ulletin No. 1 1
Tung Oil Industry
By DUANE W. HADSELL
STATE OF FLORIDA^ DEPARTMENT OF AGRICULTU Nathan Mayo, Commissioner Tallahassee
Bulletin No. 1 1
Tung Oil Industry In Florida
By DUANE W. HADSELL
STATE OF FLORIDA DEPARTMENT OF AGRICULTURE Nathan Mayo, Commissioner Tallahassee
This bulletin presents an outline of the Tung Industry in Florida and related factors affecting it. The data covers orchard location, establishment, 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. 1). \\ Madsell (B.S.A. Cornell), was formerly connected with the largest turn: grove development in Florida: with the U. S. Department ol Agriculture as Investigator in Marketing and Food Products Inspection: with the Federal Land Bank as Land Hank 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.
N ATHAN MAYO
State Commissioner of Agriculture
COVER SHOT: This beautiful shot of the tung blossoms in color was made possible through the courtesy of Charles I. Belden. photographer in St. Petersburg.
PREFACE ............. 2
WHAT IS TUNG............ 4
WHERE GROWN........... 4
SOILS FOR TUNG........... 6
TOPOGRAPHY ............ 6
LAND PREPARATION.......... 6
PLANTING PLANS........... 7
PLANTING STOCK........... S
PLANTING THE ORCHARD........ S
TRAINING AND PRUNING TUNG....... 8
CULTIVATION AND COVERCROPS...... 10
FERTILIZER RATES AND RECOMMENDATIONS 13
FERTILIZATION AND COVERCROPS...... 17
INSECTS AND DISEASES......... IS
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
ORCHARD COSTS AND RETURNS...... 30
ORCHARD PROFITS.......... 30
STABILITY OF TUNG INDUSTRY....... 31
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 hears 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 lie profitable, and stable under good management, with a probable period of 30 to 40 years profitable returns.
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 season, a dormant period or chilling requirement, of from 350 to 400 hours per season at 45 degree's 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-
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. IB. 17)
A snowfall of tung blossoms.
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 lalior. Tung mills are in operation in this area at Altha, Capps, Compass Lake. Gainesville, Lfeyd, and Monticello, Florida, to hu\ and adequately handle the tung crop. Such sites with suitable soil and terrain max be selected as . old farms with more or less improvements and cleared land for orchard planting ... or as virgin land commonly in second-growth timl>er. some of it marketable as pulpwood and logs. The best sites and soils have
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. Hat land should never be planted to tung. being subject to poor drainage and heavy frosts. The best soil types the Huston, Red Hay, 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 heavv crop production. Appendix References (I, 2, 4, 11, 13, IS).
Frost damage to the early Spring bloom and late Fall immature 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 s1o;h> 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-tolcrarjt of wet feet and poor soil aeration.
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 ol 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 carelulK -designed sodded outlets extending down into the bottom lands or swamps. This terrace system may be laid out
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.
Planting rates vary Irom 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 S or 10 years, but at the ex-
pensc 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 harvest space.
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 himself. 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 conditions will grow, during the first year, a well-branched head with branches well-spaced at wide angles between the branches and
trunk, and with the central leader larger than the lateral branches. This type1 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 S 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 branching. Branching docs not occur until the tree under favorable grow-
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 "Cartwheel 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 10 or IS inches, allowing all
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. Alter 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 aeration 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 promise as a valuable fertility builder, and in addition furnishes several months of late Winter or early Spring grazing lor 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
October first in the tree-row centers and disced under the following April or Maw Then native vegetation protecting the soil against erosion, takes over until late \ugust when the orchard is again well-disced to clean up the soil surface lor the fall ol tung nuts in September. . and for the growth of the seeded or volunteer leguminous covercrop in October.
Both young and old groves require one or two hand-hocings 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 ot the tree rows accompanied b\ cover-cropping in the middles as above described, has been the most common cultural practice, . sod culture has also been snccess-
Closcup of the tung nuts.
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.
Most soils in the Tung Belt are inherently low in fertility and available plantfood, and will not support a profitable tung enterprise 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;
In bearing trees it assures a vigorous annual growth of new shoots and terminals upon which the next season's crop is born;
It supplies the necessary food elements to grow and mature the crop, while simultaneously growing new bearing wood for the next season's crop;
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 elements (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-pcr-acre planting, the following analyses and amounts of the primary elements are commonly applied annually as mixed fertilizer, . as further detailed in Farmers Bulletin No. 2031 by Dr. George F. Potter and Dr. ITarley L. Crane, (page 30).
3rd -4th -5 th -
Inside look at a tung nut.
fertilizer Rates and Recommendations
Year Phosphoric Pounds Pounds
of Nitrogen Acid Potash per per
ri >\vtli N P25 K20 Tree Acre
1 6% 6% 6% 1 lb. 100 lbs.
2 6 6 6 o 200
3 10 5 10 3 300
4 10 5 10 4 400
5 LO 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 12% 1250
The above table lists a general recommendation for the fertilization 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 mixture per acre. If planted 70 trees per acre, the poundages are increased 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 lour 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 corrected with applications of Manganese Sulphate, Copper Sulphate, and Magnesium Sulphate. The need for such corrections is de-
Workmen gathering nuts which dried on the ground
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, I,con 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 deficiency 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 h 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 be readily acquired with the assistance of existing advisory sources listed in the Appendix (1, 4, 2, 10, 11, 13). Supplementary applications 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 broadcast 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 applications of about half the regular dose, containing potash, magnesium, and/or nitrogen according to the deficiency evidenced, . are both curative and productive of tree vigor, thriltiness and health.
The foregoing Table on page 13 (extracted from Farmer's Bui. 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 (PjO.-,); and 12% or 240 pounds is Potash (Kl.O). The ratio of these nutrients
Or plantfoods is thus 2-1-2.4. . The same ratio would he supplied by an analysis of 4-2-4.8, ... or 8-4-11.2. . The ratio represents the calculated proportion of nutrients supplied by the fertilizer, and estimated as the tree requirements. The proper ratio of nutrients 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 requirement. 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 woidd require using a 4-2-4.S.
The amounts of fertilizer given in the above table represent the approximate average requirements of specified tree plantings, and inferentially, the average production resulting therefrom. Poorly, lightly, or insufficiently fertilized orchards normally produce crops tending to be small in quantity, lower in oil content, and unprofitable. Heavy applications, other conditions being favorable, can produce very large crops of high quality. Poor soil, deficient in plantfood, can produce a first year's growth of 3 feet or less; rich, fertile soil with a high percentage of plantfood can produce a growth of S 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 superior planting stock and management, and of well-adapted generous 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 arc returned to the tung soil, the farming system is theoretically Non-Depleting, as very small quantities 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.
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 (pH 4.7 to 5.3) and Dolomite, a magnesium limestone, is commonly 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.
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 possibly ten tons or more of green-manure per seccled-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 . arc 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 lung orchards. Terracing and soil conservation measures arc essential 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 piecework rates. The "tung nuts" are then sacked and placed in tree crotches to dry further, or hauled to specially constructed slatted
aerated drying sheds. Finally, when dried down to between 12 and 15 percent moisture, the crop is hauled (frequently in the miller's truck) to the mill for oil extraction. It is a definite advantage 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) Tung mills are equipped with drying units to remove the excess moisture which the grower may fail to remove.
The Market Supply and Demand
Previous to 1932 the United States imported 100 percent of her domestic consumption of tung oil from China, averaging some 120 million pounds of oil per year. In 1932 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 some 150.000 acres
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
a market and sale for any amount ol tung oil we have produced in this country. (10)
The production of tung nuts and milled tung oil from our orchards has expanded proportionately . from 14 million pounds of oil in 1951. to 40 million in 1953, and 15% million in 1954 (the crop damaged this year by frost). During these same years the production ol tung oil in China ran from 200 million pounds in 1951. down to 154 million pounds in 1954, . none of this Chinese oil being exported to the United States since 1952 owing to communist control. Production in Argentina during these years ran from 29 million pounds to 2H% million pounds, averaging 20 million pounds annually. Some of this has been imported into the United States. (6)
Previous to World War II, our domestic consumption of tung oil used by industry in the manufacture of all drying-oil products, was around 100 million pounds per year, and was derived mostly Irom China. During the war it fell to an average of about 33 million pounds annually. After the war a stored surplus of Chinese oil arrived in this country, and our consumption jumped to an average ol 112 million pounds annually. The outbreak of hostilities in Korea and lied China again interrupted the export of Chinese oil. We received II million pounds from China in 1951. . S million in 1952 . and none since. As a result of these interruptions in our imports from China, our government during World War II promoted vast research in the effort to find or produce substitutes for tung oil, urgently needed for protective coverings 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 our 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) there are many oils that can be used to replace or be substituted for tung oil. Among these are dehydrated castor oil, oiticica oil, perilla oil, and heat-treated mixtures of other vegetable drying oils: also synthetics such as the alkyds. phenol formaldehyde resins, and distilled oils of high iodine number, as well as spirit-soluble compounds, celulose, and other materials. Many of these materials are now being widely
will be in large demand in the future provided that the supply is uniform and the price is competitive and fairly stable in comparison 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. . and to 50 million pounds of tung oil in 1954, . apparently a new level of Normal Domestic Consumption in this country.
Tung oil ranks fourth amongst all drying-oils used in domestic industry in 1954, . linseed oil being first constituting 50 percent of all these oils used; soybean second with 21 percent utilization; . 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 lOli percent of all drying-oils. And finally, as synthetic coverages were perfected and adopted, from 1951 through 1954, tung oil use dropped to 5 percent ol 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. T1k> average amount of all drying oils used in domestic manufacture per gallon 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 obtained 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 materials 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.
Synthetics and chemically-altered linseed, soybean and tall oil, have at least temporarily filled the gap in the demand tor, 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 drying 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. Potentially 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 million pounds of tung oil. Our domestic consumption by industry since 1951 has been a little over 50 million pounds. Argentina produced some 38 million pounds of tung oil in 1953 and has exported 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 15% million pounds. It was recently announced by Senator Spessard 1,. Holland that foreign tung oil import quotas have been cut n e a r 1 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)
Marketing the Crop
After harvest and preliminary drying the orehardist ean 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 nonbasie 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 lollowing tables data is given covering the following: TUNG OIL-
PRODUCTION OF TUNC OIL IN LKADING COUNTRIES 1951-1954
(in thousand pounds)
Country 1951' 1952- 1953- 1954;
United States ........ 14,000 42,000 10,000 [5,500
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 ................. 200,000 188,000 151.000 151.000
Others 7.200 8.000 8,000 5,500
TOTALS ..... 250.000 253.000 250.280 211.320
'Foreign Agriculture Circular FFO 18-53. June 5. 1953. -Foreign Agriculture Circular FFO 19-54. Oct. 11, 1954. 'Agricultural Marketing Service tentative estimates.
ANNUAL AVERAGE PRICE OF TUNG OIL BY YEARS, 1951-1954
Year Cents per Pound
Drums, New York
Source: Fats and Oils Section, (14) Statistical and Historical Research Branch, Agricultural Marketing Service, Department of Agriculture
U. S. IMPORTS OF TUNC OIL ANNUALLY, 1951-1954
(in thousand pounds)
Country of Origin 1951 1952 1953 1954
Argentina ........___ 14,398 23,191 20,943 30,464
Brazil __________...... 703 1,913 0 1,102
Paraguay 1,723 4,295 2,056 4,118
British East Africa 0 336 100 457
Rhodesia & Nigeria 0 66 168 336
China ............ 1 1.179 8 0 0
I long Kong.......... 1.702 0 0 0
Indo-China ............ 0 0 218 0
Japan .......... 0 60 0 0
'Includes 114,000 pounds from France and 412,000 pounds from Madagascar.
Source: Bureau of the Census, U. S. Department of Commerce, FT-110, Annual.
U. S. SUPPLY, DISPOSITION, AND UTILIZATION OF DRYING OILS AND TUNG OIL
All Drying Oils Including Tung Oil Tung Oil
(in million pounds) (in million pounds)
1951 1952 1953 195-1 1951 1952 1953 1954
Domestic Materials .. 840 605 547 13 22 43 32
Imported Materials .. 22 16 17
Imports ....................... 44 38 33 46 30 30 24 36
Stocks Jan. 1 708 726 695 591 39 16 16 31
Total .................... 1620 1385 1292 82 68 83 99
Stocks Dec. 31 ............
I )omcstic I )isappearance
92 56 92
726 095 567 282
802 633 633
1 9 C
0 1 0 (i
16 16 31 51
65 51 51 48
Soap .............................. 0 0
Paint and Varnishes 568 464
Linoleum & Oilcloth 103 90
Resins....................... 37 21
Oilier Drying Oil
Products .................. 60 41
Sub-Total ........... 768 616
Foots & losses ......... 12 13
Other uses .................... 23 1
Total ............. 802 633
II ii i) 0
54 44 47 40
1 3 4 co
6 i 1 3
65 51 51 48
Less than 500,000 pounds.
'Totals computed from unrounded data.
Source: U.S.D.A. publications.
TUNC OIL. I. S. PRODUCTION, STOCKS AND UTILIZATION
1951 1952 195:$ Tabic No.
(in tlious.mil pounds) In Source
Factory Production 12.667 23,151 43,153 1
Factory Consumption ..... 65.019 17,863 48,571 1
Slocks, end of year 15.786 15,879 30,946 1
Paints & Varnish ........ 53.991 40.607 40.559 12
Lubricants cV Creases 12
Linoleum & Oilcloth 435 12
Other Inedible Total 6,646 7,523 12
Rubber 00 13
Insulation ................ 2,461 1.241 13
Core Oil .................... * 13
Protective Coating 00 13
11 ydraulic brake Moid,
linings & packings 514 559 13
Resins .............. 3,573 3,125 4,004 13
Artificial leather ........ 13
Glue and Adhesives 13
Paint c\ Ink Vehicles 00 13
Misel. Industrial " 13
Printing Ink 823 848 1.184 13
0 Included in "Total of vegetable oils not shown separately" to avoid disclosure 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."
On suitable soils and sites and with the best strains of planting stock now available, the grower using the best proven practices should be able to produce 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 bv various factors, one of the most common being frost damage. On the
average, one-half a crop every five years is lost by frosted bloom and terminals. This does not usually injure the tree, and the following crop is likely to be heavier than normal, insufficient fertilizer 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. However, 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 insulation, linoleum and other products, have been thoroughly established and the product is highly acceptable if supplied in stable quantities and at a competitive price. New treatments and new
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 . 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, establishment, 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 definitely effective in increasing the profit in tung orcharding.
A good orchard under good management, having passed the eight year mark of low net returns, should begin to get into profitable 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.
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-
A chemist checks the finished tung oil.
cicnt supply of tung oil from our orchards and mills. This made it necessary to depend upon foreign imports which resulted in instability 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 chemical 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.
REFERENCESTo Literature, Authorities, and Sources. PUBLICATIONS:
ITUNG PRODUCTION: By Dr. George F. Potter, and Dr. Ilarley 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.
2SUITABILITY OF VARIOUS SOILS FOR TUNG PRODUCTION: By Dr. Malhcw Drosdoff.
Cir. No. S40, U S. Dept. of Agriculture.
For sale by Supt. of Documents. U. S. Government Printing Office, Washington, D. C. Price 10 cents.
3TUNG 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.
4GENERALIZED SOIL MAP OF FLORIDA: By Florida Agricultural Experiment Station,
Dept. of Chemistry and Soils. University of Florida, Gainesville. Fla. Available in Agricultural I .ibraries.
.5TUNG: Processing and Marketing Practices and Costs.
For sale by Supt. of Documents, U. S. Government Printing Office. Washington. D. C. Price 20 cents.
6THE FATS AND OILS SITUATION:
A pamphlet published every three or four months by the Agricultural Marketing Service, U.S.D.A. Free Distribution. Issue consulted herein, released March 30. 1955.
-STATISTICAL BULLETIN NO. 147: June 1954: "Oilseeds, Fats and Oils, and Their Products, 1909-1953"
Published by Statistical and Historical Research Branch, Agricultural 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 II. L. Crane. Bureau of Plant Industry. U.S.D.A.
Pamphlet issued June 1950.
A Minieo-release of August 1954, bv Agricultural Marketing Service,
P. O. Bos 273, Orlando, Fla. An estimate of production in tons, price and value of Tung Nut Crop, 5 states.
10TUNC BULLETINS AND CIRCULARS:
Numerous bulletins and circulars published by the
Florida Agricultural Experiment Station. University of Florida, Gainesville, Florida.
Numerous bulletins and circulars published by the
Bureau of Plant Industry, U.S.D.A., Washington, D. C. Agricultural Researeli Administration, Bureau of Agricultural
and Industrial Chemistry, U.S.D.A. Proceedings of American Society for Horticultural Science,
Michigan State College, East Lansing, Mich.
11DR. 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 slock, soils, fertilization, etc.
12DR. R. S. Me KINNEY, 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.
13DR. F. B. SMITH, Head. Department of Soils,
Agricultural Experiment Station, Gainesville, Florida.
!4RALPH 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.
15FRAS1ER 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.
16RAY HURLEY. Chief,
Agricultural Division, Bureau of the Census. Department of Commerce. Washington 25. D. C. Census Agricultural Statistics on Tung and other data.
17H. G. HAMILTON, Agricultural Economist, Head of Dept.. Department of Agricultural Economics, Agricultural Experiment Station, Gainesville, Fla. Authority on Agricultural Economics, Data and Statistics.
IS"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.