A STUDY OF THE COMPARATIVE MERITS OF ROCK PHOSPHATES AND SUPERPHOSPHATE ON A GRAIN CROP SEEDED TO A HAY MIXTURE ON THREE MAJOR SOIL TYPES OF THE EASTERN TOWNSHIPS OF QUEBEC, CANADA §y Basil J. Finn AN ABSTRACT Submitted to the School of Graduate Studies of Michigan State College in partial fulfillment of the requirements for the degree of * v * DOCTOR OF PHILOSOPHY Departments of Farm Crops and Soil Science Year Approved 1955 Basil J. Finn This problem was concerned primarily with the comparative evaluation of rock and superphosphate, with and without lime, on oats undersown to a mixture of timothy and alfalfa on different soil types. The data were ob­ tained from a greenhouse experiment in which two commercial forms of rock phosphate were tested against ordinary superphosphate# The two rock phosphates were Aero-phos from Florida and Reno Hyper­ phosphate from North Africa; and the three soil types, Greensboro loam, Magog stony loam and Sheldon sandy loam, are common to Richmond, Sherbrooke, £>tanstead and Compton counties of the Eastern Townships region of Quebec# Yields of oats, grain and straw were obtained and certain plant characters of the grain crop were measured during the growing period. Hay yields, on the basis of five cuts, were taken from an alfalfa-timothy mixture. After the fifth cut the roots of the alfalfa-timothy mixture were thoroughly washed, oven-dried and weighed. The data show conclusively the merits of ordinary superphosphate in increasing the yields of oat grain and straw, over Reno Hyperphosphate and Florida Aero-phos# Certain plant characters of the grain crop, such as the height of plants, the number of leaves, the degree of tillering and the earliness in heading out, showed definitely more improvement with superphosphate treat­ ment than with either of the rock phosphates, attributable to the immediate availability of the phosphorus in superphosphate* On all soil types, Reno Hyperphosphate, in increasing the oats by 55 percent for all grain yields, and by 22 per cent for all straw yields, proved significantly better than Florida Aero-phos# Basil J. Finn On all soil types, superphosphate plus lime, in increasing the grain and straw yields, proved significantly better than superphosphate alone. The addition of lime to rock phosphates failed to produce significant increases in grain and straw of yields* Rock phosphates proved definitely superior in increasing the yields of alfalfa-timothy tops and roots, when compared with ordinary superphos­ phates. The superior merits of Reno Hyperphosphate were manifested in better hay and root yields which were significant, in 33 and 44per cent, respect­ ively, of all comparisons, over those induced by Florida Aero-phos* The value of lime at the rate of one and four tons in the production of alfalfa-timothy top and root yields, crystallized in significantly higher yields from the more acid Greensboro and Sheldon soils, when superphosphated or rock phosphated. However, with the high rate of lime, these yields pro­ duced on superphosphated Magog soil, the least acid of the three types, lacked significance, and registered a significant decrease with rock phosphate treat­ ments* Further studies designed to evaluate the merits of rock phosphate-super­ phosphate combinations are recommended. The results of this study would seem to indicate that rock phosphates complemented with superphosphate may have a place in certain fertility programs in Quebec* A STUDY OF THE COMPARATIVE MERITS OF ROCK FHDSIHATES AND SUPERHIOSHIATE ON A GRAIN CROP SEEDED TO A HAY MIXTURE ON THREE MAJOR SOIL TYPES OF THE EASTERN TOWNSHIPS OF QUEBEC, CANADA By Basil J. Finn A THESIS Submitted to the School of Graduate Studies of Michigan State College in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Departments of Farm Crops and Soil Science Year 1955 ProQuest Number: 10008299 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. uest ProQuest 10008299 Published by ProQuest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code Microform Edition © ProQuest LLC. ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 TABLE OF CONTENTS ACKNOWLED GMENTS LIST OF TABLES LIST OF FIGURES I. II. III. INTRODUCTION REVIEW OF LITERATURE 3 A. B. C. D. 3 4 5 8 Soils and Treatments Greenhouse Procedure Root Washing Procedure Chemical Analysis Procedure 10 10 11 14= 15 16 A. ®. 16 F. Influence of Phosphates on Oat Yields Influence of Phosphates on Various Growth Characters of Oats Influence of Phosphates on Alfalfa-Timothy Hay Yields Influence of Phosphates on Alfa Ifa-Timothy Root Yields Influence of Phosphates on the Ground Cover of an Alfalfa-Timothy Hay Mixture Chemical and Physical Composition of Soils DISCUSSION A. B. C. VI. METHODS RESULTS C. D. E. V. General Review Effect of Phosphate Fertilizer on Soil Reaction Effect of Lime on Phosphate Availability Effect of Organic Matter on Phosphate Availability MATERIAIS AND A. B. 0. D. IV. Page 1 Influence of Phosphates on Oat Yields and Plant Growth Characters of Oats Influence of Phosphates on Alfalfa-Timothy Hay and Root Yields Fertility of the Soils SUMMARY AND C0NCHJSI0I& BIBLIOGRAPHY 17 19 20 22 23 24 24 26 27 56 58 LIST OF TABLES Page 28 1. Fertilizer Treatments 2. Yields of Oat Grain as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 29 Yields of Oat Straw as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 30 Total Yields of Alfalfa-Timothy Hay from Five Cuttings as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 31 Yields of Alfalfa-Timothy Hay by Cuts as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 32 Root Weights of Alfalfa-Timothy Plants after Five Cuts as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 33 3. 4. 5. 6. 7. percentage Increase or Decrease in Ground Cover over Check Treatment of Timothy and Alfalfa as Influenced by Super­ phosphate and Rock Phosphates with and without Lime on Different Soil Types 34 Botanical Composition of Herbage in Hay Mixture as Influ­ enced by Superphosphate and Rock Phosphates with and with­ out Lime on Greensboro Loam 35 Botanical Composition of Herbage in Hay Mixture as Influ­ enced by Superphosphate and Rock Phosphates with and with­ out Lime on Magog Stony Loam 36 Botanical Composition of Herbage in Hay Mixture as Influ­ enced by Superphosphate and Rock Phosphates with and with­ out Lime on Sheldon Sandy Loam 37 11. Chemical Analysis of Rock Phosphates (per cent) 38 12. Chemical and Physical Composition of Soils 39 13. Influence of Treatments on Soil Reaction as Estimated after the Removal of One Crop of Oats and Five Cuts of Hay 40 8. 9. 10. LIST OF FIGURES I. II. m . IV. ¥. VI. VII. VIII. IX. X. XI. XII. XIII. XIV. The Response of Oats to Superphosphate Page 2 The Influence of Phosphate Carriers on the Height of Oats after Sixty Days* Growth on Sheldon Soil 41 The Influence of Superphosphate with and without Lime on the Height of Oats after Sixty Days* Growth on Sheldon Soil 42 The Influence of Hyperphosphate with and without Lime on the Height of Oats after Sixty Days' Growth on Sheldon Soil 42 The Tray Used for Washing Roots 42 The Influence of Phosphate Carriers with Four Tons of Lime on the Maturity of Oats on Greensboro Loam 43 The Influence of Lime Treatments on Superphosphate on the Maturity of Oats on Sheldon Soil 43 The Influence of Lime Treatments on Aero-phos Prior to the First Cut of Hay on Magog Soil 44 The Influence of Lime Treatments on Superphosphate prior to the First Cut of Hay on Greensboro Soil 44 The Root Growth of Alfalfa after Five Cuts of Hay as Influenced by Phosphate Carriers on Magog Soil 45 The Root Growth of Alfalfa after Five Guts of Hay as Influenced by Lime Treatments on Hyperphosphate on Magog Soil 45 The Root Growth of Alfalfa after Five Cuts of Hay as Influenced by Lime Treatments on Aero-phos on Magog Soil 46 The Root Growth of Alfalfa after Five Cuts of Hay as Influenced by Phosphate Carriers on Sheldon Soil 46 The Root Growth of Alfalfa after Five Cuts of Hay as Influenced by Superphosphate on Greensboro, Magog and Sheldon Soils 47 X¥. 3OTI. Xfll. XVIII. XIX. XX. XXI. XXII. Yields of Oat Grain and Straw as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types Page 48 The Height of Oat Plants after Thirty and Sixty Days* Growth as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 49 The Number of Oat Leaves after Thirty and Sixty Days' Growth as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 50 The Tillering of Oats after Thirty and Sixty Days' Growth as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types The Heading Out of Oats as Influenced by Superphos­ phate and Rock Phosphates with and without Lime on Different Soil Types 51 52 The Height of Oat Plants at Harvest Time as influ­ enced by Superphosphate and Rock Phosphates with and without Lime on Different Soil T y p e s 53 Total Yield of Alfalfa-Timothy Hay from Five Guts as Influenced by Superphosphate and Rock Phosphates with and without Lime on Different Soil Types 54 Root Weights of Alfalfa-Timothy Plants after Five Cuts of Hay as Influenced by Superphosphate and Rock Phosphates on Different Soil Types 55 ACOTCflSnmGffillENTS The writer recognizes the interest and helpful suggestions offered by Dr. C. M. Harrison, Professor of Farm Crops, Dr. R. L. Cook, Head of the Department of Soil Science, and Dr. K. Lawton, Professor of Soil Science of Michigan State College, during the progress of this work. Financial assistance Government of Canada dertaken. Dr. E. S. Farm System, and Dr. Husbandry, Soils and gave their help. and facilities were provided by the Federal without which this work could not have been un­ Hopkins, Director of the Canadian Experimental P. 0. Ripley, Chief of the Division of Field Agricultural Engineering of Canada, generously The Research Council of the Province of Quebec provided grants-in-aid, and Mr# J. A. Ste. Marie, formerly Superintendent of the Agriculture Experimental Station at Lennoxvilie, Quebec, and Dr. H. Berard, Director of the Dairy School at St. Hyacinth, Quebec, both members of the Quebec Research Council, gave valuable help and counsel. The author appreciates the unstinted technical assistance and trust­ worthiness of Mr. S. A. Pleszczynski of the Agriculture Experimental Station at Lennoxville, Quebec. INTRODUCTION The marked increase in phosphate fertilizer use in Eastern Canada has emphasized the need of more quantitative and precise information on the phosphorus needs of different soils and the factors affecting the efficient use of different phosphate fertilizers. Because of the extensive acreage of phosphate deficient soils, the question arises whether there could be an economically justifiable place for rock phosphate in the soil fertility programs of Quebec and Eastern Canada. In general, crops on the main soil types of the area show a very pronounced response to phosphate fertilization as compared with application of nitrogen and potassium. Grain, legume hay and pasture crops respond markedly to phosphate fertilizers. Recent figures show that hay is the predominant crop in the area due to its importance in dairy and livestock farming, which is the chief agricultural occupation of the Eastern Town­ ships of Quebec. The comparison of phosphate carriers on the establish­ ment and maintenance of alfalfa is of particular interest. As yet it has been impossible to maintain alfalfa stands for more than a year or two but still, every spring, throughout the Eastern Townships of Quebec, thousands of pounds of alfalfa are seeded in ordinary hay mixtures with practically no returns whatsoever. There have been relatively few publications on the study of phos­ phate carriers during the past fifteen years. Much of the old data on the comparison of superphosphate and rock phosphates are conflicting and quite z inconclusive. More basic information is needed concerning the effect of soils, crops and climatic conditions on the comparative value of different phosphates. Soil phosphorus problems vary so much in different regions and under different soil, climatic and crop conditions, that generalizations on re­ search needs for a country as a whole have only limited value. Far this reason only one phase of the problem was studied specifically for a limited number of crops and on only a few of the major soil types of the area. This problem was concerned primarily with the comparative evaluation of rock and superphosphate, with and without lime, on oats undersown to a mixture of timothy and alfalfa on different soil types. The data were ob­ tained from a greenhouse experiment in which two commercial foims of rock phosphate were tested against ordinary superphosphate. Figure 1. — The response of oats to superphosphate The soils of Central Quebec respond markedly to phosphorus. Fertility test on oats in 1954. Plots, left to right, received the following fertilizers: 4-0-12; 4-0-0; 4-24-0. 3 REVIEW OF LITERATURE General Review During the past fifteen years especially, marked advances have been made in the knowledge of phosphorus reaction in soils with the result that the literature on the subject has been very extensive. The present review of literature is limited to the more pertinent aspects of this problem. Previous investigators report no definite agreement on the merits of rock and superphosphate. When compared with superphosphate, rock phos­ phate showed up relatively well in a number of studies, Bartholomew (2), Roll and Irvin (23), Smith (34), Weeks and Miller (41), and not so well in a number of others, Erear (12), Gilbert and Pember (15), Roberts (28), Salters and Barnes (29), Wiancko et al. (43). This suggests that condi­ tions where rock phosphates can be used successfully may be somewhat more specific than for most other fertilizer materials. McKenna (21), in a recent study in South Africa, tested mixtures of superphosphate and rock phosphates against superphosphate alone. The tests were conducted on acid soils, high in aluminum and iron and under high rainfall conditions. These conditions, incidentally, are analogous to those in the Eastern Townships of Quebec. The South African worker found that a mixture of three parts of superphosphate and two parts of finely ground rock phosphate gave yields similar to those from an equal amount of superphosphate, and that mixtures showed advantages over super­ phosphate in reversion, physical conditions and ease of handling. The South African farmers are now using well over 20,000 tons of mixtures of superphosphate and rock phosphates annually. 4 It is important, in evaluating different phosphate fertilizers, to take into account both the immediate and residual effects as suggested by Frear (12), The more soluble phosphates, such as superphosphate, exert their maximum effect immediately, whereas the less soluble fertilizers, such as phosphate rock, may exert a more or less constant effect for several years or become slightly more available with time, as mentioned by Roberts (28) and other workers. Such an increase might be expected on the basis of the greater amount of phosphorus generally added in the rock, if the phosphorus shows any noticeable availability a few years after it has been added* The Effect of Phosphate Fertilizer on &oil Reaction The effect of fertilizers on the reaction of the soil has long at­ tracted the attention of many investigators• Such materials as sodium nitrate and calcium cyanamide are known to leave basic residues, while ammonium sulphate and potassium chloride have been found to leave acid residues in the soil* The results of studies on the effect of fhosphate fertilizers on the reaction of soils, however, have been quite variable* A slightly higher pH reading for the soil due to additions of superphos­ phate was reported by Harrison (17) and by Sewell and Latshaw (32). On the other hand, Skinner and Beattie (33) and Snider (35) found an increase in acidity following its use, while Hance (16) and Jensen (18) noted no change in the reaction of the soil. In some cases rock phosphate appeared to have a neutralizing effect on acid soils, S&ider (35) and Thor (38), but Brown (5) and Pierre (26) noted no such effect* 5 The claim has been mad© that rock phosphate can take the place of lime in acid soils. Rock phosphate may supply calcium as a plant nu­ trient and it may neutralize sane of the soil acidity hut, because of the difficulty of separating the nutritional effects of calcium-bearing materials frcm their neutralizing powers, investigators have been doubt­ ful of the relative importance of the two functions. Peterson et al. (24) found that a 500 pound per acre application of finely ground rock phosphate produced a slight decrease in the acidity of one particular soil but their study of several soil types showed quite a variation between soil types in the effect of different phosphate fertilizers on soil reaction. The Effect of Lime on Phosphate Availability An extensive literature review indicates that the availability of all nutrients obtained by plants from the soil is influenced to scene degree by the level of lime present. The application of lime influences the quantity of available phosphorus in soils according to many workers. This fact was borne out both by laboratory analyses and field experiments. Truog (39) stated that at pH 6.5 calcium bicarbonate becomes suffi­ ciently abundant in the soil solution to keep a considerable portion of the phosphorus in the form of calcium phosphate, which is soluble in carbonic acid and, therefore, readily available to crops. This applies to both the phosphorus naturally present in soils and that provided in the fozm of manures and fertilizers. When lime is present or added in sufficient quantity to raise the pH beyond 7.5, the influence on phosphate availability gradually bee ones 6 less favorable, but this is not serious until the pH goes beyond 8.0 and there is present 2 to 3 per cent or more of free calcium carbonate. Truog explains this by the following reactions:CaOOg ®-2p^3 " T 2HgC03 fc ^ C a g H g C P O ^ g CagCPO ^g ■+■ O gl{ W O q ) 2 The first reaction shows the action of carbonic acid on calcium carbonate and the second reaction shows the action of carbonic acid on calcium phosphate. If there is sufficient calcium carbonate present, the action of carbonic acid on it will create a soil solution saturated with calcium bicarbonate which will greatly retard, or even stop, the second reaction as it also produces calcium bicarbonate. In other words, in the face of a saturated condition, all reactions involving the forma­ tion of the product are brought to a standstill until some of the product is removed by leaching or plant feeding. This explanation is in conso­ nance with the well-known principle of chemistry usually referred to as the law of mass action. Truog (39) maintained that plants which require large amounts of calcium remove the soluble calcium salts at a rate sufficiently rapid to allow the accumulation of phosphate to continue. Therefore plants utiliz­ ing large quantities of calcium are considered to be strong feeders of rock phosphate. On the other hand, plants which are low in calcium re­ quirement quickly allow an accumulation of CafHCOgig to a point of satura­ tion, after which further solution of the phosphate is very slow. Cook (7) reported that the addition of lime to soils caused signifi­ cant increases in the amounts of readily available soil phosphates. Sewell and Latshaw (32) observed that fertilization with superphosphate 7 did not increase the percentage of phosphorus in alfalfa hut that appli­ cation of lime with superphosphate produced the opposite result. Davis and Brewer (11) pointed out that liming soils low in calcium content enabled winter legumes to utilize larger quantities of the phosphorus supplied by superphosphate. However, very little is known of the precise nature of the trans­ formation process and also of the type of phosphorus compounds that contribute towards the increased availability. Seme investigators en­ tertain the opinion that a part of the iron and aluminum phosphates becomes soluble by chemical interaction with lime while, according to others, the availability of phosphorus is due to the mineralization of organic phosphorus compounds in the soil. Since, as found by G-hani and Aleem (14), acid soils are frequently characterized by high accumulation of organic phosphorus and also by a large percentage of iron and aluminum phosphates, transformation of one or both of these types of compounds seems to be the most probable thing to happen during the process of conversion. The change in the soil re­ action brought about by lime is a fundamental factor in both these kinds of transformation. It is known that native and soluble phosphates applied as fertilizers remain more readily available when the pH of the soil is about 6.5 or higher (barring a great excess of calcium carbonate), and that rock phos­ phate is usually more effective when the soil is at least slightly acid. On the more acid soils, the phosphate rock is more soluble and is fre­ quently equal or superior to the superphosphate, according to Salter and Barnes (29) and Wiancko et al. (43). In certain cases yields are depressed 8 by lime with, rock phosphate as compared with rock phosphate alone, but in other cases yield increases have been attributable to lime and superphos­ phate. Cook (7) maintained that, although an increase in base saturation of soils lowered the immediate availability of rock phosphates to crops like corn and oats, it tended to keep the native soil phosphates and those add­ ed as soluble salts in the foim of calcium phosphate rather than as less available basic iron phosphates. It is well established that the use of excessive amounts of lime on certain soils may cause detrimental effects on plant growth, at least temporarily. Mann (20) and Pettinger, Henderson and Wingard (25) claim­ ed that these were due to a lack of soluble manganese. Karraker (19) and Pierre and Browning (27) found that liming had a delayed effect. The immediate effects of liming, particularly in excessive amounts, may be entirely different, as far as the availability of phosphate to plants is concerned, frcm the ultimate effect. Plants grown on soils, to which large amounts of liming materials have recently been added, may show symptoms of phosphate starvation and respond markedly to high phosphate fertilization. Schmehl et al. (30) expressed the opinion that the poor growth associated with acid soils was a complex function of many contributing factors. The Effect of Organic Matter on Phosphate Availability Many investigations during the last eighty years have shown that only 10 to 20 per cent of applied phosphate is utilized by crops and that the rest is fixed in a form not readily available. The process of 9 phosphate fixation has received considerable attention and many theories have been advanced in explanation. Copeland and Merkle (9 ), Gerretsen (13) and Midgley and Danklee (22) observed that organic matter increased the availability of soil phosphate and rock phosphate, when added to the soil as fertilizer. Struthers and Sieling (36) and Swenson et al_. (37) presented evidence of the pronounced effectiveness of many organic substances commonly found in soils in pre­ venting the precipitation of phosphate by iron and aluminum between pH values of 3 to 9. Dalton et al. (10) have recently attributed this effect of organic matter to the ability of certain metabolic products of microbiological decomposition to foim stable complex molecules with iron and aluminum 10 MATERXAIS AND METHODS Soils and Treatments Two commercial foims of rock phosphate were tested against ordinary superphosphate in this study. The two rock phosphates were Aerophos from Florida and Reno Hyperphosphate from North Africa. Detailed analyses of these two phosphates are given in Tables 1 and 11. The three soil types under study, namely, Greensboro loam, Magog stony loam and Sheldon sandy loam, are common to Richmond, Sherbrooke, Stanstead and Ccsnpton counties of the Eastern Townships region of Quebec. The soils of this area lie in the climatic belt which favors the develop­ ment of podsols. Greensboro loam, when cultivated, has a dark brown surface soil. This soil type is developed on glacial till which is found at an average depth of from SO to 36 inches. The smooth, rolling topography and its good physical condition make the Greensboro loam suitable for a wide variety of crops. In general the soil is well supplied with phosphorus but it is usually difficultly available. Under field conditions there is enough gravel in this soil to keep it fair3y open and ensure good drainage; yet 80 to 90 per cent of the gravel free soil is silt and sand which impart a good moisture-holding capacity, giving at the same time satisfactory internal drainage. Magog stony loam, like Greensboro loam, is developed on glacial till. When cultivated it develops a distinctly characteristic greyish white appearance on the surface, visible frcm a considerable distance. The topography varies from level to undulating. The drainage is usually very poor owing to a very stony, compact layer close to the surfaoe. The soil under the compact layer is quite friable and loose but tends to become very compact soon after cultivation and, despite its moderate fertility, has apparent physical problems. Sheldon sandy loam, according to Cann and Lajoie (6), is developed from fluvial glacial material deposited on lacustrine clay. good and the soil responds readily to fertilization. The drainage is Great care must be taken in soil management and crop planning as this soil type is easily sub­ ject to erosion even on fairly smooth topography. Greenhouse Procedure Surface soils which had been under cultivation for at least twenty years were used for the greenhouse studies. Trash and stones were removed from the soils by sifting them through a one-half inch screen after they had been dried and mixed. The soils were then transferred to one-gallon glazed pots where drainage was provided through a side opening near the bottom. The soils were measured on a volume basis, id,, est, for each soil type the weight of that volume of soil required to fill a pot was obtained, and the remainder of the pots for that soil type were filled with equivalent quantities of soil by weight. All treatments were replicated three times, and the pots within each replication were randomized. An effort was made to reduce the effects of light and temperature variations in the greenhouse by a weekly reshuffling of the cultures within each replication. rotated at weekly intervals. Entire replicates were also 12 The treatments are shown in Table 1. nitrogen and potassium re­ quirements, for all cultures, were satisfied by the application of 200 pounds of nitrate of soda (16% N) and 200 pounds of muriate of potash (50% KgO) per acre, at the beginning of the experiment. Deficiencies of nitrogen and potassium were checked periodically by means of plant tissue tests after the method of Cook (8). All cultures received minor elements in sufficient quantities to supply the Mg., Bo., Cu., Mn. and Zn. needed. The mixture of trace elements was applied to the oat seedlings shortly after the grain was up, at the following rates per acre: 125 lbs. MgS04 50 lbs. Na2B 407 . 5H20 50 lbs. MnS04 15 lbs. CuS04 15 lbs. ZnS04 The fertilizers were applied to the soil in the pots in a layer at a two-inch depth. In the case of treatments which contained lime, the lime was thoroughly mixed with the top five inches of soil before the fertilizer was added. Immediately after the addition of the fertilizers, Roxton oats were seeded at a one-inch depth, and alfalfa and timothy at a one-half inch depth. Rates of seeding were 14 seeds of oats, 50 of timothy ana 8 of inoculated alfalfa. Later the crop was thinned to 7, 15 and 4 per culture of oats, timothy and alfalfa, respectively. In the thinning operation a special effort was made to remove the entire plant. 13 All cultures were checked dally for the need of water and the plants were watered with a fine spray whenever water was required. made to maintain a night temperature of 50° E. An effort was During the winter months the length of day was increased by the use of artificial lights to simulate the normal length of day required. S’or example, oats seeded November 1 in the greenhouse received 4.7 additional hours of artificial light per day for the month of November which was comparable, on the basis of hours of sunshine, to the month of May at the Lennoxville Experimental Earm. Eor December 5.1 hours of artificial light were added to parallel the number of hours of sunshine for June, etc. Insects were controlled with Benzo- fume and Loro insecticide. Measurements of certain plant characters of the grain crop were ob­ tained during the growing period. The following plant characters were measured: (a) Height of oat plants after 30 and 60 daysT growth (b) Number of oat leaves after 30 and 60 days' growth (c) Degree of tillering in oats after 30 and 60 days' growth (d) Earliness in heading out of oats (e) Height of oats at harvest time. These measurements were calculated on the basis of the entire popula­ tion of oat plants. In the ease of measurements of the height of oat plants after 30 and 60 days' growth, 410 measurements for each soil type were required. This number was greatly increased for the measurements of the number of leaves after 30 and 60 days' growth. 14 The grain crop was harvested starting on June 9, 1953. There were slight differences in the dates of maturity on the three soil types. Both oat grain and straw were thoroughly oven dried at 212° F and weighed to the nearest tenth of a gram. Samples were left in the oven until ccm- plete dryness was assured and weighings were made immediately after re­ moval from, the oven. The alfalfa-timothy hay plants were cut when the alfalfa was 10 per cent in blocm. Five cuts were gathered between July 31, 1953, and March 17, 1954, the dates of the first and fifth cuts. The forage samples also were oven dried and weighed in the same manner as the oat grain and straw. Root Washing Procedure The following method was used for washing the roots of the alfalfatimothy plants. Right after the last cut of hay, cultures containing the samples were soaked for several hours. During the washing process the force of a coarse spray of water and some rubbing were sufficient to break up all lumps of soil. The washing was done in a low rectangular wooden box as shown in Figure VII. This box was divided into two sec­ tions with a medium-coarse screen in the partition between the two sec­ tions. The water outlet on the bottom of the small section of the box was covered by a fine screen. After a thorough soaking, the roots were first washed in the large section with a coarse spray. Washing was con­ tinued until practically all soil was removed from the first compartment, and such soil as did remain was free of root fiber. The roots and root fiber, freed in this way, collected on the screens and were transferred to fine mesh circular screens where they were cleaned again. A forceful 15 spray of water was used a second time to loosen soil particles, and then the roots were placed in a metal pan containing three or four inches of water. Here the roots were washed by gentle manipulation, and the root fiber floating on the water was removed the roots for total root weight. later added to the rest of It was frequently necessary to repeat the washing by manipulation and the collecting of the root fiber. The crowns of alfalfa and timothy plants were separated frcm the roots. Finally the samples were dried in an oven held at a temperature of 212° F for approximately five hours. As soon as the containers had eooled suf­ ficiently to permit handling, the absolute dry weight was determined to the nearest tenth of a gram. Chemical Analysis Procedure The pQ values were obtained with a Leeds and Northrup pH meter using a soil : water ratio of 1 : 2.5. Exchangeable bases (calcium, magnesium, potassium) were determined on an ammonium acetate extract as given in Chemical Methods of Soil Analysis (1). Exchangeable hydrogen was obtained by leaching the soil with ammonium acetate and then titrat­ ing the leachate to the original pH of the ammonium acetate solution a 3 determined by a glass electrode. The method used was essentially that described by Schollenberger and Simon (31). The sum of the exchangeable cations (calcium, magnesium, potassium, hydrogen) was taken as the base exchange capacity. The values reported for adsorbed phosphorus were obtained by the laboratory technique given by Bray and Kurtz (4). 15 RE3UL1S Influence of Phosphates on Oat Yields Table 2 shows the grain yields as influenced by superphosphates and rock phosphates, with and without lime, on the three soil types studied, and that the highest yields were obtained from superphosphated soils. On Greensboro loam, with a pH of 5.4, superphosphate, in increasing the grain yields, proved significantly better than Florida Aero-phos in the one and four-ton lime series, or Reno Hyperphosphate with four tons of lime. The increase in oat grain yields on Magog stony loam, with a pH of 6 .6 , was significant in favor of superphosphate over Reno Hyperphosphate with all treatments, but these yields laeked statistical significance over those ascribable to Florida Aero-phos in the no-lime cases. Hie oat grain yields produced on superphosphated Sheldon sandy loam (pH 5.1), the most acid soil, were significantly greater than those resulting from the fertilization of this soil with either of the rock phosphates. Figure XV graphically delineates consistently higher grain yields from the three superphosphated soils, than those obtained from these soils when treated with Florida Aero-phos or Reno Hyperphosphate. In most cases Reno Hyperphosphate brought about heavier grain yields than Florida Aero-phos, especially on Sheldon sandy loam. The straw yields of oats, as presented in Table 3, followed trends similar to those of the grain yields, but which were more pronounced in 17 favor of ordinary superphosphate. Superphosphate produced statistically significant increases in straw yields over rock phosphates on the three soil types under all treatments, except Greensboro loam in the one-ton lime series and Sheldon sandy loam in the no-lime series. yields are graphically presented in Figure XV. The straw It is interesting to note that lime treatments augmented the grain and the straw yields on the three soils. Figure XT' demonstrates grain and straw yields of oats as influenced by superphosphate and rock phosphates, with and without lime, on the three soil types. There was no doubt as to the superiority of super­ phosphate in increasing both oat grain and straw yields. The addition of lime to superphosphate augmented the grain and the straw yields under all treatments, on the three soil types, with only one exception, namely, a slight reduction in straw yields on Greensboro loam in the oneton lime series. The Influence of Phosphates on Various Growth Characters of Oats The growth characters of the oat plants ascribable to phosphate carriers on the three soil types have been outlined under the heading "Materials and Methods." Reference is made to Figures XV to XX inclusive for a graphic presentation of the effect of the treatments on plant characters. The height of plants, the number of leaves and the degree of tiller­ ing, as measured after 30 and 60 days' growth, emphasize the superior merits of superphosphate when compared with either of the rock phosphates, in increasing these growth characters. According to Figures XVI, XVII 18 and XVIII, liming contributed to a degree to the better utilization of superphosphate. An addition of four tons of lime to either of the rock phosphates, (treatments 9 and 10), depressed the height of plants, the number of leaves and the degree of tillering. Under each treatment the three soil types responded similarly with only slight differences in plant characters. Superphosphate with four tons of lime (treatment 8 ) increased sub­ stantially the number of leaves between the 30 and 60 day growth periods. On the other hand, rock phosphate treatments (9 and 10) caused much smaller increases in the number of leaves between the 30 and 60 day growth periods. Figures II, III and IV indicate the extent of the in­ creases in the number of leaves nud height of plants after 60 days' growth. Considerable interest was evinced in the very definite improvement in the tillering under superphosphate treatments as shown in Figure XVHI. After 60 days of growth all plants treated with superphosphate had developed tillers while the check plants treated only with (HE) had failed completely to do so. soil type.) (Compare treatments 1 and 2 for each This interesting property of phosphorus would seem to point the way to an important role for the phosphate carriers in grass­ land farming, predicated of course on their ability to induce the tillering of grasses just as much as apparently they do in the case of grain. Rock phosphates were inefficient in the production of tillering, particularly with high applications of CaCOg as indicated by treatments 9 and 10 . 19 Figure XIX shows that the early heading of oats was ref errable to superphosphate. Applications of lime with superphosphate apparently had very little influence on the early heading out of oats on Grreensboro loam and Magog stony loam. But the most acid soil type, namely, Sheldon sandy loam, seemed to profit from a four-ton application of Ca003 with superphosphate, which reduced the heading out of oats by approximately ten days. (Compare treatments 2 and 8 .) The earliness in heading out of grain is an important aspect to consider under Eastern Townships con­ ditions where an early September frost is not uncommon. The influence of treatments on the height of oat plants at harvest time is shown in Figures VI, VII and XX. Ordinary superphosphate exerted a much more pronounced influence than that of either of the rock phos­ phates on the height of oats. Under superphosphate treatments with high or low rates of lime, Greensboro and Magog soils showed slight increases in the height of oats, but on Sheldon sandy loam this increase was more pronounced* Bock phosphate applications were less influential, notably with four tons of lime. Influence of Ihosphates on Alfalfa-Timothy Hay Yields The total yields of alfalfa-timothy hay as influenced by phosphate carriers, after five cuts, are given in Table 4. Table 5 presents the yields by cuts* On Grreensboro loam, Reno Hyperphosphate and Florida Aero-phos, in in­ creasing hay yields, proved significantly better than ordinary superphosphate for all treatments. There was very little to choose between the per­ formance of the two rock phosphates on this soil type. Figure IX shows 20 a pronounced growth increase in the hay of the first cut, due to the addition of one ton of ground limestone to superphosphate* (Compare cultures 38 and 57.) Both rock phosphates on the slightly acid Magog stony loam caused significant increases over the yields induced by superphosphate with all treatments, except treatment 10* With a four-ton rate of lime, there was a statistically significant reduction in the hay yields from this soil, with the three phosphate carriers, which was even more pronounced where the rock phosphates had been applied. (See Figures VIII and XXI.) Reno Hyperphosphate with one ton of lime gave the only increase in hay yields on Sheldon sandy loam, which yields were significant over those referred to superphosphate and Aero-phos, as shown in Figure XXI. The four-ton rate of lime reduced the hay yields from all phosphated cultures, compared with the yields obtained from this soil under the one-ton treatment of lime. The yields of hay by cuts of the three soils, as presented in Table 5 , indicated that, although they differed between cuts, the trend of all phosphatic treatments remained quite similar within each cut. Influence of phosphates on Alfalfa-Timothy Root Yields Table 6 gives the weights of roots of alfalfa-timothy hay plants as influenced by superphosphate and rock phosphates, with and without lime, on the three soils. Figure XXII. The root weights are also expressed graphically in A comparison of Figures XXL and XXII shows similar trends for the yields of top and root growths of an alfalfa-timothy mixture, and that the root weights were less affected than the hay yields by applications of lime. 21 With, all treatments heavier yields of hay were obtained from Magog than from Sheldon soil; yet Magog soil gave alfalfa roots of smaller weights than Sheldon. A probable explanation of these differences may be derived from the data in Table 13 showing the pH of these two soils under different treatments. The roots from Greensboro loam treated with either of the rock phosphates increased significantly in weight over those obtained from this soil when superphosphated. On a comparative basis with Reno Hyper­ phosphate, Florida Aero-phos with one ton of lime produced significantly heavier roots and, with four tons, it promoted yields which were superior, though not statistically significant. On Magog stony loam, the least acid soil, both rock phosphates with the low rate of lime proved just about equally effective in root produc­ tion but, in the no-lime series, Florida Aero-phos registered a signifi­ cant gain over Reno Hyperphosphate. With all treatments, excepting the four-ton application of lime, both rock phosphates were superior to superphosphate. With four tons of lime, the heaviest roots were produc­ ed by Reno Hyperphosphate, superphosphate and Florida Aero-phos, in this order. Figures X, XX and XII show the response of individual alfalfa roots to phosphate carriers on Magog soil. Figure X demonstrates the more extensive root system of alfalfa on this soil type with rock phosphates as compared with superphosphate. According to Figure XI, additions of lime to Reno Hyperphosphate failed to augment the growth of alfalfa roots while, in Figure XLI, it can be noted that applications of lime to Florida Aero-phos depressed this character. 22 Alfalfa roots grown in Sheldon soil, under all treatments, fertiliz­ ed with either of the rock phosphates, showed statistical significance over those produced when superphosphate was applied. The property of rock phosphates to promote a greater root system of alfalfa on Sheldon sandy loam is demonstrated by Figure XIII. On this soil this crop gave roots whose weights were significantly in favor of Reno Hyperphosphate over Florida Aero-phos. Nodulation in all three soils appeared to be more numerous with rock phosphate than with superphosphate fertilization, but no means could be found to establish a basis for comparison. Influence of Phosphates on the Ground cover of an Alfalfa-Timothy Hay Mixture Tables 8 , 9 and 10 list in detail the ground cover of the components of a hay mixture during their period of production as influenced by the different treatments on the three soil types. The data show a gradual decrease in the ground cover of timothy and a corresponding increase in the stands of alfalfa. Estimations of ground cover were made prior to the first, third and fifth cut of hay. In general, rock phosphates when compared with superphosphate caused considerable percentage increases of alfalfa ground cover, but these increases lacked statistical significance. With one and four tons of ground limestone per acre, added to each of the phosphate carriers, the percentages of the ground cover of alfalfa on the Greensboro and Sheldon soils registered increases over those in the no­ lime series. Table 7 shows the percentage increases in ground cover over, or decreases from, the check treatment, for timothy and alfalfa plants on 23 tli© three soils. A comparison of the ability of rock phosphates with that of superphosphate to induce alfalfa ground cover points out only one instance where the rock phosphates failed to produce an increase. This exception occurred on Magog stony loam (treatment 10) which, under Florida Aero-phos treatment and with four tons of lime, had a reduced stand of only 9.4 per cent. Chemical and Physical Table Composition of Soils 12 expresses the physical and chemical analyses of Greensboro, Magog and Sheldon soils. In Table 13 are shown the initial pH of the soils, the pH values resulting from the treatments and those obtained after the fifth cut of hay, just prior to the washing of the roots. There was an increase in the pH readings of the soils in the check treatments, attributable to a slight neutralizing value ofthe water used in the greenhouse for this experiment. Although the initial pH readings of Greensboro and Sheldon soils were 5.4 and 5.1, respectively, the influence of four tons of lime leveled off the difference and brought about quite similar pH readings. Greensboro loam possessed the highest potential fertility of the three soils and had the highest values for organic matter, base exchange capacity and adsorbed phosphorus. 24 DISCUSSION The Influence of Phosphates on Oat Yields «nd Plant Growth Characters of Oats The data show conclusively the superiority of ordinary superphos­ phate in increasing the yields of oat grain and oat straw, when com­ pared with Reno Hyperphosphate and with Florida Aero-phos under the con­ ditions of the ezperiment. These findings are in agreement with those of many workers including Frear (12) and Roberts (28) who contend that a more soluble phosphate, such as superphosphate, exerts its effect sooner after fertilization than the less soluble rock phosphates. In other workers' comparative tests with superphosphate and rock phosphates the same rates of total PgOg were used, which meant that the rock phosphates provided much less available citrate soluble PgOg. Under the conditions of this experiment identical rates of PgC^were used for all phosphate carriers, calculated on a readily available citrate soluble PgOg basis. The rock phosphates held additional reserves of P 205 because of their high total PgOg, as compared with superphosphate which held all its PgOg on a readily available citrate soluble basis. The lower yields obtained for oat grain and oat straw under the rock phosphate treatments may be explained to a degree by the contentions of Cook (7) and Truog (40). These workers stated that oats, like corn and millet, is a low feeder of calcium and is capable of taking up a higher proportion of phosphorus to calcium than exists in rock phosphates. As already mentioned in the review of literature, there is a gradual accu­ mulation of calcium bicarbonate which, in excess, suppresses the 25 ^ilization of soluble phosphate. In this study the oat yield results and the trends of oat growth characters appeared consonant with this reasoning, id. est, under rock phosphates the yields and trends for oats were suppressed, as compared with the results produced by ordinary super­ phosphate. Although no review of literature was available on the in­ fluence of phosphate carriers on plant growth characters, it was only reasonable to expect a corresponding reduction in growth characters with a reduction in crop yields. The graphical presentation of oat yields and oat growth characters, as shown in Figures Xlf to XX inclusive, is in agreement with the comments by Cook (7) in his review of literature. He stated that in certain cases lime with rock phosphate depressed yields, when compared with rock phos­ phates alone, while the opposite result was obtained with lime and super­ phosphate. Figures ST to XX inclusive indicate that, in general, the yields of oat grain and straw were depressed by lime and rock phosphate applications, and that these yields were increased by lime with super­ phosphate . Truog (40) reported that when lime was present, or added, in amounts sufficient to raise the pH beyond 7.5, the influence on phosphate availability gradually became less favorable, and that this was not se­ rious until the pH went beyond 8.0. The pH values for phosphate treat­ ments applied to the three soils are given in Table 13. In several cases the pH values for treatments 8 , 9 and 10 approached or were beyond 7.5, and in the case of Magog stony loam the pH values reached approximately 8.0. This condition resulted in low yields of oat grain and oat straw on the Magog soil, especially with the rock phosphates (treatments 26 9 and 10). Treatment 8, superphosphate, was an exception and maintained, hi^i yields of grain and straw at a pH of 8.0. The pronounced increase in the tillering of oats attributable to superphosphate should be considered in the fertilization of oats for hay or pasture • It might even be applicable to grassland farming on the phosphorus deficient soils of Central Quebec when viewed in the light of its property to induce tillering. Possibly another aspect of the merits of superphosphate deserving of attention for this area where the growing season is very short, is its beneficial effects on the early heading out of grain. The Influence of Phosphates on Alfalfa-Timothy Hay and Root Yields Truog (4-0) maintained that plants which required large amounts of calcium removed the soluble calcium salts at a rate which allowed the accumulation of phosphate to continue. Crops like alfalfa, sweet clover and sugar beets, which require large amounts of calcium, are considered strong feeders on phosphorus from rock phosphate. The data in Table U and in Figure XXI, expressing total yields of alfalfa-timothy hay after five cuts, point out the same fact. Rock phosphate treatments produced higher yields of hay than superphosphate in all cases except two instances. The yields of roots, as presented in Table 6 and in Figure XXII, gave similar results, and the trends were almost identical for the hay yields except that the lime treatments were less effective. Obviously there was some overliming injury on Magog soil, as reflect­ ed in the hay yields for treatments 8, 9 and 10 and depicted graphically in Figure XXI. The lime treatments raised the pH values to approximately 27 8 *0 , indicated in Table 14. Pierre and Browning (27) observed that overliming injury occurred on alfalfa when the pH values were brought to neutrality* They found that the injury was more apparent in the early cuts of hay and that it did not persist much after the third cut of hay. In this study the observations were based on a total of five cuts of hay, and the injury could have been residual from early cuts. There were no reductions in yield due to overliming on Greensboro loam and only slight reductions on Sheldon sandy loam when both of these soils were brought to a pH of approximately 7.4. Figure VIII is a good example of overliming injury on Magog soil but Figure IX presents no depression under high rates of lime on Greensboro loam. The Fertility of the Soils Greensboro loam, Magog stony loam and Sheldon sandy loam evidenced marked variations in both the chemical and physical properties as presented in Tables 12 and 13. In general the crop yields were in direct relation to the fertility levels of the soils, the highest crop yields having been gleaned on Greensboro loam which possessed the highest organic matter, base exchange capacity and absorbed phosphorus of the three soils. The high gravel content of Magog soil retards its productivity under field conditions but this characteristic was not a limiting factor under greenhouse conditions where controlled watering was maintained. 28 TABLE 1 FERTILIZER QBEA33MTS Treatment 1 Available P 2O5 per acre per year 1 Check (UK) — 2 Superphosphate (20$ available P 205) 40 3 Reno Superphosphate (11$ available P 205) (27.5$ total P 2O5 ) 40 4 Florida Aero-phos (3.75$ available P 2O5 ) (35.0$ total ^2°5^ 40 5 Same as treatment 2 with 1 ton GaCOg 40 6 Same as treatment 3 with 1 ton CaCOg 40 7 Same as treatment 4 with 1 ton CaCOg 40 8 Same as treatment 2 with 4 tons CaCOg 40 9 Same as treatment 3 with 4 tons CaCOg 40 10 Same as treatment 4 with 4 tons CaCC^ 40 1 All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda {16$ N) and 200 lb. muriate of potash (50$ KgO). 29 TABLE 2 TJXEIDS OF 0AT GRAIN AS INFLUENCED BI SUPERPHOSPHATE AND ROCK PHOSPHATES WITH AND mTHGUT T. T W ON DUPEEtELNT SOIL TIPES (absolute dry yield in grams, average of three cultures) Soil Type Treatment1 Greensboro Loam 1 Check (NK) 2 Magog Stony Loam Sheldon Sandy Loam 9.0 4.3 7.0 No-lime series Superphosphate 12.9 10.8 12.9 3 Hyperphosphate 12.4 9.5 11.5 4 Aero-phos 10.6 9.8 10.4 5 lime series (1 ton) Superphosphat e 14.7 14.7 15.4 6 Hyperphosphat e 13.8 4.4 10.5 7 Aero-phos 11.4 6.2 9.2 8 Lime series (4 tons r Superphosphate 17.0 15.5 15.9 9 Hyperphosphate 13.8 5.2 9.9 Aero-phos 12.9 5.0 10.3 1.6 1.2 0.9 10 L.S.D. at 5# level All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16# N) and 200 lb. of muriate of potash (50# KgO). All phosphates were applied on an equivalent available basis, at seeding time, at the rate of 160 lb. P 2O5 , simulating 40 lb. per acre per year. 30 TAB US 3 YXEIDS OF OAT STRAW AS U3HBEH0ED BY SUPEE^PHOSPHATE AND ROCK PHOSPHATES TOTH AM) WITHOUT ITME ON DIFFERENT SOIL TYPES (absolute dry yield in grams, average of three cultures) Soil Type Treatment1 Greensboro Loam Magog Stony Loam Sheldon Sandy Loam 1 Check (NK) 15.3 8*2 15.3 2 No-lime series Superphosphate 22.0 18.6 19.6 3 Hyp erphosphate 17.6 15.1 17.2 4 Aero-phos 14.3 16.4 18.2 5 Lime series (1 ton) Superphosphate 19.5 21.2 22.6 6 Hyperphosphate 17.6 11.1 17.2 7 Aero-phos 16.6 10.9 15.8 8 Lime series (4 tons) Superpho sphate 26.4 25.2 21.5 9 Hyperphosphate 21.4 11.9 15.0 Aero-phos 20.0 7.8 14.0 3.3 1.6 1.5 10 L.S.D. at 5# level All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16# N) and 200 lb. of muriate of potash (50# KgO). All phosphates were applied on an equi­ valent available basis, at seeding time, at the rate of 160 lb. PgOg, simulating 40 lb. per acre per year. 31 TABLE 4 TOTAL YIEIDS OF ALFALFA-TIMOTHY HAY FROM FIVE CUTTINGS AS INFLUENCED BY SUPERPHOSPHATE AND ROCK PHOSPHATES WITH AND T73ITHOUT L T M B ON DIFFERENT SOIL TYPES (absolute dry yield in grams, average of three cultures) Soil Type rreaxme nx Greensboro .LOflm Magog Stony Loam Sheldon Sandy Loam 1 Cheek (NK) 12.4 6.5 7.3 2 No-lime series Superphosphat e 18.5 23.1 11.9 3 Hyperphosphat e 25.0 28.8 15.4 4 Aero-phos 24.5 30.0 14.5 5 Lime series (1 ton) Superphosphate 22.2 23.0 20.9 6 Hyperphosphate 32.5 34.2 26.6 7 Aero-phos 30.1 25.5 21.5 8 Lime series (4 tons) Superphosphate 29.5 20.0 20.2 9 Hyperphosphate 31.9 23.2 22.4 Aero-phos 33.6 13.9 18.5 1.8 1.5 3.9 10 L.S.D. at 5$ level 1 All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16$ N) and 200 lb. of muriate of potash (50$ K<>0 ). All phosphates were applied on an equivalent available basis, at seeding time, at the rate of 160 lb. P 2°5 » simulating 40 lb. per acre per year. n 0 • to O• in to IS * IS • rH t* • CM o>* CM CM • rH •tp * rH ^P • CM Oi * 1—1 o> • O in •H . to IS• IS t*. to to» to * CM cr> to in e*• CM CO * rH Oi• 1—I -tp • CO rH * in CT» • o> in rH rH to * rH CM. rH 0 IS . CM ■tP • to IS • IS rH ♦ rH to * CO CO CM • O in • CM CM to • O • in rH o> • rH in• W IS in to • * to m I Q 0 d to © CO d 0 t4 02 rH V jd CO © © Pi a> s 3 a, 3 44 P Jf a CM• IS CM • CO to » to . ■tp ^1 • m • CO IS to O H O to rH • CM O• to rH CM • in 0 CO • r-1 to • 1—1 CM • Pi to O 43 © ^"4 M © rH * • • ’M* • cs CO • to 0 to in * Hi rH CS • to ■p CI CD 00 00 CS 00 CM • in O• to• to IS CO* in CO • 00 <0 0- • * O 43 Pt i P 0 ft to 1 O U ■« • • in . CO • © d O P •P 0 0 44 ft rH 00 * in © 0 to rH CV2 O (D in • to P © CM• CM* d P «©H Pi a. © W 01 o £ 1 & rH Ia O S c? 00 • c*- CM 0 '&Vt 0 p rA UJ t<0 0 s m CM © P Mft © O ,44 44 Pt P. © ft © ft ft 09 O 44 ft ft cS to cO © © ■©8 ft © fH © Pi o © 44 © ft p © © 0 a 1 g o £ ft Pi © ft >» W CO o> Pi 1 5 © ft m a © 0 44 1 S 4 All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16$ N) and 200 lb. of muriate of potash (50$ KgO) . All phosphates were applied on an equivalent available basis, at seeding time, at the rate of 160 lb. P2O5 , simulating 40 lb. per acre per year. 32 33 TABLE 6 ROOT WEIGHTS OF ALFALFA-TIMOTHY PLANTS AFTER FIVE COTS AS INFLDEMIED BY SUPERPHOSPHATE AND ROCK PHOSPHATES WITH AM) WITHOUT LIME ON DIFFERENT SOIL TYPES (absolute dry yield in grams, average of three cultures) Soil Type XX Oa UUvllV Greensboro Loam Magog Stony Loam Sheldon Sandy Loam 1 Check (m) 16.5 6.1 10.6 2 No-lime series Superphosphate 19.6 15.5 IS.5 3 Hyp erphosphate 23.2 17.5 23.4 4 Aero-phos 22.6 19.4 21.4 5 time series (1 ton) Superphosphate 20.5 14.6 20.3 6 Hyperphosphate 26.5 17.5 25.4 7 Aero-phos 28.3 16.4 24.2 8 time series (4 tons) Superpho sphate 21.9 13.7 19.3 25.0 14.7 25.4 26.6 10.2 24.5 1.6 1.2 0.9 9 Hyperphosphate 10 Aero-phos L.S.D. at 5$ level All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16$ N) and 200 lb. of muriate of potash (50$ KgO). All phosphates were applied on an equi­ valent available basis, at seeding time, at the rate of 160 lb. P 2O5 , simulating 40 lb. per acre per year. 34 TABLE 7 PERCENTAGE INCREASE OR DECREASE IN GROUND COVER OVER CHECK TREATMENT OF TIMOTHY AND ALFALFA AS INFLOENCED BY SUPERPHOSPHATE AND ROCK PHOSPHATES WITH AND WITHOUT LTME ON DIFFERENT SOIL TYPES (estimation made previously to fifth cutting) Treatment Greensboro Loam Timothy Alfalfa Magog Stony Loam Timothy Alfalfa Sheldon Sandy Loam Timothy Alfalfa 2 No-lime series Superphosphate 2.3 3.7 2.7 14.4 1.0 4.6 3 Hyp erphosphat e 3.0 11.7 1.3 24.4 2.3 8.6 4 Aero-phos 0.6 13.0 - 1.0 28.0 2.0 7.0 5 Lime series (1 ton) Superphosphate 4.6 7.7 1.7 15.7 1.0 10.3 6 Hyperphosphate 6.0 33.0 3.3 41.0 7.0 27.0 7 Aero-phos 4.3 30.7 4.3 17.0 5.3 19.6 8 Lime series (4 tons) Superphosphate 1.0 23.3 0.7 13.0 2.3 10.3 9 Hyperphosphate 0.3 32.7 - 0.3 16.0 5.0 17.0 Aero-phos 0.0 37.7 - 1.0 9.4 5.6 20.6 10 1 All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16$ N) and 200 lb. of muriate of potash (50$ KgO) . All phosphates were applied on an equivalent available basis, at seeding time, at the rate of 160 lb. P 2O5 , simulating 40 lb. per acre per year. © to < + H 02* o O to* CO• CO 0 rH to to* to CO H« tO 0 0 tn in n Q to n to to 0 to O 0 02 O iH 1—1 (H 1 — 1 rH o• to• O• ^• 00 D- tO tO tO tO <0 04 04 rH «H O O CO rH 1—1 GO in rH to s' co tO tO tO 04 02 8 to to to rH CM* CO 02* ■H rH rH rH to tO O tO 1—1 02* HI 02 rH rH 1— 1 r—1 tO O to to O rH 02* rH rH 1—1 rH rH tO O O 0 CO in in to rH 02 02 CO to 0 CO to 02 IN tO 02 o to o o to hi L mD I —I rH 02 02 02 8 to to tji P in I i ra © o p >* u 3 o -H Pi PH O tQ O (O O tO go a» to go to 0 0 EH © © Pi X p p © <§ <—I © q-i O © t£ © S © p 5 4 Pi § Pi >> .© p 1 EH to in CO Eh 3 8 in to s in to d o O • r H GO 04 * to tO O IN tO H* CO iH rH 1—I 0 to o 01 to go 00 IN to tn s’a 8 8 to to to • • • IN • * * • • to CO GO C» n o Q oo rH 02 02 rH in 00 4 01 Or Pi d? {§* r©H in p © Q CO All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16% N) and 200 lb. of muriate of potash (50% KgQ). 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i—1P ft o P ©4 © 38 TABLE 11 CHEMICAL ANALYSIS OF ROCK PHOSPHATES (PER CENT) Composition Moisture and organic matter Florida Aero-phos^ Reno Hyperphosphate2 4.64 4.93 35.05 27.50 Iron oxide (FegOg) 0.81 0.70 Aluminum oxide (AlgOg) 1.05 1.25 Fluorine (F) 3.66 2.56 Eq.. to Calcium Fluoride (CaFg) 7.52 5.25 Phosphoric acid 1 Florida Aero-phos had a degree of fine­ ness allowing 50 to 85 per cent to pass through a 200-mesh TJ. S. standard screen. 2 Reno Hyperphosphate had a degree of fine­ ness such that 90 per cent passed through a 300-mesh French standard screen. The 300-mesh French standard screen has an aperture of 0.05 mm. comparing closely with the aperture of the 270-mesh U. S. standard screen of 0.053 mm. 39 TABLE 12 CHEMICAL AND PHYSICAL COMPOSITION OF SOI IS Analysis Chemical analysis Soil pH Organic matter {per cent) Greensboro Loam Soil Type Magog Stony Loam Sheldon Sandy Loam 5.4 4.9 6.6 2.4 5.1 4.3 6.54 0.41 0.42 5.95 5.55 4.17 0.11 0.95 0.75 0.07 0.08 7.44 Base exchange capacity m.e./lOO gm. 11.52 8.58 8.34 Adsorbed phosphorus (P) p.p.m. 46.1 3.3 3.0 8.0 40.0 47.0 12.5 23.0 45.2 36.8 18.0 0.0 58.6 30.6 10.8 Exchangeable cations m.e./lOO gm Calcium Magnesium Potassium Hydrogen Physical analysis (per cent) Gravel < 1 mm. Sand 1 - .05 mm. Silt .05 - .005 mm. Clay >.005 mm. 40 TABLE 13 THE INFLUENCE OEF TREATMENTS ON SOIL REACTION AS ESTIMATED AFTER THE REMOVAL OF ONE CROP OF OATS AND FIVE CUTS OF HAT Treatment** Greensboro Loam Soil Type Magog Stony Loam Sheldon Sandy Loam 1 Check (NK) 5.52 6.81 5.20 2 No-lime series Superphosphate 5.63 6.78 5.32 3 Hyperphosphate 5.68 6.82 5.45 4 Aero-phos 5.70 6.84 5.40 5 Lime series (1 ton) Superphosphate 6.22 7.10 6.28 6 Hyperphosphate 6.27 7.18 6.48 7 Aero-phos 6.25 7.12 6.52 8 Lime series (4 tons) Superphosphate 7.33 8.00 7.40 9 Hyperphosphate 7.52 8.13 7.51 Aero-phos 7.44 8.11 7.46 5.40 6.60 5.10 10 Soil pH before test 'All treatments received N and K, at seeding time, at the following rates per acre: 200 lb. nitrate of soda (16# N) and 200 lb. of muriate of potash (50# KgO) • All phosphates were applied on an equivalent available basis, at seeding time, at the rate of 160 lb. PgOg, simulating 40 lb. per acre per year. 41 4 0 --- ------- Figure II.-The influence of phosphate carriers on the height of oats after 60 days’ growth on Sheldon soil. Left to right: Check (NK); 153, super­ phosphate; 154, Hyperphosphate; 155, Aerophos. 40 - . ----------- Figure III.-The influence of superphosphate with and without lime on the height of oats after 60 days’ growth on Sheldon soil. Left to right: Check (HE) *, 145, super­ phosphate, no lime; 149, superphosphate, 1 ton; 153, superphosphate, 4 tons. 42 Figure IV.-The influence of Hyperphosphate with and without lime on the height of oats after 60 days' growth on Sheldon soil. Left to right: Check (NK); 146, Hyper phosphate, no lime; 150, Hyperphosphate, 1 ton; 154, Hyperphosphate, 4 tons. Figure V.-The tray used for washing roots. Inside view showing two circular sieves pnfl replaceable rectangular screen for segregation. 43 1 ton of lime; 74, superphosphate, 4 tons of lime. > d P *o4 •V p © H d © 3 Xl O p o *#s © •» © r Ca O © d a *r“{ XJ P d o *g © © p d © © o H Vi o © O >* p © -H P d © d Xi p ft © w o XI © ft XI p Vi o d o © © © d g © ■H d H rH VI 'a o © © d XI o Eh p l * H M d > o Vi © #* S •*» © "© XI ft © o xl ft • d © © o ft XI § ?■ o •* d to © to •* p lO xl to • feO g *rl .n © u © O p i—1 o © p o ft d p © o VI o X © X © 1-1 ft d d © © © d e CiJ 44 Figure VIII.-The influence of lime treatments on Aero-phos prior to the first cut of hay on Magog soil. Left to right: 10, Aero-phos with 4 tons of lime; 7, Aero-phos with 1 ton of lime; 4, Aero-phos without lime; 12, cheek (NK). Figure IX*-The influence of lime treatments on superphosphate prior to the first cut of hay on Greensboro soil. Left to right: 52, superphosphate with 4 tons of lime; 38, superphosphate with 1 ton of lime; 57, super­ phosphate without lime; 45, check (NK). Figure X.-The root growth of alfalfa after five cuts of hay, as influenced by phosphate carriers, on Magog soil. Left to right: Check (HK); superphos­ phate; Hyperphosphate; Aero-phos. Figure XI.- The root growth of alfalfa after five cuts of hay, as influenced by lime treatments on Hyperphosphate, on Magog soil. Left to right: Check (NK); Hyperphosphate, no lime; Hyperphosphate, 1 ton; Hyperphosphate, 4 tons. 46 Figure XU.-The root growth of alfalfa after five cuts of hay, as influenced by lime treatments on Aero-phos, on Magog soil. Left to right: Check (NK); Aerophos without lime; Aero-phos with 1 ton of lime; Aero-phos with 4 tons of lime. Figure XIII.-The root yields of alfalfa after five cuts of hay, as influenc­ ed by phosphate carriers on Sheldon soil. Left to right: Check (UK); superphosphate; Hyperphosphate; Aero-phos. Figure XIV.-The root growth of alfalfa after five cuts of hay, as influenced by superphosphate on Greensboro, Magog and Sheldon soils. Left to right: Check (UK) and superphos­ phate on Sheldon soil; check (KK) and superphos­ phate on Magog soil; check (UK) and superphos­ phate on Greensboro soil. _________ 031 (—1 ©.in^no «*©£ sureaS uf M 9jq.s pun CO| ^.eo jo sp^eiX ____ by superphosphate lO a 5 U Q U & 00 o •—i . d o -p 1----T 00 bo §> ZS I 00 in „■ CM ■••. - •-->.••- V"'i .-• - I (m) 3(0sqo -in •a a cd o o .O 00 d © CD '.-;.,c ■ & --- (3M) 3(09^0 CM I CM CDI in 3 4Sitep 09 P^b 02 *i©hje s©i(oni tti sq.treid q.eo j.o q.qSp©H -p a) ® Figure XVI— The height of oat plants after 30 and 60 days* growth as influenced and rock phosphates, with and without lime, on different soil types. d co M >» © 50 & d d TOffcf in WCh >> d eo d o d rH n © c§ (Stt) ^OGI© © P TO a. X0 co p< © 1 -P o ,d s J3 CM 00 CD O ft 41 © J3 • d *H & 0 o & d » ■p W (30 o w r _ TZZE (3N) 3{o©qo ■H* m % 3 a) o n o n © d © © O >> S © d m 1 1 gi hi1 S' si si 91 yi (XM) *>©^0 1jji 21 qq.M.oa:S ,sitBp 09 P**© 02 J©^J© GJnq-ino jod sgaggi quo jo Jeqnm^ Figure XVII— The number of oat leaves after 30 and GO days* growth as influenced and rock phosphates, with and without lime, on different soil types* by superphosphate 8Kv> ' . v . 1 ______ a 4 T3> © 3 3 a ■s a1 I M M g H H i wSefttq? -'V:: §> r;-;r.’* J/**'''•* ’■ ; •:.-’ ."'*H'f*', — * • -'A — :V^'^P'-'O.1.. - ■ .../.'i'i'• ^>| «*J cvl| CM ' "■ qq./inoj:9 ,siep 09 ptre 0£ .ieqj® sjeiipq. Su t /aohs ejnq.-[no Jed sqjreid jo jaqnrtift i ca +j a © -P © © £ (pH 5.1) loam sandy Sheldon Magog stony loam (pH 6.6) 1 --- a) . f , •'*> <•''•.■ ~:■“ -*•'.••■.’.I- ..- ' ‘ :'’V ’ • * ’'•'•' j . W •.•„'•i'/' ,:"''r->. V-''-..- -•••*•' f» ‘ - L (m) *00*10 © © xl ft § d fi* © ft 8 m >> ©ft •° Sf © i—I O P cO p© © X! ft "S d ft © o d e & cS © O XI to d ® o © w rH -P ft 0 xl ft 1 s © o rH ft t>» © 8 ft & o

to CO S1 3ft I © ao © u a o TO d x> © © u c!> I ■ i — vZB^ S1 S1 _ -■ _ CM _________ {m) *o©qo 8 ' 9 $ ejnqpno j©d seqotrf uf sqiiBxd q.©o jo qqST©* ©S b j q a v I © P d 1 © © XI ft (pH 5.1) sandy loam Sheldon © © CO x\ o On X » X3 rH p iiH — ----- - -------- -P — __________ --------- _ _ _ ---------r:‘;L'i.S2 VJii-;z-ks- -’- ■ I C©h — I | (m) (pH 5*4) » P loam Eh X Greensboro M _ — ___ — — - (3N) W £3 03 $ ©jnq-x^o nod a©qq.BnT /jp jo si'rej3 trx iteq iCqq.otcrxq.-TBjXT3jXT3 jo spx©TA HO _ ---------------------- — ------ ! ---------------------- ©jnq-tno J © d g w s j c S trf sqooj £qqoTn-fq.-ejT©jT© jo ^qSi©M Xjp "[eq.O£ Figure XXII— Hoot weights of alfalfa-timothy plants after 5 cuts of hay as influenced and rock phosphates, with and without lime, on different soil types. --- --------------- (Htf) *o ®*10 *3 s