Chapter V: Part 5

The special composts used are prepared from organic materials such as straw, hop waste and sawdust. The mechanism by which they stimulate growth is still obscure. All of them contain small amounts of directly available plant foods such as phosphates and potash, but careful investigation both in laboratory pot cultures and in the field, has shown that these can account for only a relatively temporary effect on growth. It is suggested that the composts act mainly by modifying the course of humus decomposition, thus bringing about drastic changes in the biological activities of the organic substrate of the soil.

This demonstration of the profound influence of biological factors on the nutrition of trees challenges the attention of foresters and has important practical applications. By making use of suitable composts, it will be possible to carry out the successful afforestation of land formerly regarded as wholly unproductive.

For further information see "Problems of Tree Nutrition"[5].

From the two foregoing examples it is seen that in the case of banana blight, fungi had to be suppressed by bacteriae, but that for pine trees on poor English soils fungi had to be activated for proper tree nutrition.

4) Inorganic Tree Nutrients

Other information also from England concerns the use of so-called "minerals" which I prefer to call "essential inorganic nutrients," and name by the element or the compound in which the element is contained. "Minerals", strictly speaking, refers to compounds formed by nature as rocks, ores, brines, salt deposits, etc.

Professor Wallace, Director of Britain's Long Ashton Research Station[6], has laid the foundation for diagnosing mineral deficiencies by leaf symptoms. These are reliable indicators of what nutrients to furnish plants when they are distinct and easily recognized. But for subacute deficiencies, plant analysis and injections are resorted to. Injections of manganese sulphate as pellets into holes drilled in trunks of cherry trees caused orchards that had been barren, to bear heavy crops a few months later.

Manganese, boron, zinc, copper, iron, magnesium also lend themselves quite readily for applications as nutritional sprays, when applied as suitable compounds such as the sulphates. Both spray applications and tree injections have great diagnostic values, because a response to them, if needed is relatively quick. When trees are deficient their foliage will show marked improvement from a spray application within a few days, so that a test can be made on a few trees before an entire orchard is treated. Trunk injections should of course be made during the dormant season for results to show the following summer.

5) Nutritional Sprays

Florida and California lead in the application of nutritional sprays on citrus and other fruit[7]. Vegetables, too, respond remarkably thereto[8]. I see no reason why nut trees likewise should not benefit from them, especially when other spray materials are used. Copper sulphate, zinc sulphate, manganese sulphate, magnesium sulphate, iron sulphate, cobalt sulphate and borax are all compatible with each other and with most other spray materials. Combination sprays seem to perform better, anyway, than single sprays, and the only objection would seem to be that some element is applied that is not deficient. It can be taken for granted, however, that nothing is wasted, even though the benefits may be invisible. Soils benefit in the long run from sprays. One element, even though not noticeably needed, may make another available or it may antidote toxicity of some element present to excess. Indirect results in all likelihood are always obtained.

In Florida, recommendations for spray applications to citrus are made annually[9]. They can be obtained from the Florida Citrus Commission, Lakeland, Fla. A typical formulae is as follows:

_
3-5 lbs. zinc sulphate |
3-5 lbs. manganese sulphate | per 100 gallons of water or
2-5 lbs. copper sulphate with | other spray material
equal amounts of lime. _|

1 gallon of lime sulphur or 1-1/2 lbs. of lime is used for every 3 lbs.
of sulphate of manganese or zinc.

Cherries, apples, plums are quite responsive to such applications, and I have seen the defoliation of prune trees in New York State corrected with a mixture containing:

_
Manganese 10% | All as metallic, in the form of hydrated oxides,
Copper 10% | and applied at the rate of 4 lbs, for the combination
Zinc 5% | material per 100 gallons.
Boron 1% _| The addition of 2 lbs. lime is optional.

In California a manganese deficiency has been observed on English Walnuts[10], and 5-15 lbs. commercial manganese sulphate was used per 100 gallons of water during late May, through June, to correct this.

Sprays should be applied at ten day intervals until the deficiency symptoms no longer persist.

Plausible reasons for the somewhat quicker action of sprays than fertilizers may be furnished by two prominent authorities:

McCollum[11], one of our foremost nutritionists, first noted the discovery that the leaf of the plant is a complete food, and that none of the storage organs of plants, seeds, tubers, roots, fruits enjoy that distinction. In the leaf, biological processes are most active. It is the site of synthesis of proteins, carbohydrates and fats. The leaf is rich in actively functioning cells which contain everything necessary for the metabolic processes, and they supply all the nutrients which an animal requires. ("All flesh is grass").

Hoagland[12], another authority, writes on this subject thus:

"It is now certain that soils are not invariably capable of
supplying enough boron, zinc, copper and manganese to maintain
healthy growth of plants. This knowledge has come mainly during the
past ten years. Within this period thousands of cases from many
parts of the world have been reported of crop failure, of plant
disease, resulting from deficiencies of micro nutrient elements....
The statements do not imply that most soils are deficient in any of
these elements, but the areas involved are large and important
enough to warrant the view that the recognition of micro nutrient
deficiencies constitutes a development in applied plant nutrition
of major significance.

"When I refer to deficiencies of boron, copper, manganese, or zinc,
it is not a question of absolute deficiency in total quantity of
the element present in the soil, but rather a physiological
deficiency arising from the insufficient availability of the
element in the plant; in other words, not enough of the element
can be absorbed and distributed in the plant for its physiological
needs at each successive phase of growth."

Nutritional sprays under such circumstances may prove the remedy, and we have experimental evidence to support this. Nut trees as is shown by the above mentioned experiment, may respond to spray applications equally as well as citrus, other fruit and vegetables, and effects, too may possess special diagnostic values, showing the need of trees, and therefore also the need of soils on which they are grown.

Investigators are constantly confronted with determining whether foliage shows symptoms of disease or starvation, and whether this is due to a deficiency or an excess of any particular nutrient; whether fungicides inhibit the generation of fungi from the spore state, or whether the plant is fortified from sprays or dusts to become disease resistant, or repellent.

Fungicides are valueless where plant disease is caused by bacteriae which invade the water conducting tubes, (roughly corresponding to the blood vessels of mammals), of plants, tree trunks, etc. and prevent the flow of water and nutrient solutions from roots to leaves. Deprived of water and nourishment, the plants or trees will wilt and die. Where, however, soils furnish these plants with protective inorganic nutrients, such as manganese, copper, iron, zinc, borax, etc. these bacterial diseases are prevented. Similar actions may take place in leaves.

Deficiency Symptoms. Kodachrome Slides.

Many acute deficiency symptoms have been identified by authorities and photographed, and I am able to show Kodachrome slides of the following:

Manganese starvation on Swiss chard, spinach (five illustrations),
courtesy of Dr. Robert E. Young, Waltham, Massachusetts.

Apricot, sweet cherry, lemon, onions, peanut, soybean (two
illustrations), tobacco (4 illustrations), sugarbeets, walnuts,
wheat, all by different authors.

Manganese deficiencies in Indiana on soyabeans, hemp, corn, by
courtesy of George H. Enfield, Purdue University.

Manganese on beets (mangels), (4 illustrations), and Romaine
lettuce, Nassau County, Long Island. Courtesy of Dr. H. C.
Thompson, Cornell University.

Many more are published in "Hunger Signs of Crops," an illustrated reference book popular with scientific farmers and growers[13].

Other deficiencies that have been observed on nut trees are the so-called "little leaf" or "rosette" of pecans and black walnuts[14], which is due to a lack of zinc. Strangely enough, healthy orchards in this case contained a preponderance of fungi, whereas in affected orchards the soil microflora was predominantly bacterial[15].

We now have definite experimental evidence that lime, manganese and zinc are required in appreciable quantities for the growth, health and bearing quality of nut trees. It is well to make sure of these elements in the soils devoted to nut tree planting, but it cannot be emphasized too often that all essential elements and factors should be taken care of; anyone of them may be the limiting factor in crop failure; the one that is absent is always the most important.

In regard to inorganic nutrients, more attention has probably been devoted to citrus trees than to any other tree species, largely because the soils of Florida and California require additions thereof. It would be unfair to say that such main fruit crops as apples, cherries, peaches, plums have been neglected; we merely possess more information on the nutrients of citrus trees than on other tree crops, as far as the micro essential nutrients are concerned. Most orchards and groves are fertilized only with nitrogen, phosphorus and potash, and limed when necessary. Nitrogen can stimulate size of fruit at the expense of quality.

A paper by P. W. Rohrbaugh[16], Plant Physiologist of the California Fruit Growers Exchange, Ontario, California, deals with eleven mineral nutrient deficiencies and their causes, viz: calcium, magnesium, potash, phosphorus, sulphur, nitrogen, iron, boron, zinc, manganese, copper, and this might well be used as a guide for nut trees.

6) Miscellaneous

A few oddities may also be mentioned for anyone inclined to experiment:

From Holland it is reported that an avenue of large handsome shade trees close to a century old, all died in one year, except where a junk dealer had stacked a pile of old metals. The trees had exhausted the inorganic nutrients within reach of their roots in the soil, but the junkpile had replenished them sufficiently, so that those within reach of it kept alive to this day, twenty years later.

A rock mulch is reported to have improved the growth of lime and lemon trees considerably[17], and it would seem that similar experiments should be made on young nut trees, just before bearing age in a comparative test with a check planting. Stones can be selected for the nutrients they contain, and a geologist can easily point out those containing the greatest number of elements. No one could go wrong in placing a few rocks of limestone or dolomite near the base of a tree, and let rain and sunshine, heat and frost attend to the fertilizing in a slow but perpetual manner.

Maple sugar contains manganese[18], showing this as a distinct quality over cane sugar. Manganese and other essential nutrients are known to facilitate the production of proteins[19], and the question of better quality nut production may well be examined from the viewpoint of the indirect effect from activities of soil microbiology by manganese, copper, cobalt and zinc. Some of these elements have also been classed as inorganic plant hormones[20]. "Chlorosis," the yellowing of leaves, may not only be a deficiency symptom of manganese, but also one of iron, copper and magnesium. Lack of manganese can cause a decrease in photosynthesis[21], so much so that in manganese deficient leaves the CO2 assimilation may be reduced to half of normal. Herein, too, may lie the cause of low yields, smaller roots and lowered resistance of those roots to invading detrimental organism.

Contemporary work on soil microbiology may show that manganese and other essential nutrients are perhaps most important in their functions for the preservation and balancing of microbial life and actions in soils. There is where tree nutrition must begin; whatever is neglected in soils can at best only temporarily be adjusted afterwards. After all, deficiency symptoms on foliage show lack of soil fertility, and while we should welcome them for their diagnostic value, our corrective measures to be most economical must be taken on soils.

Transmission of Inorganic Nutrients from Soils to Plants to Animals

Soil analysis and plant tissue tests both have their value, but also their limitations. Many laboratories and experiment stations are equipped to make rapid soil tests, and some engage in leaf analysis. It is important that they be correctly interpreted. For instance, at the Citrus Experiment Station, Riverside, California[22], bark and leaves were collected from healthy and diseased Persian Walnuts. They were analyzed for calcium, magnesium, inorganic phosphate, manganese and iron. A higher percentage of ash was found in the diseased than in the healthy bark, and calcium, magnesium, manganese and inorganic phosphates were also generally higher.

It would be a fallacy I think to conclude therefrom that these elements were not necessary, or were present to excess. They were probably present because they had failed to function properly, due to changes in weather, excessive rains or droughts, and could not eliminate themselves.

We must consider the results from the functions of the essential elements, and discard the popular belief that inorganic nutrients in soils are transmitted from soils to plants, and therein contained for the express purpose of satisfying the need of animals and humans[23].

The plant has only one purpose to perform which is to grow and to reproduce itself, and such is the case with all other forms of life.

Plants contain very often inorganic elements in a form in which they cannot be utilized. It is therefore quite easy to mistake their presence either as a toxicity symptom or as a high requirement, when as a matter of fact these elements are present due to conditions unfavorable to metabolism, and they remained in bark and leaves as end products, in an inert form. Rather than being transmitted from soils to plant, their functions may consist of the formation of enzymes, proteins, hormones, chlorophyll, antibodies, vitamins, in carbon assimilation. When they have served such purposes they are not likely to be present in plants in anything like the amounts or forms as present in soils. They may come into question as catalysts or bio-catalysts, as sources of energy for microorganism, from which their optimum effects have been secured when they are not transmitted at all, causing changes, but remaining themselves unchanged. They are essential in the sense that the elements composing soils, sea, atmosphere are constantly energized, changed and used over and over again to create plant, animal and human life. In this cycle nothing is lost, only changed from old to new generations.

Summary

Soil factors for tree growth are physical, chemical and biological. To control the organisms of soils and plants is probably the most difficult problem in microbiology. It is not wise to alternate neglect with feverish attention when blights or other pests become epidemic or threatening. They may be of a nutritional, preventable rather than curable nature. Pathology and tree nutrition may as well become a constant part of your activities.

References to the Literature

1. BEESON, K. C. The Mineral Composition of Crops U.S.D.A. Bulletin No. 369. March, 1941

2. FEARON, W. R. A Classification of the Biological Elements Sci. Proc. Royal Dublin Soc. Vol. 20 No. 35. February, 1933

3. WISCHHUSEN, J. F. Minerals in Agricultural and in Animal Husbandry Manganese Research & Development Foundation Cleveland 10, Ohio

4. RODALE, J. I. The Organic Forest--Editorial Organic Gardening, Emmaus, Pa. April, 1945, pp. 4-9

5. SCARSETH, GEORGE D. Growing Bananas on Acid SoilsAgriculture in the Americas, Vol. IV. October, 1944, No. 10

6. RAYNER, M. C. and NEILSON-JONES, W. Problems of Tree Nutrition Faber and Faber, Lt. London

7. ROACH, W. A. Soil Fertility and Trace Elements Soil Conservation, Washington. October, 1945 Condensed in Farmer's Digest, Ambler, Pa. January, 1946

8. CAMP, A. F. The Minor Elements in Citrus Fertilization Commercial Fertilizer, Atlanta, Ga. January, 1945

9. CHAPMAN, H. D.; BROWN, S. M.; and RAYNER, D. S. Nutrient Deficiencies in Citrus California Citrograph, May, 1945

10. McLEAN, F. T. Feeding Plants Manganese through the Stomata Science 66 (1927). Exp. Sta. Rec No. 58

11. SPRAY AND DUST SCHEDULES, Published Annually Florida Citrus Commission, Lakeland, Fla.

12. BRAUCHER, O. L. and SOUTHWICK, B. W. Correction of Manganese Deficiency Symptoms of Walnut Trees Proc. Horticultural Science 39. 133--6. 1941

13. McCOLLUM, E. V. ORENT-KEILES The Newer Knowledge of Nutrition. Fifth Edition The MacMillan Company, pp. 661-2

14. HOAGLAND, D. R. Inorganic Nutrition of Plants Chronic Botanica, 1944, pp. 32-3

15. HUNGER SIGNS OF CROPS--A Symposium National Fertilizer Assn. Washington, D. C. 1941 Judd & Detwiler, Baltimore, Md.

16. BLACKMON, G. H. Variety and Stock Tests of Pecan and Walnut Trees Florida Agr. Exp. Sta. Annual Report 1936, 75 (1937)

17. BLACKMON, G. H. Pecan Variety Response to Different Soil Types, Localities: Zinc Treatments Florida Agr. Exp. Sta. Ann. Rep. 1935, 74-5, (1936)

18. ARK, P. A. Little Leaf or Rosette of Fruit Trees VII. Soil Microflora and Little Leaf or Rosette Disease Proc. Amer. Soc. of Horticultural Sci. 34, 218-21. 1937

19. ROHRBAUGH, P. W. Mineral Nutrient Deficiencies in California Citrus Trees and their Causes California Citrograph, April-May, 1946

20. WHITE, CLARENCE Decorative Rock Mulches Organic Gardening, November, 1945--Emmaus, Pa.

21. RIOU, PAUL and DELORME, JOACHIM Manganese in Maple and Cane Sugars Comptes Rendues 200 1132-3 (1935) C.A. 294617

22. DELORME, JOACHIM Manganese in Maple and Cane Sugars Contrib. Lab. del'Ecole Hautes Etudes Comm. Montreal No. 7, page 32 1937

23. BAUDISCH, OSKAR Biological Functions of Minor Elements Soil Sci. Vol. 60 No. 2 August, 1945

24. ELLIS, CARLETON; SWANEY, MILLER. W. Soilless Growth of Plants Reinhold Publishing Co. 1938

24. WILLIS, L. G. and PILAND, J. R. Minor Elements and Major Soil Problems Jour. Amer. Soc. Agronomy. 30--385--874 (1938)

26. HAAS, A. R. C. Walnut Yellow in Relation to Ash Composition, Manganese, Iron and Ash Constituents Bot. Gazette 94 (1933) E.S.R. 69, 511

27. WISCHHUSEN, J. F. Recommendations for Feeding Manganese Manganese Research & Development Foundation, Cleveland 10, Ohio

Nut Tree Propagation As a Hobby for a Chemist

By Dr. E. M. Shelton, Cleveland, Ohio

Not so long ago we saw a movie by the title of "Cluny Brown." The heroine was possessed with a passion for repairing plumbing, but was continually inhibited by well-meaning relatives who told her that she "didn't know her place." A scene early in the story shows Cluny on the floor under a stopped-up kitchen sink explaining her problem to a sympathetic professor who states a philosophy something like this. "To be happy, one should not have to be bound by what is appropriate. If it is customary to throw nuts to the squirrels and you prefer to throw squirrels to the nuts, it should be all right to throw squirrels to the nuts."

It is obviously not always advisable to be so unconventional, but it seems to me that in matters pertaining to one's hobby it should be permissable to throw "squirrels to the nuts."

A hobby, like a shadow, is necessarily a very personal thing. Without the person with which it is associated it could not exist. Therefore, I feel that it is appropriate to present throughout this paper a liberal use of the pronoun in the first person.

Years ago, as a boy on an Ohio farm, I tried repeatedly, without success, to graft on small hickory trees along the river bank scions from one especially good tree that stood out in a cultivated field. Time that followed was too crowded for further attempts at nut tree propagation until about fifteen years ago, when, living in Connecticut, I bought a grafted walnut, a Thomas, and set out to produce more like it. Before we left Connecticut, I had been able to present grafted walnut trees to many of my neighbors who had persisted, hitherto, in calling hickory-nuts "walnuts." They would listen with some show of interest while I expounded on my enthusiasm for black walnuts, but sooner or later would inevitably ask, "Do you mean the shagbark kind?"

Last summer we drove back to Connecticut for a brief visit, and, on calling at the home of one of these friends, we found that the first nut borne on their Thomas tree had been carefully saved. Forthwith there was a solemn nut-cracking ceremony, and all present tasted the meat and pronounced it good. We hope that that tree and many others will thrive for years to come to add to the bonds of friendship with these neighbors we have known.

Lately I have arranged my work so that we may once again live in Ohio not too far from my boyhood home. Last year I tried once again to graft along the hillside scions from that prized hickory, and this time six out of seven grafts have grown.

My field of work has been that of a chemist, engaged in industrial problems related to animal and plant products. Hence, my hobby and my day's work are productive of mutually helpful ideas. The literature which I review frequently contains suggestions applicable to the various phases of tree propagation. Though a few references are quoted in the bibliography at the end of this paper, these are for illustration only and comprise a very small number of those which have appeared.

My experiments in nut tree propagation have been reported from time to time in the yearbooks of the N.N.G.A. and I intend in the remainder of this paper only to outline problems under a number of general headings in which I am particularly interested, and give some indication of procedures which seem worth while investigating.

An important phase of nut growing to which I have given little attention is the search for new varieties. I find my interest in this aspect growing as I associate with the group of nut growers in Ohio, who through prize contests and active personal work are trying to discover superior nut trees in nature, yet I do not find in this the opportunity I seek for experimentation unless it may be in the matter of hybridization.

Rootstock Propagation

Rootstocks for walnuts and hickories are very easily grown from seed. Chestnuts are grown with variable success, and it would seem that particular care in drainage of the seed bed, and possibly the use of one of the seed fungicides, should improve chestnut germination.

The present trend in the propagation of fruit trees is toward selection of particularly suitable rootstocks. Do some nut tree seedlings accept grafts more readily than others? We do not know. Numerous writers have discussed the idea of varying degrees of compatibility of rootstocks with scions and Jones[1] has brought together considerable evidence to relate incompatibility among plants with something parallel to allergy in animals. Initial growth of the scion leads to a flow of foreign bodies into the stock. The theory is advanced that the stock develops antitoxins to these foreign bodies which succeed in killing the scion a few weeks later.

If a particular strain of nut tree stock is some day found to be of particular value for grafting, or for propagation of a disease resistant type, as in the chestnut, the propagation of such stock vegetatively would be essential. A present illustration is the series of Malling apple rootstocks which are grown from cuttings.

I have tried many times to grow chestnuts from cuttings with no success. A few experiments now in progress are limited to Malling IX apple stocks which I assume are not especially difficult to root. I am trying several modifications of a principle of making the cuttings at some time after girdling the stem. The hope is that in this way there will be accumulated at the base of the cutting more than the usual reserve of nutritive elements together with whatever plant wound hormones and plant growth substances the twig is capable of synthesizing.

Scion Storage

In earlier papers I described the use of sodium sulfate crystals (Glauber's salt) for controlling the humidity in scion storage. This season I have adapted the practice to the shipping of fresh walnut bud sticks. A sack of Glauber's salt in the bottom of the mailing tube keeps the cuttings moist, and if, in addition, the container is kept in a refrigerator when not actually in transit, the buds have been kept in condition for use up to twenty-five days.

A low temperature is essential in storage of any scions. Variations in this factor may have been the cause of some of the objections which have been raised to the practice of coating scions with wax when they go into storage. If wax is to be applied over a scion, it can be done more uniformly and in a thinner coating by immersion of the scion in melted wax. The scion so coated seems to be in better condition than an uncoated scion when it comes out of storage provided the storage temperature has been low. However, if the wood has not been kept dormant by low temperature, gases are evolved which form blisters under the wax and injure the scion. It is quite probable that a wax coating then aggravates this damage.

Grafting and Budding

Until this year I had not tried budding, and have gotten into it first of all to learn whether an ordinary laboratory cork borer is not a usable substitute for a patch bud cutter. It seems to do very well. The patches are small, but as an aid in tieing them in I prepared short strips of painter's masking tape with a thin coat of a plastic grafting wax on one side. In the center of each piece of tape is a hole just large enough for the bud to show through. The tape is pressed on over the bud patch, after which the usual binding with rubber strips is applied.

The whole technic of budding is fascinating and I plan to experiment as extensively next season as time and stock permit.

Wax and Tape

In 1937, Shear[2] published a report on a number of wound dressings for trees in which he observed that lanolin exerts a marked action in stimulating cambial growth. This led me to try various wax combinations in which lanolin was incorporated, and a mixture of equal parts of lanolin and beeswax has become the base for most of my experimental grafting wax mixtures. I have commented already on the importance of incorporating an opaque ingredient to exclude light. Experiments in progress this season have had to do with introduction of green vs. red dye and with the incorporation of a wax soluble pyrridyl mercuric stearate[3] as a fungicide.

I have recommended painter's masking tape for tying in scions in all cases in which moderate tension is sufficient. A winding of such a tape of course excludes the grafting wax from contact with the line of cambial contact, so any favorable action which any ingredient in the wax might have must be largely interfered with. If a tape is prepared with a thin coating of plastic grafting wax on one side to serve as the adhesive, it should be possible to bring the wax into contact with the cut cambial surface without, however, introducing such a mass of wax as would make its way between stock and scion and interfere with contact.

Nutrition

My own field of work has recently changed to nutrition, infant feeding, and I shall undoubtedly come to have more of an understanding of plant nutrition as well as of babies as I study longer on this subject.

Our recollections of the "good old days" are often mistaken, but I think there is no doubt that the nut trees bore more and better nuts when I was a boy than we can find now. Can it be a matter of nutritional failure?

The first consideration in plant nutrition seems to be the water supply, and perhaps in many localities the water table has fallen sufficiently to threaten our trees with malnutrition.

The supply of the common mineral elements may or may not be adequate. These elements should not be difficult to supply. The matter of the trace elements and their significance catches our fancy at present and many of us will undoubtedly begin to explore the effect of this or that panacea for restoring a favorite old tree to a second youth.

Medication

It is only a step from the consideration of nutrition of a plant or animal to that of medication. Remedial agents are readily introduced into plants, either through the roots, or by spray on the foliage, or by direct injection into the trees. Going a little further, such methods become means of killing trees.

A few years ago, I became interested in killing trees in a way which would prevent sprouting and also protect the wood to some extent from insect attack and decay organisms. More recently my interest has turned toward the use of hygroscopic chemicals injected in the living tree for the purpose, not only of killing the tree, but of preventing the wood from cracking radially or drying. A number of government publications[4-10] have contributed information along this line.

To inject enough chemical to accomplish this purpose it seems necessary to introduce the chemical solution through a cut the depth of the sap wood and extending entirely around the tree. A collar of water-proof paper cemented to the tree provides a means of supplying the chemical solution to the cut. All this is described in the literature cited. The only contribution I have made is the use of urea in the solutions.

Many salts are more soluble in a water solution of urea than in water alone, and many such mixtures are very hygroscopic. Moreover, it seems that in the presence of urea higher concentrations of salt may be introduced into the sap stream of trees, though I do not as yet have experimental data to confirm this statement quantitatively.

An example of a solution injected into a small ash tree is as follows:

90 grams urea

120 grams copper sulfate crystals

300 cubic centimeters water

I hope in another year to cure a number of varieties of woods on the stump and later to compare their qualities in the shop with lumber cured in the usual way.

By-Products

Any object as juicy and colorful as a black walnut hull may well become a subject for search in recovery of by-products. The thermally active carbon made from the shells has actuated laboratory thermostats for me for several years.

But more real and immediate by-products have been the personal associations which have arisen from this hobby. Physicians, engineers, teachers, farmers, persons from every calling are among those whom I have met through a common interest in nut tree propagation. I can recommend this hobby to anyone mature enough to take an interest in the future, and to chemists in particular.

Bibliography

1. W. NEILSON JONES Plant Chimaeras and Graft Hybrids Methuen and Company, London

2. SHEAR-LANOLIN As a Wound Dressing for Trees Proc. Am. Soc. Hort. Sci. 34, 286-8 (1937)

3. HORNER, KOPPA and HERBST--Mercurial Fungicide Wax Problems Ind. Eng. Chem, 37 1069-73 (1945)

4. U. S. BUREAU OF ENTOMOLOGY AND PLANT QUARANTINE--E-409--June 1937. A method for preventing insect injury to material used for posts, poles, and rustic construction.

5. E-434--May 1938, An efficient method for introducing liquid chemicals into living trees.

6. E-467--February 1939, Chemicals and methods used in treatments of trees by injections, with annotated bibliography.

7. Conn. Agr. Expt. Sta.--Cir. No. 123--July, 1938 The use of water soluble preservatives in preventing decay in fence posts and similar materials.

8. U. S. D. A.--Cir. No. 605--June, 1941 The internal application of chemicals to kill elm trees and prevent bark-beetle attack.

9. FOREST PRODUCTS LABORATORY--November, 1938 A primer on the chemical seasoning of Douglas fir.

10. REPRINT FROM JOURNAL OF FORESTRY--Vol. 35--March, 1937 (Procured from Forest Products Laboratory) Seasoning transverse tree sections without checking.

Notes on Propagation and Transplanting in Western Tennessee

By Joseph C. McDaniel, State Horticulturist

Tennessee Department of Agriculture

Nashville 3, Tennessee

These observations are presented as a preliminary report of the results obtained by three enterprising amateurs of nut growing in the western counties of Tennessee, whose work points the way toward overcoming some of the weaknesses previously encountered in nut culture in the northern part of the cotton belt states. These growers are the "three R's" of our Association in west Tennessee: Dr. Aubrey Richards of Whiteville, Mr. George Rhodes of Covington, and Mr. W. F. Roark of Malesus. I am giving this brief account of some of their experiences, with the hope that it will stimulate others to try their methods under various conditions, and to report their results at later N.N.G.A. meetings. We do not expect these methods to work equally well in all parts of the United States and Canada represented here today, but they are giving promising results in the mid-South territory, and perhaps will have value in a wider area. As Mr. Davidson has so ably done at this meeting in the case of his Ohio plantings, we expect to give you a follow-up report on this work in west Tennessee at the Toronto meeting or later.

"Twin-T" Budding in Chestnut Propagation

Of the nut trees grown in this area, the chestnut has been the most difficult to propagate by budding. Nurseries in the upper South have propagated their pecan and walnut trees mostly by patch-budding or the similar ring-budding method, with very good success. When applied to chestnuts, patch-buds have seldom grown. The common T-bud, likewise, has been a general failure on chestnuts in America, though reported successful in Japan. Chip-buds have not been much-better.

Several years ago, Dr. Max B. Hardy told me that the inlay bark-graft had been used successfully with Chinese chestnuts at the U.S.D.A, laboratory in Albany, Ga., following Dr. B. G. Sitton's use of this method with pecans in Louisiana. (It is described in a bulletin from Michigan State College, East Lansing, Mich.) I tried it in a small way, and had some success using it on chestnuts in July and August. This spring I suggested it to Mr. Roark and Dr. Richards, both of whom tried it out, using Castanea mollissima stocks and various scion varieties.

Mr. Roark used the inlay bark-graft in the spring, topworking a C. mollissima seedling with scions of the Colossal, a hybrid variety from California. About 50 per cent of these have grown this year. Dr. Richards tried it during July, on C. mollissima seedlings from a different source. None of the Colossal would grow on his trees, but he was partially successful with scions of the C. mollissima varieties, Hobson, Carr and Zimmerman. He then devised a variation in the method which was highly successful with C. mollissima varieties. This I shall call the Richards "Twin-T" bud.

In "Twin-T" budding, a vertical slit is made in the bark of the stock. Then horizontal cuts are made through the bark at both top and bottom of the vertical cut. The bud piece is cut from the well matured part of a current season's twig, leaving a rather thick slice of wood beneath the bud. (It may be as thick as half the diameter of the twig.) The bud is inserted in the stock as in ordinary T-budding, then wrapped with a large sized rubber budding strip. (Westinghouse electrician's tape and Curity adhesive tape have also been used. Some other brands poisoned the buds.) The "take" of Chinese chestnut buds by this method has run from 60 to 90 per cent on Dr. Richards' trees of various sizes this year. In a short nursery row, buds were placed under first or second year bark, while larger trees were topworked by placing the buds mostly under the bark of second year limbs.

The Colossal failed again on Dr. Richards' trees when budded by the "Twin-T" method, but Carr and other Chinese varieties were budded successfully. The graft-compatibility problem in chestnuts is one of considerable complexity. Thus Carr, which has presented incompatibility with certain stocks of C. mollissima at other places, grew on these trees, and Colossal, compatible on another C. mollissima tree, failed on trees which are apparently compatible with Carr. The Chinese chestnut species varies in its graft-compatibilities possibly as much as in other characteristics (growth, productivity, size and quality of nuts, etc.) so that nut nurserymen should begin to select their seed for chestnut understocks with a view toward getting strains with a greater degree of compatibility to the leading scion varieties.

Mr. Roark has been able to propagate the Colossal upon its own roots by layering a small tree in his orchard. Two limbs pegged into the ground in the spring of 1945 had produced roots a year later, and were then detached from the parent tree. This is a slow but sure method of propagating nut tree varieties that are not congenial with the stocks available for grafting or budding. He has also layered sweet cherries and prune trees by this method which is described in U.S.D.A. Farmers Bulletin 1501 with reference to filberts.

A Heartnut Variety Compatible with Black Walnut Stocks

Seedling black walnuts are common on farms of west Tennessee. Dr. Richards and Mr. Rhodes have been most active in showing that these can be topworked readily to improved black walnut varieties under the conditions prevailing there. Mr. Rhodes has also fruited such older Persian walnut varieties as Lancaster, Mayette, and Franquette on black walnut stocks, but finds them generally unproductive in his climate. Newer varieties, including some selections of the Carpathian strains are now being tried and should be of fruiting age soon. Mr. Rhodes has also found, at Covington, a heartnut that is vigorous and productive under west Tennessee conditions. He finds that it buds readily on the native black walnut. Some budded trees of it are over a dozen years old. They have medium sized nuts, smooth shelled (with fairly thick shells for a heartnut) and kernels of good flavor, coming out whole when the nuts are cracked carefully. I am giving this variety the name Rhodes, and suggesting it for use in west Tennessee because of its adaptability and the fact that it can be budded upon black walnut. Others have reported Japanese walnut (including heartnut) varieties incompatible with black walnut at other locations. Dr. Richards has propagated some other heartnut varieties on black walnut, but finds them more variable than the Rhodes, in obtaining a good union.

Paper Wrap Gives Summer-Long Protection to Transplanted Trees

Too commonly, transplanted nut trees suffer from sunscald injury on their southwest sides during the first summer in the orchard. This injury is particularly common on pecans, which suffer a severe shock from transplanting and are slow in re-establishing vigorous growth. In west Tennessee, as one grower puts it, "A pecan is doing well if it holds one green leaf its first year." Pecans have been known to remain dormant in their tops until the second spring after planting, and then start growth. During this initial period of establishment in the orchard, it is beneficial to give some kind of shade to the tree trunk, to keep the bark from "cooking" and dying on part of the most exposed side. Waxing of the trunks before planting helps reduce drying out of the tops before the roots are partially regenerated and top growth begins, but waxing alone, under our conditions, is not sufficient to prevent the frequent occurrence of a dead area starting on the southwest side of the trunk during the summer following tree setting.

Dr. Richards has found that a heavy wallpaper of a cheap grade, cut in strips and wrapped spirally to cover the tree trunk from the ground up, lasts through the season and eliminates nearly all of the sunscald injury on pecans which he has moved from his farm nursery row to the orchard. With trees that are shipped long distances, and allowed to dry out too much before resetting, the results are not so uniform. We are still in favor of the use of wax coatings on trees that must be shipped, but would recommend that they be given additional protection by some means, to shade the trunks throughout the first growing season. This paper wrap of Dr. Richards seems as efficient as any method, and is the most economical I have observed. It should be beneficial on most species of nut trees under summer conditions in the mid-south region.

Propagating Nut Trees Under Glass

By Stephen Bernath, Poughkeepsie, New York

About ten years ago I decided to try a few nut grafts in my small propagating house. The results were so satisfactory that since that time I have grafted from a few hundred to several thousand each year.

I found by experiment that I could not graft nut trees exactly as I did ornamental trees and shrubs, due to their extra sap content. Nut trees bleed excessively and I had to overcome this or my losses were heavy. I use no wax on grafts. My method is as follows: I take a strong light string and wax it with beeswax and parafin mixed fifty-fifty. I use a modified side graft, tying with this waxed string.

Late in December or early in January, I pot the understock, using black walnut seedlings for four varieties (Persian walnut, butternut, black walnut and heartnut). I make sure the understock has had its rest period by not digging and storing them until they have been really hit by frost and left for a period, to be sure the wood has matured for the season. The mature understock is then stored in moist sand in a cool cellar.

In late-December, as I have stated, I place the understock in benches using 3-1/2 to 4 inch pots, wetting them thoroughly after imbedding them in peat moss. Keep the moss damp and at a temperature of 55 degrees at night. After two or three weeks examine the roots by knocking several loose from the pots. If root action has started, the roots will show white thread-like fibers and are ready for grafting. This is important, because if grafting is done too soon the loss is heavy. If delayed too long the top starts growing. So I caution, do grafting when the understock is ready.

Place newly made grafts on their side, imbedded in moss, and refrain from watering until the union has formed. Open grafting case after third day and daily thereafter, until union is complete. Each day wipe glass off with cloth to prevent moisture from dripping on grafts. Increase bottom heat after grafts are laid in benches from 68 to 75 degrees. In about three to four weeks, if union has formed, place grafts in up right position, then watering is resumed and heat is reduced to around 60 degrees at night. When graft shows two inches or more growth, cut understock off close above the union, and then give house plenty of ventilation to avoid soft growth.

I find nut trees very tender subjects and delay planting these under-glass grown grafts out in nursery rows until every vestige of frost has passed. Also be sure to sever the waxed string as this is tougher than the green graft.

If this method sounds like a great deal of work and trouble generally, remember the reward will be heavy rooted, easy to transplant, healthy, named varieties of nut trees. Who can say that, at the present, there is an abundance of such trees in this country.

The Economic, Ecological and Horticultural Aspects of Intercropping Nut Plantings

By F. L. O'Rourke Michigan State College, East Lansing, Michigan

Mature nut trees are usually large trees, and large trees demand space. Young nut trees, therefore, must be planted relatively far apart from each other and for the first few years, at least, there is an abundance of unused land between the trees, which may be used for intercropping. The choice of just what crop or plants to use is often perplexing and should be considered for several aspects.

The economic factors are of prime importance. The cost of growing the crop, the specialized farm machinery and equipment needed, the availability of labor, the distribution of the seasonal labor demand, the time of the critical cultural practices or of harvesting, the potential market, and the expected price of the saleable product must all be considered.

The staple farm crops of the region are often preferable to specialty crops, particularly from the labor standpoint. Corn, wheat, oats, potatoes, and legumes can all be grown with a minimum of labor and the use of power machinery. There is less risk involved with farm crops than with specialities, both in securing an adequate crop and in the price received for the product. Fruit, vegetables and ornamentals often have very critical requirements. They must be sprayed, harvested, and shipped at exactly the right time or all the proceeds will be lost. Staple crops are not so demanding in either culture or harvesting.

The labor distribution throughout the season or even throughout the year must be considered and well planned in advance. No two crops should require exact and demanding attention at the same time. They should be chosen and planted so that a regular, even distribution of labor can be maintained with as little of a rush period as possible and yet with a minimum of idle time.

The general agricultural pattern of the region must be considered. In a sparsely settled grain and livestock region it would be quite inadvisable to grow strawberries or other crops which require a maximum of hand labor during a very brief period. Berries, however, may be perfectly well suited to sections where either transient workers or city children can be secured with little effort.

The crop should suit from the ecological viewpoint. It must not compete with the young, growing trees for mineral food and water, particularly during spring and early summer when the trees make most of their annual growth. On the other hand, if planted too close to the trees, some intercrops may be shaded too severely to produce a normal yield.

Success in intercropping is usually found between plants which are quite dissimilar in form and habit. Black walnuts and pasture grasses furnish a typical example. The long taproots of the walnuts penetrate deeply into the soil, while the grass roots are shallow and fibrous and feed in the soil surface layer. The aerial portions of these plants are likewise quite different, the walnuts tower high in the air, while the grasses form their crowns on the very surface of the ground. The light shade cast by the walnuts does not interfere with the photosynthetic activity of the grasses, but it is sufficient to discourage growth of broad-leaved weeds which have a higher light requirement than that of grass. This light shade also tends to provide a greater supply of available moisture for the grass, in that it reduces temperature and, consequently, water loss from the grass and soil by keeping down both transpiration and evaporation.

Experiments in both Tennessee and Ohio have shown that the quantity of grass produced from beneath walnut trees is greater than on equal areas in the open and that the quality, as represented by a larger protein content, is also higher. For this reason, one may well consider livestock as the income-producing portion of a walnut-pasture planting. Over one fourth of the agricultural land of the United States is devoted to pasture and much of the land is suitable for interplanting to walnuts, butternuts, and other pasture trees, as honey locusts and black locusts, all of which are known to improve the pasture grasses to some extent. The potential income which may be derived from such plantings over this vast acreage is enormous and is the more striking in that these pasture trees occupy a plane that is now idle and unproductive, that is, the area lying above the grass tops. The nuts produced on this "upper story" will represent almost all "clear profit" in that very little care need be given these walnut trees after they have been properly planted. Livestock guards will need to be placed about the trees at planting time and kept there until the trees have grown to the point where they may no longer be harmed by straddling and browsing.

Pastures are excellent sites from another angle. The closely grazed sod furnishes an ideal place to rake the nuts together at harvest time. Anyone who has hunted for nuts in a dense ground cover will appreciate this factor.

While the walnut responds best to the deep, fertile soil of the river bottoms and flood plains, it will grow well on the lower portions of slopes if water is available and the site is not too exposed to the force of drying winds. Contour strips should be prepared by plowing several furrows downhill, each a little less in depth than the preceding, and the walnuts planted thereon. The walnut is a spreading tree and plenty of space should be allowed. Perhaps it may be wise to plant the walnuts at extended intervals and fill up the contour row with black locusts, for post wood, and honey locusts to produce succulent pods for cattle feed. In any event, it is better to allow too much, rather than too little space, as walnuts are long-lived trees and will thrive best where there is least competition. In Iowa, black walnuts are responding well to "basin culture" in sites which were prepared by "scalping" the sod from the upper portion of a slope and depositing it on a lower portion in order to catch and retain more water.

Nut trees are like all other trees in that they react favorably to good horticultural practice. Fertilizer, particularly nitrogen, is usually always helpful. The addition of lime when the soil is acid and of organic matter when humus becomes depleted will aid in better soil aeration and an increased moisture supply. This, in turn, will be reflected in more vigorous tree growth and greater nut production. Occasional spraying may be necessary to control the Datana caterpillar in the summer.

Chinese chestnuts seem to be admirably adapted for interplanting with mulberries, cherries, pears, and the like in poultry runs and hog lots where the pigs and chickens will control the weevils by gleaning the prematurely dropped and overlooked chestnuts which contain the grubs of the weevil. The fruit portion of the integrated planting will maintain a high carbohydrate ration during the season for the use of the livestock. Here, again, plenty of space should be allowed between trees to allow each its full measure of water, food, air and sunlight.

Careful and thorough research is needed to determine the full requirements of nut trees and to work out the interplanting relationships. In view of the vast potentialities for their use, investigational programs may soon be under way and much more definite information be made available to the farmer and landowner.

References

AIKMAN, J. M.--A Basin Method of Nut Tree Culture. Proc. Iowa. Acad. Sci. 50:241-246. 1943

NEEL, L. R.--The Effect of Shade on Pasture. Tenn. Exp. Sta. Cir. 65, 1939

SMITH, R. M.--Some Effects of Black Locusts and Black Walnuts on Southeastern Ohio Pastures Soil Sci. 53:385-398, 1942

Nut Work At the Mahoning County Experiment Farm, Canfield, Ohio

By L. Walter Sherman, Superintendent

My interest in nuts dates back to the turn of the century when, as a boy in high school, I delighted in gathering wild nuts for my own use. I knew of several black walnut trees bearing very fine nuts and also one excellent hickory. These were near my home in northern Ohio.

After my school days were over, I married and went to Oklahoma, where I found the most miserable wild nuts imaginable. However, I stayed but a short time and returned to my native state where the wild nuts were reasonably good. In 1935, I made a trip to California and visited the Persian walnut orchards at harvest time. As if that were not enough to convince me that it would be worth my while to do what I could in behalf of the nut industry, the Agricultural press of the time published several intriguing accounts of Persian walnuts growing in and near Toronto, Ontario which had been brought there by Rev. Paul C. Crath from the Carpathian Mountains of Poland.