MINERAL NUTRITION OFYELLOW-POPLAR . (LIRlODENDRON TULIPIEERA' L.) V " Thesis for the 'Dogreé of Ph. D- ‘ MICHIGAN STATE UNIVERSITY . Raymond ' FTancisirFi‘nnfi . 1966 Michigan State University . IIIIIIIIIII||l||||||l|||||ll||||||||I|||||||||lI|||||||||||I|||I . 3 1293 191993.02; This is to certify that the thesis entitled MINERAL NUTRITION OF YELLOW-POPLAR (LIRIODENDRON TULIPIFERA L.) presented bg BY Raymond Francis Finn has been accepted towards fulfillment of the requirements for Ph.D. degree in Forestry /5mq,ae£. fl ”fig; ‘ Mainr nrnfpecnr ._ fl’ééy Date RC’UET’: WE ONLY ABSTRACT MINERAL NUTRITION OF YELLOW—POPLAR (LIRIODENDRON TULIPIFERA L.) by Raymond Francis Finn Yellow-poplar (Liriodendron tulipifera L.) is an im— portant timber tree species that occurs over a wide geo; graphical range in the United States. It is one of the most commonly planted tree species in the hardwood region of the United States. However, yellow—poplar plantations and other hardwood plantations usually have not grown and developed satisfactorily. Part of this failure has been ascribed to the inadequacy of available soil nutrients. It is desirable, therefore, to have a standard which can be used to Judge the adequacy of available soil nutrients. Foliar chemical analyses offer a possible means of providing this standard. To use foliar analyses for diagnostic pur— poses, the relationships between nutrient concentration, growth or yield, and foliar concentration must be estab— lished. This information is not available for yellow—poplar. In 1960, experiments were initiated to supply the needed in- formation. A sandeculture technique was used to Establish the relationships between solution nutrient concentrations, growth, and foliar nutrient concentrations. Nitrogen, Raymond Francis Finn phosphorus, potassium, and calcium solution nutrient con- centrations were varied; all other nutrients were main— tained at a fixed concentration. Deficiency symptoms induced by omitting nitrogen, phosphorus, potassium, and calcium singly and in combi— nations from the nutrient solutions were studied in a sand— culture medium. Fertilizers were applied to sand, sandy—loam, and clay-loam soils in pots containing yellow-poplar seedlings. Nitrogen, phosphorus, potassium, and calcium were applied to the soils at several rates, singly and in combination. The effects on growth and foliar nutrient concentrations re- sulting from the application of fertilizers were observed. Since mycorrhizae are known to affect the inorganic nutrition and growth of forest tree species, an experiment was designed to determine to what degree mycorrhizae are important in the inorganic nutrition of yellow—poplar seed— lings growing on a sand and a sandy—loam soil. The results from the first experiment in which the solution concentrations of N, P, K, and Ca were varied in— dicate that there is a significant positive relationship between solution nutrient concentration and foliar nutrient concentration. The relationship in some cases is linear and in others is defined by a second order polynomial eQuation. Growth was significantly related to N, P, and Ca solution concentrations, and hence, to foliar Raymond Francis Finn concentration. The relationship between solution potassium concentration and growth was not statistically significant. The omission of N, P, or K from the cultural solutions resulted in the death of the seedlings. The omission of calcium, however, did not retard growth. Fast—growing seed— lings produced more severe deficiency symptoms than slower growing seedlings. The omission of N + P or N + K or higher order combinations of these three elements produced less severe symptoms than when one of the three elements was omitted. When two or more elements were omitted from the basic nutrient solution, the foliar deficiency symptoms were generally characteristic of the symptoms produced by the omission of only one element. Thus, when nitrogen and phosphorus, simultaneously, were omitted from the basic solution, a characteristic nitrogen deficiency symptom was produced. Foliar analyses indicated an increase in inorganic nutrient uptake following fertilization. Growth response to fertilization was not great. The most consistent re- sponse was associated with the phosphorus fertilizer ap— plied to the sandy-loam soil. Soil texture and associated' soil physical factors played a more dominant role in growth than fertilization. The adequacy of available soil N, P, K, and Ca was indicated by the small growth response to fertilization. Raymond Francis Finn Foliar analyses indicated only a slight deficiency of avail- able N, P, K, or Ca. Seedlings in soil inoculated with organic material from a yellow—poplar stand grew no better than those in un— inoculated soil. There was no evidence of the formation of mycorrhizae. It is suggested that this result may be due to the use of inoculum in which the fungi were not active; and hence, did not invade the seedling roots. The main findings of this study are that a solution nutrient concentration of a single varied element can be identified for maximum growth. Foliar nutrient concentration is correlated with solution nutrient concentration. There— fore, a foliar nutrient concentration can be identified which coincides with maximum growth. However, maximum growth values determined separately in the N, P, K, and Ca series differ by as much as seventy percent. This appears to be caused by the strong ion antagonism between N, P, K, and Ca. This antagonism is reflected in different foliar concen- trations for elements which have the same solution concen- tration in two or more of the series. It is, therefore, doubtful that foliar nutrient con— centration derived from single element studies will be very useful as a standard for estimating the adequacy of soil nutrients. Apparently, there is a range of foliar percent— age combinations of elements that are correlated with es— sentially the same amount of growth. MINERAL NUTRITION OF YELLOW—POPLAR (LIRIODENDRON TULIPIFERA L.) By Raymond Francis Finn A THESIS Submitted to Michigan State University 1 fulfillment of the requirements for the degree of in partia DOCTOR OF PHILOSOPHY Department of Forestry 1966 7 _ rivaiia. -fi..- -.-. - vr—rrw" ".‘T—.':" 'E—. . ' I" I I - 4 ACKNOWLEDGMENTS for his suggestions for conducting the study, interpreting the results, and for other assistance. The author's thanks are due the late Dr. Terril D. Stevens and Dr. A. G. Chapman for unfailing support. Dr. Charles Schomaker provided valu— able assistance in conducting the experiment and Dr. Alvin Grateful acknowledgment is made to Dr. Foster Cady of Iowa State University's Statistical Laboratory for much aid in computing and interpreting statistical results. And lastly, special thanks are due the author's wife, Mary, who encouraged him to complete the work when he most needed encouragement. ii VITA Raymond Francis Finn Candidate for the Degree of Doctor of Philosophy Final Examination: July 28, 1966 Guidance Committee: The late T. D. Stevens and the late George Steinbauer, Wade McCall, Victor Rudolph, Herbert Beeskow, Boyd Ellis and Donald P. White, Major Professor Dissertation: Mineral Nutrition of Yellow—Poplar, (Liriodendron tuli ifera L.). _____________.____E_____ Outline of Studies Major: Forestry, Plant Nutrition Minor: Soil Science Biographical Items: Born October 14, 1909, New Windsor, New York Undergraduate Studies: New York State College of Forestry, 1931—32 University of Alabama, 1933 University of Minnesota, 1936—1938 B.S. in Forestry, 1938 Michigan State University, 1957—1958 M.S. Forestry (Plant Nutrition and Soils), 1958 Michigan State University, 1958—1961 Ph.D. Forestry, 1966 Experience: . Research assistant, staff member, and Assistant Director of the Black Rock Forest, Cornwall—on—Hudson, New York 1933—1949; Staff member and Research Center Leader, U. S. Forest Service, Athens, Ohio, 1949—1957; Project leader, U. S. Forest Service, Ames, Iowa, 1961 to present date. Member: Xi Sigma Pi Sigma Xi Gamma Sigma Delta Society of American Foresters . . The American Society of Plant PhySiologists Soil Science of America IoWa Academy of Science iii TABLE OF CONTENTS Page ACKNOWLEDGMENTS . . . . . . . . . . . . ii LIST OF TABLES . . . . . . . . . . . . vi LIST OF FIGURES . . . . . . . . . . . . ix LIST OF APPENDICES . . . . . . . . . . . xv Chapter I. INTRODUCTION. . . . . . . . . . . 1 II. STATEMENT AND SCOPE OF THE PROBLEM 5 ! III. REVIEW OF LITERATURE 7 I General. . . . . . . . . . . 7 Site—Fertility . . . . . . . 8 Field Fertilization of Hardwoods . 9 Other Effects of Fertilization . . . 12 pH and Nutrients. . . . . . . . 14 Residual Effect of Fertilizer . . . 15 Soil Moisture and Nutrients . . . . 16 Light and Nutrients. . . . . . 17 Interaction Among Nutrients . . . . 18 Mycorrhizae—Hardwoods . . . . . . 19 Evaluation of Soil Fertility. . . . 21 Soil Analyses . . . . . . . 21 Foliar Analyses. . . . . . . 22 IV. METHODS AND PROCEDURES . . . . . . . 25 Sand Culture Experiments . . . . . 25 Containers and Sand . . . . . 25 Culture Solution . . . . . . 26 Seedlings. . . . . . . . . 29 iv Chapter Soil Experiments Soil. . Fertilizers . . . . . Inoculum and Sterilization Harvesting Chemical Analyses of Seedling Parts: Experimental Design and Statistical s . . . . . . . . V. RESULTS AND DISCUSSION. Sand Culture Growth Experiment Nitrogen Series Phosphorus Series Potassium Series. Calcium Series Deficiency Symptoms Experiment Discussion . . . . . . . Fertilizer Experiment Mycorrhizae Experiment VI. GENERAL SUMMARY AND CONCLUSIONS. Growth Experiment. . . . Deficiency Symptom Experiment. Fertilizer Experiment . . Mycorrhizae Experiment LITERATURE CITED APPENDIX. 137 140 140 147 148 149 150 158 LIST OF TABLES Yellow—poplar seedling Nitrogen series. weights (OD) and stem/root ratios. Yellow—poplar seedling Nitrogen series. weights (fresh) and stem/root ratios. Nitrogen series. Yellow-poplar stem di— ameters, size and number of leaves Nitrogen series. Moisture percentages of yellow-poplar stems, roots, and leaves Length of yellow-poplar Nitrogen series. stems, roots, and petioles . Nitrogen series. Nitrogen percent and con— tent of yellow-poplar leaves, stems, roots, and petioles. . Nitrogen series. Mineral percent compo— sition and content of yellow—poplar leaves (ODW). . . . . Nitrogen series. Correlation and regres— sion Phosphorus series. Yellow— —poplar seedling weights (OD) and stem/root ratios. Phosphorus series Yellow-poplar seedling weights (fresh) and stem/root ratios. . Moisture percentages of Phosphorus series. yellow—poplar stems, roots, and leaves Yellow—poplar stem di— Phosphorus series. ameters, size and number of leaves Phosphorus series. Length of yellow— poplar stems, roots, and petioles. vi Page 36 37 39 38 4O 41 42 45 53 57 57 59 6O Table 14. BO. Phosphorus percent and stems, Phosphorus series. content of yellow— poplar leaves, roots, and petioles . . Phosphorus series. Mineral percent compo— sition and content of yellow—poplar leaves (ODW). . . . Correlation and re— 0 Phosphorus series. gression. . . Potassium series. Yellow—poplar seedling weights (OD) and stem/root ratios . Potassium series. Yellow—poplar seedling weights (fresh) and stem/root ratios Potassium series. Yellow-poplar stem di— ameters, size and number of leaves . Potassium series. Length of yellow- poplar stems, roots, and petioles. . Potassium series. Moisture percentage of yellow-poplar stems, roots, and leaves. Potassium percent and stems, Potassium series. content of yellow—pOplar leaves, roots, and petioles Potassium series. Mineral percent compo— sition and content of yellow—poplar leaves . . . . . . . . Potassium series. Correlation and re— gression. . Calcium series. Yellow—poplar seedling weights (OD) and stem/root ratios Calcium series. Yellow—poplar seedling weights (fresh) and stem/root ratios . Calcium series. Moisture percentages of yellow—poplar stems, roots, and leaves. Calcium series. Yellow—poplar stem di— ameters, size and number of leaves Page 60 62 63 72 72 73 74 74 76 77 78 89 9O 9O 91 J _I I I I I I I Table 29. 30. 31. Page Length of yellow-poplar . 92 Calcium series. stems, roots, and petioles . Calcium series. Calcium percent and content of yellow— poplar leaves, stems, roots, and petioles . . . . . . . . 93 Calcium series. Mineral percent composition and content of yellow-poplar leaves (ODW) . 94 96 Calcium series. Correlation and regression Survival, weight, and length of six—week-old seedlings grown for 83 days in complete and nutrient deficient sand—culture solutions . . 105 Stem diameter, leaf size, and number of leaves per seedling of six—week—old seedlings grown for 83 days in complete and nutrient deficient . . . . . . 106 sand—culture solutions Survival, weight, and length of two—week—old seedlings grown for 112 days in complete and nutrient deficient sand-culture solutions . . 117 Stem diameter, leaf size, and number of leaves and branches per seedling of two—week—old seedlings grown for 112 days in complete and deficient sand—culture solutions . . . . 117 Fertilizer experiment. Weight of stems and roots in grams and stem diameters in milli- meters. . . . . . . . . . . . 129 Fertilizer experiment. Nutrient percent of leaves (ODW) in relation to fertilizer rate of application (lbs/A) . . . . . . . 135 Mycorrhizae experiment. Weight and length of stems and roots. . . . . . . . . 138 Comparison of yellow-poplar stem plus root weights to optimum solution concentrations of N, P, K, and Ca and to foliar nutrients. . . 145 viii igure LIST OF FIGURES General View of the fertilizer and sand— nutrient culture experiments (August 5, 1960) . The arrangement of pots and nutrient reserVOir glass jugs used in the sand—culture nutrient studies. Jugs are below the bench. Solutions were hand poured through the glass tubes seen in the middle of the pots. . . . . Yellow—poplar growth experiment. Regression of foliar nitrogen percent on nitrogen solution concentration. . . Yellow—poplar growth experiment. Regression of foliar nitrogen content on nitrogen solution concentration. . . . . . . . . . . Yellow-poplar growth experiment. Regression of stem weight (CD) on nitrogen solution concen— tration. . Yellow-poplar growth experiment. Regression of root weight (CD) on nitrogen solution con— centration. . . . . . . . . . c Yellow—poplar growth experiment. Regression of stem length on nitrogen solution concentration Regression of Yellow—poplar growth experiment. leaf weight (CD) on nitrogen solution concen- tration. . Nitrogen series. Pots are arranged in order of increasing nitrogen concentration from left to Optimum growth (300 ppm N) pot fourth right. from left Phosphorus series. Pot arrangement same as in Figure 9. Optimum growth at 50 ppm second pot from left . . . . . . . . . . . . . ix Page 27 27 46 47 48 49 50 51 54 54 gure Yellow—poplar growth experiment. Regression of stem weight (OD) on phosphorus solution concentration . . . . . . . . s Yellow—poplar growth experiment. Regression of root weight (OD) on phosphorus solution concentration . . . . Yellow-poplar growth experiment. Regression of stem length on phosphorus solution con- centration Yellow—poplar growth experiment. Regression of leaf weight (CD) on phosphorus solution concentration . Yellow—poplar growth experiment. Regression of foliar phosphorus percent on phosphorus solution concentration . Yellow-poplar growth experiment. Regression of foliar phosphorus content on phosphorus solution concentration . . . . Yellow—poplar growth experiment. Regression of foliar potassium percent on potassium solution concentration . . . . Yellow—poplar growth experiment. Regression of foliar potassium content on potassium solution concentration . . . . Yellow—poplar growth experiment. Regression of stem weight (CD) on potassium solution concentration . Yellow-poplar growth experiment. Regression of root weight on potassium solution con— centration . . . Yellow—poplar growth experiment. Regression of stem length on potassium solution concen— o o tration Yellow—poplar growth experiment. Regression o o o of leaf weight on potassium solution concen- a tration Page 65 66 67 68 69 7O 81 82 83 84 85 86 gure 24. 25. 26. 37. 28. \O Page Potassium series. Pots are arranged in order of increasing solution potassium concen- tration from right to left. Optimum growth at 400 ppm fifth pot from right . . . . . 87 Calcium series. Pot arrangement same as in Figure 23. Optimum growth at 50 ppm second pot from right. _. . . . . . . . . 87 Yellow—poplar growth experiment. Regression of foliar calcium percent on calcium solution concentration . . . . . . . . . . . 97 Yellow—poplar growth experiment. Regression of foliar calcium content on calcium solution concentration . . . . . . . . . . . 98 Yellow—poplar growth experiment. Regression of stem weight (CD) on calcium solution concentration . . . . . . . . . . . 99 Yellow—poplar growth experiment. Regression of root weight (OD) on calcium solution concentration . . . . . . . . . . . 100 Yellow—poplar growth experiment. Regression of stem length on calcium solution concen— tration . . . . . . . . . . . . . 101 Yellow-poplar growth experiment. Regression of leaf weight (CD) on calcium solution con— centration . . . . . . . . . . . . 102 —N leaves show typical yellowing as a result of nitrogen deficiency. The upper leaves, from seedlings growing in complete solution, are normal. Photo 10/1959. . . . . . . 107 —K leaves on the left are beginning to show first stage of potassium deficiency along leaf margins. Leaf size much reduced. The upper leaves, from seedlings grown in com— plete solution, are normal. Photo 10/1959 . 107 —P leaves all are beginning to bronze, which begins on the margins. The upper leaves, from seedlings grown in complete solution, are normal. Photo 10/1959. . . . . . . 107 xi re Page —Ca The effect of omitting calcium from the solution had no apparent adverse effect on either leaf color or size. The upper leaves, from seedlings growing in a complete solu— tion, are normal. Photo 10/1959 . . . . . 109 -NP The deficiency color symptoms are less pronounced than in either the -N or —K photos. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 . . . . . . . . —NK The color symptoms are intermediate be— tween the color for —N and —K. The upper leaves, from seedlings growing in a complete solution, are normal. Photo lO/l959. . . . 109 109 —NCa Little difference in color symptoms be— tween this photo and the —N photo. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959. . . . lll —PK Here typical —K deficiency is shown by leaf on right while the leaf is beginning to show some bronzing which is typical of -P deficiency. The upper leaves, from seed- lings growing in a complete solution, are normal. Photo 10/1959 . . . 111 —PCa The deficiency color is probably associated with —P rather than with -Ca. Al— though color looks yellow, it is actually a metallic bronze color. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 . . . . . . . 111 -KCa Color is almost normal only size of leaf is affected. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 113 —NPK The color here is almost normal except for leaf on the left. The upper leaves from seedlings growing in complete solution, are . . . . . 113 normal. Phote 10/1959 . xii II‘e —NPCa Here too, as more than one of the ele— ments is omitted there is less abnormal color than when nitrogen or phosphorus are omitted singly from the solution. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 . . —NKCa Only the leaf on the left shows pro— nounced color deficiency symptoms. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959. . . . . . . . -PKCa The dominant color deficiency symptom is due to -K. The upper leaves, from seed— lings growing in a complete solution, are normal. Photo 10/1959 . . . . . —NPKCa The color of these leaves is almost normal. It is clear that low levels of the four elements do not cause marked color de— ficiency symptoms. It is only when the balance is greatly altered that the symptoms become pronounced. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 . . Complete solution (September 9). Seedlings are from 12— to 40-inches tall and leaves have normal color. Photo 1960 . —N (July 15) All of these seedlings subse— quently died. Photo 1960 -P (August 17) The actual color is bronze for most of the leaf with the margins a delicate pink due to formation of antho— cyanin. All seedlings died. Photo 1960. —K (July 15) Typical potassium deficiency symptom showing disintegration of chloro- phyll in interveinal areas. Photo 1960 -K (August 17) The veins remain green but interveinal areas show further breakdown of chlorophyll. All the seedlings died. Photo 1960. . . . . . . xiii Page 113 115 115 115 118 118 118 120 120 Ire Page —Ca (September 9) These seedlings are as large as those growing in the complete solution and leaf color is normal. Photo 1960 . . . . . . . . . . . . . . 120 Z. -NP (September 9) The leaves Show a combi- nation of nitrogen and phosphorus deficiency symptoms but principally nitrogen symptoms. Photo 1960 . . . 122 3. -NK (September 9) Typical nitrogen de— ficiency. Very little potassium symptoms evident. These seedlings all died. Photo 1960 . . . . . . . . . . . . . . 122 I. —NCa (September 9) The deficiency symptoms are becoming evident and these are due to -N since seedlings in the —Ca solution grew as well or better than in complete solution. Photo 1960 . . . . . . . . . . . 122 3. —Pk (September 9) The first leaves have died and the young leaves show a bronzing along the margins. Photo 1960 . . . . 124 —PCa (September 9) The bronze color is due to —P since -Ca has little effect on leaf color. Photo 1960 . . . . . . . . . 124 —KCa (September 9) Typical potassium de— ficiency symptom but no effect from —Ca. Photo 1960 . . . . . . . . . . . . 124 Root development of seedlings after one grow- ing season in a clay—loam soil (Belfontaine B)- a c o u o c a u» s u o o a 132 Root development of seedlings after one grow- ing season in a sandy—loam soil (Conover A) . 132 Root development of seedlings after one grow— ing season in a sandy— soil (Spinks B) . . 134 ndix LIST OF APPENDICES Plant Tissue Analyses Procedures Fertilizer Experiment. Growth Experiment Nutrient Deficiency Experiment. XV Page 159 162 163 168 CHAPTER I INTRODUCTION Inorganic nutrition of forest tree species in the States has reached a level of practical importance nitant with the advent of the intensification of practices which evolved during the past decade or This is a result of the recognition by foresters oils may not have a sufficient supply of some of the ial inorganic nutrients to meet the tree's require— for satisfactory growth and development. Foresters cognize that application of inorganic fertilizers to nutrient deficiencies in plantations is a practical 1 practice. It is now commonplace to fertilize hard- antations. In the West a large timber company re— fertilized thousands of acres of coniferous plan— ; and in the South, pulp companies are fertilizing Europeans have reages of planted cottonwood. Efficient d forest fertilization for many decades. ctive fertilization of hardwood plantations is 1y important, since many hardwood species are in pply. They often are planted on sites which may kedly in their capacity to supply all the essential l Ients in amounts required for the fastest growth and Ilopment. The major problem of efficient and effective ferti- ,tion is the determination of the kind and amount of ilizers to apply to achieve the maximum growth response a particular species on a specific site. This entails iled knowledge of the tree's ability to absorb and ize nutrients from the soil. Field fertilizer studies acted on an emperical basis have yielded very little rmation on the nutrient requirements of forest tree Les. Soil factors that affect the growth and development ’ees exert their influence through interactions with other and with the tree. Therefore, it is extremely cult, if not impossible, to isolate the independent t of a single soil factor on the growth of a tree. liS reason, field fertilization trials have yielded a fundamental information on the nutrient requirements 'est tree species. It is important, however, to know dependent effect of single soil factors before inter— effects can be clearly understood. In approach to the solution of the nutrition problem :row seedlings under uniform environmental conditions. dlings are grown on chemically inert quartz sand. t solutions are prepared, using distilled water, itain all the essential elements at fixed, non— ; concentrations except the concentration of the ant under study. The concentration of the element . study is varied from deficiency levels to concen— .ons beyond the optimum level where growth is depressed. these data it is possible to describe the mathematical ionship between yield and the concentration of the d element. This relationship cannot be used directly for inter— ng the nutrient status of field—grown seedlings or because the concentration of available soil nutrients : be determined directly. Available soil nutrient concentrations can be esti— by analyzing the leaves of soil—grown seedlings. results can then be compared to foliar nutrient con— tions obtained from the controlled experiments. The ve quantitative availabilities can then be employed dict the probable growth response to fertilization. [n 1959 and 1960, investigations were started to :he nitrogen, phosphorus, potassium, and calcium .on of yellow-poplar seedlings. Specifically, the were designed to: (1) determine the relationship yield and nutrient concentration; (2) determine ationship between nutrient concentration and foliar 3 concentration; (3) induce nutrient deficiency I at low nutrient concentrations; (4) determine the ,ship between yield and fertilized representative ndy—loam, and clay—loam soils; and (5) determine at of mycorrhizae on yield and nutrient uptake. Yellow-poplar was selected for study because it is mportant timber species distributed over a large geo— hical area, and is one of the most widely planted tree ies. The wood is in demand for furniture, doors, ow sashes, and musical instruments. The root system sually deep and profusely branched. Fertility seems a an important factor in the growth of this species, 3 classified by Mitchell and Chandler (1939) as a rogen—demanding" species. The specific nutrient re— aments of yellow—poplar have not been determined. This *mation is required for evaluating the adequacy of soil .ent availability required for satisfactory growth and opment. CHAPTER II STATEMENT AND SCOPE OF THE PROBLEM Mineral nutrition of forest tree species is receiving sed attention from foresters. In the past, their 3 were concentrated on coniferous species almost to :lusion of hardwood species. The increasing impor- >f hardwoods in the forest economy has focused at— I on the need for information that will assist land '3 to grow quality trees on the shortest rotation e. Adequate nutrition of the growing trees is a equisite for satisfactory growth and development. tudies have shown that yellow-poplar, a very im— timber species, grows best on well—drained, moist Lth a thick upper organic-enriched mineral horizon 1945). McCarthy (1933), however, states that, "the e of chemical composition of the soil on growth of oplar is apparently slight." Mitchell (1939), (1933), Finn (1953), and Finn and White (1966) hat the chemical composition of the soil has a Lgnificant effect on the growth of yellow—poplar. .low—poplar is planted on a wide variety of sites e of the most important hardwood species used in tion and afforestation. Consequently, a knowledge 5 s nutrient requirements would greatly aid the forest .nd manager in selecting sites best suited to the .ent requirements of the species. Nitrogen, phosphorus, potassium, and calcium are the Ints most likely to be deficient on sites planted with w-poplar. This study was designed to investigate the K, and Ca requirements of yellow-poplar in sand— ent culture medium and to describe induced foliar iency symptoms. It was also designed to study the t of N, P, K, and Ca fertilizers on yellow—poplar ings planted in pots containing sand, sandy-loam, and ‘loam soil. And lastly, the study included an investi— n to determine the effect of mycorrhizae on the growth llow-poplar seedlings planted in two forest soils. CHAPTER III REVIEW OF LITERATURE General Forest tree nutrition was ignored by most foresters a United States until the third decade of this cen— About this time, a small group of foresters with ng in soils and physiology initiated studies de- to increase knowledge of the nutrient needs of s species, factors that affect mineral nutrition of trees, and methods of diagnosing nutrient require- The Harvard Forest symposium on forest tree physi— .n 1957 summarized the work to that date and it was ,ed in book form by the editor, Thimann (1957). The ricultural Station (1957) sponsored a symposium n the same year which covered the important topics ral translocation in forest trees, mineral nutrient nent of forest trees, techniques and analyses of :issue, mycorrhizae and light. :her important summaries of work on mineral nutrition It trees were provided by Leyton (1958), Duke Uni— (1959) symposium and by Gessel (1962). Kozlowski (1956) edited a bibliography of forest tree ology, and White and Leaf (1956) compiled a complete bibliography with abstracts on the use of fertilizers mendments in forestry. A compilation of the general iques of using solution and sand culture methods in :ion studies was provided by Hewitt (1952). Most of the work on the mineral nutrition of forest Ipecies has been directed toward conifers and this Ias been ably documented in a voluminous literature. latively few studies that have dealt with hardwood s will be the subject of review in the following sions. Site—Fertility fertility is one of the important factors of site a it exerts a profound influence on growth and develop— However, it is only one of a host of factors. : and White (1956) have emphasized the necessity idering all site factors and to identify those dominant influence. Some factors like physiography perature cannot be manipulated; but others including soil moisture, and fertility can be changed by thinning, irrigation, or fertilization (Kramer and C1, 1960; Mitchell and Chandler, 1939; Rudolph, 'owth is a complex process that results from the .ted interaction effects of environment and genetic tial. Growth probably never reaches the maximum set a limit of genetic potential. One or more factors llways be limiting. This is so, because the numerous Indent factors would all have to be at optimum in Iation with each other, which is unlikely. For ex— using N, P, K , and Ca at five levels in all combi- 45 s, (1024) combinations would be required to ish an optimum concentration of these elements in ition. The response that can be expected when the deficiency limiting factor is corrected is given by Mitscherlich . statement, "the increase in a crop produced by a crement of a deficiency factor is proportional to rement of that factor from the maximum" (Bray,l954). whenever a factor approaches a minimum its relative becomes very great (Spurr,l964). Field Fertilization of Hardwoods .rly foresters generally emphasized the role of water growth to the almost total exclusion of nutrients as tant factor in site quality (Wilde,l958). Many s were convinced that sufficient nutrients were in all soils for satisfactory growth. This belief changed by numerous field fertilizer trials which >nstrated an increase in growth of trees following .tion. 10 In Iowa, McComb (1940) fertilized seedling black and green ash growing on an acid, infertile glacial Neither species responded much to nitrogen, but the se to phosphorus was "tremendous." Denuyl (1944) >tained a marked increase in height of black locust .ng application of a complete fertilizer (2-12—6) at ;e of one tablespoon per tree. First year response .ow—poplar seedlings on a Georgia stream bottom was .rked (McAlpine,l959). The increased height growth e of yellow—poplar to phosphorus fertilization con- through the fourth year. Yellow-poplar in south— Michigan growing on a light soil and showing nutri— iciency symptoms responded to fertilization signifi— in increased height and diameter growth. Increased rate was still evident at the last measurement which i at the end of five growing seasons (Finn and White, [ny species of hardwood trees in New York increased - growth following an application of nitrogen ferti— Mitchell and Chandler,l939). nt (1947) fertilized several species of coniferous woods. The growth of pine, spruces, and red oak ersely affected by lime, but sugar maple and white benefitted by it. Hybrid poplar growth response gen and to lime was highly significant. Chapman und a delay of one year in height growth response —poplar to nitrogen fertilizer. He also found 11 1e greatest height growth response resulted from 40 and 100 pound applications of nitrogen. Hannah Inke (1964) concluded from soil pot studies in south— liana that phosphorus may be one factor limiting of planted hardwoods on abandoned old fields. IcComb (1949) grew seedling green ash, American elm, :, and black locust in gray—brown podzolic forest ' and prairie Clarion, Tama, and O'Neill soils. as a marked differential growth response by species ilizers. Black locust did not respond to nitrogen zation, but did respond to phosphorus fertilization. C horizon soil with residual total nitrogen at 600 per acre, the response of American elm to added nitro— acre responses were small or nil. Phosphorus was 3 be consistently and significantly deficient on soil only. On O‘Neill soil, red oak showed a marked )wth response to phosphorus fertilization. Potassium deficient on O'Neill or Clarion soils. ‘d oak was the only species with ectotrophic mycor— nd was least tolerant to high soil pH. Green ash most tolerant of the four species to alkaline soil. e examples that have been cited indicate that some a deficient in one or more inorganic nutrient ele— Lative to a particular species. Ieral coverage of the practical aspects of forest ilization have been provided among others by 1959), Mayer—Krapoll (1956), and Wilde (1958, 1961). F) 12 ’lots containing a mixture of red oak and red maple artilized with rock phosphate. The results showed 'emely high correlation between rate of fertilization .iar concentration. However, the phosphorus concen— l of the maple leaves was 100 per cent greater than usphorus concentration of the red oak leaves (Mitchell :n,l935). ‘he mineral composition of leaves may be influenced cent stands (Schomaker and Rudolph,l964). An adja— xed hardwood stand contributed litter higher in ts than the litter found on an area of poor growth. rients from the contributed litter resulted in nutrient content of the leaves of yellow—poplar grow— re the litter from the adjacent stand was deposited. ier nutrient content of the yellow—poplar leaves was :ed with greater diameter and height growth (Scho— id Rudolph,l964). Black locust may favorably affect tth of associated species by increasing soil nitrogen. Ioplar, black walnut, and black cherry in mixture bk locust had higher foliar nitrogen concentrations n grown without black locust. The trees planted in with black locust also grew faster in diameter and man trees without black locust (Finn, 1953). Other Effects of Fertilization 'tilization may affect plant processes other than Increased seed production by beech and basswood 13 chieved by applying basalt or diabase rock dusts to reduced in productivity as a result of degradation 0,1956). Agricultural workers protect alfalfa against frost e by applying potassium fertilizer. Yellow—poplar s in southwestern Michigan suffered less mortality frost damage during a hard freeze in May when foliar ntrations of potassium were relatively high (White and 1964). Six coniferous species and two hardwood species in sand cultures containing no potassium and in solu— containing potassium were exposed to low temperatures. iecies except one showed more cold resistance with ‘ amounts of potassium in the nutrient solution. High .c pressure was related to the supply of large amounts Sato and Muto,l951). Jack pine seedlings grown under imum nitrogen supply of 200—250 ppm were as drought ant as seedlings growing in a soil deficient in nitro— However, increasing the supply of nitrogen above the a level resulted in lower drought resistance (Bensend, In northern Wisconsin, Kopitke (1941) grew white and 'uce, and white pine seedlings in quartz sand cultures sandy nursery soils. Application of potash ferti— promoted the accumulation of simple and invert sugar seedling tissue, increased total solid content and pressure, and lowered the freezing point of the ex— sap. These changes indicate a marked improvement 14 ability of nursery or planting stock to withstand Lnjury. .oblolly pine fertilized with nitrogen showed an in— in height and diameter growth, a decrease in wood I, decrease in proportion of summerwood, decrease in rall thickness and fiber length and no change in ridth. These changes are beneficial for some pro— .nd detrimental for others (Posey, 1965). pH and Nutrients ilde (1954) supports Aslander's (1952) contention n the presence of a sufficient supply of available ts the concentration of H ions in the soil is of nportance to the growth of plants. Examples are E acidophile plants, Tsuga, (Abies balsamea (L.) (Picea mariana (Mill.) B.S.P.), and basophile yellow—poplar, and Platanus spp., which in suitable tents grow well on alkaline (pH 7.3—8.0) and strongly i 4.6) soils respectively. Auten (1945) found no between yellow—poplar site index and pH for any within the range of conditions encountered in his study in Iowa evaluated the effect of soil acidity Lents on the growth of one—year—old black locust 1 ash. Four acidity levels were maintained: 4.3, 7.7, and three fertility treatments: no nitrogen, and potassium, nitrogen, phorphorus, and potassium. 15 . end of five months, seedlings of both species grew regardless of pH when no fertilizer was added. Both 5 showed a tremendous response to NPK fertilizer at levels and no response to nitrogen or potassium indi— that phosphorus was most limiting. Both species grew ; pH 4.3 when phosphorus was added and growth decreased 'alues increased. When phosphorus was omitted growth species increased up to pH 6.9 but decreased at pH reen ash developed almost as well at the alkaline pH ther pH levels but black locust grew poorly at pH 7.7. and Kapel (1942) interpreted the results largely in ? phosphate availability. The fact that best growth I at pH 4.3 is attributed to the relatively high base on and the apparently adequate quantities of indi- important bases. Residual Effect of Fertilizers lumber of fertilized plots in the Black Rock Forest, were resampled four to five years after fertilizer s were applied. The leaf samples were analyzed for phosphorus, or potassium. The following results rved: (1) plots fertilized with sodium nitrate— sulphate showed a significant decrease in available (2) plots fertilized with an organic fertilizer Iod) showed a significant increase in available (3) rock phosphate plots, a decrease in available 5 and (4) potassium availability increased slightly ots fertilized with potassium chloride (Finn, 1942). and Finn (1966) found the residual effect of ferti- on growth of yellow-poplar to be evident five years application. Although the effect was decreasing, it 1y would continue for an additional number of years. fect of fertilizer on growth of a mixed plantation of Id hardwoods in Belgium was still apparent forty years he fertilizer was applied (Delevoy, 1946). Soil Moisture and Nutrients >lice (1944) found little correlation between mineral by twenty tree species and precipitation as such, but uptake was correlated with ground water table. oisture withdrawal was found by Smika et al. (1961) ease at all soil depths with the addition of ammonium fertilizers to range soils. Moisture extraction was 21y correlated with fertilization rates. Early re— Idicated that fertilization stimulated root growth ture use in the subsoil. Eck and Fanning (1961) the uptake of nitrogen and phosphorus in relation to placement under different soil moisture regimes. v conditions uptake of phosphorus ceased when the ahed the vicinity of the wilting point but nitrogen >parently continued. Nitrogen absorption increased In of placement under dry conditions. On the wet hosphorus increased with depth of placement; hence, 17 increasing soil moisture. Nitrogen uptake was not ted by depth of placement under this moisture condition. Varying moisture, under laboratory conditions, from to one hundred percent of the moisture equivalent ound by Burns and Barber (1961) to have no effect on elease of non—exchangeable potassium except in one The higher the temperature the greater was the rate Iease of non—exchangeable potassium. Hacskaylo (1960) ;igated the water requirements of white pine, black :, and sweet gum. He defined water requirement as the ;e amount of water taken up by plants in any given , per gram weight of dry matter produced. He found enerally, mineral deficient trees require more water it dry weight produced that non—deficient trees. The of efficiency in water utilization was black locust, gum, and white pine. Water requirements were different ass with different nutrient deficiencies. For example, er requirements for the ”complete" series and —P, —K, 'o, and —S series were similar. The remaining series, , —Mg, —Fe, —B, ~Zn, and —Mn all had higher water ments than the other series. The water requirement ”complete" series was 368.25 ml. and 596.00 ml. for series. Light and Nutrients .e relationship between nutrient requirements and tensity of American ash was investigated by 18 bauer (1932). He concluded that if the supply of nutri- Nas sufficient to satisfy the needs of the plant, the 1m light requirement was not lowered by increasing the ant supply. However, positive growth response to in— ad concentration of nutrients could be obtained at ‘ light intensities. Interactions Among Nutrients Seedling growth of Sugi in relation to different concen— ns of potassium applied in combination with nitrogen, orus, and calcium was investigated by Furukawa (1963). rmal seedling growth he concluded that a potassium tration above 100 ppm was necessary. Nitrogen and orus uptake were depressed as the uptake of potassium seedlings increased. [ngestad's (1962) work on the nutrition of pine, spruce, éch is very complete and includes comments on ion anta— In birch, he found ion antagonism effects of NBA on I, magnesium, and potassium. He also found potassium Iistic to calcium and magnesium especially in birch. was antagonistic to magnesium in pine and spruce and gnesium to potassium and calcium. However, the vari— En the percentages of the unvaried affected elements hlly small according to Ingestad. Interactions be— he uptake of nitrogen, phosphorus, and potassium were a L gertilization study. The data indicate that an by Finn and White (1966) in a plantation yellow— l9 ase of soil nitrogen increases phosphorus uptake and a large increase in soil potassium decreases nitrogen e. A small increase in soil potassium increases nit— uptake. It was also apparent that the interaction t on growth of the nutrients applied in combination ifferent in some instances from the additive effects 9 elements applied singly. Mycorrhizae—Hardwoods Much attention has been given to the mycorrhizae re— Iship in coniferous species for the past forty years, Ie importance of this relationship in the nutrition of rous species has been demonstrated in many studies. (1936), Mitchell et a1. (1937), Kessel (1927), McComb , Rayner and Neilson-Jones (1944), Bjorkman (1942), s (1958), and many others have contributed to the know— Df the function and mechanism of mycorrhizae in the I nutrition of conifers. Almost without exception, I recognized that the mycorrhizal relationship benefits I e, and that their presence usually results in in— growth. ardwood tree species have received relatively little 1on; and consequently, the mechanism and function of Iizae in hardwood species is uncertain. The few that have been conducted on hardwood mycorrhizae the most part only preliminary. Some mention of 2O rhizae in relation to hardwoods is made by Henry (1932), gall (1914), McComb (1949), Trappe (1962), Dominik ). ‘ Clark (1964) grew yellow-poplar in pots containing ‘rom adjacent areas with different vegetative covers. ils were sterilized with methyl bromide and some were lated" with plugs of soil from a forested area. He that seedlings in the sterilized soil were consistently r than seedlings grown in the inoculated soil. Micro— sections of the roots of seedlings growing in the ited soil showed that the roots contained endotrophic Iizae, while those from the sterilized soil were non— :izal. Moose (1957) working with cuttings from apple howed cuttings infected with an endotroph were 1y larger than uninfected cuttings. a New Zealand the roots of a species of Cornaceae in- :ed by Baylis (1959) exhibited endotrophic mycorrhizae. gs with mycorrhizal roots were larger after one to *s than non—mycorrhizal seedlings grown in sterilized minik (1958) identified the type or types of mycor— ound on a number of species of hardwoods occurring e natural vegetation growing on a slag heap in and describes the anatomy of the mycorrhizae. a present state of knowledge of hardwood mycotrophy Lfficiently advanced to provide definitive answers ,portant problems, but the available evidence seems 21 indicate that endrotrophic, like ectotrophic mycorrhizae, rt a positive effect on growth and probably on nutrient ake. Evaluation of Soil Fertility . Analyses The various methods that have been used to obtain a ure of soil fertility have been summarized and described itchell (1934). Direct chemical analyses of the soil or extract, as well as indirect biological methods, have employed to obtain a measure of soil fertility. The ogical method consists of growing plants in a soil for stain period, and then using the weight of the plants or . nutrient content as an index of soil fertility. Direct chemical analyses of the soil occassionally are factory for an element; but the results for nitrogen enerally inconsistent in relation to nitrogen values termined by the biological method. However, some other tigators including Gessel (1962), Wilde and Patzer ) have attempted to use direct soil chemical analyses Iluate soil fertility. Schomaker (1964), studying r-poplar in Michigan, concluded that soil analyses .ot suitable for evaluating soil fertility. He did correlation between growth and phosphorus content subsoil, but no correlation with growth was found 11 nitrogen and potassium. Heiberg and White (1951) ad soil and foliar analyses successfully to identify 22 ;assium deficiency and to use the information in pre— ‘ing a treatment for its correction. The deficiency red in young coniferous plantations on sandy soils in ern New York. Strong correlations were found between r potassium and growth response and between soil and r content of potassium. Positive relationships between P nitrogen, soil nitrogen supply, and growth were de— ad by Mitchell and Chandler (1939) for a number of >od species in New York. The principal reasons why direct chemical analyses of 11 are generally unsatisfactory for estimating soil ity is the failure of chemical extraction methods to tely duplicate the tree's nutrient extractive mechan- and to the complexity introduced into nutrient ab- an in the presence of mycorrhizae. Soil analyses are a useful adjunct to foliar analyses armining whether deficiencies are due to a lack of :ment in the soil or to unavailability resulting from sence as an insoluble compound or in being fixed or within the space lattices of the clay crystal. Analyses iliar analyses have been used successfully by many in the field of plant nutrition. Mitchell (1936) l foliar analyses in studies on the nutritional f forest tree species. Kenworthy (1950) adapted od for diagnosing nutrient-element problems in 23 Iit trees. Goodall and Gregory (1947) reviewed the :erature on this subject and indicated the nutrient Icentrations associated with plants showing symptoms of 'iciency or excess. This method of assessing soil fertility has been adopted r the relatively simpler and more direct soil analyses hods because foliar concentrations indicate the level of ilability of soil nutrients with greater precision and iability than soil analyses do. Since nutrients in the res have been extracted from the soil by the roots, it is Lcal that no other method of extracting soil nutrients can :tly duplicate the extractive action of the roots. Also, 'ient uptake in roots is dependent on active transport, h involves an expenditure of energy by the plant as well n purely surface physical phenomenon and other physical es. Many workers have shown that the foliar concentration lements is a good indicator of the level of availability 16 elements in the soil. However, the chemical compo— >n of the leaves varies with a number of factors, in— .ng their position in the crown, physiological age of .eaves, incidence of insect or disease damage to the ‘8, species of plant, availability and concentration of lements in the soil. Leaf sampling can be standardized to hold most of factors constant. This standardization permits mean— 1 comparisons to be made of foliar nutrient concen— Dns obtained through use of foliar analyses. 24 ntially, foliar analyses are used to evaluate the level vailability and concentration of soil nutrients. This be done when leaf sampling is standardized. Foliar analyses have been used by many workers to :e abnormal leaf color to nutrient deficiencies. For >1e, Fowells and Krauss (1959) nitrogen deficiency :oms; Mitchell and Chandler (1939) phosphorus deficiency toms; Lunt (1947) calcium deficiency symptoms; Stone ) magnesium deficiency symptoms; Wallace (1961) em- d tissue analyses and color photographs to relate ab— 1 leaf color to nutrient deficiencies occurring in cultivated plants, ) including some fruit trees. Ashby described induced nutrient deficiency symptoms in >od (Tilia americana L.). Mitchell and Chanler (1939) found a high degree of .ation between the nitrogen concentration of yellow— leaves and nitrogen supply. Also, the leaves of —poplar from trees receiving high nitrogen supply econd only to basswood in nitrogen concentration. ound that an increase of 180 pounds in the nitrogen resulted in a 250 per cent increase in radial incre— 1nd that the radial increment increase was linear. >nc1uded that a further increase in nitrogen supply >robably result in still greater radial growth rates. CHAPTER IV METHODS AND PROCEDURES Sand Culture Experiments .iners and Sand A sand nutrient culture technique was employed to the effect on growth of varying the nitrogen, phospho— potassium, and calcium solution concentration. The ntration of each of the four elements was varied itely. The concentration of all other elements, ex— :he one being varied, was maintained at a fixed con— ition. The sand nutrient culture technique was used Idy the visible foliar deficiency symptoms. The Ims were induced by omitting nitrogen, phosphorus, Iium, and calcium singly and in combination from a complete nutrient solution. For the first study, allon glazed crocks were used. These contained 10 of quartz gravel (1/8”—1/4") and 35 pounds of Ottawa silica sand. A one—inch glass tube extended from the the gravel through the fine sand to one—inch above 1d in the crock. A one—gallon glass amber jug was :ed by a rubber tube to the crock at a drain hole >ove the bottom of the crock. Solution was applied 25 26 the crooks by pouring the jug solution into the glass es. After pouring, a pinch clamp on the rubber hose released and the solution was allowed to drain back 3 the jug. The same procedure was used in the deficiency eriment, except that three—gallon crocks were used con— iing 7.5 pounds of quartz gravel and 26.25 pounds of Iwa white silica sand. :ure Solution The basic nutrient solution in the growth study con— ed of the following elements with the concentration essed as parts per million: nitrogen 300, phosphorus potassium 319, calcium 364, sulfur 232, iron 3.4, esium 176, boron 0.5, manganese 0.5. Nitrogen, phospho— potassium, and calcium concentrations were varied ly in separate studies. Six liters of the appropriate :ion were added to each pot to saturate the sand, after 1 the pinch clamp was released allowing the solution to 1 into the reservoir jug. After complete drainage, the ;ion level in the reservoir jug was permanently marked line. To replace water lost by evapo—transpiration, lled water was added to bring the level of the solution 9 line on the jug. This procedure maintained the concen— on at a constant strength. Solutions in the growth study changed twice during the course of the investigation to ce nutrients absorbed by the seedlings. 27 Figure 1.——General view of the fertilizer and sand nutrient culture experiments (August 5, 1960). Figure 2.——The arrangement of pots and nutrient reservoir glass jugs used in the sand—culture nutrient studies. Jugs are below the bench. Solutions were hand-poured through the glass tubes shown in the middle of the pots. 29 The concentrations of the nutrient solutions were dually increased over several weeks until full strength reached in order to avoid too rapid a change in concen— tion with consequent injury to the seedlings. The basic procedure of adding nutrients to pots in deficiency study was the same as that used in the growth 1y. However, only five liters of solution were applied :he deficiency study because the crooks (3 gals.) were Ller than those used in the growth study. Smaller crocks a used because they were just as suitable as the larger :ks for inducing deficiency symptoms, and required less trials and solution. The concentrations of the elements 1 in the deficiency study were as follows: nitrogen and (phorus 300 ppm, potassium and calcium 200 ppm, sulfur ppm, magnesium 176 ppm, iron 3.7 ppm, boron 0.5 ppm, anese 0.5 ppm. The concentrations stated are for the ents, not their salts. line All seedlings used in the four experiments conducted 960 were essentially the same. Seed was collected from 1d growth stand on Michigan State University's Russ st in southwestern Michigan in the fall of 1959. The was stored moist in polyethylene bags on February 1, . at 40° F. The seed was planted on April 5, in 18 I containing brick sand to a depth of 1/4— to l/2—inch, 30 1 covered with burlap and subsequently kept moist with stilled water. First germination occurred on April 25. Seedlings planted in each study were straight, approxi- ;e1y the same length, having one or two secondary leaves, . one to four lateral roots. In the growth experiment, the seedlings were planted the pots on May 18 and 19. Seedlings were planted in deficiency experiment on May 19, in the fertilizer eriment on June 9 and 10, and in the mycorrhizae experi- t on July 26. The seedlings used in the 1959 deficiency experiment a collected from the same source as those used in the J experiment, but were sowed in the fall of 1958, in Bogue Nursery. They were lifted from the nursery and Ited in the pots on July 22, 1959. At the time of plant— they were six weeks old and partially leafed out. Soil Experiments All soil used in the fertilizer and mycorrhizae experi- s was obtained from Michigan State University's experi- 11 forests. The Spinks sand and Conover sandy-loam were Irred from the Baker Woodlot near the main campus on June 1 the Bellfontaine clay—loam (B horizon) was collected the Kellogg Forest. Some chemical and physical charac— itics of these soils are shown in Appendix B. 31 These soils were chosen because yellow-poplar is idely planted on these and similar soils. The soils hosen for this experiment provide a range in texture from and to clay—loam and are expected to vary in fertility. iey were studied to learn if increasing certain soil nutri— its would stimulate growth. The response would then be sed as a measure of the adequacy of the level of the supply ‘ available nitrogen, phosphorus, potassium, and calcium. The three soils were used in the fertilizer experiment It only the Spinks sand and Conover sandy—loam were used in Ie mycorrhizae study. Each soil was thoroughly mixed before placing it in 5 container. The soil was placed in polyethylene bags d the bags were then placed in metal cans 9 l/2—inches in ameter and 12 l/2—inches tall. rtilizers Fertilizers applied in the soil experiment were reagent ade chemicals. Nitrogen was added as sodium nitrate, Dsphorus as phosphoric acid (H3POu), potassium as potassium loride (KCl), and calcium as calcium chloride (CaCl2.6H2O). a appropriate amounts were dissolved in distilled water and 3 resulting solution was added to the pots as a single )1ication. No more additions were made during the experi— m. 32 >culum and Sterilization The inoculum for the mycorrhizae experiment was col— :ted on July 25, from the soil beneath a 12- to 15—inch I yellow—poplar growing in the Baker Woodlot. The inocu— I consisted of soil collected from six sample points from upper six—inches of the A horizon. The soil from the points was composited, placed in a polyethylene bag, and t moist at room temperature. One—half of the inoculum material was steam autoclaved three hours at 15 psi and one—half of the soil was auto- ved at 11 psi for eight hours. The soil was placed in polyethylene bags which were 1 placed in #10 cans (6" dia. x 7" tall). Inoculum, either sterilized or non—sterilized, was ad to the cans designated to receive this treatment by Iving a plug of soil approximately one—inch by five-inches replacing the removed soil by a like plug of inoculum rial. Soil moisture in both the fertilizer and mycorrhizae riments was maintained approximately at field capacity dding distilled water to replace water losses. Harvesting Seedlings in the sand—nutrient culture experiment harvested at the end of the first growing season be— 1 August 29 and September 8 and seedlings from the de— ancy study between September 9 and 14. Those from the ,3 liar—3., ,1, 33 ertilizer study were harvested between October 7 and 10, nd seedlings from the mycorrhizae study between October 3 and November 1. Seedlings growing in sand culture were removed from 1e pots and carefully washed with a minimum of water to amove adhering sand particles from the roots. The same ‘ocedure was followed for seedlings growing in soil and vcorrhizae experiments. The seedlings were allowed to 'y until the rinse water had evaporated. Leaves, petioles, ems, and roots were then weighed separately to obtain ‘esh weights. Following oven-drying at 70°C for twenty— ur hours, seedling parts were reweighed and their weights corded. Chemical Analyses of Seedling Parts The oven-dried leaf parts were ground in a Wiley mill 1 stored in stoppered glass bottles. Nitrogen was determined by a modified Kjeldahl method. :assium was extracted from the ground material and the :assium percentage was determined on a Beckman Model B ectrophotometer. All other elements were analyzed spectro— Lphically. Details of the methods used are given in tendix A. «l 34 Experimental Design and Statistical Analyses The treatments in the four experiments were arranged n a randomized block design. Blocks were oriented north— :uth on the greenhouse benches, which is in the direction f the short axis of the greenhouse. Each treatment in the two sand-nutrient culture experi- ants were replicated three times, and each pot contained Lve seedlings. The three tallest were used in computing pot )tals. This was done because some seedlings were shorter Ian others, and were shaded by the faster growing seedlings. ’ the shorter seedlings had been used, nutrient effects would ve been confounded with light effects. Treatments in the fertilizer experiment were replicated ice, and in the mycorrhizal experiment three times. Four edlings were grown in each can of the fertilizer experiment, t only two seedlings were grown in each can of the mycor- izal experiment because of the smaller sized can used. All edlings in each can were used to compute the treatment mean ice the seedlings were approximately uniform and did not ertop one another. All data were initially analyzed by analysis of vari— :e if the mean treatment differences were great enough to Ltify this. The sand-nutrient growth experiment data were further lyzed be regression methods. The percentage of the ele- t in the leaves, milligrams of the element per leaf, 35 .ven-dried weight of stems, roots, and leaves and stem ength were the dependent variables and external nutrient oncentration of the varied element was the independent ariable. The model used for regression was a second order olynomial as follows: x+ax y = a + a1 2 Separate regression equations were calculated for 1ch dependent variable in each of the four varied element aries. Tests of significance were made for the slope co- ?ficients, lack of fit of the data to the curve, and cor- elation coefficients. CHAPTER V RESULTS AND DISCUSSION Sand Culture Growth Experiment trogen Series The mean oven-dried weights of stems, roots, and aves were greatest at 300 ppm solution nitrogen concen— ation. The dry weight of stems was greater than the dry ight of roots. The stem—to—root ratios were markedly fferent only at the 800 ppm level. At the 800 ppm level e ratio decreased markedly (Table l). 3LE l.-—Nitrogen series. Yellow-poplar seedling weights 3) and stem/root ratios. Nitrogen solution concentration (ppm) adling art 100 200 300 400 800 —————————————————— grams em 3.2 5 2 6.1 3.5 1.5 rt 2.2 3 5 4.4 2.1 2.2 m + Root 5.4 8 7 10.5 5.6 3.7 ves 0.61 0 66 0.72 0.69 0.55 ioles 0.05 0 09 0.07 0.10 O 04 dling 6.06 9 1M 11.29 6.39 4 29 ratio m wt. t Wt. 1.45 1.48 1.39 1.67 0.68 36 37 Fresh weights of stems and roots were also greatest , the 300 ppm nitrogen concentration. The fresh weight roots, in contrast to the dry weight of roots, was 'eater than the fresh weight of stems at all concentrations. ‘esh weight of leaves was constant between the 100 and 300 m level, but decreased at the two higher nitrogen concen— ations. In general, petiole fresh weight decreased as trogen concentration increased. Stem—to—root ratios on fresh weight basis were not markedly different over the 0—400 ppm range, but were much less at the 800 ppm level able 2). BLE 2.—-Nitrogen series. Yellow—poplar seedling weights resh) and stem/root ratios. Nitrogen solution concentration (ppm) edlin Part8 100 200 300 400 800 grams ——————————————————— am 10.2 17.3 21.3 9 4 4.9 >t 16.1 30.2 42.1 15 8 18.1 em + Root 26.3 47.5 63.4 25 2 3.0 Ives 2 9 2.9 2.9 2 5 .0 :ioles 0 35 0.39 0.33 O 31 0.29 edling 29.6 50.8 66.6 28 0 25.3 ratio m wt t Wt 0 63 O 57 O 50 0 59 0 27 The primary criterion used for evaluating the re— nse to change in nitrogen solution concentration was dry r .- 38 ight. However, other indicative measurements were also ed to aid in evaluating the growth response. It was und that branches per stem, number of leaves per seedling, d the size of leaves were also at maximum values at 300 m nitrogen (Table 3, see page 39). The percent moisture of the stems and roots on an en-dried basis was greatest at a solution nitrogen concen— ation of 300 ppm (Table 4). BLE 4.—-Nitrogen series. Moisture percentages of yellow— plar stems, roots, and leaves. nghggzgion Stem Roots Leaves ppm ------- percent (ODW basis) ————————— 100 219 632 375 200 233 763 339 300 249 857 303 400 168 652 262 800 227 723 264 Root moisture percentages increased as nitrogen con— Itration increased from 100 to 300 ppm. Leaf moisture 'centages generally decreased as the solution nitrogen .centration increased. Roots had the highest moisture percentages, followed decreasing order by leaves and stems. Length of roots petioles were not much affected by changes in nitrogen .wogoCH CH woman one no numsoa nopsoo one Sena: pmoowz no nonconm* w.mm Hm.o w.mH H.N m.w w.m m.m oow w.m: mm.o :.mH H.NH m.w m.: m.n oo: m.m: nm.o H.mm m.wH m.oH m.w 0.0 com NH H.o: :N.o 0.2m m.>fi H.m w.m H.m oow m.mm wm.o m.ma m.m w.m m.: m.» ooa *xoosfl ES III wcwaooom and Lopez: IIII gonads SE Egg mo>moq wmoQROHSB onsmeEH mazes: mmoq + casmeEH chops: Eopm .q.w SOHpMLQCoosoo Mo mem ensue: wasps: nod swam soapzaom _ monosmhm Sopm sowOLsz mo>moq .mo>moH mo hopes: one onwm «whopoEmHU Ewen anQoQIBOHHoM .mownom Gomonpwzll.m mqmmmH mmmsxOng casemeeH Empm .H.O COHpmnpdmquO essed: mama + magpmssH mazes: mom .OHO COHpsHom go mNHm mazes: chaps: monodmsm smpm mssondmogm mm>mmH .mm>mmH no senses Ode mNHw emsmpmsmHO scum anQOQISOHHmw .mmH msnosgmosmll.mH mqmmmH mchXOHne oMSpOEEH . . mnznmz noon + onzmeEH onsnmz Ewwm .MHO QOHWMMpMmocOO no ONHm mnzpmz ensue: mm n .O .u Hom sodmnm Empm Eszmmpom mw>moH .mo>mmH no genes: Odo oNHm nonopoEmHO Eopm anOOQISOHch .OOHnmm ESHmmmponII.mH MHmmmq mmocxofige myomeEH madam: mood + mezumEEH whopmz Eopm .q.c sowpmmpsmosoo go oNHm magpmz opzpmz mom .mwo sowpsaom moaosmmm Scum Eswofimo mm>mmq .mo>me . mmfihmm ESflOHmOII . mm mgmdnb 93 TABLE 30.--Calcium series. Calcium percent and content of yellow-poplar leaves, stems, roots, and petioles. Calcium solution concentration (ppm) Seedling Part 50 100 200 400 800 Calcium percent (ODW) Leafl 0.42 0.65 1.01 1.22 1.84 Stem 0.22 0.30 0.36 0.46 0.64 Root 1 0.18 0.27 0.32 0.41 0.58 Petiole 0.23 0.26 0.23 0.40 0.48 Calcium content per seedling part (mgms) Leafl 4.2 6.0 9.9 10.6 13.6 Stem 22.0 23.1 25.9 25.3 25.6 Root 15.3 18.4 15.4 16.8 12.8 Petiole 0.3 0.4 0.3 0.5 0.3 Total calcium content (mgms) Leavesl 105 84 119 117 68 Stem 22 23 26 25 26 Root 15 18 15 17 13 Petioles 8 6 4 6 2 Seedling 150 131 164 165 109 1Only mature leaves were analyzed for calcium. The contribution of the small immature leaves are not included in the above values but their weights were small and their omission does not materially affect the relative numerical values presented. .. .. 441.5... H11+111J..“L1.Il.|. . . . . ..q 1 I . ... I. .— 94 TABLE 31.——Calcium series. Mineral percent composition and content of yellow-poplar leaves (ODW). Calcium solution concentration (Ppm) Element 50 100 200 400 800 Percent N 2.73 3.16 3.34 3.66 3.68 K 1.62 1.72 1.77 1.91 1.61 P 0.90 0.77 0.64 0.61 0.44 Ca 0.42 0.65 1.01 1.22 1.84 Mg 0.81 0.73 0.55 0.38 0.30 Parts per million Mn 40 38 39 33 42 ‘ . Fe 168 123 121 99 119 7 Cu 10 13 12 14 13 5 B 10 7 7 5 12 Zn 64 35 50 49 40 Mo 2 3 4 5 6 A1 76 65 55 45 48 g 1 Content (mgms per leaf) * N 27.3 28.4 33.4 32.9 29.4 K 16.2 15.5 17.7 17.2 12.9 P 9.0 6.9 6.4 5.5 3.5 Ca 4.2 5.8 10.1 11.0 14.7 Mg 8.1 6.6 5.5 3.4 2.4 Mn 0.040 0.034 0.039 0.030 0.034 Fe 0.168 0 111 0.121 0.089 0.095 Cu 0.010 0.012 0.012 0.013 0.010 B 0.010 0.006 0.007 0.004 0.010 Zn 0.064 0.032 0.050 0.044 0.032 Mo 0.002 0.003 0.004 0.004 0.005 A1 0.076 0.058 0.055 0.040 0.038 95 next highest amount, followed by roots and petioles. Only about 11 percent is found in the roots. Stems contain 18 percent and petioles 3 percent of the total calcium. The relationship between solution calcium concentration and the main factors considered in the calcium series are summarized in Table 32 and shown in graphic form in Figures 25 to 30. The most notable result for the calcium series is the low solution concentration of calcium required for maximum growth. The relationship between foliar calcium percent and content, stem and root weight and stem length was linear. Foliar calcium percent and content increased linearly with increasing calcium concentration but stem and root weight and stem length decreased linearly as calcium concentration decreased. It is evident from the data that the solution concentration of calcium which will produce maximum growth is relatively low and probably lies between 25 to 75 ppm solution calcium concentration. In the Figures 25 to 30, the zero concentration actually is not zero. The solution actually contained about eight parts per million of calcium introduced into the solution in the reagents and distilled water and from other sources of contamination. Stem weight at 50 parts per million calcium was 10 grams and at 800 parts per million 4 grams, which is a 250 percent decrease. An even larger difference was observed for root weights. Roots weighed 8.5 grams at 50 ppm calcium and 2.2 grams at 800 parts per million, which is a 386 percent decrease. 96 TABLE 32.--Calcium series. Correlation and regression. Foliar Foliar Stem Root Stem Ca Ca Weight Weight Length percent mgms/leaf grams grams inches Correlation coefficients Foliar Ca \ mgms +.824** Stem weight —.692** —.497 Root weight —.755** -.589* +.943** Stem-length —.682** —.556* +.934** +.883** Leaf weight —.496 +.0493 +.476 +.443 +.283 Regression equations ** Y (Foliar Ca percent) = 0.3448 + 0.1497X - 0.00357X2 ** Y (Foliar Ca mgms) = 3.5924 + 1.3247X - 0.0452x2 ** 10.0627 — 0.8154X + 0.0275X2 Y (Stem weight) *9! 8.8059 — 0.9382x + 0.0398X2 Y (Root weight) * 26.3194 — 1.8424x + 0.0682x2 Y (Stem length) 2 Y (Leaf Weight) 1016.5857 — 18.3074X + 0.101X The independent variable (X) is solution calcium con— centration in ppm. Regression coefficients are coded in units of 50 ppm. *Indicates statistical significance at the 5 percent level of probability. **Indicates statistical significance at the 1 percent level of probability. 97 .QOHpmppcmosoo soapsaom Eswoamo so pcoopoa E hmflaoe mo COHmmchwmm .pcoEHpoaxo szoum hmHQOQISOHHmeI.mm mesmHm SHOHMO AEQQV Cowpmppcmocoo Eswoamo OOO OOs OOO OOm Ooe OOm OON OOH Om fl 1 1 1 1 mZNQ **HQ me:aooooo.o I Xmoo.o + m::m.o u ‘4 1 1 [I111] w 4. 11m.o (queoaed) wnroteo JBIIOJ III) II . I. .. 40.11: ‘.l!. ll:n.|.1|.. lull . I . .-. 14. ..ll- .. 4 . .4». - . .. .. . .. 6.. il..l.ll II. E . 98 .COHQNLDE®OQOO COHPSHOW ESHO hmwfloe e0 GOMmmmhmom .pcmeflmmaxo £p30hm pmaaoq AEQQV cowpmmpcmocoo Eswofimo Hmo so pcoucoo Ezfioamo l30HH®MII.©N mgsmfim Dom CON 00m 00m 00: 00m 00m OOH cm 0 1 1 1 .1 1 1 1 _ 1 mZNQ **HQ \. NMH®HOOOO.O I Nmzmmo.o + :mmm.m H M. ‘ llm .4 IJOH ILmH llom 11mm (Jest Jed swfiw) wntoIeo Jettog 99 pgmwmz Eopm no cowmmomwom com com com .QOMQmppqoocoo QOHPSHOm Sofioamo so AQOV .pcoeflmmgxm zpzohw hwaaoglzoaamwll.wm maswfim AEQQV COprppcmocoo ESHono 00m 00: com com OOH om o 1 1 1 1 1 1 1 a 1 mZNQ **HQ AV mxwmofloooo.o n Nammfio.o I NNQ0.0H n W .l o.m 4 I.o.: 4 4 4 4 I.O.m \ \ \1 o.m 4. 4. 4.\ 3 IIO.OH 4 1 (smeafi) quteM weds 100 com poop eo sofimmogmmm .QOHpmmpcooQoo cofipsaow ESHono so AQOV pswfloz .pcoefipmaxm cpSOLw awaaoalzoaamwll.mm mmsmwm AEQQV :oflpmppcmosoo ESHono OOe OOO OOm Ooe OOm OOm OOH Om O 1 1 1 1 1 1 1 1 1 OZNQ *er mxmmmmHOOOO.O + xmeonHO.O I OmOO.O u e 4. IlO.m 4 I: 4 4 .VO.O \ 4 \ \ 4 \ 4 lo.m .1O.OH qqfitam qooH (smeafi) 101 eBMQmH Empw mo QOHmmmhmmm .QOHpmmpsooQoo cowpdaom Esflono co .pqmsfipmaxm £p30hm mmHQOQISOHHmNII.mm mpsmwm AEQQV cowpmmpcoocoo ESHOHmo OOO OS. OOO OOm OO1. OOm OOm OOH Om O 1 1 1 1 1 1 1 1 1 mZNQ :5 Im 4 mOHOSEOOOOO + xmwmmOO I eOHmOm n 1H IOH 4 O (seuour) qqfiueq megs 102 -. Ilflfl .|IIIIIIIIIIIIIIIIIIIHHIIIIIIIllllllI------Fllll‘-— .QOHuwmpcmoQoo cowpsHom Esaono so pnmwoz mmmH eo COHmmmpmmm .psoeflmmmxo cpzomw LMHQoQIBOHHoWII.om opswam AQOV AEQQV :owpmppsoocoo Esfioamo OOO OON OOO OOm Ooe OOm OOm OOH Om O mZNO man mxzozoooo.o + xfimmm.o I wam.©HOH n w .1 com 4 I.OON 4 4 4. «WI/IIII/llllllillmv VJOOO (JBSI Jed swfiw) qqfitem Jeaq ‘ 4 I. OOHH I.QQMH 103 It is clear that under the conditions of this experi- ment relatively low concentrations of calcium are adequate for maximum growth. Phosphorus and magnesium uptake were inversely re— lated to increasing solution calcium concentration (Table 31). However, the foliar percentage of phosphorus even at the high calcium levels seems adequate as Judged by the per— centage of phosphorus found in yellow—poplar growing satis— factorily under natural conditions. In the case of magnesium, no information is available from controlled experiments de— signed to indicate the growth response of yellow—poplar to different levels of magnesium concentration. However, Scho— maker and Rudolph (1964) reported a value of 0.32 percent for the magnesium concentration in yellow-poplar leaves from fast-growing trees in southwestern Michigan. Their Value is comparable to the lowest value found in this series, which was 0.30 percent foliar magnesium at 800 ppm solution calcium concentration. Thus, it seems that sufficient magnesium was available at all calcium concentrations. Deficiency Symptoms Experiment Deficiency symptoms were induced in seedlings growing in a sand-culture medium from which nitrogen, phosphorus, potassium, and calcium were omitted singly and.in all combi- nations. Seedlings grown in a solution containing a complete complement of required nutrient elements in adequate amounts were used for comparison with the deficiency grown seedlings. 104 The results of two eXperiments are reported. In one experiment, six—week—old seedlings were grown for 83 days in 1959; and in the second experiment, two-week—old seed— lings were grown for 112 days in 1960. Nutrient composition and concentration were the same for both experiments, ex- cept that in the 1960 experiment, third and fourth order combinations of the nutrient elements were not omitted from solutions. The results of the 1959 experiment are summarized in Tables 33 and 34, and the deficiency symptoms are shown in color photographs in Figures 31 to 45. The 1960 experi— mental results are given in Tables 35 and 36, and the de— ficiency-symptoms are illustrated by color photographs in Figures 46 to 57. At least three—fourths of the seedlings which were planted in 1959 survived until harvest. However, growth of seedlings in the complete solution was very slow and the stem + root oven—dry weight was only 2.1 gramsgthe total length of the seedlings was only 11.6-inches. The omission of calcium from the solution resulted in a greater dry weight, 2.8 grams, as compared to 2.1 for seedlings from the complete solution. However, the omission of any of the other elements from the solution reduced growth by at least fifty percent. In the 1960 experiment, omission of nitrogen, phospho- rus, or potassium resulted in the death of all seedlings growing in solutions from which the three elements had been 105 TABLE 33.--Surviva1, weight, and length of-six-week-old seedlings grown for 83 days in complete and nutrient deficient sand-culture solutions. Weight (OD) Length Treatment Surv1val Stem Root Stem Root Petiole percent -— grams —- ----- inches ------ Complete 100 0.5 1.6 3.7 7.9 2.4 —N 83 0.2 0.8 2.2 8.6 1.2 —P 92 0.2 0.5 2.9 7.3 1.8 —K 83 0.3 1.2 2.6 8.9 2.3 —Ca 92 0.6 2.2 4.2 9.4 1.9 —NP 92 0.1 0.4 2.5 8.0 1.0 ~NK 67 0.2 0.7 2.6 6.1 1.6 —NCa 83 0.1 0.6 2.2 7.6 1.1 -PK 83 0.1 0.3 2.2 6.1 1.6 -PCa 83 0.2 0.4 2.5 6.3 1.3 —KCa 83 0.2 0.7 2.6 7.2 1.8 —NPK 92 0.2 0.8 2.1 8.4 1.1 -PKCa 92 0.2 0.4 2.3 5.9 1.2 ~NPKCa 75 0.1 0.6 2.0 8.6 1.2 106 TABLE 34.--Stem diameter, leaf size, and number of leaves per seedling of six—week—old seedlings grown for 83 days in complete and nutrient deficient sand culture solutions. Stem Diameter Treatment . Maximum Leaves 088361886. Leaf Size Per Seedling mm index* number Complete 3.4 23.6 28 —N 1.9 7.7 21 —P 1.9 7.4 12 —K 2.6 15.2 30 —Ca 3.5 23.3 37 -NP 1.7 4.7 12 -NK 1.7 7.7 17 -NCa 1.7 3.6 24 —PK 1.6 5.1 6 ~PCa 1.8 5.5 17 —KCa 2.4 8.1 32 ~NPK 1.7 4.9 16 —PKCa 1.8 5.4 12 —NPKCa 1.6 4.3 20 *Product of widest part of blade by the length of the blade in inches. 107 Figure 31. —N leaves show typical yellowing as a result of nitrogen deficiency. The upper leaves, from seedlings growing in complete solution, are normal. Photo 10/1959 Figure 32. —K leaves on the left are beginning to show first stage of potassium deficiency along leaf mar— gins. Leaf size much reduced. The upper leaves, from seedlings grown in complete solution, are normal. Photo 10/1959 . Figure 33. —P leaves all are beginning to bronze, which begins on the margins. The upper leaves, from seedlings grown in complete solution hoto 10/1959 , are normal. P 109 Figure 34. —Ca The effect of omitting calcium from the solution had no apparent adverse effect on either leaf color or size. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 35. —NP The deficiency color symptoms are less pronounced than in either the —N or —K photos. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 36. —NK The color symptoms are intermediate betgien the color for —N and —K. The upper leaves, from see ings growing in a complete solut‘ Photo 10/1959 lon, are normal. 111 Figure 37. —NCa Little difference in color symptoms between this photo and the —N photo. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 38. —PK Here typical —K deficiency is shown by leaf on right while the leaf is beginning to show some bronzing which is typical of —P deficiency. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 .Figure 39. —PCa The deficiency color is probably assoc1ated with —P rather than with —Ca. Although color looks yellow, it is actually a metallic bronze color. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 1 color symptoms lpper leaves, ion, are normal. iciency is SW“ in to show some The upper ete solution, 113 Figure 40. —KCa Color is almost normal only size of leaf is affected. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 41. —NPK The color here is almost normal except for leaf on the left. The upper leaf, from seed— lings growing in complete solution, are normal. Photo 10/1959 Figure 42. —NPCa Here too, as more than one of the elements is omitted there is less abnormal color than when nitrogen or phosphorus are omitted singly from the solution. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 am //6 /6’1/ 6 (7 émal only size 70m seedlings L. Photo almost normal .eaf. from seed' Photo 1e than one Of .nor‘mal color tted Singly .om seedlings 13.1. photo plen- 115 Figure 43. —NKCa Only the leaf on the left shows pronounced color deficiency sumptoms. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 44. —PKCa The dominant color deficiency symptom is due to —K. The upper leaves, from seedlings growing in a complete solution, are normal. Photo 10/1959 Figure 45. —NPKCa The color of these leaves is almost normal. It is clear that low levels of the four elements do not cause marked color deficiency symptoms. It 18 only when the balance is greatly altered that the symptoms become pronounced. The upper leaves, from seed- lings growing in a complete Solut‘ 10/1959 ion, are normal. Photo :he left shows a‘upper leaves, tlon, are >r deficiency Photo 10/1959 a1. lese leave51 [615 Of the four :iency sympto ltered that thed leaves, fromsee’ re normal' Phwo 117 TABLE 35.—-Survival, weight, and length of two-week-old seedlings grown for 112 days in complete and nutrient deficient sand-culture solutions. Weight (OD) Length Stem Root' Stem Root Petiole Treatment Survival percent —- grams -— ----- inches ———————— Complete 92 3.5 2.3 16.6 8.9 3.9 -N 0 — _ _ _ _ -P O — _ _ _ - -K O _ _ _ _ _ —Ca 100 3.7 6.6 15.9 10.0 3.9 —NP 67 0.1 0.1 1 6 5 8 0 2 —NK 0 — — — — — -NCa 75 0.1 0.4 2.4 8.4 1.7 -PK 25 0.4 0.8 4.3 7.1 0.8 —PCa 25 0.1 0.2 1.3 2.3 0.4 —KCa 17 0.6 0.4 4.7 7.7 2.8 TABLE 36.—-Stem diameter, leaf size, and number of leaves and branches per seedling of two week old seedlings grown for 112 days in complete and deficient sand culture solutions. Stem Diamiter Maximum Leaves Per Bragghes Treatment 488:; 88L. Leaf Size seedling Seedling mm index* number number. Complete 5.8 34.2 12.1 4.4 —N _*x _ _ _ ‘P ‘ ‘ : _ -K _ _ 4 3 5 _Ca 6.8 40.5 150 000 -NP 0.9 l l 2 7 -NK _ _ _ -NCa 1.6 3.2 3.; 8.8 —PK 3.6 . . . -PCa 0.9 0.5 2'5 8-8 "Kca 3.2 1703 70 ' *Product of widest part of the blade by the length of the blade in inches. **Dash indicates that seedlings died before harvest. 118 Figure 46.——Complete solution (September 9). Seedlings are from 12— to 40—inches tall and leaves have normal color. Photo 1960 Figure 47. -N (July 15) All of these seedlings subsequently died. Photo 1960 Figure 48. —P (August 17) The actual color is broizg f0: mgst of the leaf with the margins a delicate pin ue o orma ion of anthoc anin. died. Photo 1960 y All seedlings ember 9) - Ind leaves se seedlings dal 001” is gins a delicate 120 Figure 49. —K (July 15) Typical potassium deficiency symptom showing disintegration of chlorophyll in inter- veinal areas. Photo 1960 Figure 50. —K (August 17) The veins remain green but interveinal areas show further breakdown of chlorophyll. All the seedlings died. Photo 1960 Figure 51. —Ca (September 9) These seedlings are as large as those growing in the complete solution and leaf color is normal. Photo 1960 deficiency inter- n green chlorophyll- .ines are 1011 and 122 Figure 52. -NP (September 9) The leaves show a combination of nitrogen and phosphorus deficiency symptoms but principally nitrogen symptoms. Photo 1960 Figure 53. -NK (September 9) Typical nitrogen deficiency. Very little potassium symptoms evident. These seedlings all died. Photo 1960 Figure 54: —NCa (September 9) The deficiency symptoms are becoming eVldent and these are due to -N since seed— lings in the —Ca solution grew as well - o n complete solution. Photo 1960 r better than 1 ‘ptoms 124 Figure 55. —Pk (September 9) The first leaves have died and the young leaves show a bronzing along the mar- gins. Photo 1960 Figure 56. —PCa (September 9) The bronze color is due to —P since -Ca has little effect on leaf color. Photo 1960 . .Figure 57. —KCa (September 9) Typical potassium def101ency symptom but no effect from -Ca. Photo 1950 126 omitted. Seedlings in the -Ca solution were heavier than the seedlings growing in the complete solution, but the in- creased growth occurred mainly in the roots. This was also true for the 1959 experiment. The omission of the second order combination of the four elements resulted in death or in greatly reduced growth of many seedlings before harvest. However, the omission of combinations of elements caused less mortality than the omission of nitrogen, phosphorus, or potassium singly. Discussion The failure of the 1959 experiment to produce marked color deficiency symptoms can be attributed to slow growth resulting mainly from two causes. One, the seedlings were in leaf when lifted for planting from the nursery and proba— bly suffered severe shock, which slowed growth. The second cause can be attributed to the high temperatures prevailing in the greenhouse during the summer of 1959. This, too, slowed growth. No cooling devices were available for re— ducing the temperature. The 1960 seedlings were very small when planted, and suffered little planting shock and also the greenhouse temperatures could be held at or below 900 F. by a water cooling device. This permitted faster growth and induced early and more severe deficiency symptoms since the limited supply of the omitted nutrient was quickly ex— hausted. 127 The omission of N, P, and K in combinations of two elements at a time rather than singly, in the 1960 experi— ment, did not cause seedling mortality but did greatly re- duce growth. This can be attributed perhaps to the fact that the omission of N, P, or K singly prevents a main metabolic pathway from operating while permitting other pathways to operate at near full capacity. The net result being that products and by—products of the operating path— ways pile up until the whole system is unbalanced and death of the seedling ensues. When two or more elements required . in relatively large quantities for the seedling to grow satisfactorily are present in very short supply, several metabolic pathways may be slowed and the products from the pathways will be greatly reduced. The seedlings will sur- vive and grow but at a much reduced rate because essential compounds can be produced even though in relatively small quantities. The —Ca solutions actually contained about seven ppm of calcium. The sources of this calcium were the reagent grade chemicals used to prepare the culture solutions and the distilled water used in the experiment. This low con— centration of calcium seems adequate under the conditions of the experiment to supply sufficient calcium to the seed— lings for satisfactory growth. 128 Fertilizer Experiment Nitrogen fertilizer depressed growth of seedlings on the sand soil (Spinks)as compared to growth of control seedlings. It slightly increased growth of seedlings on sandy-loam soil (Conover) receiving the complete fertilizer, and substantially increased growth of seedlings on the clay— loam soil (Belfontaine) receiving the 1000 pounds per acre of nitrogen fertilizer and the complete fertilizer. The increase in seedling weight was 47 and 22 percent for the 1000 pound and complete fertilizer treatments respectively. The results of all fertilizer treatments are shown in Table 37. All seedlings receiving phosphorus fertilizer treat— ments on the sand and sandy—loam soil were heavier than the control seedlings. The complete fertilizer on the clay~ loam-soil was the only effective treatment in increasing growth. Maximum increases in weight of seedlings resulting from phOSphorus fertilizer treatments were 32 percent and 20 percent for the sand, and sandy—loam soils respectively, and 25 percent for the clay-loam soil. Potassium fertilizer had little effect on weights of seedlings growing on the sand or on the sandy-loam soil. However, seedlings were 42 percent heavier on the clay—loam soil receiving 450 pounds of potassium or complete fertilizer. 129 TABLE 37.--Fertilizer experiment. Weight of stems and roots in grams and stem diameters in millimeters. 1' plant Nitrogen Fertilizer Part Mean 500 1000 1500 Complete2 Soil Z O :5 (D Sand Stem 3 Root S + R Stem dia. H~quit- llll Illl U)N mJ: Sandy loam Stem Root S + R Stem dia. JZ'N‘JO‘xH WOUND :mner uHAFJO 4:0me WWI—’0 oxxn—Im room-I: oxle-m I—Jl—‘Oow m-fl l—‘I—J Clay loam Stem Root S + R Stem dia. K»FURJO niouexn -4cnn):r FJRrflkn UHUFJO \HCJRwh tfiO‘JN £LEUJH -4xnnn» Illl uubnio UHwCDH mazxnu> \ncntwh um» 03H l P til 8011 Plant hosphorus Fer izer Mean Part None 250 500 750 Complete2 Sand Stem 0.5 0.8 0.7 0.8 —3 Root 2.7 3.3 3.0 3.5 — S + R 3.2 4.1 3.7 4.3 — 3.8 Stem dia. 3.1 4.1 3.5 3.5 - 3.6 Sandy loam Stem 1.4 1.6 1.8 1.5 1.6 Root 6.2 7.1 7.3 7.0 6.4 S +R 7.6 8.7 9.1 8.5 8.0 8.4 Stem dia. 4.7 4.6 4.9 4.5 5.5 4.8 Clay loam Stem 0.5 0.4 0.5 0.5 0.9 Root 2.1 1.6 1.7 1.9 2.5 S + R 2.6 2.0 2.2 2.4 3.4 2.5 Stem dia. 3.2 3.3 3.2 3.2 3.9 3.4 1 TABLE 37.——Continued Plant 8011 Part 130 Potassium Fertilizerl Mean Z O .‘3 (D 150 300 450 Complete2 Stem Root S + R Sand Stem dia. Sandy loam Stem Root S + R Stem dia. Clay loam Stem Root S + R Stem dia. J:\10\l—’ WWNO NONE—‘Ul NONIUJ‘: l—‘NNUl UUNI'UO tTDONH UHNRJO Hreoufi ~3Lfl0\n L:O-:Ch uuoeeo unner UMNR)O . .. . . .. . . .. . NF4OMfl muweqw Ole-tow :wm01H unoreo ~4~40\F1 LUkHU)N \HU)GNN wwmo U‘lCDO\I—‘ I Io~quno Ulo.:O\ .:~q U)N w to WNl—‘O WUUNH Jra) DOM Plant Soil Part Calcium Fertilizerl Mean None 500 1000 1500 Complete2 Stem Root S + R Sand Stem dia. Sandy loam Stem Root S + R Stem dia. Clay loam Stem Root S + R Stem dia. -D~JO\H Oiuln>c Kiow4U1 ~q0\m.t Hr0135 (wFDRDO 3 £roun+4 MFUR)O M-DCDO\ kn\UN—t m>o\L{n t\n£:H unusem 935J5JP ‘rU7£:H UJR)N(D H ' '° - ~ - .. ‘O‘EUT LUUlH.: muncnm 5°9JFJF> Uloboxw ‘04:ka m‘QL'Q“ I 5““ an» U)R)FJC WMi—‘Q ulm Mun 1Composition of complete fertilizer is: + 500 lbs. H3P04 + 300 lbs. K01 + 1000 lbs. CaC12°6H20 NaNO per 3acre. 1000 lbs. 2Pounds/acre of NaNO3, H3PO4’ KCl, and CaCl2‘6H20 respectively. 3Dash indicates that all seedlings died before harvest. 131 Generally, calcium fertilizer either depressed growth or where a stimulating effect was observed it was small. The weight of roots exceeded the weight of stems by two to five times. This was true for all fertilizer treat— ments on all soils with one lone exception. The heaviest seedlings were always found on the sandy—loam soil either in the presence or absence of fertilizers. Roots in the sand soil were very finely fibrous, less so in the sandy-loam soil, and quite coarse in the clay-loam soil (Figures 58 to 60). Foliar nitrogen, potassium, and calcium percentages generally increased as the rate of fertilizer application increased. The growth response to phosphorus fertilizer was more consistent and greater than for the other ferti— lizers. The relationship between foliar phosphorus percent and amount of applied fertilizer was erratic and differences in foliar percentages were small (Table 38). Some characteristics of the three soils are shown in Appendix B. The fertilizers applied to the three soils were avail— able to the seedlings; and this is shown by foliar analyses, which indicated increased uptake as the rate of fertilizer application increased. Foliar percent of nitrogen, potassium, and calcium increased more with increasing rate of fertilizer application on the sand soil than on either the sandy-loam or Clay—loam soils. 132 Figure 58.—-Root development of seedlings after one growing season in a clay-loam soil (Belfontaine B). Figure 59. —-Root development of seedlings after one growing season in a sandy— loam soil (Conover A). 134 Figure 60. Root development of seedlings after one growing season in a sandy soil (Spinks B). TABLE 38.—-Fertilizer experiment. leaves (ODW) in relation to fertilizer rate of application Nutrient percent of (lbs/A). Nitrogen Fertilizerl Soil 2 None 500 1000 1500 Complete Sand. 2.82 3.41 3.90 -3 2.78 Sandy loam 2.34 2.98 3.92 3.46 3.43 Clay loam 2.54 3.30 3.28 — 3.52 Phosphorus Fertilizerl Soil None 250 500 750 Complete2 Sand 0.16 0.18 0.16 0.16 —3 Sandy loam 0.14 0.16 0.15 0.17 0.20 Clay loam 0.16 0.18 0.22 0.24 0.20 Potassium Fertilizer Soil None 150 300 450 Complete2 Sand 0.49 0.78 1.01 1.36 -3 Sandy loam 0.64 0.70 0.86 0.90 1.20 Clay loam 0.68 0.72 0.72 0.94 0.96 Calcium Fertilizer1 Soil None 500 1000 1500 Complete2 Sand 1.46 1.68 2.07 2.47 —3 Sandy loam 1.72 1.73 1.78 2.01 2.05 Clay loam 1.43 1.52 1.78 2.05 1.58 I; lPounds per acre of NaNO3, H3P0u, KCl, and CaCl2-6H2O respectively. 2Composition of complete fertilizer is: NaNO3 + 500 lbs. H3 per acre. 3 1000 lbs. P04 + 300 lbs. KCl + 1000 lbs. CaC12’6H20 All seedlings died before harvest. 136 This greater increase probably results from less of these elements being involved in cation exchange. The cation exchange capacity of the sand soil is 75 percent or less than the cation exchange capacity of the other two. soils. There was no correlation between total soil nitrogen and foliar nitrogen percent. The sandy-loam soil total nit— rogen percent was 0.179. This is two to three times as great as for the other two soils. The foliar nitrogen per- cent for the sandy—loam soil was, in most cases, less than for either the sand or clay-loam soil. The lack of corre— lation between total soil nitrogen and foliar nitrogen could be expected, since a large part of the total soil nitrogen is in organic form and not available to the seedlings. The effect of the phosphorus fertilizer on the foliar phosphorus percent was small. Even on the clay—loam soil, where the relationship was strongest, the relationship be- tween foliar percent phosphorus and growthHwere not meaning— ful. Comparing the foliar analyses for the soil experiment to those obtained in the calcium series of the sand nutrient growth experiment, where growth was greatest, foliar percent nitrogen is satisfactory. However, foliar phosphorus per— cent is about one-fourth optimum, potassium about one—half optimum, and calcium is two to three times too great. It is unlikely that calcium per se is restricting growth, but rather that it is causing an imbalance between other ele— ments. This vieu.is somewhat supported when the effect of —1 137 single element application on growth is compared to the complete fertilizer effect on growth. Generally, growth associated with the complete fertilizer is greater than growth associated with single element fertilizer. It seems evident from the data for this experiment that texture is the principal factor correlated with the observed differences in growth along with other associated soil factors. Under the conditions of this experiment, of the four fertilizers applied, only phosphorus significantly increased the dry weight of the seedlings. Mycorrhizae Experiment There were no significant differences in weights or length of seedlings due to treatments. The results of this experiment are summarized in Table 39. The seedlings were grown for 56 days and then were harvested. This apparently was too short a period in which the mycorrhizal relationship could be established between the seedlings and the fungus. However, Clark (1964) grew yellow—poplar seedlings for 84 days in soil and the seedlings developed endotrophic mycorrhizae during this time. His mycorrhizal seedlings were about five times heavier than non-mycorrhizal seedlings. It is also possible that the inoculum used did not contain fungi capable of forming the mycorrhizal relationship With seedlings, although this is not very probable. 138 H.: O.H O.e O.m s.m e.m one: e.O O.m O.H m.m m.m O.e O.m ooNHHHeooo ooz AsooH sooonv :.O O.m s.m e.O e.m m.m H.O ooNHHHooom eoeocoo H.m 0.0 m.O O.O m.O _H.H :.O ooNHHHnoon ooz s.e m.e s.H O.O O.m m.O O.e ooNHHHooom Aooenv nscHom Amozocflv mecoq v.0 m.o v.0 m.o m.o m.o new: e.O 0.0 m.O m.O m.O s.O m.O eoNHHHnoon ooz AsooH soonnv m.O 0.0 m.O O.O m.O e.O H.O ooNHHHeoom ooeoeoo O.O 0.0 m.O 0.0 m.O H.H e.O OONHHHeoon ooz m.O m.O m.O s.O m.O :.H :.O ooeHHHooom Hoeenv oonom Amsmmwv osmfioz m 00 m m + m u m wE pm mpoom mEmpm mpoom mEmpm meEpmth coo: ESHSooczw ooNHHHsopm ooponooscH ooHMHSOOQH poz Hflom Hwom .mpoom one mEopm mo Someofi pew unmaos .pcoefihoaxo ommfismmoozzll.mm mqm.: ww.m mm.: mH.m OOH OH.m w>.: Hm.: mm.: :H.m Hm.: om HH.m ON.: OO.m mw.m om.: :H.m O mmflhmm ESHOHQO mmflhmm Edflmmmpom II II II OS.: mm.m OO.: OOO :H.: Om.: O>.m II II II OOP mm.: we.: we.: mm.: Hm.m m>.: OO: II II II Om.m mm.: sm.: OOm OO.: mm.: mm.: em.m se.: O:.m OON H:.: m>.: mm.m :m.: mw.: Ow.: OOH mm.: mm.: Hm.: II II II om HH.: mm.: mw.: m:.m 3:.m NO.m O mownom mnnonmmonm moflnom nomoanz mmH .noo mmH .ooon mH sHoO mmH .ooo mmH .ooem HmH sHoO Asaov . nOHpespnoonoo Ammv noHpenpnoonoo nOHInowonomm pnoannz .mnoHanom pnoflnpnn modem npzonw mo n OHpenpnconoo nOHInomonohm Nutrient deficiency experiment. 168 Composition and concen— tration of the nutrient solution used in the 1959 and 1960 study. Milligrams Concentration of nutrient elements (ppm) Source of Source Per Liter N P K Ca Complete solution NHuNO3 857 300 -— -- -_ KH2POLI 658 —_ 150 189 __ H3130“ 474 -- 150 —— .. K2CO3 19 -— .. 11 __ CaC12-2H20 737 -- -- -- 200 Total 300 300 200 200 -N solution Same as complete -NHuNO3 —P solution NHANO 857 300 -- -— -- CaCl2-2H2O 737 -- -- -' —K solution NHuNO 857 300 —- -- :: H3P043 948 —— 300 I: 200 Ca012-2H2O 737 —— -— -Ca solution Same as complete -CaCl2-2H2O -NP solution K2093 35” " " 299 200 Ca012°2H20 737 -’ " —NK solution H3POI 9“8 -- 399 :: 266 CaC12-2H2O 737 ‘— 169 Milligrams Concentration of nutrient elements (ppm) Source of Source Per Liter N p K Ca -NCa solution KH2Pou 558 -— 150 189 __ E3Pou M74 —— 150 ll :: 2CO3 l9 —— __ —NPCa solution K2003 354 —- -- 200 -- —PKCa solution NHMNO3 35“ 300 —— __ -_ -NPKCa solution In all pots Mg ppm 176 and S = 232 derived from magnesium sulfate. Iron 4 ppm from ferric citrate. 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