THE EFFECT OF ALFALFA AND SUGAR BEET RESIDUES ON FOLLOWING CROPS by LAWRENCE J. O 1GRADY A THESIS Submitted to the School of Graduate Studies of Michigan State College of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Department of Soil Science 1947 ProQ uest Number: 10008398 All rights reserved INFO RM ATION TO ALL USERS The quality o f this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a com plete m anuscript and there are missing pages, these will be noted. Also, if m aterial had to be removed, a note will indicate the deletion. uest ProQ uest 10008398 Published by ProQ uest LLC (2016). Copyright of the Dissertation is held by the Author. All rights reserved. This w ork is protected against unauthorized copying under Title 17, United States Code M icroform Edition © ProQuest LLC. ProQ uest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 4 8 1 0 6 - 1346 ACKNOWLEDGMENTS The author wishes to express his gratitude to Brs* C* E* Millar, R. L. Gook and L* M. Turk, of the Soil Science Department of Michigan State College* Their kind suggestions and valuable criticisms in regard to the experimental work as well as the presentation of the manuscript have been most ap­ preciated* TABLE OF CONTENTS Bage INTRODUCTION ............................ 4 REVIEW OF LITERATURE Historical Survey of the Beneficial Effects of Legumes ..... .......... Sugar Beet Residues Used as Green Manure PLAN OF INVESTIGATION 6 .... ................................ 19 22 EXPERIMENTAL WORK I- 1, 2 and 5-year-old Alfalfa, Fertilized and Un­ fertilized, Turned Under at Various Growth Stages A- Greenhouse experiments ••••............... .... B- Laboratory studies 25 54 49 C- Discussion of results •••••.... II- 4, 8, 9, 11 and 14-month-old Alfalfa Fertilized and Turned Under as Green Manure A- Greenhouse experiments ........... 56 B- Laboratory studies ............... 66 C- Discussion of results........... 76 III- Sugar Beets (tops and roots) Used as Green Manure A- Greenhouse experiments B- Laboratory studies •••• ...... C- Discussion of results....... 95 Ill 122 SUMMARY AND CONCLUSIONS............................. BIBLIOGRAPHY............................................. 127 131 INTRODUCTION Historical records reveal that green manuring was practiced by the Chinese 5000 years ago. The use of alfalfa (medicago sativa) as a green manure crop has long been in vogue in most of the countries where the plant exhibits normal growth. The quality of alfalfa (medic) has been recognized by the Latin writer Columella (De Re Rustics, second book, first century A. D.) who stresses the value of the plant as cattle food as well as green manure. And throughout the centuries that followed, alfalfa has figured among the best soil-improving plants. When - according to historical records, of course - agriculture ceased to be an art and acquired the characteristics of a science, that is at the beginning of the seventeenth century, scientists became more concerned with the causes of the phenomena they observed. In the field of agriculture, the search for *causes® became more and more intense and the era of scientific experimentation was bora. Dealing with the influence of alfalfa on the following crops, various workers arrived at different conclusions according to the prevailing ambient factors. A certain number of those factors were identified and studied separately in order to secure an explanation for the discordant results obtained. As research progressed, the value of certain factors became more and more conspicuous. It has been established that the quality of a plant for green manure depends upon both quantity and quality of 5 material produced; that quantity is influenced by soil fertility, soil structure, climate; that quality is, in addition, a function of plant chemical composition. The chemical nature of a plant is, in turn, dependent upon the productivity level of the medium in which it grows and also upon the stage of maturity of the plant. The part played by climate in the rate of plant growth also comes into play as a determin­ ing factor. In view of these praenotata, and in hope to secure more adequate information, the author has been interested in studying the effect of age of alfalfa plants when used as green manure under the climatic con­ ditions that prevail in Michigan. In this study, the value of fertiliz­ ed and unfertilized plants has been compared and also the most favor­ able growth stage of plants for plowing under has been investigated. Along with alfalfa studies, some work on sugar beet (Beta sac­ charine) green residues used as green manure was undertaken in order to find out to what extent these residues could be returned to the field as a means of increasing soil productivity. This report summarizes the studies on the subject and points out the conclusions that have been deducted. REVIEW OF LITERATURE This review of literature deals mostly with the history of legumes and the steps that have marked the progress of legume knowledge up to the present time. Wilson (105),* Fred (24) and Russell (72) give a ra­ ther detailed expose' of the matter and several references have been selected from their works. Following this historical development, a general survey of the most representative experimental findings is argument given as corroborative towards the conclusions deduced from the experimental work herein reported. Ancient Greek and Roman Agriculture. That Leguminosae, even before the Christian era, were known to be soil-improving crops is made obvious by the writings of Latin authors such as Virgil, Varro, Cato, and Greek authors such as Xenophon, Theo­ critus. Fred (24) and Harrison (28) cite these writers and give a description of the agricultural situation that prevailed in those days of early history. In regard to legumes, Columella (De Re Rustica, second book, first century A. D.) discusses the use of vetches, peas, beans, lupines, lentils and alfalfa (medic). Varro states that lupines should be turned * Figures in parentheses refer to Bibliography, p. 131* 7 under as green manure when the plants are young and that the residues should be incorporated with the soil before they dry out. He gives good advice thatstill holds true as to the preparation of the seed­ bed, the rate of seedingand the harvesting; he recognizes the out­ standing value of medic (alfalfa) as green manure and as cattle food, saying that the crop can be harvested four and six times per annum and that one jugerum (2/5 acre) will support three horses for one year. The death of Theodosius the Great, in 595, marked the fall and disintegration of the Roman Empire. With the Collapse of Rome, most arts, including Agriculture (which, at the time, was more an art than a true science) were soon forgotten and lost in the obscurity of the Dark Ages that followed. eval period were Moreover, the continuous wars of the Medi­ nothingto favor the expansion of art or science. Mow and again, however, a monk would copy the works of Columella, Virgil, Cato, Varro, and these copies would be deposited in libraries. During the entire period that ended with the fall of Constantinople, in 1455, the few writers, such as Palladius, Crescenzi and the various authors of the Geoponici, plagiarized the Roman and the Greek. The Roman agricultural literature was condensed into one volume around 1240 by a senator of Bologna, Petrus Crescentius (De Agricultura Vul­ gare. Augsburg, 1471)* Beginnings of Agricultural Science (XVIth century). a) Principle of vegetation (1600-1750). It was not until the Renaissance, in the sixteenth century, that agricultural literature came back to life. 8 As a general rule, up to 1700, most authors were inspired by the Roman and the Greek writers as to both form and substance* According to Mc­ Donald (58), in his 11A gricultural writers®, only 5 writers are to be found from 1200-1500; from 1500-1600, 12 authors; from 1600-1700, 65 authors; from 1700-1800, over 200 authors* The earliest writers publish­ ed modest tracts, but later Markham, Hartlib, Bradley, Young, required from 10 to 20 volumes. As reported by Johnstone (57, 58), these writers would generally include Virgil* s classical ”0 fortunatos nimium, sua si bona norint, Agricolas** (Ex Georgies, IX, 458-459) and would praise the farmer by all kinds of flatteries* It would be mentioned, for instance, how the Roman senate ordered a Latin translation of the 28 books on agriculture written by the conquered Carthaginian general Mago; how Cincinnatus was called from the plow to become dictator* Later on, along with classical doctrines, consideration would be given to the possibility of agricultural practices varying with locality, and state­ ments were issued that suggested the logic of a change in the absolute rules given by the Latin or Greek predecessors. The minds were open to research and people felt the need for more controlled knowledge* Oli­ vier De Serres, in 1600, seems to be the first to have given importance to agriculture and might well be considered the Father of Agriculture of the Western World. One of the first questions to be investigated was that of the principle of vegetation. Francis Bacon (5) in 1627, believed that water Tims the only plant food. And so did Van Helmont (31) and Boyle (14). Glauber (26), in 1656, and Mayow (57), in 1674, thought that * salpetre was the principle of vegetation. Woodward (110), in 1699, regarded earth as the sole plant nutrient. Tull (82), in 1731, 9 summarizes the prevalent ideas of1 the time by saying that no one knew which really was the plant food: water, nitre, earth, air or fire* As the search for the principle of vegetation was progressing, more and more became known about agricultural practices* Andrew Yar- ranton, in 1663, (The Great Improvement of Lands by Clover, or the Wonderful Advantage by Right Management of Clover) thought that clover improved the soil and was profitable to succeeding crops* vised to lime freely. He also ad­ John Worlidge, in 1681, (Systema Agriculturae* The Mystery of Husbandry Discovered) and Giles Jacob, in 1717, (The Country Gentleman* s Vade-mecum) , recommended that clover and rye grass be sown together to improve the soil and furnish better herbage for cattle* At this time, no schools were to be found, although Columella (first century A* D.) had complained about not having any. In 1651, Samuel Hart proposed the establishment of schools for the teaching of Agriculture and outlined a program of studies. granted. His requests were never However, some serious consideration was now being given to Agriculture: in 1664, the Royal Society of London, founded in 1660, sent out to landlords a questionnaire bearing on agricultural prac­ tices. These reports can be found in Volume X of the classified papers of the Royal Society, and have been analyzed by Lennard (46) in 1952. The answers to this inquiry were of scant scientific value. Those that answered the questions belonged to the well-educated class and did not know too much about farm practices. They were primarily interested in social activities, arts and literature, and their Greek and Latin quotations reveal that Rhetoric was more important in their reports than scientific accuracy. They seem to be more interested in 10 making a. good impression and their answers appear to be based more upon what they read than what they actually did. Nevertheless, mention is made of the use of the microscope, which indicates that some scientific interest was to be found* b) Plant nutrients (1750-1850). In 1757, as no one yet had solved the problem of the principle of vegetation, Home (54) tried to tackle the question by studying the mode of plant nourishment. His conclusions were that not only one, but several things, such as air, water, earth, salts and fire in a fixed state were taken in by plants. Other workers became interested in Home's conclusions and re-oriented their research according to the new goal. Wallerius (97), in 1761, basing himself on the principle "Nutritio non fieri potest a rebus heterogeneis, sed homogeneis", suggested humus as the "nutritiva® and the other soil consti­ tuents as "instrumentalia®. De Saussure, in 1804, proved that plants respire, i.e. absorb oxygen and expel carbon dioxide, and that they take their carbon from the air. This work marks a turning point in the history of the young science of Agriculture and also marks the point of bifurcation from which Plant Physiology has originated and developed as a separate science. Priestly and Ingenhous claimed that plants used up molecular nitrogen, but De Saussure rejected the statement. Neglecting the numerous scientific findings of De Saussure, Thaer published his "Grundsatze der rationellen Landwirtschaft® in 1809. Four years later, in 1815, Davy (££) launched his "Elements of Agricul­ tural Chemistry®. This book deals with chemistry, plant physiology and botany, and may be considered the first serious textbook on agriculture. 11 However, both Thaer*&‘and Davy* s. books became the classical texts of* the day. Davy, prior to Liebig, anticipated the value of mineral fertilizers and stressed the importance of ammonia as a source of nitrogen. Establishment of Agriculture as a Science (XlXth century) • It was not until J.-B. Boussingault, the leading French chemist, started to experiment on his farm at Bechelbronn, Alsace, that true scientific agricultural research began. agricultural experiment station. His farm became the first He investigated the composition of various foods and the effect of climate on crops. Making use of De Saussure* s analytical methods, he studied rotations in the field and in the greenhouse. In 1837, he turned to the question of atmospheric nitrogen absorption and issued the statements *Azote may enter the liv­ ing frame of plants directly (10)... The observations of vegetable physiologists are not generally favorable to this view**. He reported his work in 1841 (23) but his findings on rotations and his balance sheets of crop nutrients were overlooked by the contemporaries. The first survey of agricultural science was made by Liebig, the outstanding organic chemist of the time, for the British Association for the Advancement of Science* Liebig (48, 49) advanced the theory that plants could get nitrogen from the air in the form of ammonia which was carried down by rain, snow or dew into the soil, or even by direct ab­ sorption of ammonia by the leaves. He rejected nitrate as a possible source of nitrogen and claimed that the beneficial effect encountered with sodium nitrate fertilizer was due to the sodium ion. He also object­ ed to the use of nitrogenous fertilizers, except to save time (50)#, 12 and put forth the Idea that the mineral constituents of the soil should be restored to it in order to maintain fertility, Liebig introduced the *Law of the Minimum**, that has ever since remained classical. The publication of Liebig*s **Die Chemie in ihrer Anwendung auf Agricultur und Physiologies marked the birth of popularized agriculture as an applied science. Following the volume, experiment stations were established and agricultural societies were formed, both in the Old and the New World. Professors wrote books for students and farmers; agri­ culture was being popularized for the first time. Then originated a period of controversy among the various invest­ igators, and as the dispute grew more bitter, so much more favored was research. De Saussure denied that plants absorbed gaseous nitrogen* The best chemists, such as Boussingault, Liebig, Gilbert, Ville, con­ ducted experiments and published reports. Boussingault, in 1838, found that peas and clover could get nitrogen from the air, but not wheat. Ville, in France, shared Liebig* s view on the non-necessity of nitrogen as fertilizer birt denied the sole intake of ammonia nitrogen. Ville claimed that nitrogen was also absorbed in the molecular form from the atmosphere. This conclusion he reached after the French Academy of Science appointed a commission to study the question. The commission was composed of brilliant scientists such as Chevreul, Payen, Regnault, Decaisne, Peligot, Dumas, and they all agreed with Ville* s theory (88). Liebig was not the only one opposed to the molecular intake of nitrogen by plants, as proposed by Boussingault and Ville; a whole group of other workers sided with Liebig, such as Cloez (18), who was Ville*s co-worker, Harting (29) and Boussingault himself (11, 12), who had cast aside 15 his previous theory of 1858* Meanwhile, Lawes and Gilbert were studying the Rothamsted experiments, which they had set up in 1845 and which were based on the same prin­ ciple as those of Boussingault* By 1855, they had reached interesting conclusions, such as regard the salt requirements of plants; the nitro­ gen requirements of non-legumes; the maintenance of soil fertility; the beneficial effect of fallowing due to the nitrogen increase of the soil. Later, in 1857, they showed that plots continuously cropped to legumes remained at high yields, whereas those continuously cropped to non-leg­ umes without addition of organic fertilizer soon declined and remained at low yields* In 1861, after careful investigation they (42) arrived at conclusions opposing Ville*s theory, i.e. that plants do not use at­ mospheric nitrogen. These findings convinced all but Ville and a few of his followers. And even Ville himself (89), later on, in 1879, suggested applications of sodium nitrate or ammonium sulfate to non-leguminous plants, but not to legumes, a practice that was common on his farm, at Vincennes. Along with the progress of chemistry, bacteriology, born from Pas­ teur, was rapidly growing as a child filled with hope and promise. Pasteur’s diversified research lead him to emit the opinion that nitri­ fication was a bacterial process. confirmed Pasteur’s statement. Schloesing and Muntz (75), in 1877, Warington (98), in 1878, found that there were two stages in the process of nitrate formation and that two distinct organisms were involved: ammonia was first converted into ni­ trite and then into nitrate. organisms. But he did not succeed in identifying the It was Winogradsky (104) who isolated them in 1890 and called them Nitrosomonas and Nitrosococcus (nitrite formers) and Nitro- 14 bacter (nitrate former) • Following the conclusions of Lawes and Gilbert, in 1861, that plants did not use atmospheric nitrogen, the question remained closed and set­ tled. But twenty years later, in 1881, the American workers stirred the still waters when 0. W. Atwater came to the conclusion that peas obtain­ ed large quantities of nitrogen from the air, thus confirming forty years later Boussingault1s findings. In a paper presented before the British Association for the Advancement of Science, he stated that legumes could use free nitrogen but that such an opinion was ”contrary to the general belief and the results of the best investigators on the subject”. Later, in 1885 (3) and 1886 (4), he recognized that both plant and bacteria might be responsible for nitrogen fixation, but did not succeed in solving the problem. Once more, new series of experiments were outlined to reinvestigate the old question. Hellriegel (30) and Wilfarth came to the conclusion that the nodules formed by infection of the organisms were the cause of free nitrogen fixation. Wolff (108), in 1887, obtained results similar to those of Hellriegel and Wilfarth, but he disagreed with them in regard to the form of nitrogen absorbed. Wolff maintained that the nitrogen was obtained from atmospheric ammonia which diffused into the substrate and from free nitrogen fixed by the soil in the presence of calcium carbonate; that legumes had a greater evaporating power favor­ ing more *pumping” (103) of soil nitrogen* He did not accept the idea of bacteria in the nodules and said that these nodules were the result and not the cause of better plant growth: they were storage organs. Gilbert (25), in 1887, explained the differences in behavior between legumes and non-legumes by the fact that legumes might simply 15 have a greater extractive power for nitrogen in the soil and sub-soil* Lawes and Gilbert remained skeptical before Hellriegel and Wilfarth’s findings. After further experiments at Rotharasted they came to an agreement with the German workers, and in 1891 (41) finally ac­ cepted the conclusion reached by Hellriegel and Wilfarth that legumes fix free atmospheric nitrogen through the activity of a specific or­ ganism present in the nodules. The organism had been isolated by Beijerinck in 1888 and he called it Bacillus radicicola. But, even though it has been established that legumes fix free atmospheric nitrogen through their nodules, other interrogation marks have appeared all around the subject of symbiotic nitrogen fixation: for example, do all legumes fix nitrogen? gen, even if nodules are present? Do they always fix nitro­ These questions have not yet been adequately answered. Ho discussion of the mechanism of nitrogen fixation by symbiotic bacteria will be made here. Suffice it to say that several explana­ tions have been proposed, among y/hich the asparagine hypothesis, previously proposed by Pfeffer, the botanist, and others, and developed by Schulze and co-workers (71, 59, 105); the amino-acid hypothesis, first suggested by Boussingault and supported by Priaanischnikow (65), a student of Schulze; the aspartic acid hypothesis, supported by many contemporary authorities (15, 94, 95, 87). However, the three main hypotheses for symbiotic nitrogen fixation are: a) the ammonia hypothesis, supported by Winogradsky and others (105, 106, 107, 59, 40); b) the hydroxylamine hypothesis, more popular than the previous and defended by Blom (9|, Virtanen (90, 91, 94), Virtanen and Arhirao (9.2) and others such as Lemoigne, Monguillon and Desveaux 16 (45), Michlin (61); c) the organic nitrogen hypothesis, suggested by the Wisconsin workers such as Orcutt (66), TJmbreit and Burris (85) and others* Which of these three main hypotheses is most probable? Accord­ ing to Wilson (103), Virtanen*s hydroxylamine theory is most explana­ tory and most widely admitted under the present day knowledge of the subject* Further investigation is needed to supply workers with the true answer. Alfalfa Material as Green Manure. Whether or not the process by which nitrogen fixation takes place in alfalfa is discovered, this will not affect the value of the plant as green manure* From a more practical standpoint, some of the extensive work dealing with the value of alfalfa as green ma­ nure can be considered. Nearly every experiment station located in those areas naturally adapted to alfalfa production has done some work on the value of alfalfa as green manure, its influence upon the following crop or its effect upon a whole rotation. As compared with non-legumes, there is general agreement on the superiority of alfalfa as green manure, provided the plant exhibits normal growth, i.e. that the circumambient conditions are favorable to its normal development. The list of experiments that support this statement is rather long and it is judged sufficient to mention the works of Lyon (51), Ripley (70), Gustafson (27), Lyon and Bizzell (53, 54), Sprague (77), and publications such as *Alfalfa in Michi­ gan11 (l), **Sugar Beets in Michigan** (79), that are representative of 17 most of the work done along this line. If we parallel alfalfa with other legumes, the comparison becomes much more difficult and the conclusions far less obvious. Apparently, from the literature, it seems that sweet clover*, 9ither white or yel­ low, is a little better than alfalfa, as measured by the yields of fol­ lowing crops. Several investigators (21, 2) have come to this conclu­ sion, although others (52, 55, 54) have found that alfalfa gave better results than sweet clover. Many factors can be accounted as responsible for this divergence of opinions, such as climate, soil composition, amount of material pro­ duced, plant chemical composition, ability of one plant to do better than another on a given soil, and especially this factor of utmost importances age of plant when turned under. The influence of these factors is easily recognized because of the intimate relationship that links them all to plant chemical composition. A great deal of research has been carried in regard to the effect of age of plants upon their manurial value when turned under. Lyon (51, 52) found that 1-year-old alfalfa gave just as good results as 2 or 5-year-old plants. Davis and Turk (21) showed that with advanc­ ing maturity the total potassium and calcium increased in sweet clover or alfalfa plants, tops and roots combined. It is stated in “Sugar Beets In Michigan* (79) that early spring plowing of alfalfa is best for sugar beets and that sweet clover should not exceed ten inches high when plowed under in the spring. Pieters (69) and Morrison (65) realized that as the alfalfa plant grows older its percentage of pro-* TFhite sweet clover: Melilotus alba. yellow sweet clover: Melilotus officinalis. 18 tein decreases while its percentage of fiber increases# According to Willard (101), the commonly accepted difference in protein content between alfalfa and red clover* is due largely, if not entirely, to the fact that alfalfa is usually cut earlier in the season and at an earlier stage of maturity# Martin (55) concludes that rye, oats and buckwheat benefit the soil most when turned under at the half-grown stage, because the more succulent the plant, the more rapid the de­ composition and liberation of nitrates. Munts (64) states that the value of a green manure is proportional to the rapidity with which nitrogen is converted into nitrates. Hutchinson and Milligan (55) and also Maynard (56) claim that the rate of nitrification decreases markedly with advancing age of the green material. White (99) wor­ king with crimson clover* as green manure found that the younger the plant, the more rapid the decay and greater the tomato yields. Waks- man and Tenney (81) state: ®The rapidity and nature of decomposition of plant residues under aerobic conditions depend primarily upon the chemical composition of the particular plant materials®• According to Waksman, these most important chemical constituents are: 1— amount and nature of constituents soluble in cold water; 2- abundance of cel­ luloses and hemicelluloses; 5- amount and nature of nitrogenous com­ plexes; 4- abundance of lignins. Furthermore, the chemical composi­ tion of a plant varies with age and nutrition. Snider (76) points out that phosphorus applications increase the phosphorus content of alfal­ fa and that the phosphorus content of the plant will also vary with the date of cutting. Wiancko and Mulvey (102) say that sweet clover * Red clover: Trifolium pratense. Crimson clover: Trifolium incsrnatum. 19 as green manure in Indiana does best when plowed under the latter part of April the spring following its seeding, Davis and Turk (£1) found that fertilized alfalfa contained more nitrogen, phosphorus and potas­ sium in the tops and roots than did the unfertilized, and that fertiliz­ ed alfalfa or sweet clover gave better results than did the unfertiliz­ ed plant material when turned uhder for a pro so crop. Davis (20) has found that fertilizing sweet clover causes an increase of nitrogen in the plant, Vandecaveye and Bond (86) found that fertilizers and climate will change the nitrogen, phosphorus and potassium content of alfalfa* A complete review of the literature on the effect of ferti­ lizers upon the chemical composition of various crops is given by Beeson (7), Many other workers (96, 66, 36, 47, 32, 100) have found that the younger the plant turned under, the more rapid the chemical breakdown and liberation of beneficial nutrients. Sugar Beet Green Residues (and Cane Trash) as Green Manure, The literature dealing with the quality of sugar beet material as green manure is much less extensive than that dealing with legumes. The reason for this might be that sugar beets cannot be profitably grown as a green manure crop: the high cost of the work involved in producing sugar beets cannot be counterbalanced by the relatively low value of the fertilizers they contain. The question is different, how­ ever, when It comes to making use of the residues of a crop grown for other purposes, and in this respect some work has been done of which a succinct resume^ will be given. 20 Woodman and Bee (109) studied the fertilizing value of sugar beet tops and concluded that they should be used as fertilizer on account of their appreciable nitrogen, phosphorus and potassium content. (80) also studied the manurial value of sugar beet leaves. Tancre7 Merkle (60) compared the rate of decomposition of sugar beet roots, sweede roots and rape tops. Sugar beet roots gave off the most carbon dioxide and in all cases the carbon dioxide production curves reached a peak at the end of two weeks incubation and then dropped abruptly to assume a practically identical and constant value along the X-axis (time). Daji (19) found that sugar beet tops had a beneficial effect on a barley crop. He secured better results when the tops were bnrried at once than when they were first allowed to decompose on the surface of the soil or were composted previous to turning under. Hirst and Greaves (35) conclude that the nitrogen content of sugar beet tops, on a dry basis, approximates that of first crop alfalfa, but that the phosphorus content is lower. Comparing tops and roots, they state that the tops account for 50 per cent of the green weight of the plant, 65 percent of the total nitrogen in the plant and 50 per cent of the total phosphorus; that the percentage of calcium and of magnesium is greater in the tops than in the roots; that phosphorus was increased in both tops and roots by fertilization, phosphorus being lower in the roots than in the leaves. Phosphorus in the total plant fertiliz­ ed amounted to 4.8 pounds per acre; in the non-fertilized, 1.9 pounds. The nitrogen in fertilized tops was 64.6 pounds per acre; in the non­ fertilized, 27.6 pounds. Sturgis (78) observes that cane trash caused a marked lowering of nitrates in the soil. lasted three months. The depressive effect Cane trash turned under in the fall, in Louisi- El ana, had decomposed sufficiently by the following April to liberate available nitrogen* The addition of five pounds of inorganic nitrogen per ton of trash increased the rate of decomposition and insured avail­ able nitrogen* PLAN OF INVESTIGATION The research work reported in this paper was divided into three experiments: I- Comparison of 1, 2 and 5-year-old alfalfa, fertilized and unfertilized, and harvested from the field at three different dates in the early spring. Roots and tops were collected and used as green manure for a sugar beet crop in the greenhouse. Nitrification studies were made on the alfalfa material in the laboratory. II- Comparison of 4, 8, 9, 11 and 14 months old fertilized alfal­ fa grown in the greenhouse and used as green manure in the "same soil" and in "new soil", for sugar beets followed by barley in the greenhouse. Nitrification studies were made on the alfalfa material in the laboratory. Ill- Influence of field-harvested sugar beet tops and roots used as green manure for corn, barley and proso in the greenhouse, oats following the proso crop. Nitrification studies were made on the sugar beet mate­ rial in the laboratory. A study of all soils receiving different treatments to es­ tablish, if possible, a correlation between the yields recorded and the percentage saturation of the soil colloids as regards both total and individual cations. EXPERIMENTAL WORK I- Comparison of 1, 2 and 3-year-old alfalfa, roots and tops, fertilized and unfertilized, harvested from the field at three different dates in the spring and turned under for a sugar beet crop in the greenhouse. A- Greenhouse work, a) Sampling of alfalfa material; The alfalfa samples were taken from field plots on a Brookston clay loam, near Chesaning, Saginaw Co., Michigan, which is located in the central part of the State. The fertilizer applied to the alfalfa crop at seeding time was 0-12-12 at the rate of 1000 Areas in which samples. pounds per acre. a good stand was found were chosen to collect the This was done in an attempt to of plants per area. Three squares 3 X 3 gain uniformity in the number feet were marked plant within the squares was used for the triplicate sample. plant was collected. off andevery The whole The roots were dug up with a spade and as much soil as possible was shaken off. They were then separated from the tops (crowns always included with roots), washed clean under the tap and then rinsed with distilled water. After oven-drying at 80° C. until constant weights were obtained, both tops and roots were ground. Samples of 1, 2 and 3-year-old plants, fertilized and unfertilized, 24 were taken on April 17, April 27 and May 10, 1944. Tables 1, 2 and 3 contain the sampling data, and Table 4 summarizes all three. Fig. 1 af­ fords a graphic representation of the data in Table 4. k) Sugar beet crop: The alfalfa material sampled was used as a green manure for sugar beets grown in the greenhouse. The set-up was as follows: The beets were grown in two-gallon glazed jars containing 8 kilo­ grams of Miami silt loam soil. The soil was passed through a 1-cm. mesh screen to remove pebbles and other debris. The alfalfa material was mix­ ed with the top 6 inches of soil and distilled water added in sufficient quantity to bring the soil to a moisture content equal to that of its moisture equivalent as previously determined by the Bouyoucos method (13). The moisture equivalent so determined was 20.7 and, for prac­ tical purposes, moisture was maintained at 20 per cent of the air-dry weight of the soil: thus, the percentage of moisture in the jars was a trif/le higher than the moisture equivalent. Three days elapsed before seeding. The sugar beet seed used was U. 3. 216. planted on June 20, 1946. Eight seeds per jar were Distilled water was added to the jars when­ ever necessary, and once a week they were brought up to their 20 per cent moisture weights* The jars were placed at random -and moved oc­ casionally. All treatments were triplicated. In mixing alfalfa material with the soil, the field top/root ratios have been maintained and a constant 25 Table 1.- Alfalfa sampled on APRIL 17, number of plants per sample and yields of tops and roots per sample and per acre. Field Age 0-12-12 Plants Roots# Roots Tops# Tops Roots# Tops# of sample lbs per per gms.per lab. gms.per lab. lbs per lbs per No. plants acre 9sq.ft. 9sq.ft. No. 9sq.ft. No. acre acre 1 2 5 1-yr. 1000 n it Sum 4 5 6 * w 0 0 0 Sum 7 8 9 2-yr. •t it 1000 Jf fl Sum 10 11 12 it it tt 0 0 0 SUm 15 14 15 5-yr. 1000 n ft » ft Sum 16 17 18 tt n it 0 0 0 Sum 220 221 205 91.1 86.8 74.7 646 252.6 214 205 164 87.0 70.0 76.8 585 255.8 51 64 55 211.5 156.2 158.5 170 526.2 65 58 58 154.1 224.6 190.0 179 568.7 64 81 48 245.5 320.5 174.9 195 740.9 0 44 64 60 - 189.3 257.2 210.0 0 0 0 168 656.5 R-I 31.0 28.1 35.9 T-I 95.0 R-II 31.2 28.6 25.0 0 0 0 0 0 0 R-VI 0 0 0 0 302 1872 0 2023 0 2635 0 2335 0 — 0 R-V 832 — 0 R-IV 338 T-II 84.8 R-III 899 — — * Oven-dry weights. amount, 60 grams of air-dry plant material per jar, incorporated with the soil. This amount represents approximately 7.5 tons of air-dry material (tops plus roots) per acre. It is difficult to calculate the 26 Table 2.- Alfalfa sampled on APRIL 27, number of plants per sample and yields of tops and roots per sample and per acre. Field Age 0-12-12 Plants ;ioots# Roots sample of lbs per per gms.per lab. No. plants acre 9sq.ft. 9sq.ft. No. 19 20 21 1-yr. n m 1000 11 tt Sum 22 23 24 « u tt 0 0 0 Sum 25 26 27 2-yr. 1000 tt n 11 Sum 28 29 30 « n n 0 0 0 Sum 31 32 33 5-yr. » ti 1000 tt tt Sum 34 35 36 n ii n 0 0 0 Sum 163 208 179 61.1 60.6 42.4 550 164.1 194 190 145 R-VII 183.5 60 87 100 137.0 201.0 209.9 247 547.9 60 80 99 216.2 160.8 169.5 239 546.5 50 72 62 236.2 232.7 200.0 184 668.9 83 37 76 280.0 152.6 192.7 196 625.3 41.7 32.5 29.6 31.8 26.7 33.8 24.1 30.9 34.9 33.7 25.2 25.2 14.0 8.2 4.9 9.3 5.3 13.1 27.7 328 1949 320 1944 299 2379 96 2224 99 r-xi 27.1 l-XII 653 T-X 84.1 R-XI 369 T-IX 89.9 R-X 584 T-VIII 92.3 R-IX Roots# Tops# lbs per lbs per acre acre T-VTI 103.8 72.6 50.5 R-VIII 60.4 529 Tops Tops# gms.per lab. 9sq.ft. No. r-xii * Oven-dry weights. quantity of green material corresponding to the grams of air-dry material because the conversion factor from dry to green weight varies with the age of the plant, the date of harvest and the fertilizer applied. 27 Table 3.- Alfalfa sampled on MAY 10, number of plants per sample and yields of tops and roots per sample and per acre. Field Age (D-12-12 Plants lootstt Roots of sample gms.per lab. 3S per per No. No. slants acre 9sq.ft. 9sq.ft. 37 38 39 1-yr. ii n 1000 It ft Sum 40 41 42 tt » tt 0 0 0 Sum 43 44 45 2-yr. «t tt 1000 tt tt Sum 46 47 48 n 0 0 5> Sum 49 50 51 3-yr. tt «t 1000 tt tt Sum 52 55 54 tt tt n 0 0 0 Sum Topstt Tops gms.per lab. 9sq.ft. No. 73 73 73 44.2 45.6 42.8 219 132.6 152.4 109 95 63 56.1 52.2 33.5 58.2 55.6 44.1 267 141.8 78 74 58 163.4 161.5 155.1 210 460.0 54 57 59 160.0 114.5 129.3 170 403.8 179.2 83 85 55 233.0 227.5 175.0 42.7 41.4 36.8 223 635.5 120.9 58 68 71 164.2 222.1 205.9 47.4 45.1 29.9 197 592.2 122.4 R-XIIX R-XIV 50.8 51.6 50.0 T-XIII 54.4 68.6 43.7 R-XVII 69.3 50.2 59.7 542 504 562 1636 593 1436 637 2260 430 2106 455 T-XV 166.7 R-XVI 472 T-XIV 157.9 R-XV Rootstt Topstt lbs per lbs per acre acre T-XVI T—XVII r-xvni tt Oven-dry weights. Moreover, the two components, roots and tops, vary independently. Green tops weighed from 2.9 to 3.7 times as much as air-dry tops, the mean being 3.2. Green roots weighed approximately twice as much as air- 28 Table 4.- Summary of data for alfalfa harvested on APRIL 17, APRIL 27 and MAY 10. Age of plants Sampling date 1-yr. April 17 Roots,lbs/acre* fert. unfert. 2-yr. • H i 3-yr. it April 27 Tops*lbs/acre# fert. unfert. Roots+toDS.lbs/acre* fert. unfert. 899 832 338 302 1237 1134 1872 2023 0 0 1872 2023 2635 2335 0 0 2655 2335 584 653 369 328 953 981 2-yr* St 1949 1944 320 299 2269 2243 3-yr. ft 2379 2224 96 99 2475 2325 472 504 542 562 1014 1066 1-yr. May 10 2-yr. n 1636 1436 593 637 2229 2075 3-yr. n 2260 2106 430 435 2690 2541 1-yr. April 17 899 832 538 302 1237 1134 w April 27 584 653 369 328 953 981 Tt May 10 472 504 542 562 1014 1066 2-yr. April 17 1872 2023 0 0 1872 2023 it April 27 1949 1944 320 299 2269 2243 9 May 10 1636 1436 593 637 2229 2073 3-yr. April 17 2635 2335 0 0 2635 2355 it April 27 2379 2224 96 99 2475 2323 it May 10 2260 2106 430 435 2690 2541 * Oven-dry weights. 29 Lbs/be.re (even-dry pin*n ts) Apr/7 2500 2000 /soo fOOO 500 Apr 2 7 2500 2000 /SOO /ooo Soo 3yr 2500 2000 500 Apr/7 Fig. 1.- Yields of 1, 2 and 3-year-old alfalfa, tops, roots and total plants, fertilized and unfertilized, harvested at various dates in the spring* 30 Table 5.- Outline of various soil treatments preceding the sugar beet crop. Jar No Alfalfa material turned under Top/root ratios Date of Age, previous Symbols used in gins. harvest treatment 1-2-3 T,16.4 R,43.6 4-5-6 T,16.0 R,44.0 n v 7-8-9 T, 0 R,60.0 n 2-yr. 10-11-12 T, 0 R,60.0 « 13-14-15 T, 0 R,60.0 16-17-18 T, 0 R, 60.0 19-20-21 T,23.2 R,56.8 22-23-24 T,20.1 R,59.9 51 n 25-26-27 T, 8.4 R,51.6 If 2-yr. 28-29-30 T, 8.0 R,52.0 If 51-32-35 T, 2.3 R,57.7 tt 3-yr. 54-35-36 T, 2.5 R,57.5 tt * 37-38-59 T,32.1 R,28.4 40-41-42 T,31.6 R,28.4 tt w 43-44-45 T,15.9 R,44.1 ti 2-yr. 46-47-48 T,18.4 R,41.6 » n 49-50-51 T, 9.6 R,50.4 52-55-54 T,10.3 R,49.7 55-56-57 Checks. April 17 1-yr. unfert. * May 10 fert. unfert. 1-yr. fert. unfert. fert. *' unfert. 1-yr. 3-yr. « fert. unfert. 3-yr. April 27 fert. w fert. unfert. fert* unfert. fert. unfert. fert. unfert. A-17;1Y F. A-17;1Y UNF. A-17;2Y F. A-17$2Y UNF. A-17;3Y F. A-17;3Y UNF. A-27;1Y F. A-27$1Y UNF. A-27;2Y F. A-27;2Y UNF* A-27;3Y F. A-27;3Y UNF. M-lOjlY F. M-10;1Y UNF. M-10;2Y F. M-10;2Y UNF. M-10 j3Y F. M-10;3Y UNF. 51 Alfalfa turned under* Tops, gms. Green Air-dry A-17$1Y$ F. 469.2 89.2 369.4 14.0 51.7 A-17$1Y$UNF. 455.8 CD OJ * 00 Table 6 ,- Yields and sucrose content of sugar beets following the turning under of alfalfa* Figures give sum of triplicates. 229.8 14.4 55.1 A-17$2Y$ F. 555.0 75.0 305.0 15.6 47.6 A-17$2Y$UNF. 506.4 65.4 309.4 14.6 45.2 A-17;5Y; F. 526.6 63.6 259.8 15.6 37.1 A—17$3Y$UNF. 521.4 69.4 247.0 15.0 37.1 A-27jlY; F. 416.2 76.2 237.6 15.1 55.9 A-27$1Y$GNF. 452.2 81.2 191.0 14.9 23.5 A-27$2Y$ F. 525.6 61.6 194.4 15.4 29.9 A-27;2Y;UNF. 555.4 67.4 167.6 14.6 24.5 A-27;5Y$ F. 520.4 67.4 280.8 15.7 44.1 A-27$5Y$UNF. 276.6 66.6 251.2 14.7 36.9 M-10$1Y$ F. 341.5 94.8 285.0 15.0 42.7 M-10$1Y$ IMF. 559.9 68.9 283.1 15.8 44.7 M-10$2Y$ F. 342.2 60.2 251.4 13.6 34.2 M—10$2Y$UNF. 399.8 78.8 249. 4 15.9 39.6 M-10$5Y$ F. 310.2 61.2. 274.6 14.7 36.2 M-10$5Y$UNF. 287.0 63.0 251.6 14.4 36.2 Checks 115.4 25.4 104.1 12.4 12.9 * See symbols, table 5. ** Average of triplicates. Green roots, gms. Total sucrose %** Gms. 3£ Table 7.- Sugar beet yields of roots and of total sucrose following the various soil treatments with alfalfa. Figures give sum of triplicates. Alfalfa turned Beet roots* after under alfalfa Age Sampling Fert.alf. Unfert.alf. date 1-yr. 2-yr. 3-yr. 1-yr. April 17 Total sucrose* after alfalfa Fert. alf. Unfert. alf. 369.4 ££9.8 51.7 33.1 n 305.0 309.4 47.6 45.£ U £39.8 £47.0 37.4 37.1 £37.6 191.0 35.9 £8.5 April 27 2 - yr. R 194.4 167.6 £9.9 24.5 5-yr. tt £80.8 £51.£ 44.1 36.9 1-yr. May 10 £85.0 £83.1 4£. 7 44.7 2-yr. R £51.4 £49.4 34.£ 39.6 3-yr. tt £74.6 £51.6 40.4 36.£ 1-yr. April 17 369.4 ££9.8 51.7 33.1 tt April 27 £37.6 191.0 35.9 £8.5 f? May 10 £85.0 £83.1 4£.7 44.7 2-yr. April 17 305.0 309.4 47.6 45.2 it April £7 194.4 167.6 £9.9 £4.5 tt May 10 £51.4 £49.4 34.£ 39.6 3-yr. April 17 £39.8 £47.0 37.4 37.1 u April £7 £80.8 £51. £ 44.1 36.9 tt May 10 £74.6 £51.6 40.4 36.£ * Grams. 53 dry roots# Based on these data, 60 grams of dry material composed of 0 grams of tops and 60 grams of roots is equivalent to 0 grams of green tops and 120 grams of green roots per jar (15 tons of green material per acre)* In comparison with these figures, 60 grams of dry material composed of 31.6 grams of tops and 28.4 grams of roots would be equiv­ alent to 101.1 grams of green tops and 56.8 grams of green roots per Jar (19.75 tons of green material per acre). Perhaps it would have been better to have used a quantity of al­ falfa material in the pots equal to or double the amount actually har­ vested from the plots. Thus, the quantity would have varied in the different pots according to the yields in the field. At the time, how­ ever, it was deemed advisable to use the same quantity of material in each pot. In Table 5 are recorded the quantities of top and root material added to the various jars before the beets were planted. Wa.eu the beet plants were 3 inches tall, they were thinned to 4 plants per jar, and when they had reached a height of 6 inches, they were further thinned to 2 plants per jar. The strongest plants were sav­ ed. The sugar beets grew normally. No nitrogen deficiency symptoms were noticed, except in the checks where the tops were a yellowish brown and much less developed than in all other jars. On December 18, 1946, the beets were harvested after six months growth. The tops (with the crowns) were separated from the roots, and tops and roots were weighed separately. The tops were put aside to dry, and later on the air-dry weights of the tops were recorded. The per­ centage of total sucrose was determined immediately after harvest. A 34 description of the method used is given along with the other laboratory procedures. Table 6 contains the yields of the sugar beet crop and Fig* 5 affords a graphic comparison of the beet root yields with the nitrogen accumulation in the soils. B- Laboratory work. a) Sucrose analysis; The percentage of total sucrose in the sugar beets was determined by the hot water digestion method as described in ”0fficial and Tentative Methods of Analysis of the Association of Official Agricultural Chemists®, 5th ed., 1940, p. 516. This method makes use of the saccharimeter with a 400-mm. polarizing tube. However, instead of using basic PbCCHgCQO)^ as a clarifying agent, as provided for in the method, basic FbCNOgJg consisting of a mixture in equal volumes of a 50$ solution of PbCHOg)^ and a 5$ solution of NaQH was substituted. In these tests, 10 ml. of basic PbfNOg)^ was used as a clarifying agent. The sampling of the sugar beet is of utmost importance since the sucrose is not evenly distributed throughout the whole root. The most representative sample is obtained from a V-shaped slice cut lengthwise of the beet and the wide edge at the beet’s surface. Each sample consisted of the six beets from the three jars which received the same treatment. tions were made. of six beets. On each composite sample, two determina­ Therefore, two 25-gm. samples were taken from each lot All the saccharimeter readings of the duplicate determina­ tions agreed within 0.2$ sucrose, except in A-17;2T;UNF. (see Table 6) 35 where the duplicates showed a difference of 0.4$. This slight discrepan­ cy was overlooked. b) Nitrification studies of the alfalfa material used as green manure: The alfalfa material used as green manure was submitted to nitrifi­ cation studies in the laboratory. Two grams of air-dry ground alfalfa material were mixed (tops and roots separately) with 100 grams of air-dry Wisner soil in a glass tumbler and distilled water was added to bring the soil to a moisture content equal to its moisture equivalent. The moisture equivalent was 19.7, as determined by the Bouyoucos method (13) . To simplify the subsequent cal­ culations, it was considered as being 20.0 and calculated on an air-dry basis. All treatments were quadruplicated, 2 duplicates serving for the 4-week incubation period and 2 for the 8-week period. The tumblers were covered with lids containing 2 holes for aeration and were set in a dark locker in the laboratory. The tumblers were weighed every week and brought up to their respective weights with distilled water. At the end of the incubation period, nitrate and ammonia nitrogen were extracted from the soils with a 4$ KC1 solution. The soils were allowed to soak 12 hours in the salt solution; the liquid was then filter­ ed out and distilled (Kjeldahl method) into a 4$ solution of HgBO^. Titrations were made with N/l0 H^SOq using bromphenol blue as an indicator. The incubation was started on March 30, 1945, and ended on April 27, 1945 (4-wesk period) and on May 25, 1945 (8-week period). Chemical determinations made on the Wisner soil used in the incuba- 36 tion studies revealed the following#* pH value, 7.48; total adsorbed phosphorus, 10.0 p.p.m.; acid-soluble phosphorus, 162.5 p.p.m.; total ad­ sorbed acid-soluble phosphorus, 172.5 p.p.m.; exchangeable potassium, 0.094 m.e. per 100 grams (75.5 lbs/acre); exchangeable magnesium, 0.123 m.e. per 100 grams (29.8 lbs/acre); exchangeable+ free calcium, 17.172 m.e. per 100 grams (6890 lbs/acre); exchange capacity, 10.665 m.e. per 100 grams; magnesium/exchange capacity, 1.1555; potassium/exchange capacity, 0 .88&; potassium/magnesium ratio (m.e. basis), 0.76. The results of this nitrification study are shown in Tables 8 , 9, 10, 11, and are graphically presented in Fig. 2. After studying the rate of nitrification of alfalfa material as related to its chemical composition at various stages of maturity, the data were used to compute the amounts of nitrogen produced in the soils growing the sugar beets. Knowing the amounts of nitrogen produced by 1 gram of root and 1 gram of top material of a given sample, it is easy to calculate the amounts produced by any given quantity of top or root material of an identical sample. So, respecting the relative amounts of tops and roots turned under for the beet crop, the figures shown in Table 12 were obtained. They represent the calculated quantities of nitrogen formed in the soils during the growth of the crop. Fig. 3 compares the yields of the beets with the amounts of nitrogen produced in the soils. c) Study of soils: In a search for correlations which might exist bet­ ween the contents of various nutrients present in the soil and the yields * See paragraph ”Study of soils”• 37 Table 8.- Mgms. of nitrogen accumulated during a 4-week incubation period in 100 gms* of soil receiving 2*0 gms* of alfalfa material. Alfalfa incubated* n h 4-n Alfalfa tops N0s-N (nh4*ng5*n n h 4-n Alfalfa roots N05-N (NH4*N05)N F. 2.58 21.00 25.58 1.27 22.79 24.06 A-17;1Y;UNF. 1.15 26.17 27.52 1.22 17.64 18.86 A -17;2Y; F. 0 0 0 1.83 11.67 13.50 A-17;2Y;UNF. 0 0 0 2.45 14.41 16.86 A-17;5Y; F. 0 0 0 1.55 8.30 9.65 A-17;3Y;UNF. 0 0 0 1.41 10.64 12.05 A-27;1Y; F. 1.60 27.15 28.75 1.62 13.22 14.84 A-27;1Y;UNF. 0.88 25.77 26.65 5.09 15.25 18.34 A^27;2Y; F. 5.71 51.29 57.00 1.57 8.78 10.15 A-27;2Y;UNF. 15.55 25.51 41.04 1.58 8.01 9.59 F. 8.44 25.91 54.55 1.41 7.50 8.91 A-27;3Y;UNF. 5.42 28.85 52.27 1.60 7.14 8.74 M-10;1Y; F. 1.11 25.52 24.65 0.80 8.95 9.75 M-10 ;1Y; UNF. 2.10 22.96 25.06 1.12 7.41 8.53 M-10j2Y; F. 0.77 29.75 50.52 1.01 7.25 8.26 M-10;2Y; UNF* 5.04 50.58 55.42 1.15 10.91 12.06 M-10;5Y; F. 1.52 25.72 25.04 1.22 6.86 8.08 M-10;3Y;UNF. 1.15 29.55 30.68 1.60 6.61 8.21 Checks (See 3-v/eek i:acubation, table 9) A-17;1Y; A-27;3Y; * See symbols, table 5. 38 Table 9.- Mgms. of nitrogen accumulated during an 8-week incubation period in 100 gms. of soil receiving £.0 gms. of alfalfa material* Alfalfa incubated*- Alfalfa tops (NH4-1J^05)N Alfalfa roots (hh4*nos)n n o 3-n n h 4-n n o 5-n F. 9.85 28.92 29.77 0.74 23.72 24.46 A-17;1Y;UNF. 1.06 28.28 29.34 0.85 22.20 23.05 A-17;2Y; F. 0 0 0 0.83 16.06 16.89 A-17;2Y;UNF. 0 0 0 0.85 15.72 16.57 A-17;3Y; F. 0 0 0 0.81 11.37 12.18 A-17;3Y;UNF. 0 0 0 0.73 13.80 14.53 A-27;1Y; F. 0.95 29.54 30.49 0.66 16.06 16.72 A-27;1Y;UNF. 0.99 26.82 27.81 1.25 18.24 19.49 A-27;2Y; F. 1.43 36.20 37.63 0.84 12.03 12.87 A-27;2Y;TJNF. 2.24 38.25 40.49 0.85 12.42 13.27 A-27;3Y; F. 1.22 34.43 35.65 0.80 10.96 11.76 A-27;5Y;UNF. 1.13 32.84 33.97 0.71 9.79 10.50 M-lOjlY; F. 0.84 24*11 24.95 0.73 12.68 13.41 M-10 ;1Y; UNF. 0.78 25.77 26.55 0.73 13.45 14.18 M-10;2Y; F. 0.81 30.21 31.02 0.83 11.51 12.54 M-10;2Y;UBF. 0.92 33.07 35.99 0.85 10.86 11.71 M-10;3Y; F. 0.92 27.09 28.01 0.78 10.05 10.83 M-10;5Y;UNF. 0.85 29.60 30.45 0.74 10.04 10.78 Check n h 4-n * See symbols, table 5. Ma O • C o 03 •t M A-17;1Y; h h 4-n N0s-N: 1.34; (n h 4*no S)N: 2..17 59 Table 10*— Mgms* of nitrogen accumulated during a 4—week incubation period in 100 gms. of soil receiving £.0 gms* of alfalfa material. A summary of table 8* Alfalfa incubated* A-17;1Y. Tops (NH^NO.ON Fertilized Unfertilized 25.58 27*32 Roots (NH>i+N03)N Fertilized Unfertilized 24.06 18.86 A-17$2Y. 0 0 13.50 16.86 A-17 $3Y . 0 0 9.63 12.05 A-27,*1Y. 28.75 26.65 14.84 18.34 A~27;2Y. 57.00 41.04 10.15 9.59 A-27;3Y. 54.55 32.27 8.91 8.74 M-10;1Y. 24.65 25.06 9.75 8.53 M-10;2Y. 50.52 33.42 8.26 12.06 M-10 55Y . 25.04 30.68 8.08 8.21 1Y;A-17 23.58 27.32 24.06 18.86 lY;A-27 28.75 26.65 14.84 18.34 1Y;M-10 24.63 25.06 9.75 8.53 13.50 16.86 2Y;A-17 0 0 2YJA-27 37.00 41.04 10.15 9.59 SIjM-10 30. 52 33.42 8.26 12.06 9.65 12.05 5Y 5A—17 0 0 3Y;A-27 34.35 32.27 8.91 8.74 3Y;M-10 25.04 30.68 8.08 8.21 * See symbols, table 5. 40 Table 11,- Mgms, of nitrogen accumulated during an 8-week incubation period in 100 gms, of soil receiving 2,0 gms. of alfalfa material. A summary of table 9. Alfalfa incubated* A-17*1Y. Tops Fertilized 29.77 Unfertilized 29.54 Roots (NH„+IK)Z)N Fertilized Unfertili zed 24.46 23.05 A-17;2Y. 0 0 16.89 16.57 A-17;3Y. 0 0 12.18 14.53 A-27$1Y. 50.49 27.81 16.72 19.49 A-27j2Y. 57.65 40.49 12.87 13.27 A —27;5Y. 55.65 33.97 11.76 10.50 M-10;1Y. 24.95 26.55 13.41 14.18 M-10;:2Y, 31.02 55.99 12.34 11.71 M-10j5Y. 28.01 30.45 10.83 10.78 1Y;A-17 29.77 29.34 24.46 25.05 lY;A-27 30.49 27.81 16.72 19.49 1Y;M-10 24.95 26.55 13.41 14.18 16.89 16.57 2Y;A-17 0 0 2Y;A—27 37.63 40.49 12.87 13.27 2Y;M-10 51.02 33.99 12.54 11.71 12.13 14.53 3Y;A-17 0 0 3Y;A-27 35.65 33.97 11.76 10.50 5Y;M-10 28.01 30.45 10.83 10.78 * See symbols, table 5. 41 A pr 17 3o 20 fO Apr 27 JL 30 20 // /O 30 zo ■7#- /o A p r /7 Apr27 May/o Dote, o f h a rve s t /yr Zyr Aye of />/$7?ts Fig. 2.- Mgms Mgms. of N accumulated during an 8-week period in 100 gms. of soil receiving 2.0 gms. of 1, 2 or 3y e a r - u i u x c r u i x iz,cu ux uuiox uxxxxcu a.x.x a x x a. uupa and roots harvested. at various dates in the spring 42 Table 12.- Calculated mgms. of nitrogen produced during an 8-week incubation period in soils growing sugar beets and receiving 60 gms. of alfalfa material with varying top/root ratios. See ratios, table 6 . Tops (n h ^ n o O n Fert;. unrert. Fert. Unfert. Fert. Unfert. A-17,*1Y. 244.0 234.7 555.2 506.9 777.2 741.6 A-17*2Y. 0 0 506.4 496.8 506.4 496.8 A-17J5Y. 0 0 365.4 455.6 365.4 435.6 A-27;1Y. 365.6 279.4 307.6 388.6 661.2 668.0 A-27|2Y. 168.0 161.9 331.8 344.8 489.8 506.7 A-27*5Y. 41.0 42.4 339.3 301.9 380.3 344.3 M-10;1Y. 400.5 419.3 186.9 201.4 587.2 620.7 M-10j2Y. 246.6 312.6 272.1 243.4 518.7 556.0 M-10;3Y. 134.4 156.8 272.7 267.9 407.1 424.7 1Y;A-17 244.0 234. 7 535.2 506.9 777.2 741.6 lY;A-27 553.6 279.4 307.6 388.6 661.2 668.0 1Y;M-10 400.3 419.3 186.9 201.4 587.2 620.7 2Y;A-17 0 0 506.4 496.8 506.4 496.8 2Y;A-27 158.0 161.9 531.8 344.8 489.8 506.7 2Y;M-10 246.6 512.6 272.1 243.4 518.7 556.0 3Y;A-17 0 0 565.4 435.6 365.4 435.6 Alfalfa incubated* Roots Total plants 3Y;A-27 41.0 42.4 539.3 301.9 380.3 344.3 5Y;M-10 134.4 156.8 272.7 267.9 407.1 424.7 * See symbols, table 5. 45 Mjnts- (A0/y+N03)N Gins 750 500 400 &40 ---- -— 450 __ _ /ao 300 /Z0 /SO 4o ly r- Apr /7 Leyz+ict-' ---- - Beets ------ Roots 7S0 '^ La$o7id (con dj: ----- Totqf p/onts • • • F o rt if t zed 300 400 Z40 4SO /so _______ " ' /ZO 500 40 /SO Apr 27 ^ 7S0 -—^ ______ - 500 240 400 ~~' « - ' 1VT"-* , ^ . too /ZO /SO 40 ' 3 y r. A p r ./7 3 y r. AprZ7 D$.te o f harvest Fie ^ Mzy/0 A y e o f p k 'n t s 3 - Sugar beet yields and calculated amounts of H produced in 8 weeks per 100 gins, of soil by the various quantities of alfalfa tops and roots turned under as green fertilizer. 44 of the crop, all soils were submitted to a rather complete chemical ana­ lysis# An attempt was made to correlate the percentage base saturation and the crop yields# A study of different cation ratios as found in the soils was also undertaken and all the data secured are presented in tab­ ular form in Tables 13 and 15a, and in graphic form in Figs. 3, 4 and 5# Representative soil samples were taken from each jar in the greenhouse and passed through a 0.84 mm. sieve. All three soil samples correspond­ ing to a given treatment were well mixed and two sub-samples taken from them# These two sub-samples were considered as duplicate samples in all the chemical analytical work. The pH value of the soils was obtained with the Macbeth pH-meter* The soils were soaked 12 hours in HgO previous to the determinations. A 1:1 soil-water ratio was used, i.e. 15 grams of soil - 15 grams of water. Duplicate determinations were made and since the duplicates checked within 0.1 pH unit, the arithmetic mean of the duplicates was recorded. The difference between the true mean of H-ion concentrations and the apparent arithmetic mean when the variations in pH values are so small is not significant. Two phosphorus fractions were determined after the Bray and Kurtz method (16), using NH4F for extracting the total adsorbed phosphorus and HC1 for the acid-soluble phosphorus. Readings were made with the Evelyn photoelectric colorimeter and the results were expressed in terms of p.p.m. in the soil. The exchange capacity, the exchangeable potassium, calcium and mag­ nesium were determined by the Peech method (67) - a micr©analytical method - using centrifuge and spectrophotometer. Evelyn photoelectric colorimeter was used* In this work, the A slight modification was Table 13.- pH value, phosphorus, potassium, calcium and magnesium content of the soils before and after the beet crop. 45 f-t ft Pr ft f-t 05 O ft XI ttu S • ft 05 ft. s Eft « 0 o •o as • c05 <35 O O . * o o 04 05 O . o -cP 05 o * o 60 O »H • O CO © rH . O LO CD CD rH © H • . O O 60 rH rH rH © rH rH rH rH © rH . • • » © © o © LO to rH rH rH i—! • • O © © rH rH • © to rH O 04 04 LO CD D05 04 i— 1 04 O © CD rH LO Tp rH 04 LO 55 CO rH C4 C^P CO © 02 © to 04 1— 1 CM o rH CM CM © LO © rH © rH CM CM t!>— rH CM LO rH © CM O CD i— t o ■— ! iH a * o O O © o rH © rH . • o © ft *H o d CM CM o CD O CM • O . . . . . . LO to LO LO 04 CO CO © 1— 1 * © r-j rH Osi 04 04 CO CNJ • • • . . to to 60 CD to rH CO © © o rH rH i— 1 rH CM . 60 CrH CO 60 m • © to LO rH tH rH © © CM rH CO co . * CO CD O © i— 1 CO • CO © CD 60 rH • o O CM e- CO i— 1 rH « • o O CM to rH • O 60 LO CD 02 LO © CO rH tH rH rH . » « • O o © O rH CO CM © CM CM rH • • . © © o © CD rH • O CO 60 to CM rH tH . • © O to CM tH . O ft OS cm XI S3 o- tCD CO * . ♦ • • . to to 04 04 CD to 02 02 04 04 04 04 * u ft ft ftr & 5o • ft . s 3 rH *H O CO © rH rH . O LO i— 1 o 04 CD LO 60 04 rH rH • « O O CO to rH . © CM to rH . © o C1— 1 t>CM rH CM CM ft LQ LO • • 04 oCD 60 i — 1 04 © jt ;£ C4 LO • CM 60 i— 1 o © « « • o o LO to CO 60 rH i— t rH LO © LO LO LO LO • . • • . • c- LO c- c— t- C~CO GO -^p rH i— i rH 1— 1 1— 1 rH i— 1 LO • CM CM rH V 1—I O • LO LO o O © LO © ft . . • • • 04 Q to to e- LO to to to to LO © © © © © • . • • • . 04 LO LO LO © LO to to 60 LO © LO © © to . • • . • • O- © CM © to CLO H 1 H* to 60 to • c60 LO • 04 CO rH CO rH • co 04 l>- LO CD OD— 60 to ^P LO • • • • . • to to LO LO LO LO © © rH O CM CD LO LO © LO CO . . • • • • LO LO LO LO LO LO H 1 © O CO rH LO O- CO CO CO © © • • . . . • LO LO LO LO CD LO © rH • CD LO LO • • • o t>- D— «sp 05 04 i— t rH rH (X. tc fti H© i —§• o LO » fc“ E1— t A $ C •ft • @ * Oh • a o LO © rH o * LO CD rH LO O « • C— o © 0i— 1 rH O © © • • © © rH to 04 04 LO • 02 00 tH LO • 04 CO rH LO . cLO rH LO . CM CD rH LO LO • • • © CM Ce- CM t>rH CM rH © O LO © • • • LO C- to 60 CO © CM rH CM LO © © • • • CM LO to c- 60 © tH rH rH LO to . . CM tLO co rH rH t di~i * o aj d<+ LO • CM rH CM ft ■O8 CO © * LO c*1— 1 d at to i —©i • § r-1 O CO • I lo d *H ® a ■— I at cd ~ If?t 5 8 S I +5 CM Pm (xh Ch Q • *rv •*> • (Ii Ih M M M H M O H H W W w w • fV **N f *V C~-O - C"- t> - C '- C^r l H rH r l r l H < Hj i - t- C-C*-t<-tCM fM CM CM $M CM 01 o 'cH •H • • • • • • O i DO f \ i t • • • • W H • • ^ to C- w O D4 ca to to 'Cj* -Cf 00 4 -P h .bjQ -8 H a* -P o ct) O CO • ^ <31 C O O to t o LO LQ t o ID ^ • a, to M to to H CD CD U ) ^ « « * * • ^ « H co t>- 04 N O LO L O r H rH cv rH <31 <31 to H O €31 to co *sjtco C31 O lO CO o a> is S o Fh A a> Ph <31 LO co to w oo 00 CD CD CD CO CD cn rH O O O H • to CO fc- CO Cd Cm tO W 03 rH O 00 <3> O O rH • • t- QVJl rH CO iO tO O O H ^ C O CO 60 ^ r H r H rH cvi H IS CO o to 6- O 00 00 O rH O O O) ^ H H to to rl tO 04 <71 tQ LO CO O O q O i H H <31 rH <— I i— I rH O i— I i— I rH H tO S CSi W rH t * i—! C tO o rH to ca w t o co io ^ ^ I— I LO rH t o l o t o t o "ct* to LO O 'd*6 0 <31 r f to $ \i ^ li) vt* ^ IO O 't * IO H 1 tO O to o O £- o to to o • • • o o rH 1— 1 rH rH O * Ti- CO LO LO ^ LO LO CO O O LO LO O to O e- t- O O- LO to oo O O LO C« • • • • • o €31 o rH O a to o LO CSi • <31 rH rH rH rH cd & 0 T0 J1 to -p P 0! 1 S -P < 0d ) fH -P T0J) fH -P cd -P &H &h |X| Oh O §•..... fH •H (D fH P*H• P o f H f H fH oa to to 0 • *V »*V »»N p) ^(D «*.C'->«S »V t* t* C“ 0 Cm - P i— Ii— I H i— I r— (i— I t t I I f f 01 Cm CQ (*H f t , f t , ( 3L| rH H W f H f H fH f H f H rH rH C\t tO C*-C— C— C*-C— C02 CVi p * P4 gvi <3} ■<( W t O tO o o o o o o rH i—I i—I rH i—I i—I I I I ! I I s a s as s m CD 2.0 mm., 2 .0-1*0 mm., 1.0—0.5 mm., 0.5—0.25 mm., 0.25—0.1 mm. The fraction < 0.1 mm. was not determined because it had been judged of no practical importance in this particular study. The state of aggregation of the soil primary particles was expres­ sed as follows: b State of aggregation*^ |% aggregates aggregates^ where a a 0.1 mm. b > 2.0 mm. The results of this aggregate analysis are given in Table 22, c) Nitrification studies: Portions of the alfalfa material of 5 different ages that w*s turned under for sugar beets were put aside for nitrifica­ tion studies in the laboratory. The soil used and the methods followed were the same as already described in part one. However, instead of using 2.0 grams of plant material per 100 grams of soil, as previously, 1.0 gram only was used. Tables 25 and 24 give the results obtained, and both are summarized in Table 25. Nitrification was started on January 17, 1946, and ended on February 14, 1946 (4-week period) and on March 14, 1946 (8-week period). Based on the nitrogen produced in 8 weeks in 100 grams of soil by 70 Table 22.— The state of aggregation of the nsam9 soil1* as compared to that of the '"new soil*', while beets were growing after turn­ ing under alfalfa. Soil treatment (alfalfa Size of turned -aggreg. under) in mm. 4 months 8 9 11 14 * » « * Check "Same soil* A g - gregates > 2.0 5.5) 2 .0-1.0 5.5)20.5 1 .0-0 .5 9.7J 0.5-0.25 £1.5 0.25-0.1 22.5 Idem » tt at 5.4) 6.8118.4 6.2) 19.0 22.0 4.9) 4.7)16.7 7.1J 19.5 £1.1 5.2) 5.5)17.3 7.1) 18.1 21.2 5.6) 6 .8)20.0 7.6) 21.1 19.6 "New soil* State Soil of moist. Ag­ aggreg. gregates % 64.3 59.4 57.1 57.1 60.7 14.5 10 .8) 8.3)29.2 10 .ll 19.4 18.9 67.6 12.3 14.2 13.2) 8.7)31.3 9.4) 19.4 19.5 70.3 14.1 14.9 12.4) 8.7)30.5 9.4) 20.4 20.5 71.5 10.5 14.4 11.5) 8.3129.2 9.4) 19.9 21.0 70.3 11.1 15.4 12 .1) 9.0)31.8 10.7) 19.0 19.2 70.1 12.4 11.9) 8.5)30.2 9.8) 18.8 18.2 67.3 14.0 it - Soil State of moist. aggreg. % - 71 Sfate o f a.ggrcga.t/on % $99ref$tes o s to S o / / 'moisture o-t ' m m A LegendStztc % 99 re 9$. t e s > o £ m m - \ of / oggregactiof) JJ 7 * aggycgsLtes os to o fm m ' % a g fre g ^ te s > o s m m So/J irioisturc 70 AO 60 3S SO 30 40 2S 30 20 20 /S \ 10 S^Trte soil 4 & 1 Age II 14 o f blfdilfa /0 SO/•/' "No W I____I 4 6 4 1/ 14 turned under ('months) ck . Fig. 7.- State of aggregation, % o f larger and smaller aggregates and moisture content of "same soil" and "new soil" growing the sugar beets following the alfalfa turned under at various stages of maturity, 72 Table 23.- Milligrams of nitrogen accumulated during a 4-week period in 100 grams of soil receiving-1.0 gram of alfalfa material. Age of Roots Tops a x x a J L ia incubated n h 4-n n o 5-n 4 months 0.98 3.48 8 » 1.42 9 * 11 14 (n h 4+n o s )n n h 4-n n o 5-n 4.46 0.94 9.24 10.18 5.58 6.80 1.00 9.80 10.80 1.26 4.60 5.86 0.94 8.70 9.64 * 1.17 4.82 5.99 1.06 7.50 8.56 » 1.29 4.40 5.69 0.94 10.52 11.26 Check (HH4+N0 )N (See 8-week peiciod, table 24] Table 24.- Milligrams of nitrogen accumulated during an 8-week period in 100 grams of soil receiving 1.0 gram of alfalfa material. Age of alfalfa incubated nh 4-n N0g-N 4 months 0.80 9.38 8 « 1.07 9 tt 11 tt 14 Check Roots Tops n h 4-n N0g-N 10.18 0.94 8.84 9.78 9.38 10.45 0.87 6.96 7.85 0.87 10.04 10.91 0.87 6.30 7.17 0.80 8.18 8.98 0.87 6.28 7.15 0.80 7.50 8.30 0.87 9.78 10.65 (NH4+N0g)N NH4-N: C>.80; N05-Nj 1.39; (NH4fN0s)N: B.19 (n h ^ n o 5)n 75 Table 25.- Milligrams of (NH vfNO*)N accumulated during a 4 and an 8-week period in 100 grams ox soil receiving 1.0 gram of alfalfa material. A summary of tables 25 and 24. Age of alfalfa incubated 4-week period Roots Tops 8-week period Roots Tops 4 months 4.46 10.18 10.18 9.78 8 « 6.80 10.80 10.45 7.85 9 w 5.86 9.64 10.91 7.17 11 tt 5.99 8.56 8.98 7.15 14 tt 5.69 11.26 8.50 10.65 1.0 gram of top and 1.0 gram of root material in the laboratory studies, the amounts of nitrogen produced from the alfalfa turned under in the greenhouse jars were calculated and are presented in Table 26. The alfalfa material of 2 different ages, i.e. 5 and 6 months old, turned under as green manure for sugar beets, was not incubated in the laboratory. The soils in the greenhouse jars were sampled when the beet plants had grown 4 months (April 29, 1947, i.e. 2 months before harvest) and were analyzed for nitrate nitrogen. A 50-gram moist soil sample was taken from each of the three repli­ cates and the percentage of moisture in each jar was determined in order to base the results on dry soil. Ammonia and nitrate nitrogen was determ­ ined immediately after sampling, according to the method mentioned in part one, laboratory work. An excex’ticn, however, is to be noted. The nitrogen was distilled into N/l0 HgS04 and titrated with N/l0 NaOH, using methyl red as the indicator. The results are found in Table 27. One week before sampling the soils for these nitrogen determinations, 74 Table £6 ,- Milligrams of nitrogen accumulated in the laboratory in 100 grams of soil by 1.0 gram of alfalfa tops and 1.0 gram of roots, and calculated milligrams of nitrogen produced by the corresponding material in greenhouse jars (8-week period). Age of alfalfa incubated produced in lab. Tops Roots Calculated Tops* produced in i a r s Roots* Total plants 4 montBus 9.78 10.18 75.5 91.6 166.9 8 * 7.8? 10.45 70.5 156.7 227.2 9 « 7.17 10.91 78.9 264.0 542.9 11 « 7.15 8.98 72.9 £06.5 £79.4 14 *» 10.65 8.50 117.1 166.0 £85.1 * See table 16. i.e. on April £2, 1947, plant tissue tests were made on the beet leaves to confirm the nitrogen deficiency symptoms observed. In all cases the tests for nitrate nitrogen with diphenylamine were negative. d) Study of soils: The methods and procedures used in the study of soils are found in part one, laboratory work. Tables £8, £ 8a, £9, 29a, 50 and 50a contain the results of the various soil analyses. 75 fyiris- thhui (tJHH+ NOh)N in Joxs (NHyfNOJhi in turntiers Myms* 700 100 soo LeyenJ*. ------- Beets A lfalfa tops ------ A lfalfa roots ------- C a lc u la te d N 400 300 - /s -------- — Vr^ - \ to / ✓ ✓ \ V x V ZOO " \ \ too » Sante soil i 8 ■ i // * 14 1 New soil" 1 8 1 i II 1 14 \ n ck- Aye of alfalfa turned under (rnonths) Fig. 8.- Sugar beet yields and amounts of N produced in 8 weeks in 100 gms. of soil receiving 1.0 gm. of alfalfa, tops and roots, and calculated amotints of N per 100 gms. of soil produced by the various quantities of alfalfa turned under in the greenhouse jars. 76 Table 27*- Milligrams of nitrogen per 100 grams of soil (oven-dry basis) growing sugar beets 4 months old, after turning under of alfalfa material* Soil treatment* n h 4-n 3, N, Milligrams of nitrogen 1 nq3-n (NH4+N0s)N F* 0.49 0.03 0.52 3, N, DNF* 0.47 0.00 0.47 3, S, F• 0.42 0.00 0.42 3, S, UNF. 0.74 0.21 0.95 6, N, F. 0.76 0.18 0.94 6, N, UNF. 0.53 0.00 0.55 6 , S, F* 0.54 0.00 0.54 6, S, UNF. 0.48 0.03 0.51 0.49 0.00 0.49 Check * See symbols, table 20. C- Discussion of results* Here again, a glance at Table 17 (Fig* 6) will indicate that the youngest alfalfa turned under caused the highest yields of sugar beet roots with the highest sucrose content of any grown in the "same soil*1* Although the youngest alfalfa material also produced beets with the high­ est sucrose content in the "new soil", it failed to cause the highest yields of roots* There was not a general decrease in yields as the age of the plant increased, as was true with the beets grown in the "same soil®• p e r 1 lb s £ CD h O cd • CD (0 Cl, & • CD o * o 6 rH E» to 02 rH . CO 02 e• o- CO rH 02 rH » CO 02 rH » 05 02 to . to 02 t. CD 02 I> a CO 02 CO • CO 02 o• CD 02 rH • 00 02 CO • 05 02 CO rH rH • O O 02 rH • O 't f o rH • O CD rH rH . O 00 1—1 1—1 • o o rH rH . O CD rH rH • O CO • B rH o o rH * •H to O CO CD 5k • 02 B • O* p. >k rH CO to rH • •5 o to • c— CO 1—1 «S cd 3 0 u <*-i ra P O 03 £ rH 03 f-j *H tkO 3 O td -P CO c- • <55 CO £ rH H O CO & CO o rH « O 05 o> O • 02 O rH a O o o• CD « CD fr - o to CO 05 CD O * O ■ ,tf r —I o • 00 VO CO * vO VO vo • VO CO OS * CM CO OS • CO vo & o bD •H s s O & to . 05 ID os » VO VO • os H4 OS * 00 H* CO * CO os • CO VO vo » to to • P o #w O K © t. i— t VO o • iH o lO o • 1— 1 OS CO • rH os « ia o ■S •H -P aj U O © t3i VO o • rH K g O # H. © cd © • w ■p SEj cd rP CO ^ © H e• o rH 02 CO !>• • Hi to o o VO o o ID . CO vo VO • to vo VO rH • to VO o rH ■ rH csi * i— 1 OS to • 1— 1 OS O • i —1 vo QA * rH VO to » T— 1 CrH * rH OS cv • rH VO cv. • «H 05 rH . i —1 02 02 . i —1 VO 02 * i— 1 • to CO c* OS CO OO * to CO VO . CO CD VO rH . 00 CO rH • CO CO o 02 • Os CO rH • OS CO O S 3 co . CO o o o o r-H •H o © VQ rH * rH w * i— 1 CM to • CO CO • CO CO CO . CvJ CO « H* • o J4 © s < h •P -P rH cd cd 3 © Vi -P o © a !~1 © 14 •H hfl P o cd -P O <5 rH VO 02 # 05 cd -P 4 • Pr crl o • o 'd* ♦ rH rH •H O CO rH 2 •H t© •H 14 O . o VO o o O to to OS o 1 —1 o rH rH o vo CO rH • os s* s P e s» c P E £ CD OS rH rH H1 00 OS rH rH rH i— ! lO CO CO * 05 t• rH o • • • os . OS vo * OS o VO c— • OS a o t4 O -H © © rQ 14 © -P CO X -P S3 o a & o © o 79 Gms- beets (yrcen roots) P (pp m in soil) K. M9, /As/^ctg Legend' B eet s __ ------Adsorbed zzs , \ -------- A t id-soh P i r V ----------Ad$-+ %cid-$o/- P \ ---------Exch- K / too — 700 •— 200 Exeh- M y! /75 §. coo /SO i 500 /25 u /OO 400 75 f 500 zoo 5-0 100 25 Sonic soil it t A ye 14 o f Silfolfe 8 "Nc VJ sot / JL X It 14 tu rn e d under (months) Fig* 9*- Sugar beet yields following alfalfa turned under at various stages of maturity, and F, K and Mg contents of the soils after the crop. 80 beets {green roots) Bo.Se sotuYotien % 700 70 400 40 400 3 00 : SO 'v ^00 40 :\ L e o e v< /: B e e ts ------ % bo.se s$t- 200 30 _ 20 to too i i Sem e i i a, o M CO O cd 5 ctrH CM to c— CM fH a a> to C4 a 00 • Oi O •o a rH cCM ■sjl * LQ o CD CO a CD iO o a o o tCM CM rH CM a CD CD ID rH a CD ID c— oa CO CO ■M' to a LO CM a CO CD to a to t- 'd1 a LO c- rH • CM CO *d« ft « ( —Hfa cd cd 3 a O to LO a rH to CM a CO CM to a rH to O a cCM LO o to CD O i— I a O 05 rH rH rH • O a • rH a a O LO 05 tCM CM to a LO CD CD 05 a co rH LO Ca LO 05 a 05 C- CD a CD LQ 05 a 05 CD ca cLO 05 o• CM O rH a O CM cO a 05 CD O a o• o o rH a LO O i— t o• o 05 rH a LO o 1 —1 o o o LO a CM LO oa LO LO a c~stf oa -M* o o to o o O LO rH CM CD E— o to ft rH •H O CQ & § CO c & ft c- oa o CO O rH a o> oa CD a eCM 30.4 per libs Table 29.- pH value, phosphorus, potassium, calcium and magnesium contents of the soil after the barley crop. acre 1 81 o d> iC | * 82 Table 29a*- Exchange capacity, percent base saturation, percent saturation of individual cations, cation ratios of the soils after the barley crop* CO to *toH CD t Q 00 o 00 o to 00 00 LO to LO c- 00 co cv CO fr~ LO t- co co CO cy c- to CO t - c O- LO o ao LO rH LO o c- o o o cy o cy cy cy cy CO 2 a to o cy •H LO LO CO g to to CO CO LO CO LO co to o- o » g •rl -P s tiD cy jS * c— ai o LO CCi LO 00 cy to LO '5l i * Cft • Cl «} O O K SS CD W $a C oD S Cl TD ■P i— I CJ si 0J a fj b Rl jl-pP o a > 00 rH o •r-i to LO o CO t- o oo o ca LO LO cy cy a> 00 LO CO to CN* * I —1 CO to • o cy Cft CO to to c— <—! cvi Cft CO o r—> CO co CD LO cy Cft oo t" LO Cft o C\c cy bto Cft to 53 a h * ® Q • 0 CO e tf—t LO co rH • Cft c- o CO CO to cy • LO CO O o o • o LO O- oo (ft • Cft • CO • cy o CQ LO CO CO i> s *a 25 cy • to co to • 1—I CD LO CO CO c- Cft cy Cft LO CO LO CO o LO • o t- LO CO LO I—i * lO 00 Cft 00 Cft Cft Cft • LO LO rH CO LO co LO o t> - • LO cy • Cft • c y CO » o LO cy Cft rH CO X! -P ri o a o 0) A 85 dnfs hurley f a r - d r y tops) p . p . i n \ s o il (P ) — ns iso ✓ / zs 100 - " " - ^ 7S so / ---------- A c id-sol / / / / / / P P ------- A d $ ■+ 3itid-$ol- P *— Exch•K Exc/J. M y -•--- - / — / * ^ ^' 3 S\ ________ __ V zs Sz.n\ c 4 B Aye 1 II 14- of soil* “A / c w soil i i i i i i 4 5 4 / / /4 Ck- t u r n e d u n d e r fa o n th s ) Fig. 10*- Barley yields after the sugar beets that followed alfalfa turned under at various stages of matu­ rity, and P, K and Mg contents of the soils after the barley crop* 84 % s^tu ration (K) \ r\ / \ / V * too --- 1— Gnts. &*r/cy ($ir-- 03 • c^- CH CH to CH ch to 1 o & a • CO cv 1— 1 i— 1 o O CO a i—\ • o C^ CH rH • . (u O •o 6 rH o GO 1— 1 1— 1 O CH rH LO CH rH O i— I rH i— 1 CH rH rH rH LO rH rH o O O O o O O o LO CH 03 LO D- CH CH CH CH CH CH O Cco . LO LO • LO . • * • to i— 1 * . . • P © P. Q) to CH p 01 o a © H * P O * O i— 1 03 O . O CO rH rH • O -xH 03 o• o o LO LO CH o• o 03 • to o » o rH rH 1 — 1 • O • t> CO LO O- LO • CO LO CH LO LO * Cxi *3* o • O « LO o • < 33 Q ch LO . c*- o* lO CH 00 rH 00 CH os O . LO O LO LO t- Cxi • tO LO o CO LO © s 0 © P © O < M 0 rH -p p © O CH 0 rH OO CQ to LO CH O • CO 03 CH . OS • LO LO . • . •k 65 ■ k Z to *k 65 » k •k CQ •k to o . to CO CO CO • • co CH CH c— • CO CD to . to oo rH ♦s w\ CO CO • os 00 CH o CQ CH O i— 1 . LO • fx< to co o % OS 00 « LO 03 . LO i— 1 • c~* LO 00 • to LO to o • CO . LO c• 00 to CO Oj . LO • h g M •k CQ •k CO o /Q IN J Jp * 1, adsorbed; 2, acid-soluble; 5, adsorbed+ acid-soluble ** See symbols, table 20. Table 5 0 pH value, phosphorus, potassium, calcium and magnesium contents of the soils after harvest of 5 and 6 months old alfalfa (before beets) and after the beet crop. 85 86 to CO to 0 0 O to X fed oo oo o o Cvi oo oo o o o o o CO o-• CO 03 to oo o to B Q *H P vO ( —) 03 to 00 to $ I —I CO to CO CO oo CO cy LO 03 03 vo oo 00 vo VO CO CO to o CO *CP fr- CO CO CO 03 CO v o vo CO oo CO cd to § •H P S3 LO 3 & ai O S Ohfed cd o O M to .tkO o to W) - rH co • 04 03 C- co co 03 lO co CO CO • 03 O VO • 03 00 • O- co C4 CO • 03 to x 0 rH to to h o Ci—I 0 to co c h P to to o Ch to Chto f—I S * sj 04 • • 03 XI P rH • 03 to LO O- c- O to o P LO VO o EXd S• H C- rO p to to to P rO Ch rH o p 243.5 0 272.9 0 Checks 195.1 0 234.4 0 maturity, on May 25, 1946, and the yields are recorded in Table 32* Following harvest, the soils in all jars were sampled for labor­ atory tests. See Tables 38 and 38a* Nitrification studies were also made of the beet material turned under, and these results are found in Table 36. To further investigate the effects of sugar beet tops and roots when turned under as green manure, the preceding experiment was sup­ plemented with another in which the beet material was allowed to decom­ pose 3 months before the seeding of a crop. Various chemical fertilizers were also added to the decomposed beet residues at seeding time in an attempt to study the nitrogen tie-up wherever it occurred. A Brookston loam was put into jars as previously described for the sugar beet crop. The moisture equivalent of this soil was 33.7, as 100 C*ns. b arle y, c o rn (Sir-dry tops) PP**l- in soil (P ) Lbs/sere ( K, My) Base s atu ratio n Plant tops Adsorbed P A cid-soh P Ads- + ccid-sol' P Exch- K £xeh- M j % base s a t u r a t io n 2S0 --a 200 ao too 40 so 20 2S0 ISO - -t> 40 SO 20 i Coyw. W i s h e r i T R ck* Soil treatment (see C o m * A/pPd'nee ----------------T TR symbols, table 3/) Fig* 11*- Yields of barley and corn in Wisner and Napanee soils, amounts of P, K, Mg, % base saturation of the soils after the crops, and amounts of N pro­ duced in 8 weeks in 100 gms. of the soils receiv­ ing beet tops (T, 2 gms.) and beet tops and roots (TR, 2 gms. of each). 101 determined by the Bouyoucos method (15) • To simplify the calculations (done on an air—dry basis to bring the soils up to their optimum moisture contentsj it was considered as being 55# Sugar beet tops and roots iden­ tical to those used in the preceding experiment were incorporated with the top 6 inches of the soil in each jar, and the jars brought up to their correct moisture contents on June 22, 1946. The soil in all Jars, in­ cluding the checks, was kept moist for 3 months, i.e. until September 21, 1946, when proso millet (also called Hog millet, Brown Corn millet) of the Yellow Manitoba variety was planted. The amounts of beet tops and roots turned under were the same as those used previously: 16 grams of air-dry tops and 16 grams of air-dry roots, each 16-gram portion re­ presenting 2 tons of dry and 10 tons of green material per acre. The fertilizers applied at seeding were: phosphorus, in the form of super­ phosphate 20$, at the rate of 4 grams per jar (1000 pounds per acre); potassium, in the form of muriate of potash 50$, at the rate of 2 grams per Jar (500 pounds per acre) ; nitrogen, in the form of nitrate of soda 16$, at the rate of 4 grams per jar (1000 pounds per acre). The treat­ ments were triplicated, the jars randomized and moved around once a week. An outline of the experimental set-up is found in Table 35. Twenty proso seeds were planted in each jar. Nearly all of the 20 seeds germinated in each case; but when the plants reached 2 or 3 inches in height, damping off took place. None of the 3 replicates correspond­ ing to treatments T+P (beet tops-fP) and TR+P (tops and roots**?) showed any sign of damping off. The disease was found to exist in all other jars and was particularly bad in those having received tops plus N-P-K and tops and roots plus N-P-K; it was also severe in the checks with and without N-P-K fertilizer. 102 Table S3*- Outline of greenhouse set-up to study the effects of decomposed sugar beet tops and roots as green manure for proso. Beet material turned under Tops; Fertilizer used at seeding Symbol used for treatment None «t T N T+N P TfP 41 K T+K W N-P-K Tops+roota> None w 41 Tops at seeding Tops+roots at seeding T^N-P-K TR N TR*N P TR+P K TR+N-P-K None T at S: it Checks: N-P-K Checks None TR at S Checks+N-P-K at £F Checks The plants in all pots were adjusted to 15 per jar, the dead plants being replaced by surplus ones from other jars* One week later* more plants had died, and this time were replaced by new seed. The following week, the new seed had germinated, but the plants were again affected with damping off. After this third attempt, it was decided to discon­ tinue reseeding and to grow the crop regardless of the uneven distribu­ tion of plants in the jars. 103 Six weeks after sowing the proso, November 6 , 1946, the soils in all jars were sampled and tested for ammonia nitrogen and nitrate nitrogen. Results are given in Table 37. The jars or the individual plants that remained unaffected by the microbial infestation exhibited normal growth. The fact that, in all cases, the 3 replicates showed exceptionally good agreement as regards the number and height of plants affords a good reason to conclude that the particular treatment was responsible for the phenomena observed. Apparent­ ly, phosphorus alone did not prevent damping off; it seems rather as if the ratio P/N+K was the determining factor. Aliis verbis, phosphorus must be in excess over the other nutrients to exert its beneficial action. R. L. Cook*, Professor of soil fertility at Michigan State College, haa observed that, when sugar beets were grown with small applications of commercial fertilizer, damping off was of common occurrence; but, as the years have passed and fertilizer applications have been greatly increased, this disea.se has become less common. If v/e consider that phosphorus fer­ tilizer was -always applied in excess of the plant *s requirements and that it is not lost by leaching, it may be assumed that this P/N+K ratio in the soil has grown larger and to an extent favorable to the preventing of damping off. It is said that phosphorus favors the development and in­ creases the vigor of the root system. In the proso crop, the most abun­ dant root growth was found where phosphorus had been applied in excess over nitrogen and potassium. (See Table 34). Shortly before harvesting the proso, pictures were taken of the crop. Plates 1, 2 and 3 show the effects of various soil treatments on * Private communication. 104 Plate 1.- Proso following the turning under of sugar beet material. 1 , tops, 5 months decomposition; 2 , tops at planting; 3 , tops and roots, 5 months decomposi­ tion; 4, tops and roots at planting; 5, tops, 3 months decomposition, plus N-P-K at planting; 6, check plus N-P-K at planting. 105 Plate 2.- Proso sown 5 months; after the turning under of sugar beet tops; and roots, 1, no fertilizer; 2, N; 5, P; 4, K; 5^ (Fertilizer added at seeding time) 106 Plat© 5*- Proso sown 3 months after the turning under of sugar beet material* 1, tops; £, tops; and roots; 5, tops plus P; 4, tops; and roots plus; P. (Fertilizer added at seeding time) 107 Table 34,- Yields of proso following the turning under of decomposed sugar beet residues* Figures give sum of triplicates* Soil treatment* Proso yields, in grams Green tops Air—dry roots Air-dry tops T 45*6 11.1 8.2 T+N 37.0 10.0 6.1 T+P 91.3 29.3 10.8 T+K- 51*6 15.6 4.8 TtN-P-K 38.0 10.0 3.8 TR 64.2 18.2 5.0 TR+N 26.6 7.6 3.3 TR+P 85.2 28.2 9.1 TRHt 53.9 13.9 3.9 TR+N -P-K 21.2 5.2 £.7 T at S 66.2 16.2 4.8 TR at S 58.4 12.4 4.9 Ck.+N-P-K at S: 22.2 5.2 2.0 C hecks 25.6 6.6 1.6 * See ^rabols, Table 55* the proso crop. At harvest, January 6, 1947, the roots were removed, washed, dried and weighed. the roots. Table 34 gives the proso yields along with the weights of Obviously, the soils where phosphorus ha4 been added in ex­ cess over nitrogen and potassium gave the best results as concerns height, number of plants (no damping off) and root development. Slight nitrogen deficiencies appeared on the check plants and in 108 Proso tops Proso roots ( N H ,+ M 0 J N i n J i rs (NH^+NOjlN iif tvTTiblers 90 30 20 to 50 40 30 20 JO Q. ■*> S o il >C > J trcn trtten t tc ^ ^ CO «— I *L. - ^ L. (see s y ^ io /s ^ t a h / c 33) 2 os ° Fig. 12.- Proso yields and amounts of N per 100 gms. of soil 6 weeks after adding fertilizers and seeding proso (jars), and 6 weeks after adding fertilizers (tum­ blers) ; beet material was added 3 months before fertilizers were applied. 109 Table 35*— Yields of oats following proso. triplicates. Soil treatment* (for proso) Figures give sum of Oat yields* in grams (air-dry basis) Total tops Grain Straw T 227.6 82.7 144.9 T+N 295.4 105.8 191.6 T+P 247.5 84.9 162.4 T+K 230.7 86.2 144.5 T*N-P-K 298.1 105.5 192.6 TR 221.7 73.9 147.8 TR+N 315.5 103.3 212.2 TR-fP 235.4 72.9 162.5 TR+K 223.8 73.8 150.0 TR+N-P-K 333.4 113.5 219.9 T at S 207.4 74.0 133.4 TR at S 135.7 52.8 130.9 Ck.+N-P-K at S' 295.3 109.7 185.6 Checka 204.6 68.3 136.3 * See symbols* Table 35. those jars where tops and roots had been turned under at seeding. Soils were sampled at harvest time and analyzed for mineral consti­ tuents. For results* see Tables 39 and 39a. Nitrification studies of this sugar beet material used as green ma­ nure were also made in the laboratory, and the results can be found in Table 37. Following the proso crop, Huron oats were seeded on January 27* 1947* 110 Table 36*- Milligrams of nitrogen accumulated in 100 grams of soil receiving 2.0 grams of beet tops or roots (or 4.0 grams of tops+roota) during a 4 and an 8-week incubation period. Beet material incubated NH4-N Wisner soil NO3-N (NH4*N05)H NH4-N Napanee soil N0g-N (NH4^N05)N 4-week period: Tops 0.56 5.39 5.95 0.21 4.99 5.20 Roots 0.56 0.77 1.33 0.35 0.42 0.77 Tops*roots 0.42 1.42 1.84 0.56 1.26 1.82 Checks 0.21 4.11 4.32 0.42 3.83 4.25 Tops 0.49 7.42 7.91 0.35 6.09 6.44 Roots 0.49 1.75 2.24 0.42 1.26 1.68 Tops+roots 0.42 4.06 4.48 0.42 3.50 3.92 C hecks 0.28 5.74 6.02 0.49 4.88 5.37 8-week period: at the rate of 20 seeds per jar. When the plants reached 6 inches in height, they were thinned to 15. The oats grew well and no damping off occurred. After 10 weeks growth, i.e. on April 7, 1947, deficiency symptoms were noticed, and plant tissue tests revealed that potassium was high in all plants, but phosphorus and nitrogen abundant in those plants only to which nitrogenous or phosphatic fertilizer had been applied, either alone or as part of a complete fertilizer.. In all other plants, phosphorus tests were low and tests for nitrogen (nitrate) were blank. These oats were harvested on May 24, 1947, and the yields appear in Table 55. Ill The soils, after harvest, were sampled for laboratory investigation, and the results of the various analyses are found in Tables 40 and 40a, B— Laboratory work, a) Nitrification studies: The sugar beet material turned under as green manure for barley and corn was incubated in the laboratory. Use was ma.de of soils identical to those that grew these crops in the greenhouse, viz., Wisner and Napanee. The procedure followed is described in part one, lab­ oratory work, with the exception that the moisture maintained in the tum­ blers was 29 per cent (Wisner) and 32 per cent (Napanee) , figures in ac­ cord with the moisture equivalents of the soils as determined by the Bouyoucos method (IS)♦ Also, nitrogen was distilled into N/lO HgSO^ and titrated with N/lO NaOH, using methyl red as the indicator. Two grams of either tops or roots were incubated in 100 grams of soil. When both tops and roots were incubated together, 2 grams of each were used. Nitrification started on November 6, 1946, and ended on Decem­ ber 4, 1946 (4-week period), and on January 3, 1947 (8-week period)* Results are given in Table 36. When the proso crop in the greenhouse was 6 weeks old (November 4, 1946), and the beet material had been decomposing for 4§ months (since June £2, 1946), the soils were sampled and tested for nitrogen. The sampl­ ing and testing were performed as described in part two, laboratory work, c). Table 37 gives the results obtained. A laboratory nitrification study was *1 so made of this same beet 112 Table 57.- Milligrams of nitrogen per 100 grams of soil in jars growing proso and in laboratory tumblers, 6 weeks after adding fertil­ izer and seeding (jars), and 6 weeks after adding fertilizer (tumblers) ; in both cases, after 4|- months decomposition of the beet material. Laboratory tumblers NO3-N (NH4*N05)N T 2.57 7.89 10.46 0.35 9.10 9.45 T+N 3.54 26.24 29.78 0.28 53.13 53.41 T*P 3.70 9.41 13.10 0.35 9.52 9.87 T+K 3.22 10.59 13.81 0.35 8.54 8.89 T+N -P-K 3.22 23.18 26.40 0.77 52.15 52.92 TR 3.06 9.82 a 00 00 n h 4-n • Greenhouse jars^ NH4-N NO5-N (NH^NO^N 0.42 7.84 8.26 TR+N 5.71 48.88 54.59 0.28 51.17 51.45 TR+P 1.18 8.90 10.08 0.28 7.70 7.98 TR+K 1.05 8.70 9.73 0.28 7.14 7.42 TR*N -P-K 1.51 45.85 45.36 1.05 48.02 49.07 T at S; 1.01 18.14 19.15 0.35 7.42 7.77 TR at S 1.05 r o • 00 Soil treatment* 13* 88 1.19 3.65 4.84 Ch.+N-P-K at S 1.34 40.58 41.93 3.92 46.20 50.12 Checks 2.43 15.04 15.47 0.42 5.53 5.95 * See symbols, Table 35. material which had been turned under and allowed to decay 5 months before seeding. The laboratory study simulated the greenhouse set-up. Brookston soil was used. Identical Two grains of either tops or roots (4 grams of tops plus roots) were mixed with 100 grams of soil in glass tumblers. The soils in the tumblers were brought up to their optimum moisture contents 115 (November 6 , 1946) and kept so for 5 months (until February 6, 1947). At the close of this period, the various fertilizers were added to the soils sand incubation continued for 6 weeks. The beet material/soil ratio and the beet material/fertilizer ratio were the same in the tumblers as in the greenhouse jars, except that in the tumblers it was magnified ten times. The quantities of fertilizer used per tumbler were 0.5 grams of nitrate of soda 16%; 0.5 grams of superphosphate 20%; 0.25 grams of muriate of potash 50%. At the end of 6 weeks (March 20, 1947) , nitrogen was determined in each of the duplicates according to the method described in part one, laboratory work, b), with the exception that ammonia nitrogen was distil­ led into N/10 HgS04 and titrated with N/lO NaOH, using methyl red as the indicator. The results are found in Table 57 along with those obtained from tests in the greenhouse jars. In comparing both laboratory results and data secured from tests in the jars, it should be remembered that in the jars, following the 5 months decomposition, proso had been growing and absorbing nutrients for 6 weeks, whereas in the tumblers, following the 5 months decomposition, nitrogen accumulated for 6 weeks. b) Study of soils: The soils were submitted to chemical analyses before re­ ceiving the various treatments and also after cropping. The methods used are those described in part one, laboratory work, c). Data for the soils ana­ lyzed are given in Tables 38, 58a, 39, 39a, 40 and 40a. fH CD Oh CO o H a c re CM • -3 ' • to to rH rH to to • to to cm • to • 04 c« CO to • Eto 00 to rH • o to rH ♦ o to to rH • O CO rH rH * O t 1 » 1 04 04 * o to * to to CM • CM * CM * CM rH • to CO to to to is h * CD CO p * a * tj0 CD O • o a i—i rH • O rH • O 3 rH • O 1 1 I CD a , a> f-i CO o ■D _1 & * 1 1 P CD P* CD U CO o fft 3 bd 05 o rH cm r-H 1—1 rH • O i—i » o to • to • E— i—1 CM • • CD CO cx a CO • uo CD O • o a rH jfe i—i ♦H fcQ O CO •1—t • cm * E'­ er) cm 1 1 cu * 05 05 «=^ rH 05 rH rH rH 05 rH • O to rH • O O • to CM CM to • to « to t— cm e- • * to o • to 1— 1 04 o 1—1 05 i—! 05 i— 1 • o 05 1—1 o o to o Er- 04 rH * o to FH • CD CQ * Q0 CD O * o a rH to 1 1 to • oo • 04 rH 05 CO rH 05 LO H I— 1 • E*- 04 • o O to • o CM o • e- • co CM rH to OO CO O rH O • c1— f to t- 1—1 CM LO • 05 rH E— i— 1 GO • o cm • 1—1 CM CO 0 CO 0 rH to 05 04 C~LO CM to Di—1 to 05 CM 04 * O 04 • O • to * 15— E— to O to CM 05 O CO to O rH O O LO 04 * 04 to CM LO to CO O 05 rH o 04 04 05 o • LO 04 to CO c— 00 rH EOO i—1 O CO cf5 E— 05 CO i—1 • o o 1—1 CO CO 1—1 CO i— 1 • o 04 rH rH • O to • VO • t- O 1—1 rH • o • 05 rH to 04 O 1—1 rH • O * OO rH to • CM »—I 3 rH • O 04 05 to to o o o cm LO CO rH to • 1 oto rH • O • * • • CO rH cm ao CM • O 05 CM • O CM • O to • O 0 o * O o • LO 00 • o 05 • to 1— 1 rH o to to to • • 0 • • O * O 05 co rH • O CM to * CO 05 rH rH LO CM • O O • O CM rH to • C— E“- to to e— to • CM 05 o to LO to to CM LO * E— LO lO • CM O 05 05 E— CM CD a • & • p * $ r-H cu ts , • o • to a a> p ^ p to • CM CO i—I K CO • to •H {>i O CQ a, 0 EH E— to • 15- P Ft CQ P 44 H H» CQ CO o © • • t- P O O • • CM ca O O O O O ca CO iH • ca CO rH • o Cvi CO rH * o ca CO rH • o CO CO rH • o ca rH • O LO CD C— LO o 00 CQ LQ ID H4 O CO LO o CO CO OO rH H4 • 'st1 rH ^ O CQ • H4 i— 1 co CO o • ID rH Ca • cn H4 rH rH • to rH CSi OO • rH a> rH 60 cca rH LO ca o o CO LO ca • o O • O ca rH LO • tco W o • LO o rH LO • c- O • LO OO LO • CCQ i —1 O • LO LO I— 1 o • LO CO o * Q o LO H1 « rH ca • to 32.9 LO u LO • ca CO CQ • ca CD rH • ca CO LO • ca 60 CO * t— I CO « CO CO rH • ca CO CQ • ca co CO CO rH • o H* CO i— 1 • O H* CO i— ! • O CO CO rH • O ca CO rH • o H4 60 i— 1 • O CQ ca rH • o c— to rH • O ca CO *H • o CO CO iH • o O ID OO LO o CO CQ LO o CO H4 LO LO H4 O CO LO rH CQ LO LO CQ 60 LO LO H4 O CO o ca c— LO LO LO CO LQ LO o CO CO LQ tH CQ LO H4 rH t— * LO rH O co LO • CO Q CD * CO rH CO CO o • ID rH ca H4 c— * CO 03 rH rH H4 rH * LO i— I ca H4 c• i— ! CO co o ♦ LO rH H* H4 • CO f— I CO LO ca • rH H4 O 05 • H1 rH LO • CO rH • to ca ca rH • co CO ca LO • CO co rH rH • CD CQ i— 1 ao • 03 03 rH 1— 1 • CO H4 ca rH • CO rH • CO 00 1— 1 CO • CQ CiH LO • CO o ca LO • CO t>t— 1 LO ao ca * CO CQ ca • o CQ CO ca • o t- CH • o CO LO ca • o rH rH 60 • O rH i— t 60 • O H1 CO ca • O CO ca • o CO ca • o co o t CVi • o o • LO • ft ta * & bG o ♦o 0 rH rH u © fit 0 Ph CQ O 3 S u 0 • a> • & • 0 R QO o o rH PH a> rH CQ rH H4 ca o • i— 1 M • © f t0 s • b O o »o S3 rH jk rH 3c •H O 0 si •H * $ • ca € f t • ft *$ rH • • • • o o rH • •H H4 o • rH » b - Ph tej ft & la* +> d 0 0 0 a •iH ca <5 0 f-t (H _p -P rH 0 0 d CO — - CO to • CO tfx rH •H •• O 0 0 0 O rH t-t td ft d •H Sh bQ 0 •H -P Pi *H O <3 E-» -p Ph >2i 4* EH Ph 4 - Sr* W + EH t t25 4EH Ph Eh £5 +Pi EH Ph 4ft Eh £ Pi Eh t*J 1 Oh 1 HCG Eh CQ +> 0 Eh CD -H cd Ph Eh t P-* 1 s 4*• M O 0 M o 0 Di o * See symbols, Table 33# * 1, adsorbed P; 2, acid-soluble P; 3, adsorbed+ acid-soluble P Table 39,- pH value, phosphorus, potassium, calcium and magnesium contents of the original soil and the soils after the proso crop that followed the turning under of beet residues. Same data for soils before the oat crop. Ph 0 ft 0 acre 1 116 10 to * rH C0 . 04 H1 05 . rH LQ CO * rH 1 —1 co • 04 03 <— * . 04 CO C• rH 00 « 1— 1 LO ♦ LO CO • CO • 04 CO 02 • rH LO O LO 00 • CO LO O lO 03 * CO 10 0 * 1 —t CO LO s 0? . ca O rH 03 • rH * rH rH rH rH LO . LO rH rH • O rH rH CO * 03 O 1— t 10 • rH O 1— I • 04 rH rH • OO O rH 03 • iH O rH CO 05 • O LO to • rH 04 04 • 1— 1 -cH 04 * rH CO to » rH O fcej • rH O rH * 1— ( 03 rH « rH LO 04 . 1— 1 LO • rH - a> ca • cri -P ,Q CQ 04 • H* c- co . LO t~- co • to 0- LO . 05 t- H* • 1— 1 c- 04 • 04 fc- CO • LO COO • 03 rH O LO 04 • O 04 0 0 0 « 1— ! 0 LO Oi . 0 04 0 0 0 * rH 04 O LO Oi • rH ot CQ IS •H CQ w of • O •O S i— 1 3?= +3 'co' jrj (D Fh FH -P -P rH CD *H Q> O 0 CO - rH •H •• O O CQ CQ O rH fn cd Cl, d •H Fh txO $se s $ tu r$ tio n 400 to 3S0 70 3oo LO zso SO zoo 40 /So 30 /oo 20 so 10 H *•* V- ou h- X i CL oc h~ H- oL i- Q. cC ad h- H I CL z <-0 oo h (.see / / v»| I— Cd QC S o i l tY C ^trricrft Lry syiri&o/s, t^b /c S3) P. z * o Fig. 13*- Oat yields following proso, amounts of P, K and Mg and % base saturation of the soils before the oat crop (or after the proso). 119 u © to to 02 O rd c d t»o a Ph • co to LO to IO LO to D- 00 LO a r-H cm * CO o O co to LO to Cto I—* o o CD CO CO CO « oo -CP o u < D P, 0) LO uo c— o CO rH CO to o a 3 o o o C— rH OO • CO 05 3k P o LO CO LO I--1 CO cvi CO C- 05 rH CO CO LO LO CO 00 i— ! t- LO 05 * cvi LO CO LO CD h o ffl oa o• o o 00 00 o CO 00 o LO o LO 05 LO o- 00 co w CO C\2 cm LO W LO <5*1 d* LO CO rH CO co CO CO CO t>- r-< • • CO CO CO t- LO LO D*- e- LO i —I o LO LO O CO CCO o 05 o 00 o• CO I— I 05 rH O 05 05 ao c— CO CD LO CO CO o o o- CM t- co CO CO CO to CO CM to CO CO co ti cd co 3 © CO CO W o iH JH f-t*0 P +5 © Ph I -P P r-H '■ ' *rH O P-P ' to ■P cd © d © >-> CO co *. p^ Eh CO Id co -p © P4 6h * f Ph I is CO M o © rP o o See symbols, Table 33. 1, adsorbed P; 2, acid-soluble P; 3, adsorbed+ acid-soluble P Table 40*- pH value, phosphorus, potassium, calcium and magnesium contents of the soils after the oats that followed the proso crop. P, © LO rH • rH (30 *0 S •H CQ J*H cd O i—1 • rH CO O • rH O CO rH • rH rH tv • i—1 rH CO » LO OO O E• to O i—I CO * tv o 1—1 H1 • rH rH rH rH rH • rH O O • •H rH O • »H cv o • rH CO co ♦ 1—1 O • i—1 cv • to o rH ao O CO • iH O i—1 LO . o o rH rH • w o 1—1 LO , c— E- o • 00 o rH to • <51 CXI 00 . rH O rH w rH • to« rH 04 • rH E'­ en • o & * 0 * a M —** * e- ok o *H -H 0 Pi <71 O • 00 d • E- • i—1 00 OO OCO CO « cv rH i—1 O • o 1—1 rH • CV o rH CO • LO o rH E— • <51 o rH « CO <51 - (30 € S3 O •H OS ■P o ffj O • (ft w $ O CO • tV rH rH to . o rH E• o> o rH O CO * o EO• O CO E• o i—1 O • rH CO CD • O CO o. o rH E— » O EE• O tv 05 * o rH 05 • o o CO • O E^ OO . O t00 • o <31 CO * O o E• o o E— • o rH E« O O E* O LO E— • o CO E• o O E* O LO E. o o o o E• o CO CO • o tv E« o 94 ■ rH E— « O « CO E- rH • LO E— o • GO c- Ol * to E- cv * ECO LO • CO E— CO • iH E- CV • oo t- tv • Tj* E- CO # CD E- o o- rH • rH E— LO • CO E*- LO • CT5 E- co * OO « 00 CO <51 » LO E*- LO . o tv • 94 o o o o o O LO cv • O • O O LO . LO • 94 o 94 o cv o 94 » rH O i—1 o M 0 O 0 (30 ss e- E— • O td 0 0 O Ph 0 o Ph 0 0 CO -P PQ cri a» • <71 0 e- EE- • c- E'­ CO CO E- CT1 E— en • LO E- CO . LO OO • E— C- o o O LO tv • O O O LO * O LO cv • LO O O LO • • 00 • • E- * CO E— • 05 E- VS. • ft Ph • cO 0 0 O • O * 0 £ a ❖ +> a 0 m 94 to • 05 rH (30 o o rH o o LO LO o O • w 94 • CV o o LO • d rH 94 o 94 o 94 t» C9 • <51 rH 0 p< o cv O LO 94, . O cv CQ 0 + 5 *H cd W 0 0 Pt Pi -P LO Cft P« 0 V TO O -P ctj C m 3 o Pi 0 0 h rH 0 •H 0 B O ,n -p C Q ^ \ Ui rCS Or i f*2 1 Ph Pi O *H 6 -i {25 + £h Ph H* EH US ■+* Eh 1 + Eh Ph EH \Zi H- Ph Pi EH Pi EH + Ui + Ph Eh Ph CO Hpi EH 0 1 !25 Eh CQ Pi 1 -P $ & •V. Pi EH o symbols, Table 33. Table 40a.- Exchange capacity, percent base saturation, percent saturation of individual cations, cation ratios of the soils after the oats that followed the proso crop. 120 CQ o 0 X3 O 0 0 CO * 121 p.p.^- in soil (P) % Mse L6s/%crc (K) 6*75 aits (lirdry tops) s $ t u Y$tio n . My, /bs/^cre Le€fG'qJ:--------A d s o r b e d P ------ A c/J-SoA P Ads. + ae id •sol P — •--- +- Exe/i- K Exch M y 34 0 30 3ZO 70 280 LO 240 50 200 40 /LO 30 /20 20 60 to 40 I____I JL XL Gk2? % £• £ J _______ |_______ L or H & + Q£ H* oc I ■■■■ I I CL. ■*1 + *- on S o i ! t r c A t n \c r ( t (sec symbols, i o i / c 33) x LO ■ ** cc h- x CO VQ- ^ I Q. tj Fig. 14.- Oat yields following proso, and amounts of P, K and Mg and $ base saturation of the soils after the oat crop. 122 C- Discussion of results. The sugar beet green residues turned under as green manure produced different effects according to the crop grown* Table 52 (Fig. 11) shows that on barley, in both Wisner and Napanee soils, the beet tops had a beneficial effect, while the tops and roots turned under had a detrimental effect* On the other hand, corn, on both soils, produced the highest yields following the incorporation of tops and roots. The turning under of tops alone caused higher yields than those produced in the check pots. The corn on both soils failed to grow normally, whereas the barley grew well* These differences in barley yields are easy to explain. It may be seen from Table 56 (Fig. 11) that beet tops caused better nitrification than did the checks, but beet roots were so detrimental that, even mixed with an equal quantity of tops, the pots into which they were mixed pro­ duced less nitrate than did the checks. Turk (85), studying the nitrogen tie-up by soybean plants, found that the roots were the cause of the nitro­ gen shortage in the soil when they were turned under at an advanced stage of maturity. The rate of decomposition of the plant parts was, in decreas­ ing order: tops, tops and roots, roots. A mere consideration of the chemical composition of sugar beets also leads to that conclusion. Carlson (17) gives the following figures, on a dry basis: sugar beet tops, 2.0% nitrogen; 0.2% phosphorus; 2.5% potassium; sugar beet roots, 0.7% nitrogen; 0.1% phosphorus; 0.7% potassium. figures may vary a These trifle with the nature of the soils and the fertilizer applied to the beet crop, as shown by Tyson (84) and Hirst and Greaves (35), but they represent fair averages. 125 Now, considering the corn yields, the picture is reversed. The only apparent explanation is to be found in the phosphorus and potassium that have been added during the growth of the corn. Had these fertilizers not been applied, the corn would have died sooner* Besides, the plants in the poorest condition when the fertilizer was applied were those plants having received beet tops and roots. As mentioned previously, it is pro­ bable that the phosphorus and potassium fertilizer added stimulated bac­ terial activity and caused a temjjorary increase in plant material break­ down or in nitrate production. The old saying that corn does well in undeeomjiosed manure might be recalled, but it affords no explanation of scientific character. That barley has done better than corn seems to be due to the fact that it requires only one third the nitrogen required by corn (8). The chemical analyses of the soils after the corn crop (Table 38, Fig. 11) showed that phosphorus and potassium were much more abundant where beet tops and roots had been turned under. correlation with corn yields. In no way was there a It is more probably due to the action of COg evolved that solubilized these soil constituents, but which were not taken in by the plants. Except for nitrogen in the barley crop on both soils, no other cor­ relation is found in Fig. 11 between yields and soil constituents. The proso yields following the turning under of decomposed beet ma­ terial (Table 54, Fig. 12) do not represent the true fertility of the soils, because damping off occurred among the proso plants, and the yields reflect the effect of the disease. With only two treatments did damping off fail to occur and those two treatments were where phosphorus alone was added (1000 pounds per acre) along with tops or tops and roots. This resistance 124 of the plants- to the disease is well illustrated in Fig. 12 where the two peaks for proso yields correspond to the treatments mentioned. The weights of the roots correspond fairly well to the weights of the tops* Since this question has been treated previously, please refer to the paragraph dealing with the greenhouse for additional comments. Of more value is the nitrification study of beet material in labor­ atory tumblers. Fig. 12 is impressive with its peaks, each one correspond­ ing to an addition of nitrogen to the beet material incubated. Several observations can be made (Table 37) • After 4J- months decomposition, the results were as follows: The beet tops proved beneficial as compared to the checks. Tops turn­ ed under at seeding time were less effective than were those allowed to decompose, but were more effective than the checks or tops and roots turned under at seeding time. Tops and roots together were detrimental as compared with the checks. Tops alone plus nitrogen were better than tops and roots plus nitrogen, thus denoting the still nocive effect of the roots after 4 months decomposition. and roots plus N-P-K. The same holds true for tops plus N-P-K and tops Tops without the addition of fertilizer were better than tops and roots without fertilizer. After 7 months decomposition, and as measured by the oat yields that followed proso (Table 35, Fig. 14), it was found that the picture remained unchanged. Oat yields were in accord with the nitrate accumulated in lab­ oratory tumblers during 4J- months decomposition (Table 37, Fig. 12) . An exception is found: topa plus nitrogen after 4j months were better than tops and roots plus nitrogen. After 7 months, the reverse was true, thus indicating that the injurious effects of roots had disappeared after the 125 longer period of decomposition. and tops and roots plus N-P-K. The same holds true for tops plus N-P-K In other words, after 7 months decomposition, tops and roots plus nitrogen were more effective than tops plus nitrogen, while tops and roots alone were still inferior to tops alone, but were better than the checks. Tenney and Wnksman (96) show that a minimum of 1.7 per cent nitrogen is required in the plant material to supply microbes with their needs, al­ though this rule might be limited by the nature of the material. They (81) showed that addition of nitrogen hastens the breakdown of carbonaceous substances. Beet tops contain 2.0$ nitrogen and do not exert any detrimental action; the beet roots contain but 0.7$ nitrogen and their depressive ef­ fect is striking. The mixture in equal portions of tops and roots con­ tains 1 .5$ nitrogen and the injurious effect is apparent. The study of the soils before the oat crop (Tables 39, 39a, Fig. 13) shows that the additions of potassium along with the beet material produc­ ed peaks in the exchangeable potassium curve, and the additions of phos­ phorus similarly affected the adsorbed phosphorus curve, although no cor­ relation with yields was obtained. The percent base saturation is cor­ related with the oat yields only where beet root material is turned under. The same holds true after the crop, but the correlation is very weak* It remains that sugar beet tops, when turned under, will increase the nitrogen content of the soil and will benefit the following crop. Sugar beet roots have a pronounced depressive effect on nitrate accumula­ tion in soils. Beet tops and roots in equal amounts will also be in­ jurious after 8 weeks, but favorable after 4 months, although less favor- 126 able than tops alone* At the end of 7 months, tops alone are still better than tops and roots, unless nitrogen is added. In this case, the reverse is true. Remarks on soils: The correlation between percent saturation of the soil colloids and the crop yields, logically stressed by Parker and Pate, Hull, and by Pierre (68), who quotes these authors, was not supported by the SA7UXA7/M results of this study. It should be expected that the percent0should correlate with yields only when all other factors affecting plant growth are favorable. It has been reported (36) that the nature of the complemen­ tary cation will affect the ease of release of a given cation of a given percent saturation. In this study, due to the fact that nitrogen often became the limit­ ing factor in plant growth, the percent saturation of total as well as individual cations failed to show any relationship with the crop yields. It remains true, however, that for soils with different exchange capaci­ ties, the percent saturation has and will yield helpful information as compared with data obtained for exchangeable cations. SUMMARY AND CONCLUSIONS A comparative study was made of the memorial value of alfalfa at various stages of maturity, and of sugar beet green residues. Total alfalfa plant samples 1, 2 and 5 years old, fertilized and un­ fertilized, were collected from the field on April 17, April27 and May 10, and were incorporated into soils for a sugar beet crop in the greenhouse. Alfalfa 4, 8, 9, 11 and 14 months old was grown in the greenhouse. At blossom time of the first alfalfa sowed (14 months old plants), the tops were cut and discarded, and another group of plants were sowed (11 months old plants), lUThen the last plants sowed (4 months old plants) blossomed, all plants (tops and roots) were harvested and incorporated into the ®same soilw (having grown the alfalfa) and into 91new soil’ ” (identical soil, not having grown the alfalfa) for a sugar beet crop in the greenhouse. Alfalfa S and 6 months old was also grown in similar manner and in­ corporated into the 11same soil11 and into *new soil1*, with and without ad­ dition of 2 grams of 2-16-8 fertilizer per jar (500 pounds per acre) at seeding of the sugar beets. A study of sugar beet green residues used as green manure was also con­ ducted in the greenhouse with grain crops. Nitrification studies were made on the plant material used as green manure, and soil chemical analyses were made to supplement the information secured from the various crops grown. The experimental data lead to the following conclusions: As regards quality, an 8-week incubation period shows that alfalfa tops of 1, 2 and 3-year-cld plants from the April 27 harvest produced the most rapid rate of nitrification, with the 2-year-old unfertilized plants proving best* The roots from the April 17 harvest nitrified most rapidly, and the rate decreased markedly from the April 17 to the May 10 harvest, and from the 1 to the 5—year—old plants* As regards quality and quantity combined (calculated nitrification of total amount of material, based on 8-week incubation tests), the 1-yearold unfertilized tops of May 10 and the 1-year-old fertilized roots of April 17 produced the most nitrate* Considering the total plant (tops and roots), the 1-year-old fertilized plants of April 17 caused the greatest accumulation of nitrate* The highest sugar beet yields were obtained with the 1-year-old fertiliz­ ed alfalfa of April 17* Fertilized alfalfa (tops or roots) generally nitrified more rapidly than the corresponding unfertilized alfalfa, although exceptions were noted• Considering either quality alone, or quality and quantity combined (calculated nitrification of total amount of material, based on 8-week incubation tests) of the 4, 8, 9, 11 and 14 months old alfalfa grown in the greenhouse, the tops of the 14 months old and the roots of the 9 months old plants proved best* Considering the total plants, the 9 months old plants resulted in the greatest accumulation of nitrates in the soil. Comparing the 4, 8 , 9, 11 and 14 months old alfalfa, the 4 months old plant resulted in the highest sugar beet yields on the ^same soil*1, where a decrease in yield paralleled an increase in age of alfalfa in- 129 corporated. In "new soil", the highest yields followed the incorpora­ tion of the 9 months old alfalfa, and a correlation existed between the calculated nitrification of the total alfalfa and the beet yields. 7.- The state of soil aggregation in the ""new soil" (soil potted for a shorter period) was better than in the "same 3oil" (soil potted for a longer period). The change occurred in aggregates larger than 0*5 millimeters, the smaller ones remained unaffected. 0*- The 5 months old alfalfa proved a better fertilizer than the 6 months old alfalfa for sugar beets in the "same soil", but in "new soil" the 6 months old alfalfa was better. The 3 or 6 months old alfalfa with­ out addition of fertilizer in "new soil" was better than the 3 months old with addition of fertilizer in the "same soil". 9.- Although sugar beet tops had a beneficial effect on the following crops when incorporated with soil at seeding time, they gave better results after 3 months decomposition. Beet roots had a depressive effect, even when mixed with an equal portion of tops. 10.- After 4 months decay, however, a mintture of equal parts of sugar beet tops and roots proved beneficial,although less beneficial than were tops alone, even when, in both cases, nitrogen had been added at the beginning to aid decomposition. 11.- At the end of 7 months, sugar beet tops and roots without hitrogen were still inferior to tops alone; but when nitrogen had been added at the beginning, tops and roots proved better than tops alone. 12.- Nitrification studies with soils not having grown the crop to be turned under gave results that did not apply to the soils that grew the crop. In "new soil", nitrification is much more rapid than in the "same soil". 15.— The percent saturation of total or individual soil cations in only a 150 few cases exhibited any correlation with the yields of the crops grown. BIBLIOGRAPHY 1* Alfalfa in Michigan. 1936. Mich. Agr. Exp. Sta., Cir. Bui. 154. 2. 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