets extending down into
the bottom lands or swamps. This terrace system may be laid out






TUNG OIL INDUSTRY IN FLORIDA 7

by the county Conservation Authorities. Tree rows are planted
on the terrace tops with intervening rows laid out between
the terraces, paralleling the upper terrace when the terraces are
converging . and the lower terrace when they are diverging.
Tree rows should be 35 to 50 feet distant from surrounding fences,
roadways, or woodland.


Tung Blossoms.


Planting Plans

Planting rates vary from 60 to 145 trees per acre generally. Most
commonly, 60 to 70 trees per acre called "wide planting" . or
100 to 145 trees per acre called "close planting" systems, are being
employed. Close planting tends to produce greater crop volume
and annual returns during the first 8 or 10 years, but at the ex-






8 DEPARTMENT OF AGRICULTURE

pense of economy and production in later years . due to tree
crowding and smaller tree structure as the trees get older. Wide
planting costs less per acre ... produces an orchard of larger trees
more valuable per acre in later years . and allows for more
pasturage, covercropping, and convenience in tillage and harvest
operations. In either system, tree rows should be wide, from 30
to 35 feet apart to provide adequate cultural, transport and har-
vest space.

Planting Stock
The most approved planting stock is the one year old seedling
nursery tree grown from the seed of one of the "progeny-tested"
parent trees certified by the U. S. Field Laboratory for Tung
Investigations, at Bogalusa, Louisiana (1, 11). These trees come
true to varietal characteristics to a very high degree. A list of
persons supplying such trees or seed may be requested from the
Laboratory, care of Dr. George F. Potter, in charge. This type of
tree has been selling for about 15 cents apiece, and its purchase
saves the grower one year's time in growing nursery stock him-
self. In the nursery all off-type trees are culled out, thus providing
much better selection of first class trees than is possible under the
old field spot-planting system formerly employed. This type of
planting stock has proven the most profitable and productive, the
fruits having a higher oil content, and the tree having the best
characteristics.

Planting the Orchard
Nursery trees as soon as dug or purchased, should be planted
immediately or heeled-in before roots dry out and die. January,
February, or early March is the best period for planting tung. The
root system should be trimmed to about one foot long and a foot
wide, and tree holes dug at the marking stakes large enough to
take the tree roots without crowding. Trees are set at about the
same depth as in the nursery. The soil should be well worked in
around the roots to eliminate all air pockets. Water poured in
the tree holes while planting is effective in preventing air-pockets
and subsequent tree loss, and in promoting early vigorous growth.

Training and Pruning Tung
Normally a tung tree under favorable fertility and climatic con-
ditions will grow, during the first year, a well-branched head with
branches well-spaced at wide angles between the branches and






TUNG OIL INDUSTRY IN FLORIDA


trunk, and with the central leader larger than the lateral branches.
This type of tree development assures strength of tree structure,
and high resistance to splits and breaks.
A nursery tree of the preferred low-headed varieties is best
pruned back to 8 or 10 inches height when planted. When growth
starts all buds are rubbed off except the strongest and best-placed
sprout, preferably two inches or more below the top of the stump,
to encourage a vigorous first year's growth and favorable branch-
ing. Branching does not occur until the tree under favorable grow-

Prip Aj ..tl*is 851~ P -


A tree loaded with tung nuts.


ing conditions reaches an inherent branching height. If the tree
fails to reach that height and does not branch during the first year,
it will develop a whorl of branches from the terminal bud at the
beginning of the second year. Such structures, known as "Cart-
wheel Trees" are weak and likely to break or split under heavy
crops or high wind. These trees must be cut back at the beginning
of the second year to a height of 16 or 18 inches, allowing all






DEPARTMENT OF AGRICULTURE


branches that come out from the trunk to grow and form what is
known as a vase-form head. The vase-form head with branches
at more acute angles than the natural head, bears well but is
more subject to breakage in later years. Progeny-selected varieties
which are inherently low-heading are preferable, usually coming
into bearing earlier. Such varieties may be obtained from listed
sources. (P. 8, Par. 1). Nursery trees of high heading varieties
may be pruned to about 16 inches at planting time, . and if
they are good strong trees with a caliper of % inches or more, they
will develop well-branched vase-formed heads. After the first
year's pruning to train the tree is completed, very little if any
more, is needed. (1)


Cultivation and Covercrops
The tung tree is a rather heavy feeder and has a shallow fibrous-
root feeding system. To do its best it requires an abundant and
continuous supply of plant food, moisture, humus and soil aera-
tion during its warm weather growing season. To maintain the
soil supply of organic matter and soil fertility, leguminous cover-
crops are grown and turned under. And to eliminate grass and
weed competition intolerable to tung, soil cultivation is carried on.
In the newly-planted and young orchard while the shaded area
under the trees is limited to narrow strips, Summer covercrops of
Crotelaria, Beggarweed, Indigo, Cow Peas, and others may be
grown in the middles. Later as the tree canopies widen out
Winter covercrops are better adapted, including the Lupines,
Crimson Clover, Hairy Vetch, Austrian Peas and others. Blue
Lupines have been used extensively with excellent soil fertility
results. The re-seeding strain of Crimson Clover is showing prom-
ise as a valuable fertility builder, and in addition furnishes several
months of late Winter or early Spring grazing for cattle after
harvest pickup of the nuts is completed. During the first three
or four years, covercrop competition right in the tree rows can
be as damaging to the trees as weeds or grass. Consequently eight
or ten strip-cultivations, six to eight feet along each side of the
tree row, are carried on at a shallow depth during the Spring and
Summer to completely control all weeds and grass, . the cover-
crops being seeded in the middles. By the first of September or
thereabouts the covercrop is chopped or disced under, . with
the exception of a narrow strip which may be left in the middles
for re-seeding purposes. This in turn is disced under after seed
eruption in early Fall.
In older bearing groves Winter covercrops are seeded about






TUNG OIL INDUSTRY IN FLORIDA


October first in the tree-row centers and disced under the follow-
ing April or May. Then native vegetation protecting the soil
against erosion, takes over until late August when the orchard is
again well-disced to clean up the soil surface for the fall of tung
nuts in September, . and for the growth of the seeded or vol-
unteer leguminous covercrop in October.
Both young and old groves require one or two hand-hoeings
per season to eliminate briars and weeds growing close to the
tree trunks, interfering with harvest pick-up, and sapping young
tree growth.
While clean cultivation of the tree rows accompanied by cover-
cropping in the middles as above described, has been the most
common cultural practice, . sod culture has also been success-


Closeup of the tung nuts.






12 DEPARTMENT OF AGRICULTURE

fully employed under certain conditions. It is not successful with
young non-bearing trees which must have frequent cultivation to
offset weed and grass competition. In bearing orchards with large
trees the soil surface is more or less completely shaded, greatly
reducing the growth of weeds and grass, and limiting the effective
growth of covercrops to those that may be grown during the
Winter when the tung tree loses its foliage. The grass that does
grow in the middles during the warm growing season, is controlled
by several mowings during the season. One or two cultivations
may be employed to work in the fertilizer, and fertilization may
be a little heavier under a modified sod-culture system.

Fertilization
Most soils in the Tung Belt are inherently low in fertility and
available plantfood, and will not support a profitable tung enter-
prise without fertilization. Well-adapted fertilization accomplishes
the following objectives:
1st It aids during the first year in growing a normal height
of head, and in producing an optimum number and
distribution of the main lateral branches of the tree;
2nd- It promotes a good growth of tree during the first four
to six years after planting, thus establishing a strong
framework of branches and a large bearing surface
as early as possible;
3rd In bearing trees it assures a vigorous annual growth of
new shoots and terminals upon which the next season's
crop is born;
4th It supplies the necessary food elements to grow and
mature the crop, while simultaneously growing new
bearing wood for the next season's crop;
5th It raises and maintains the fertility and productive
power of the soil through plantfood accumulation and
covercrop production and incorporation.
The amount and proportion of the "primary" plantfood ele-
ments (N-P-K) applied as fertilizer in Florida tung orchards, varies
considerably according to the soil type and fertility, and the
orchard condition. In general for a 100 tree-per-acre planting, the
following analyses and amounts of the primary elements are com-
monly applied annually as mixed fertilizer, .. as further detailed
in Farmers Bulletin No. 2031 by Dr. George F. Potter and Dr.
Harley L. Crane, (page 30).






TUNG OIL INDUSTRY IN FLORIDA 13


Inside look at a tung nut.


Fertilizer Rates and Recommendations

FERTILIZER ANALYSIS
Year Phosphoric Pounds Pounds
of Nitrogen Acid Potash per per
Growth N P205 KO Tree Acre

1 6% 6% 6% 1 lb. 100 lbs.
2 6 6 6 2 200
3 10 5 10 3 300
4 10 5 10 4 400
5 10 5 10 5 500
6 10 5 12 6 600
7 10 5 12 8 800
8 10 5 12 10 1000
9-and on 10 5 12 1232 1250






14 DEPARTMENT OF AGRICULTURE

The above table lists a general recommendation for the ferti-
lization with primary elements N-P-K, of a tung orchard planted
100 trees per acre. For example, 3 year old trees would receive
annually 3 pounds per tree of a fertilizer analyzing 10% Nitrogen,
5% Phosphoric Acid, and 10% Potash, or 300 pounds of this mix-
ture per acre. If planted 70 trees per acre, the poundages are in-
creased after the third year, to 6, 8, 12, 14, 16 and 18 pounds up
to the ninth year, and thereafter remain constant, both plantings
then getting approximately the same amount per acre.
In addition to the above amounts and analyses of N-P-K, from
2 to 4 ounces of Zinc Sulphate are commonly applied per tree,
annually for the first four years, either in the fertilizer mixture or
as separate applications on deficient soil areas or trees. Some of
the tung areas have other plantfood deficiencies which are cor-
rected with applications of Manganese Sulphate, Copper Sulphate,
and Magnesium Sulphate. The need for such corrections is de-

I


Workmen gathering nuts which dried on the ground.





TUNG OIL INDUSTRY IN FLORIDA 15

termined by soil analysis, leaf-tissue analysis, and visual deficiency
symptoms observed in the tree foliage and growth; and by oil
analysis of the fruits. Potash deficiency is most prevalent in some
of the best heavier clay-type tung soils in Jefferson, Ieon and
nearby areas, . while Magnesium deficiency is most serious in
the lighter, sandier soils where it is commonly applied regularly
in the fertilizer mixture at half the rate for potash. Zinc de-
ficiency is likely to be prevalent in all the tung areas, and its
shortage if not corrected as above detailed, will result in a
physiological derangement of the tree w h i c h1 prevents normal
growth and fruiting and makes the tree very sensitive to frost
damage.
In general, these deficiencies are most prevalent in the deep
sands and light and eroded soils. All of them can be and must
be corrected for successful tung production. The experience needed
to recognize and control these "physiological diseases" can Ibe
readily acquired with the assistance of existing advisory sources
listed in the Appendix (1, -1, 2, 10, 11, 13). Supplementary appli-
cations of these "secondary elements" will probably be required
from time to time throughout the life of the orchard.
Fertilizer is applied by hand to the newly planted trees, in a
circle some 16 inches in radius, about the time the new growth
starts out, and is hoed in. On bearing groves fertilizer is applied
in February or early March before blooming time and is broad-
cast beneath the trees and a little outside the branch extension.
On the larger acreages this is done with fertilizer distributors.
If a deficiency of potash, or some other plantfood element,
appears in the Spring growth, it has been found effective to make
a supplementary application containing such elements to offset
the shortage and correct the tree condition. Supplementary appli-
cations of about half the regular dose, containing potash, mag-
nesium, and/or nitrogen according to the deficiency evidenced,
S. .are both curative and productive of tree vigor, thriftiness and
health.


Fertilizers

The foregoing Table on page 13 (extracted from Farmer's Bul.
2031) is an average of the approximate fertilizer requirements of
tung trees under specified conditions. The 10-5-12 analysis for a
9 year old tree means that in one ton of fertilizer, 10% or 200
pounds is Nitrogen (N); 5% or 100 pounds is Phosphoric Acid (P0.-,);
and 12%i or 240 pounds is Potash (KO2). The ratio of these nutrients





DEPARTMENT OF AGRICULTURE


or plantfoods is thus 2-1-2.4. . The same ratio would be supplied
by an analysis of 4-2-4.8 . or 84-11.2. . The ratio represents
the calculated proportion of nutrients supplied by the fertilizer,
and estimated as the tree requirements. The proper ratio of nu-
trients supplied the tree is of great importance, just as is the ratio
of fats, starches and sugars to proteins, for people. Any analysis
with the same ratio can supply the tree with its nutrient require-
ment. However, the higher the analysis (10-5-12 instead of 4-2-2.48),
the lower is the cost per "unit" (unit is 1% of a ton, or 20 pounds),
as the mixing, bagging, tagging and overhead costs of manufacture
are about the same per bag of fertilizer. Also the costs of handling.
hauling and distribution per tree or per acre, are reduced with
"high-analysis" fertilizers, as less 10-5-12 is needed to supply 200
pounds of nitrogen than it would require using a 4-2-4.8.
The amounts of fertilizer given in the above table represent
the approximate average requirements of specified tree plantings,
and inferentially, the av e r a g e production resulting therefrom.
Poorly, lightly, or insufficiently fertilized orchards normally pro-
duce crops tending to be small in quantity, lower in oil content,
and unprofitable. Heavy applications, other conditions being favor-
able, can produce very large crops of high quality. Poor soil, de-
ficient in plantfood, can produce a first year's growth of 3 feet or
less: rich, fertile soil with a high percentage of plantfood can pro-
duce a growth of 8 feet or more. Bearing groves have ranged all
the way from less than one ton per acre nut production, to over
4 tons per acre the heaviest crops being the result of both su-
perior planting stock and management, and of well-adapted gen-
erous fertilization. The grower's investment in a well-adapted
formula and adequate quantity of fertilizer, is the most effective
factor in production economy, and the cheapest factor of profitable
cropping.
Where it can be economically accomplished (short return haul,
and profitable deal with the nut-buyer or mill) it is advantageous
to return to the orchard soil, both the Tung Meal (residue after
mill has extracted the oil) and the Tung Hulls (shucks). The Tung
Meal may be applied separately or used as an ingredient in the
fertilizer applied. The Hulls are spread evenly over the soil area.
When these by-products are returned to the tung soil, the farm-
ing system is theoretically Non-Depleting, as very small quanti-
ties of the plantfood elements are removed in the oil which is
made up largely of carbon, hydrogen and oxygen derived from
air and water. This system returns to the soil the organic matter
of both the tung crop and the covercrop. Organic matter is the
most effective factor in Soil Base Exchange. Capacity the most
significant factor of potential high fertility.





TUNGC OIL INDUSTRY IN FLORIDA 17


Closeup of gathering tung nuts.

Fertilization and Covercrops
To grow covercrops most successfully, lime and fertilizer are
generally needed. Tung soils are usually too acid for best growth
(pIH 4.7 to 5.3.) and Dolomite, a magnesium limestone, is com-
monly applied up to half a ton per acre on the lighter soils, ..
to one ton per acre on the heavier clay-type soils, the objective
being to gradually bring the soil pH to between 5.7 and 6.3, with
a pH of 6.00 being about optimum. At this range the soil plant-
food and fertilizer nutrients are generally most available for cover-
crop and tree assimilation.





DEPARTMENT OF AGRICULTURE


From 200 to 250 pounds of 20 percent superphosphate, plus
50 pounds of muriate of potash per acre applied in the middles,
should support the growth of a near-maximum crop of leguminous
covercrop (1, p. 28). Such covercrops of legumes producing pos-
sibly ten tons or more of green-manure per seded-acre, add
greatly to the fertility of the orchard soil, frequently adding the
equivalent of 600 to 700 pounds of nitrate of soda per acre, in
the nitrogen the legume root-nodules obtain from the air. The
nitrogen gathered, and the potash, phosphoric acid, magnesium,
calcium, and other secondary elements with which the covercrop
is fertilized . are assimilated and built into the tissue of the
covercrop, thus protected against leaching and soil fixation losses.
Later as the crop decays in the soil, these elements are in the best
condition for assimilation by the tung tree. This productive result
is completed by discing-under the covercrop, or by using it as a
heavy mulch around the young trees, deep enough to prevent weed
growth.
Adapted fertilization combined with heavy leguminous green-
manuring are the two most fundamental requirements, and the
most effective factors of heavy production from well-established
tung orchards. Terracing and soil conservation measures are es-
sential to protect and maintain an established and productive soil
fertility.

Insects and Diseases
Damage to the tung orchard or crop from pests and diseases is
of very little commercial importance. Occasionally grasshoppers,
weevils, and some scales attack trees or crops, and infrequently
thread-blight, nut and root rots and cankers infect some trees. None
of these diseases or insect pests are of common occurrence, or
likely to produce serious loss. Controls have been worked out
on most of them. (1) (11)

Harvesting the Crop
The tung crop starts to mature and fall to the ground about
the 5th of September and continues to fall into early November.
The fruits are allowed to lie on the prepared and cleanly-cultivated
ground to dry for several weeks until the moisture has decreased
from about 60 percent to around 30 percent. Harvest hands then
pick up the crop by hand into bushel baskets and are paid piece-
work rates. The "tmng nuts" are then sacked and placed in tree
crotches to dry further, or hauled to specially constructed slatted





TUNC OIL INDUSTRY IN FLORIDA \19

aerated drying sheds. Finally, when dried down to between 12
and 15 percent moisture, the crop is haulled (frequently in the
miller's truck) to the mill for oil extraction. It is a definite advan-
tage to the grower to get his crop as dry as possible before selling
it, thus realizing more profit by the increase in oil percentage and
the decrease in weight and hauling cost. (12) Ting mills are
equipped with drvingl units to remove the excess moisture which
thel grower may fail to remove.

The Market Supply and Demand
Previous to 1932 the United States imported 100 percent of her
domestic consumption of tiing oil from Chiina averaging some
120 million pounds of oil per year. In 19:32 we produced our first


Drying tung nuts in the trees.


plantation grown domestic tung oil, which was extracted in the
first tung oil mill in America at Gainesville, Florida. Since then
the industry has steadily expanded, covering solme 150,000 acres





DEPARTMENT OF AGRICULTURE


Unloading tung nuts at crushing plant.


of orchards in the six Gulf Coast States today. Eleven tung mills,
including six Florida mills, buy and process the crop into tung oil,
stored for sale in bonded tanks at the mills. There has always been


I~ii~;Z~Z~





TUNG O.11 INDUSTRY IN FLOR()ID)A 21

a market and sale for anii amount of ting oil we have produced
ill this country. (10)
The production of tuiin nuts and milled tmin oil from our or-
chards has expanded proportionately . from 14 million pounds
of oil in 1951, to 40 million in 19.53. and 15- million in 1951 (the
crop (ldamiaged this year by frost). During these same years the
production of tuing oil in China ran from 200 million pounds in
1951. down to 15-1 million pounds in 1951, . none of this Chi-
nese oil being exported to the I'nited States since 1952 ow\iii to
comlmunlist control. Production iln Argentina duriiln these years
ran from 29 million pounds to 2S% million pounds, averaging 26
million pous a ally. Some of' this has been imported into the
United States. (6)
Previous to world d \\iar II. lour domestic consumption of tlun
oil used by industry in the manufacture of all drying-oil products,
\was iaroulld 100 million poulinds per year, and \was derived mostly
li'(;m China. During the w\ar it fell to an average of about 33
million pouniids annually. After the war a stored surplus of Chinese
oil arrived ill this country, and our consumpiitionii jumped to an
average of 112 million pounds annually. The outbreak of (hostili-
ties in Korea and Hed C(hinia again interrupted lthe export of
Chinese oil. We received 11 million pounds from China ill 1951.
S. S million in 1952 . and none since. As a resu.ilt of these in-
terrupltions in our imports from Chiina, our government t during
World \\'lar II promoted vast research ill the effort to find or pro-
dulce substitutes for tlng oil, urgently needed for protective cover-
ings for war equipment and materials. Many were perfected and
proved to be effective. (14,


Substitutes and Synthetics
In relation to the drying-up of our former source of supply
of tung oil in China, and to the fact that our domestic orchard
production was insufficient to supply ouir normal consumption, Dr.
II. L. Crane of the U. S. Bureau of Plant Industry stated, "This
condition caused a vast amount of research to be done on ways
of making such protective coatings without the use of tung oil,
so that at present (June 1950) tlere are many oils that can be
used to replace or be substituted for tung oil. .Aong these are
dethlydrated castor oil, oiticica oil, perilla oil, and heat-treated mix-
tires of other vegetable (drying oils: also synthetics suchi as the
alkyds. phenol formaldehyde resins, and distilled oils of high
iodine number, as well as spirit-soluble compounds, celilose, and
other materials. Many of these materials are now being widely





DEPARTMENT OF AGRICULTURE


used in industry. In future years many of them as well as some
new materials are likely to be used even though tung oil is avail-
able in large quantities. It is the opinion of many that tung oil


Tung oil filter press.


will be in large demand in the future provided that the supply is
uniform and the price is competitive and fairly stable in compari-
son with other drying oils." (6)

Drying Oils and Synthetics
Along the lines of Dr. Crane's prediction, these altered oils and
synthetic substitutes for tung have been tried out and adopted by
industry for many specialized purposes, and have supplied some
of the market demand formerly supplied by tung oil. In fact, the
consumption of tung oil used in all drying-oil products, dropped to
65 million pounds in 1951, to 51 million pounds in 1952 and 1953,
S. and to 50 million pounds of tung oil in 1954, ... apparently a
new level of Normal Domestic Consumption in this country.






TUNG OIL INDUSTRY IN FLORIDA 23

Tung oil ranks fourth amongst all drying-oils used in domestic
industry in 1954, . linseed oil being first constituting 50 per-
cent of all these oils used; soybean second with 21 percent utili-
zation; . Tall oil third with about 10 percent; . and tung
oil fourth with 4.8 percent of the total drying-oils utilized in U. S.
Industry. For ten years up to 1940, tung constituted 15.3 percent
of all drying-oils used here in industry; from 1941 through 1946 its
use dropped to 2.7 percent during the World War II when Chinese
oil was not obtainable. Right after the War from 1947 through
1950 with a stored-surplus importation from China, its use jumped
to 10% percent of all drying-oils. And finally, as synthetic cover-
ages were perfected and adopted, from 1951 through 1954, tung
oil use dropped to 5 percent of the total drying-oils used in our
industry. (6)
The amount of all drying-oils used in industry in 1954 totalled
1 billion, 45 million pounds, in which is included 50 million pounds
of tung oil, our present normal consumption. The average
amount of all drying oils used in domestic manufacture per gal-
lon of drying-oil products in 1935 to 1939, was 2.2 pounds of oil
per gallon. In recent years this proportion has dropped to about
1.45 pounds per gallon. A considerable part of this reduction has
been replaced by the synthetics now being used in the protective
coatings field, including the vinyl resins, phenol formaldehyde
resins, silicone alkyd resins, water-thinned latex, styrenated alkyds,
acrylic resins, and others. (6)


Tung and the Drying-Oil Outlook
Much of the foregoing and subsequent data herein was ob-
tained from the publication "The Fats -and Oils Situation" issue of
March 30, 1955, published by the Agricultural Marketing Service,
U. S. Department of Agriculture, Washington, D. C. which the
reader is invited to consult for much more detailed information.
It contains an excellent article by Sidney Gershben and Philip B.
Dwoskin on the "Outlook for Drying Oils" and the "Outlook for
Tung Nuts," based on a comprehensive research report on drying
oils in industrial use conducted by Battelle Memorial Institute
of Columbus, Ohio under contract with the U.S.D.A.
Into this vast reservoir of demand for protective coatings, the
synthetics have made their entry, largely as the result of the much
greater research into the development of the non-agricultural ma-
terials for use in protective coatings. The use of drying oils has
increased only about 25 percent in the last two decades, . while
the production of paints, varnishes and lacquers has nearly doubled.






DEPARTMENT OF AGRICULTURE


Synthetics and chemically-altered linseed, soybean and tall oil,
have at least temporarily filled the gap in the demand for, and
supply of drying oils, initially caused by shortages in production,
and import of tung oil. (6)
Tung oil has consistently topped the field among natural dry-
ing oils in quality and price. In the above research report it is
stated that "There is reason to hope that the inroads the synthetic
products have made into the drying-oil market may be offset by a
concerted effort directed at modifying and improving tung oil and
the drying oils, making them more attractive to consumers. Po-
tentially the oils might serve as raw materials for making other
film-formers yielding products superior to those now obtained from
synthetics." It is further stated that "The resulting decline in
drying oil consumption however, will be offset by the expansion
in total markets for most of these products. We may expect new
combinations of drying oils and synthetic raw materials."


Tung Oil Market

The production from U. S. tung orchards in 1953 was 40 mil-
lion pounds of tung oil. Our domestic consumption by industry
since 1951 has been a little over 50 million pounds. Argentina pro-
duced some 38 million pounds of tung oil in 1953 and has ex-
ported some into this country, making up some of our shortage.
However the import of tung oil from Argentina has been limited
by governmental agreement to 24 million pounds during the year
up to October 31, 1955, this being one of our frost-affected years
with a tentative production estimate of 15M' million pounds. It was
recently announced by Senator Spessard L. Holland that foreign
tung oil import quotas have been cut n e a r y in half, greatly
strengthening Florida's Tung Oil Industry. (14)
A further protection to our market price and stability has been
the National Agricultural Act of 1949 which put tung on the list
of products on which Price Support is mandatory. This has ranged
from a level of 24.1 cents per pound of oil in 1949 to about 21.2
cents per pound in 1954.
Research on tung and its products is a necessary and promising
field needed to meet competition and increase industry profits.
Tung meal is toxic and cannot be fed to animals. Detoxification
of the meal might raise the price from a present one cent per pound
to 3 cents per pound. The U.S.D.A. is now conducting research
along this line. (6)






TUNG OIL INDUSTRY IN FLORIDA 25


Marketing the Crop
After harvest and preliminary drying the orchardist can sell
his tung nut crop to the mill at a delivered price, based on the
government support price, the daily quoted market price, and the
oil content of his crop. Or he can have his crop custom-milled at
a cost of from $12.50 to $15.00 per ton of nuts, and the extracted
oil held in bonded storage tanks at his disposal. He can then sell
it in various lots, or pool it with other stored stocks for sale in
larger quantities.
If the grower wishes to borrow money on his stored oil from
the government's Commodity Credit Corporation, he can get a
loan with interest at 4 percent and repay the loan October 31st,
or forfeit the oil. The amount of the loan is determined by the
government price support based on 60 to 90 percent of parity.
Tung nuts under the National Agricultural Act of 1949 were added
to the list of nonbasic agricultural commodities on which a price
support is mandatory. The support price has varied since then
from 25.1 cents per pound of oil to around 22 cents per pound.
The price per ton of nuts is commuted on a basis of 17.5 percent oil
content in the dried nuts, and varies according to the oil content.
The accompanying Table . shows the estimated number of
loans, and the pounds of oil in warehouse storage on loan, for the
crop of 1953 tung oil covering practically the entire crop. (15)


Tables and Statistics
In the following tables data is given covering the following:
TUNG OIL-
Table 1.
PRODUCTION OF TUNG OIL IN LEADING COUNTRIES 1951-1954
(in thousand pounds)
Country 19511 19522 19532 19543
United States 14,000 42,000 40,000 15,500
Argentina ---------- 29,000 9,900 38,580 28,600
Brazil 1,830 1,700 2,000 1,320
Paraguay 3,970 3,400 7,700 6,400
China 200,000 188,000 154,000 154,000
Others 7,200 8,000 8,000 5,500

TOTALS 256,000 253,000 250,280 211,320
'Foreign Agriculture Circular FFO 18-53, June 5, 1953.
2Foreign Agriculture Circular FFO 19-54, Oct. 11, 1954.
3Agricultural Marketing Service tentative estimates.







DEPARTMENT OF AGRICULTURE


ANNUAL AVERAGE PRICE
Year

1951
1952
1953
1954


Table 2.
OF TUNG OIL BY YEARS, 1951-1954
Cents per Pound
Drums, New York
40.0
40.4
29.3
23.9


Source: Fats and Oils Section, (14)
Statistical and Historical Re-
search Branch,
Agricultural Marketing Service,
Department of Agriculture


Country


Table 3.
U. S. IMPORTS OF TUNG OIL ANNUALLY, 1951-1954
(in thousand pounds)
of Origin 1951 1952 1953


Argentina
Brazil ----
Paraguay ----
British East Africa.
Rhodesia & Nigeria
China -___-
Hong Kong --------
Indo-China
Japan -------

TOTALS


14,398
703
1,723
0
0
11,179
1,702
0


29,7061


23,191
1,913
4,295
336
66
8
0
0
60

29,869


20,943
0
2,056
100
168
0
0
218
0

23,485


1954


30,464
1,102
4,118
457
336
0
0
0
0

36,477


1Includes 114,000 pounds from France and 412,000 pounds from Madagascar.
Source: Bureau of the Census, U. S. Department of Commerce, FT-110,
Annual.







TUNG OIL INDUSTRY IN FLORIDA 27




Table 4.

U. S. SUPPLY, DISPOSITION, AND UTILIZATION OF DRYING
OILS AND TUNG OIL


Supply:
Production from:
Domestic Materials
Imported Materials
Imports
Stocks Jan. 1 --


Total


All Drying Oils
Including Tung Oil
(in million pounds)
1951 1952 1953 1954


846 605 547
22 16 17
44 38 33 46
708 726 695 591


1620 1385 1292


Tung Oil
(in million pounds)
1951 1952 1953 1954


13 22 43 32

30 30 24 36
39 16 16 31

82 68 83 99


Disposition:
Exports
Re-exports
Stocks Dec. 31
Domestic Disappearance


Utilization:
Soap
Paint and Varnishes
Linoleum & Oilcloth
Resins
Other Drying Oil
Products


60 41 36


6 3 1 3


Sub-Total
Foots & losses
Other uses -


768 616 606
12 13 12
23 4 15


Total 802 633 633

* Less than 500,000 pounds.
Totals computed from unrounded data.

Source: U.S.D.A. publications.


S65


51 51 48






28 DEPARTMENT OF AGRICULTURE




Table 5.
TUNG OIL, U. S. PRODUCTION, STOCKS AND UTILIZATION
1951 1952 1953 Table No.
(in thousand pounds) In Source

Factory Production 12,667 23,151 43,153 1
Factory Consumption -- 65,019 47,863 48,571 1
Stocks, end of year 15,786 15,879 30,946 1

Utilization:
Chemicals ----* 12
Paints & Varnish .-- 53,991' 40,607 40,559 12
Lubricants & Greases 0- 12
Linoleum & Oilcloth 435 12
Other Inedible Total 6,646 7,523 12
Rubber -------- -" 13
Insulation 2,461 1,241 ** 13
Core Oil -*---" .. 13
Protective Coating *-- "* 13
Hydraulic brake fluid,
linings & packing 514 559 13
Resins ------------ 3,573 3,125 4,004 13
Leather *------- -- -- 13
Artificial leather ----- --- --13
Glue and Adhesives -_-- -- 13
Paint & Ink Vehicles ** *0* 13
Miscl. Industrial --. 13
Printing Ink -------- 823 848 1,184 13

Included in "Total of vegetable oils not shown separately" to avoid dis-
closure of figures for individual companies.
Not shown to avoid disclosure of figures for individual companies.
Source: Bureau of the Census, Industry Division, "Facts for Industry, Animal
and Vegetable Fats and Oils, 1953."







TUNG OIL INDUSTRY IN FLORIDA 29


Table 6.

TUNG NUTS


Historical Review
Production
Season In Tons

1944 ......- 7,000
1945.---- 8,400
1946 -- 15,000
1947 ... -- 11,000
1948 ----.....- 17,500
1949 -- 16,200
1950 ............ 8,200
1951 ---- 12,200
1952 .. 31,000
1953 28,400
1954 .... .- 21,600
1955 P 6,200
P Preliminary.
* Subject to revision.


1944 through 1955
Price
Per Ton

$100.00
98.00
96.00
68.00
46.00
60.00
120.00
112.00
84.00
65.00
59.00
64.00


The 1955 crop was small and the cash
a severe freeze that damaged many acres.


Total
Farm Value

$ 700,000
823,000
1,440,000
748,000
805,000
972,000
984,000
1,366,000
2,604,000
1,846,000
1,274,000
397,000


price higher because of


Production


On suitable soils and sites and with the best strains of plant-
ing stock now available, the grower using the best proven prac-
tices should be able to produce 2 tons of field-dried tung nuts per
acre after the orchard is eight years old; and from 2% to 3 tons
per acre by the tenth year. Based on recent-years data, an orchard
of this type should bring a return to the owner from crop sales
of nearly enough to pay off all costs of grove establishment and
operation, including the cost of land, by the end of the eighth
year.

Continuous heavy production may be interfered with by vari-
ous factors, one of the most common being frost damage. On the





30 DEPARTMENT OF AGRICUL URE

average, one-half a crop every five years is lost by frosted bloom
and terminals. This does not usually injure the tree, and the fol-
lowing crop is likely to be heavier than normal. Insufficient ferti-
lizer to grow abundant fruiting terminals for the next crop, espe-


Tung nut hulls for enriching soil.


cially during a year of extra heavy crop production; abnormally
dry weather combined with weed competition; tree-crowding and
competition due to close planting; poor timing of fertilization and
cultural operations; . these, and other failures to use efficiently
all proven factors of production and fertility-building are likely
to reduce the average yield well below two tons an acre. How-
ever, suitable land and all the necessary information is available
to undertake the successful establishment of a high-production
orchard in Florida. The superior qualities of tung as a quick-drying
oil in the manufacture of paints, varnish, can liners, electrical in-
sulation, linoleum and other products, have been thoroughly es-
tablished and the product is highly acceptable if supplied in stable
quantities and at a competitive price. New treatments and new






TUNG OIL INDUSTRY IN FLORIDA 31

uses of the oil loom as a further incentive for expanded use and
production.


Orchard Costs and Returns

The cost of establishing a top-quality one year old tung orchard
is calculated at around $185.00 per acre. This average figure is
based on 100 trees per acre, on land costing $100 per acre, and
includes the cost of trees, clearing, planting, terracing, cultivation,
pruning, covercrops and fertilization and is based on price levels
of 1953-54.

Accumulated operating costs, interest and taxes through the
seventh year may increase the total amount invested per acre of
orchard to around $270 per acre. During these seven years crop
returns from an estimated total of 2.5 to 2.7 tons of nuts per acre
i . may bring total accumulated returns of from $175 to $190
per acre. By the end of the eighth year, allowing for the loss of
half a crop from frosted bloom, the grower may derive a gross
income from the orchard since its planting, of around $245 to $270
per acre, . nearly enough to pay off all costs of land, establish-
ment, operation, taxes and interest.

Good management can be very effective in reducing the above
costs, and increasing the net returns. High quality tung soil, well-
adapted sites, and the best varieties of planting stock, are defi-
nitely effective in increasing the profit in tung orcharding.


Orchard Profits

A good orchard under good management, having passed the
eight year mark of low net returns, should begin to get into profit-
able production, and continue to produce a net profit for another
20 to 25 years or more. Expectations of a net' return from capital
and labor of $50. to $60 per acre from an orchard producing 2
tons of nuts per acre, . or of $90 to $150 net from an orchard
producing 3 tons of nuts per acre, . could be considerably
altered by a change in market conditions . foreign competition,
.government support price, . substitutes, . and market
demand. However, during the past 49 years since tung was
planted in Florida, the industry has prospered and expanded, the
promoters have been flushed out, and the tung orchardist is now
a substantial and satisfied citizen.





32 DEPARTMENT OF AGRICULTURE

Stability of Tung Industry
One of the causes for the low percentage (5 percent) of tung
oil used in our domestic drying-oil industry, has been the insuffi-




i ,._:


A chemist checks the finished tung oil.






TUNG OIL INDUSTRY IN FLORIDA


cient supply of tung oil from our orchards and mills. This made
it necessary to depend upon foreign imports which resulted in in-
stability of both supply and price. We are rapidly approaching
the point of being able to produce in our own orchards enough
tung oil to annually supply our normal domestic consumption in
industry.


Tanks for storage of tung oil.


Research on tung oil which is especially well suited to chemi-
cal modification, is likely to develop new products with superior
properties that cannot easily be obtained with other oils. This
would readily establish the position of tung oil as tops in quality
and price, and amongst the leaders in the drying-oil industry.







34 DEPARTMENT OF AGRICULTURE


APPENDIX

REFERENCES-To Literature, Authorities, and Sources.

PUBLICATIONS:
Ref. No.
1-TUNG PRODUCTION: By Dr. George F. Potter, and Dr. Harley L.
Crane.
Issued as Farmers Bulletin No. 2031, U. S. Dept. of Agriculture.
For Sale by Supt. of Documents, U. S. Government Printing Office,
Washington, D. C. Price 20 cents.
2-SUITABILITY OF VARIOUS SOILS FOR TUNG PRODUCTION:
By Dr. Mathew Drosdoff.
Cir. No. 840, U. S. Dept. of Agriculture.
For sale by Supt. of Documents, U. S. Government Printing Office,
Washington, D. C. Price 10 cents.
3-TUNG OIL: By Edmund C. Wood.
A publication by the U. S. Department of Commerce.
For sale by Supt. of Documents, U. S. Government Printing Office,
Washington 25, D. C. Price 25 cents.
4-GENERALIZED SOIL MAP OF FLORIDA: By Florida Agricultural
Experiment Station,
Dept. of Chemistry and Soils, University of Florida, Gainesville, Fla.
Available in Agricultural Libraries.
5-TUNG: Processing and Marketing Practices and Costs.
For sale by Supt. of Documents, U. S. Government Printing Office,
Washington, D. C. Price 20 cents.
6-THE FATS AND OILS SITUATION:
A pamphlet published every three or four months by the Agricul-
tural Marketing Service, U.S.D.A. Free Distribution.
Issue consulted herein, released March 30, 1955.
7-STATISTICAL BULLETIN NO. 147: June 1954; "Oilseeds, Fats and
Oils, and Their Products, 1909-1953"
Published by Statistical and Historical Research Branch, Agricul-
tural Marketing Service, U. S. D. A.
For sale by Supt. of Documents, U. S. Government Printing Office,
Washington, D. C. Price $1.25.
8-TUNG PRODUCTION: By H. L. Crane, Bureau of Plant Industry,
U.S.D.A.
Pamphlet issued June 1950.
9-TUNG NUTS-PRODUCTION:
A Mimeo-release of August 1954, by Agricultural Marketing Service,
P. O. Box 273, Orlando, Fla.
An estimate of production in tons, price and value of Tung Nut
Crop, 5 states.
10-TUNG BULLETINS AND CIRCULARS:
Numerous bulletins and circulars published by the-
Florida Agricultural Experiment Station, University of Florida,
Gainesville, Florida.






TUNG OIL INDUSTRY IN FLORIDA 35


Numerous bulletins and circulars published by the-
Bureau of Plant Industry, U.S.D.A., Washington, D. C.
Agricultural Research Administration, Bureau of Agricultural
and Industrial Chemistry, U.S.D.A.
Proceedings of American Society for Horticultural Science,
Michigan State College, East Lansing, Mich.



SOURCES:
11-DR. GEORGE F. POTTER, Principal Physiologist,
U. S. Field Laboratory for Tung Investigations,
Box 811, Bogalusa, La.
Authority and specialist on all phases of Tung culture, varieties,
planting stock, soils, fertilization, etc.
12-DR. R. S. McKINNEY, in charge U. S. Tung Oil Laboratory,
Bureau of Agricultural and Industrial Chemistry, U.S.D.A.
Authority on the Chemistry of Tung Fruits, and Tung Oil, Drying,
Storage, Hulling, Filtering, Processing of Oil, etc.
13-DR. F. B. SMITH, Head, Department of Soils,
Agricultural Experiment Station, Gainesville, Florida.
14-RALPH T. STEWART, Director
Agricultural and Chemical Products Div., Bur. of Foreign Commerce,
U. S. Department of Commerce, Washington 25, D. C.
Statistics on Production, Consumption, Prices, Exports, and Imports,
Acreages, . on Domestic and World Tung Industry.
15-FRASIER T. GALLOWAY, Agricultural Statistician,
Agricultural Marketing Service, U. S. Dept. of Agriculture,
P. O. Box 273, Orlando, Florida.
Specialist on Statistical Information and Crop Estimates, Prices,
Production, etc., on Tung Crop in U. S.
16-RAY HURLEY, Chief,
Agricultural Division, Bureau of the Census,
Department of Commerce, Washington 25, D. C.
Census Agricultural Statistics on Tung and other data.
17-H. G. HAMILTON, Agricultural Economist, Head of Dept.,
Department of Agricultural Economics,
Agricultural Experiment Station, Gainesville, Fla.
Authority on Agricultural Economics, Data and Statistics.
18-"THE NATURE AND PROPERTIES OF SOILS"; 1949, 4th Edition
By T. Lyttleton Lyon and Harry O. Buckman, Cornell University.
Published by MacMillan Co., New York City.




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