EFFECT OF MAGNESFUM APPLECATEONS (3N THE YIELD AND CHEMECAL SQMPGSITION OF SQYBEAN’SF EinLLET, AND EEE‘E’EEA? GRCWN QN EHM’EEN EvEECE-EEGAN SQ‘ELL’; EN ENE GEEENFEOLESE Thesis Eor E339 Degree 0E M. Se: MECHEG‘EN STATE UHZ‘EEEEESETY K» N. Satyapgi 1956 EFFECT OF MAGNESIUM APPLICATIONS ON THE YIELD.AND CHEMICAL COMPOSITION OF SOYBEANS, MILLET, AND‘WHEAT GROWN ON THIRTEEN MICHIGAN SOILS IN THE GREENHOUSE By K. N. gatyapal A THESIS Submitted to the College of Agriculture of Michigan State University of Agriculture and Applied Science in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Soil Science 1956 ABSTRACT In order to evaluate the ability of Michigan soils to supplying mag- nesium to crops, a greenhouse experiment was conducted. Thirteen soils were used. Three crops, namely, soybeans, millet, and wheat, were grown to extract the magnesium from the soil. Magnesium was added as the com— mercial magnesium-potassium carrier known as Sul-Po-Mag, under three levels, namely, 60, 120, and 2&0 pounds MgO per acre. There was a control where no magnesium was added. Each treatment was replicated three times. Dry weight determinations of the three crops were obtained, and the plants were analyzed for potassium, calcium, and magnesium. The last two elements were determined on the Beckman DU flame spectrophotometer, while potassium.was analyzed on Perkin-Elmer flame spectrophotometer. The soils were analyzed for pH, organic matter, sand, silt, and clay, exchange capacity, total exchangeable bases, and exchangeable calcium, mag- nesium, and potassium at the start of the experiment. Exchangeable magne- sium, calcium, and potassium were determined on the soils after cropping by soybeans, millet, and wheat. All soils contained more than 10 per cent ex- changeable magnesium of the total exchange capacity of the soils. Significant response from added magnesium.was obtained for soybeans in only one soil, namely, Miami sandy loam, while soybean yields were signifi- cantly decreased on Brookston clay loam. For three soils, namely, Kalkaska sand, Brookston clay loam, and Houghton muck, significant increases in yield of millet were found, while a significant decrease in yield of millet on CBhtemo loamy sand, Plainfield loamy sand, and Kent clay loam was noted. In only one soil, namely, Kent clay loam, was there a significant re- sponse in wheat yields from added magnesium, while for Warsaw loam, a signifi- cant decrease in yield of wheat was found. Results of chemical analyses of the three crops reveal that in most soils with the exception of Emmet sandy loam, Warsaw loam, and Houghton muck, magnesium uptake was not increased beyond the 60 pounds Ego per acre level. In some cases, increase in soil magnesium enhanced the uptake of potassium by the crop, particularly in the case of millet and.wheat, and this increased potassium uptake was associated with decreased yields. On the soils used in this study, no magnesium deficiency could be found. All the soils used in this study had adequate amounts of magnesium in the exchange complex, and it is apparent that much response to magnesium additions would not be forthcoming. Magnesium fixation occurred only in three soils, namely, Thomas sandy loam, Kalkaska sand, and Houghton muck, the highest values being found for the first and the last soils. The remaining ten soils released magnesium in varying amounts, but the greatest release was found in the heavier soils. ACKNOWLEDGEMENT The author is greatly indebted to Dr. Kirkpatrick Lawton for his active support, constant supervision, and assistance during the course of this investigation, and to Dr. R. L. Cook, who was entirely instrumental in the author's coming to Michigan State University. The financial assistance of International Minerals and Chem- icals Company of Chicago is hereby gratefully acknowledged. CHAPTER I. II. III. IV. V. TABLE OF CONTENTS INYI‘RODUCTICN o c o o o o c o o 0 THE OBJECT OF THE INVESTIGATION . . . . . . REVIEW OF LITERATURE. . . . . . . . . . . . Occurrence and distribution of magnesium. Availability of soil magnesium to plants. Nature of magnesium in the soil exchange complex................. Role of magnesium in plant nutrition. . . Nagnesium-calcium-potassium relationships inplantsandSOfloooooooooooo I-‘LE’I‘HODS AND I~TA.TEQIAI.S . . . . . Greenhouse experiments. . . . Fertilizer treatments . . . . Cultural methods. . . . . . . Preparation of plant materials. Laboratory procedures . . . . Soils . . . . . . . . . . . . Analyses of plant materials . RESULTS AND DISCUSSION. . . . . Partial physical and chemical analyses of house $0118 0 0 O O O O O O O O O O O O O Yields of crops on different soils. . . Uptake of magnesium by the three crops. Relation between the various cations in the green- three crops 0 O O O O O O O O O O O O O O O O 0 PAGE 15 16 17 17 1? 18 21 21 25 36 to TABLE OF CONTENTS continued CHAPTER PAGE VI. CHEMICAL ANALYSES OF SOILS AT THE END OF THE GREENHOUSE STUDY. . . . . . . . . . . . . . . . . . . S2 Magnesium fixation or release in different soils. . 52 VII. SUI’EULBY ANT) CONCLUSIOTIS o o o o o o o o o o o o o o 0 SS LIST OF TABLES TABLE PAGE 1. Some physical and chemical characteristics of the thirteen.Michigan soils used in this study. . . . . . . . 2O 2. Soil reaction, exchange capacity, total exchangeable bases, and exchangeable magnesium, calcium, and potas- sium of the soils at the start of the experiment. . . . . 22 3. The exchangeable magnesium, calcium, and potassium content of soils supplied with varying amounts of magnesium at the conclusion of'the experiment . . . . . . 2h h. Dry weight yields of soybeans grown in the greenhouse on thirteen Michigan soils supplied.with varying amountsofmagnesium...................26 5. Dry weight yields of millet grown in the greenhouse on thirteen Michigan soils with varying amounts Of added magneSium o o o o o o o o o o o o o o o o o o o 27 6. Dry weight yields of wheat grown in the greenhouse on thirteen Michigan surface soils with varying amounts of added magnesium. . . . . . . . . . . . . . . . 28 7. The effect of increasing rates of added magnesium on the yield and uptake of magnesium by soybeans grown on some MiChigan 50118. 0 o o o o o o o o o o o o o o o o 33 8. The effect of increasing rates of added magnesium on the yield and uptake of magnesium by millet grown on SOme Michigan $0113 0 o o o o o o o o o o o o o o o o o 0 3h 9. The effect of increasing rates of added magnesium on the yield and uptake of magnesium by wheat grown on some TfiChigan $0115 0 O O O O O O I O O O O O O O O O O O O I O 35 10. The magnesium and potassium contents of soybeans grown in the greenhouse on some Michigan surface soils sup- plied with varying amounts of magnesium . . . . . . . . . 37a 11. 12. 13. 15. 16. LIST OF TABLES continued PAGE The magnesium-and potassium contents of millet grown in the greenhouse on some Michigan soils supplied with varying amounts of magnesium. . . . . . . 38 The magnesium and potassium contents of wheat grown in the greenhouse on some Michigan soils supplied with varying amounts of magnesium. . . . . . . 39 The magnesium and calcium contents of soybeans grown in the greenhouse on some Michigan soils supplied with varying amounts of magnesium. . . . . . . Al The magnesium and calcium contents of millet grown in the greenhouse on some Michigan soils supplied with varying amounts of magnesium. . . . . . . 142 The magnesium and calcium contents of wheat grown in the greenhouse on some Michigan soils supplied with varying amounts of magnesium. . . . . . . A3 The total magnesium-supplying power and the fixation or release of magnesium by soils of the greenhouse study as affected by varying amounts of added magne- sium and cropping by soybeans, millet, and wheat . . . . 50-51 FIGURE 1. 2. 3. h. 6. 7. 8. 9. LIST OF FIGURES The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and wheat grown on Thomas sandy loam. O O O O O O O O C O O O O O O O O O O O O O O The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and wheat grown on Kalkaska sand. The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium.by soybeans, millet, and wheat grown on Oshtemo loamy Sand. 0 O O 0 O O O O O O O O O O O O O O O O O O O The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium.by soybeans, millet, and wheat grown on Emmet sandy 1081“. O O O O O O O I O O O O O O O O O O O O O O O The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and wheat grown on Plainfield lomsandooooooooooooooooooooo The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and.wheat grown on Fox sandy loam The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium.by soybeans, millet, and wheat grown on Warsaw loam. . The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium.by soybeans, millet, and.wheat grown on Isabella silt 10am. 0 O O O O O O O O O O O O O O O O O C O O O O The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and wheat grown on Brookston clay 10m. 0 O C O O O O O O O O O O O O O O O O O C O 0 PAGE 59 61 62 63 65 66 67 FIGURE 10. ll. 12. 13. LIST OF FIGURES continued The effect of varying amounts of added magnesium.on the yield and uptake of magnesium and potassium.by soybeans, millet, and wheat grown on Miami sandy 10am. 0 O O O O O O O O O O O O O O O C O O O O O O The effect of varying amounts of added magnesium on the yield and uptake of magnesium and potassium by soybeans, millet, and.wheat grown on Kent clay loam. O O O O O O O O O O I O O C O O O O O O O O O The effect of varying amounts of added magnesium on the yield.and.uptake of'magnesium,and.potassium'dy soybeans, millet, and wheat grown on.Wisner clay 103.111....oooooooooooooooooooo The effect of varying amounts of added magnesium on the yield and uptake of’magnesium and potassium by soybeans, millet, and wheat grown on Houghton.muck. PAGE .68 INTRODUCTION The agronomic importance of magnesium has been frequently demonstrated as a result of extensive experimental investigations. These have brought to light the very important role that this element plays in plant nutrition. Agricultural soils differ widely in their magnesium content. Some soils contain only a trace of this element, while others are relatively rich. Much of this variation is due to the nature of the parent material and the soildweathering processes. For instance, the process of podzolization re- sults in a soil that is depleted of its plant nutrients in the surface layers. Intensive cropping and a gradual transition in fertilizer composi- tion and practices are factors which have brought about the need for mag- nesium in certain areas, particularly those where the soils are coarse tex- tured. Crops may remove as much as 15 pounds of magnesium per acre of soil. Commercial fertilizers increase the removal of magnesium. These fertilizers fUrnish anions like sulfate, chloride, nitrate, which form easily soluble magnesium compounds that are readily leached from the soil. .The salts of magnesium in the order of their decreasing solubility are nitrate, chloride, squate and carbonate. Once most all soils were believed to contain adequate amounts of magne- sium for plant growth and its application was considered necessary for only a few crops grown on certain soils. Results of extensive experiments prove that this is not the case. Hence, it is evident that due consideration be given to magnesium in terms of requirements of individual crops grown on specific soils. THE OBJECT OF THE INVESTIGATION This investigation was undertaken to obtain information regarding the abilities of some Michigan soils for supplying magnesium to crops under greenhouse conditions, and also to determine the effect of varying amounts of added magnesium on the yield and chemical composition of crops. The main objectives of this study were as follows: 1. To determine the extent of magnesium deficiency as indicated by several crops grown on different soils in the greenhouse. 2. To determine the effect of magnesium fertilization on the yield of several creps. 3. To determine the uptake of magnesium and other elements by several crops as influenced by magnesium fertilization. h. To correlate the magnesium content of the crops with growth response to added magnesium. 5. To study the effect of other cations upon the uptake of magnesium by crops. 6. To classify the soils studied in relation to their need for added magnesium under greenhouse conditions. REVIEW OF LITERATURE Occurrence and Distribution of Magnesium Geochemical. Magnesium.ranks seventh in abundance in the scale of ele- mental occurrence in the earth's crust. There is a total of 2.5 per cent magnesium in the outer 10 miles of the earth's lithosphere of‘which the oceans contain 0.1h per cent (l2).* Minerals. Magnesium-bearing minerals are quite abundant and widely dis- tributed in nature. Among the primary minerals which are sources of magne- sium, the most important ones are biotite (2-20 per cent), hornblende (2-26 per cent), augite (6-20 per cent), olivine (27-51 per cent), muscovite (0-3 per cent), tourmaline (0-12 per cent), and other pyroxenes and amphi- boles. Chief among the secondary minerals containing appreciable quantities of’magnesium worthy of’mention are, montmorillonite (0-25 per cent), chlor- ite (35-38 per cent), vermiculite (22-2h per cent), sepiolite (5-23 per cent), and illite (1-h per cent). Magnesium deposits may also occur in the form of dolomite, a double car- bonate of magnesium and calcium; magnesite, Mg003; talc or soapstone, H2Mg3(5103)h; asbestos, Mg3Ca(SiO3)h3 kieserite, a hydrate of MgSOh and M3012 found in sea water and salt beds. In regions of limited rainfall, dolomite, magnesite, and epsomite may constitute appreciable sources of mag- nesium (l). *Figures in parenthesis refer to literature cited. A. Total magnesium content of soils. Soils vary widely in their content of total magnesium as indicated.by chemical analysis of soils coming from different regions. Uncultivated soils of the humid temperate regions are likely to contain about as much total magnesium as calcium. The very high- ly weathered lateritic soils of the tropics contain the least amounts of magnesium, the values for per cent Mg0 being as low as 0.2. In contrast, values as high as h to 5 per cent have been reported in some of the brown, chestnut, and black soils of the semi-arid parts of the world. In analyses of twenty soil types from New Jersey, Bear and co-workers (2) feund that the total magnesium content ranged from less than 0.02 per cent to as much as l per cent. The values for magnesium in pounds per acre that these workers report for Lakewood sand and Fox gravelly loam are h00 and 23,h00, respective- ly. Organic soils contain magnesium expressed as MgO from 0.05 - 3.0 per cent on an air dry basis. (1) Exchangeable magnesium content of soils. The quantity of’magnesium present in the exchangeable form is very small compared to the total con- tent. Roughly, ten to fifty times as much magnesium is present in the total mineral as in the exchangeable fern. In analyses of exchangeable magnesium in twenty New Jersey soils, Prince (3h) found the exchangeable magnesium to range from 0.10 to h.69 m.e. per 100 grams of soil. Analyses of several Michigan surface soils by Lawton (25) show that the exchangeable magnesium ranged from 0.23 to 2.21 m.e. per 100 grams of soil, while exchangeable cal- cium ranged from.0.26 to lh.92 m.e. per 100 grams soil. Availability of soil magnesium to plants. The supply of magnesium that is available to plants is controlled by several factors. Availability is de- pendent upon the presence and the nature of the magnesium-bearing minerals, 5. operation of magnesium.fixation phenomena, the soil weathering processes, and the balance between exchangeable cations. (2) Prince et al. (3h) attempted to evaluate the magnesium-supplying powers of twenty New Jersey soils by growing alfalfa on them and.by measuring the response obtained from applications of additional magnesium supplied at the rates of'hO and 80 pounds soluble MgO per acre. Yields were increased 38 per cent in one soil, more than 20 per cent in three soils, and.more than 10 per cent in seven soils. These results suggest the inadequacy of’magne- sium.in the soil for optimum yields on.many New Jersey soils. Studies of cation values in these soils in relation to crop needs led these investiga- tors to reach a decision that the exchange complex of the "ideal soil" should contain about 20 per cent hydrogen, 65 per cent calcium, 10 per cent magnesium, and 5 per cent potassium on an equivalent basis. In only 6 of the 20 soils studied.was magnesium present in the exchange complex to the extent of 10 per cent. CrOp response from magnesium applications was obtained whenever the amount of the element in the exchange complex fell below 6 per cent. The same authors also feund that there was no correlation between the total magnesium in these soils and their crop-producing powers. Nature of maggesium in the soil exchange complex. Much evidence has been presented to demonstrate that magnesium may occur in soils in a "fixed" or un- available state. According to Mattson (29), about two-thirds to three-fourths of the monovalent and divalent bases occur in the natural colloids in this unavailable (non-exchangeable) state. This phenomenon is attributed by Mattson to their position within the crystal lattice structure or molecular aggregate of the colloid. Magnesium displays some peculiar properties in its colloidal 6. behavior. On being subjected to electrodialysis, magnesium does not react as do alkaline metals as one would anticipate, but strangely behaves like iron or aluminum. Only upon removal of the major portion of the cations, potassium, sodium, and calcium from.soils does the magnesium become mobile. The dis- placement of the cations from a soil with a neutral salt solution shows mag- nesium to behave in quite a different way. Under the latter treatment,nag- nesium is displaced in the normal lyotropic order and in no way reseMbles iron or aluminum. Weigner and Jenny (hl) stated that magnesium was the most difficult of the divalent cations to displace from the soil complex. The order of dis- placeability is Mg, Ca, Be. This series is identical with their displacing power, as well as the insolubility of the hydroxides of these elements. The analogy between the solubility of the hydroxides and the release of the ca- tions is associated with the fact that the inner layer of ions of a colloidal particle consists in part of 0H ions in this position in the Helmholtz double layer exerting a binding effect on the Mg ions. Jenny (21) stated that magnesium-fixation occurs principally through the m ions of the clay colloids (sesquioxides), which bind the Mg ions firmly. This theory is contrary to the concept of Mattson (29), who presented evi- dence that the sesquioxides cannot be the seat of the reaction, since the bonding occurs between magnesium and the colloidal complex through a silicate group. It follows then that cation adsorption and cation exchange occur' through the free valences of the silicate ions, which is the seat of'magne- sium fixation. 7. MacIntire and his co-workers (2?) concluded that magnesium enters directly into the alumino-silicate complex when applied as a fertilizer. Exchangeable magnesium, however, continues to be released from the complex. The available magnesium is a product of isoelectric hydrolysis according to these workers. Free silicic acid is liberated, which produces a mobilizing effect on magnesium. There is other evidence to show that magnesium is often fixed by a mechanism, which does not allow a normal cationic exchange. It has been observed that considerable quantities of magnesium may be fixed in this manner, which has been substantiated by the observations of several investigators ‘working on magnesium fixation. Kardos and Joffe (2h, 22), and.Mattson (29), in working with synthetic complexes, found that magnesium was fixed in a relatively insoluble form. Concluding this topic of magnesium fixation, it may be said that although some insight has been gained regarding magnesium fixation, its exact mechan- ism is still controversial. Role of'magnesium in plant nutrition. Magnesium is indispensable for the growth and reproduction of all plants regardless of the position that they occupy in the evolutionary scale (16). The specific functions of mag- nesium within the plant and the mechanism operating to achieve these functions are not yet entirely elucidated. Magnesium is known to occur in or be re- lated to the following plant constituents and vital processes: The leaves and reproductory organs of plants contain relatively more of this element than other parts. Magnesium in plants exists in at least 3 forms - combined in the chlorophyll molecule, in a soluble state in the cell-sap, and in combined form in the protoplasm. Sunflower, tobacco, spinach and sugarbeet 8. leaves are notably rich in magnesium, the content of which ranges between 1 and 3 per cent on a dry weight basis (A). Legumes contain anywhere from 0.5 to 1.02 per cent magnesium. The latter contain two to three times more magnesium.than the grasses (lb). The functions of magnesium in plants may be summarized as follows: 1. An essential component of the chlorophyll molecule. 2. A constant constituent of cell plasma. 3. Functions as a carrier of phosphorus, being closely associated ‘with phosphorus assimilation. h. Associated with carbohydrate synthesis (35). 5. Acts as transporting agent fer starch (A2). 6. A major mineral component of reproductive organs. 7. Associated with protein and fat synthesis (35). 8. Functions in cationic balance. 9. FUnctions as a stimulant in bacterial nitrogen fixation (18). 10. A factor in the maturity and aging of’plants. Magnesium-calcium-potassium relationships in plants and soil. Ex- changeable magnesium in soil regulates the uptake of other nutrients. The absorption of'magnesium.by plants is governed by other cations and, in turn, this nutrient regulates, in part, the uptake of other cations. Plant nutri- tion in relation to magnesium and other elements is not only complicated by variations in absorption phenomena within the plant, but also by base exchange relationships and availability differences in the soil. The proper understand- ing of these inter-relationships is of fundamental importance in the field of the mineral nutrition of plants. 9. Hunter (20) prepared a resume of nutrient absorption at various CaoMg ratios and the effect of these ratios on the uptake of other nutrients. This worker found that the magnesium content of alfalfa plants grown on soils with a constant level of magnesium increased when the MgoK ratios in the soil were increased. Moreover, while the MgoK ratios in the plants roughly paralleled the CaoK ratios, the former varied widely and never at- tained.the same magnitude as the latter, commonly being only from 35 to 50 per cent as large as the CaoK ratios. It was also observed.that magnesium uptake by the plant increased with increasing CarK soil ratios, whereas the potassium uptake decreased. Hunter's data also showed that with successive alfalfa harvests, plant absorption of’magnesium increased from 0.28 per cent in cutting l and to O.h2 per cent in cutting 7. This increase in plant mag- nesium coincided with decreased supplies of available potassium in the soil. Fonder (17) showed that the quantity of’magnesium in alfalfa leaves re- mained relatively low as long as the potassium level in the plant was rela- tively high. High applications of’potash caused leaves of sugar beets to become chlorotic. Magnesium sulfate applied at the rate of 100 pounds per acre corrected this chlorosis and also increased the yields of‘beets. ‘Walsh and Clarke (38) using tomatoes in their work, showed that the nomg ratio within the plant determined the extent of'magnesium uptake. 'When this ratio was sufficiently high, chlorosis developed even when the culture medium had a relatively large content of available magnesium. 'Walsh and O'Donohoe (39),in extensive experiments conducted in potash manuring of potatoes, tObacco, sugar beets, wheat, barley, and.mangold, found that in most cases high potash fertilization induced.magnesium deficiency even when this element was abundant in the soil. The plants were also shown to 10. contain low amounts of magnesium. The authors conclude that the KtMg ratio of both the soil and plant merits attention in accounting fbr the development of’magnesium deficiency. Boynton and associates (6) made an investigation of the potassium, mag- nesium, calcium, and phosphorus contents of'McIntosh apple leaves from orchards of New Ybrk State. In comparing the results of tests in 19hl and l9h2, they found that in both years in areas where potassium was highest, magnesium was lowest, and where potassium was lowest, magnesium was highest. In l9hl, when the mean leaf potassium.percentage in lh8 sampled plots was 1.36 and the average magnesium content was 0.27 per cent, potassium deficiency scorch was more prevalent and.magnesium deficiency symptoms less prevalent than in 19b2, when the contents of leaf potassium and magnesium were 1.53 and 0.22 per cents, respectively. Bradfield and Peach (9) observed that in soils with a limited supply of potassium, addition of calcium or magnesium suppressed the absorption of potassium by the plant. In a 26-year lysimeter experiment, McIntire (28) found that a calcic liming material decreased the solubility of both potassium and magnesium of the soil. When a magnesia liming material was used, a decrease in the solu- bility of both potassium.and calcium resulted. Dolomite and limestone exert- ed similar effects on soil potash. These repressions in solubility were re- flected in the composition of the plant ash. ObenShain (31) found a decrease in magnesium and calcium in the expressed sap and tissue of corn plants when the potassium.content of the sand culture medium was increased. ll. ‘Wallace and his 00dworkers (37) grew potatoes in l9h2 on plots on which a fertilizer experiment on black currents had been in progress from l927-hl. Potassium deficiency symptoms were prevalent on the leaves where potassium had not been applied, while the need for magnesium.was evident when potas- sium had been applied. Magnesium deficiency symptoms were not too notice- able where farmyard manure had been used. Carolus (11) observed that in the case of potassium deficiency, vege- tables had an extremely low concentration of'potassium and a high concentra- tion of magnesium and calcium in the stems and petioles. A deficiency of magnesium in the presence of other nutrients resulted in a low concentration of magnesium, and generally, in a high concentration of potassium in the stems and petioles of the plants under observation. Southwick (36) working on orchard soils, presented evidence to show that potash fertilization, even with heavy mulching alone, raised the level of available potassium in some apple orchard soils so as to cause an actual shortage of magnesium. Magnesium deficiency was evident in the form of leaf scorch. This worker questioned the advisability of using potassium for apple orchards until the magnesium supply was built up. Boynton and Compton (7) observed the effect of potash fertilization in sharply raising leaf potassium and simultaneously lowering leaf’magnesium. They showed that in orchards showing magnesium deficiency symptoms, leaf potassium tended to be abnormally high even though soil replaceable potassium ‘was low and no potash supplements had been used. It appeared that high leaf potassium was a sign of magnesium.deficiency. Leaf analyses for potassium and magnesium were helpful in diagnosing magnesium deficiency. 12. Cooper (13) showed that many plants selectively absorb the relative- ly strong ions and the magnesium content in most plants was significant- ly lower than those of calcium or potassium. Webb et al. (hO), working with soybeans, found that magnesium defi- cient plants absorbed slightly larger amounts of calcium and potassium on a per cent basis. Lucas and Scarseth (26) concluded that there is a reciprocal rela- tionship between the potassium, calcium, and.magnesium contents of plants. This relationship helps to account for the need of maize for additional potassium.when growing on a high lime soil that had a high content of ex- changeable potassium (lhO-2OO pounds per acre plow layer.) In a soil high in magnesium, a magnesium-starved plant may grow if the intake of calcium, and/or potassium are high. The sum of these cations when calculated on an ionic equivalent basis tends to be a constant. Prince et al. (3), investigating the uptake of nutrients by alfalfa plants from different soils, found that when the soil was too liberally fertilized.with potassium, this element was taken up at the expense of magnesium with subsequent induction of magnesium deficiency in the plant. There was a definite correlation between the abnormal increase in uptake of potassium and low yields from some of the soils that were low in magne- sium. The sum of the potassium, calcium, and magnesium expressed as equiva- lents, was found to be constant. Response to magnesium additions was con- trolled partly by its ratio to other cations in the exchange complex, particu- larly those of potassium and calcium. Blair et al. (5) found that yields of crops as influenced by magnesium additions depended not only on the individual crop, but also upon the soil type on which they were grown. Snap beans, tomato, and cabbage yields were 13. increased on sandy soils by the additions of magnesium, while on heavier soils, little, no increase, or even a decrease in yield occurred. Mehlich and Reed (30) showed that large soil additions of calcium or potassium reduced the uptake of magnesium. Increasing the magnesium in the soil augmented the magnesium concentration in the plant, lowered the potassium slightly, and appreciably decreased the calcium concentration. Magnesium deficiency has been reported on the organic soils of'Michigan by Harmer (l9), and Davis and McCall (15). Johnson (23), working with celery on the organic soils of Michigan, found that magnesium deficiency could be controlled by broadcast application of magnesium.sulfate at a rate of two to four tons one week before transplanting. It was found that for mature sus- ceptible varieties of celery 0.07 - 0.13 per cent magnesium of the above- ground portion was indicative of magnesium deficiency symptoms and when this was raised to 0.1h per cent or above, no symptoms developed. METHODS AND MATERIALS Greenhouse experiments. In order to evaluate the effect of magnesium applications on the dry weight and chemical composition of several crops, thirteen.Michigan soils representing different soil types, and varying over a wide range of texture, organic matter, pH, exchange capacity, and base status were used in this study. Three different crops, soybeans, millet, and wheat were grown under three levels of added.magnesium, namely, 60, 120, and 2h0 pounds MgO per acre and.without magnesium fertilization. Each treatment was replicated three times. The soils were procured from farmer's fields from 13 different loca- tions in southern.Michigan. Samples were taken from two different depths, 0-6 inches and 6-12 inches, respectively. The bulk samples were air-dried and passed through % inch sieve and were mixed thoroughly. Two gallon glazed porcelain pots were used as containers, the soils being placed in each pot on a volume basis rather than on a weight basis, due to the fact that the soils show such a wide range in texture. The sample taken from the 6-12 inches layer of each soil was placed in each pot to a height of three inches, on top of'which five inches of the surface soil was added after being thoroughly mixed with the fertilizers. The object of incorporating the sub- soils in this study was not only to get a soil volume more similar to the feeding volume of the crops in the field, but also to bring in a soil layer which may be of importance in supplying magnesium to the specific crops grown. 15. Fertilizer treatments. All fertilizer applications were made on volume basis, only the first five inches of the soil being taken into consideration in all the computations, except in the case of Houghton muck, where the plow depth of seven inches was taken into consideration, as no subsoil was in- cluded in the series under this soil. 1. Blanket applications: Nitrogen was applied as (NHh)250h at a rate of to pounds N per acre. Additional applications at a rate of 50 pounds of nitrogen were made for each successive crop. Phosphorus was applied as Ca(H2POh)2.H20 at a rate of 200 pounds P205 per acre. Manganese was added as MhSOh.H20 at a rate of 100 pounds per acre. Copper and zinc were applied as the sulfates at rates of 20 and 10 pounds per acre, respectively. Boron was added as Nath07.lOH20 at a rate of 10 pounds per acre. Mclybdenum was added as (NHh)5M0202h.hH20 at a rate of 1 pound per acre. 2. Magnesium was the experimental variable, and this element was added at rates of 0, 60, 120, and 2&0 pounds of’MgO, equivalent to 0, 36, 72, and lhh pounds of'Mg per acre. These quantities under the four treat- ments expressed as milligrams of‘magnesium.per pot amounted to 0, 19?, 39h, and 788 milligrams, respectively. The magnesium was added as Sul-PoéMag, NgSOh.K280h,a.water-soluble double salt of potash-magnesia, containing 18.5 per cent MgO and 22.h per cent K20. Potassium was present in the 2h0+Mg0 series of the soils to the extent of 185 pounds per acre, and consequently, the levels of'potassium in the O-MgO, 60-Mg0, and 1204Mg0 series were brought 16. up to the same level as in the 2h0-Mg0 series by adding appropriate amounts of KZSOh. These additions of potassium were designed to keep the added potas- sium at the same level in all the series, so that magnesium.would not be thrown out of balance. Irrigation. Each soil was adjusted to an optimum moisture content as calculated from the moisture equivalent percentage. At regular intervals throughout the experiment, an attempt was made to maintain this moisture level of each soil by adding a unifbrm quantity of distilled water. Cultural methods. Soybeans, millet, and wheat were grown in succession on the same soils between June 25, 1955, and Nevember 30, 1955. Soybeans ‘were grown in the period from June 25 to August h, 1955; millet from August 6 to September 21, 1955; while wheat was grown from September 21 to November 30, 1955. Only wheat had to be provided with artificial illumination, as light conditions were far from satisfactory at this time. Soybeans (Richland variety). Twelve seeds were planted in each pot, but the seedlings were eventually thinned down to h per pot. The plants ‘were in excellent condition during the growth period, except for the fact yellowish-brown spots appeared on the lower leaves of all plants growing on the lighter soils. Plants in the 120+Mg0 and the 2hO-Mg0 series did not develop these symptoms to an appreciable extent. The yellowish-brown spots were prObably the result of boron toxicity. ‘Eiilgt. Twenty seeds were sown in each pot; plants were thinned down to 8 in each pot. Wheat (spring wheat - Illinois 120). Twenty-five seeds were planted in each pot; the number of plants per pot was brought to 8. Although growth was good at the beginning, poor light conditions during the latter part of the experiment hampered heading of the plants to some extent. 17. After the harvest of the final crop, composite samples were taken from each of the soils according to fertilizer treatment. No attempt was made to remove the roots of any crop. Consequently, calculations for fixation or re- lease of magnesium after cropping are subject to this possible error. Preparation of plant materials. The plant material of each pot in each of the three crops was dried in paper bags for 3 days at 70° C., weighed, and ground separately. Each sample was thoroughly mixed befOre chemical analyses were made. The triplicates were not combined for analyses. Laboratory Procedures ‘Sgilg, The thirteen soils used in this study were analyzed for pH, organic matter, sand, silt, and clay, exchange capacity, and exchangeable bases. Exchangeable potassium, calcium, and.magnesium were determined both at the beginning,as well as at the end of the experiment. Soil reaction was determined.by the glass electrode, using a 1:1 soil to water ratio. Exchange capacity was determined.by the neutral normal ammonium acetate method described.by Peech (32). Total exchangeable bases were determined ac- cording to the method of Bray andeilhite (10). Exchangeable potassium, calcium, and magnesium were determined on the leachates from the ammonium acetate extractions of the soils using the Beckman DU flame spectrophotometer (23). Per cent organic matter was determined.by the well-known dry combustion method as outlined by Piper (33). Per cent sand, silt, and clay were estimated.by using the hydrometer method of Bouyoucos (8). 18. Analyses of plant materials. One gram samples of the dry plant mate- rials were first moistened with 1:1 sulfuric acid, then dried on a hot plate, followed by drying in an oven at 1050 C. The dried.samples were then ignited in a muffle furnace, first at 2000 C, with the temperature being ultimately raised to 600° C. The samples were maintained at this temperature for 10-12 hours to insure complete combustion of all the carbonaceous matter. The ash was taken up in 3 ml. of concentrated hydrochloric acid, and this solution boiled over a gentle flame fer one minute, after which it was filtered through a Whatman No. h2 filter paper. The residue was washed repeatedly with hot water, and the filtrates were made up to a volume of 200 ml. with distilled water. Calcium and magnesium in these ash extracts were determined with the Beckman DU flame spectrophotometer, equipped with a photomultiplier. The source of fuel for the flame was hydrogen burned in the presence of oxygen. The instrumental conditions used for the determination of calcium and magne- sium are set out in the following table: Conditions Elements Determined Calcium Magnesium wave length h227 A0 2852 A° Phototube resistor No. 2 No. 2 Phototube Blue Blue Selector 0.1 0.1 Slit 0.01 0.06 Sensitivity a. Instrument panel variable variable b. Photomultiplier No. h Full Zero suppression 1.0 1.0 19. The standard curves for the Beckman flame photometer were reproducible from day to day, provided the same conditions were used. Due to too many electrical fields, and other mechanical disturbances in the neighborhood of the instrument, fluctuations of the gross luminosity were caused, which had to be rectified with new slit settings, and whenever this was done, it was necessary to establish a new standard curve. A slit width of 0.06 mm. with a top standard of 100 p.p.m. Mg at 2852 A0 wavelength eliminated all inter- ferences from other ions present in the solution. Sodium added in concen- trations ranging from 5 to 50 p.p.m. to the calcium standards, did not seem to interfere with calcium. Potassium was determined on the Perkin-Elmer flame photometer, Model- 52 A. The conditions for this flame photometer varied from time to time, and new settings had to be made frequently. ’20. noosobsom Mo 0252. 903505»: m. 0232: dogma—€60 E m ooofiooao madam hp 0235300 H I... II. II. ........ N .0 oceans woes esteem 0.5m :.0m 0.~m m0.m H6 «Hounds 50H head young man 4.8 0.3 $4 «a. demote: sees an? and an: «.2 0.2. 84. we define 53 head» wane: 04m 4.3 0.13 00 .m ~30 sesame»... 53 had. :38?on e28 4.4m eat me; me seem See it 3.395 028 «.3 0.0m 00.m ed cosine—ea sac.” henna: 0.0 ~.0m 0.00 mm .N «.0 03283 50H .35» Hob we the 0.3 84 no 8553 San awed 3.35.3 o.» ~.0m 0.3 m0 .H no 58000 Eco." human pea—Am 0.: «dd 0.3 mm .0 a.» coaudkeEm 93a hauoa 053:3 m.m wtm 0.4m 0m .0 0.0 2390 use» 3.33 83 it 0.8 Std .3. 3825. .53 head» 385. peooeom .33.»: 23583 news a 33 u cede a «cameo and 8383 25 Son Hanan an. 2H 9mm: gem Medan Egg: zmmaaa Mme ho mOHBmHmmaodgo dOHSMmo Bad QdOHmHmm 55m H San. RESULTS AND DISCUSSION Greenhouse Study Partial Physical and Chemical AnalySes of Soils Data of specific properties for the thirteen soils as they were col- lected from the field are shown in Tables I and II. Included in Table I are reaction values of the soils, their organic matter contents, and sand, silt, and clay contents expressed on a per cent basis. Of the twelve min- eral soils obtained, one was a sand, two were loamy sands, four were sandy loams. It should be noted that the texture of the soils, which ranged from sand to clay loam, affected the extent to which the various cations were re- moved from the soils, movement of water within the soils, soil temperature, soil aeration, and the microbiological activity of the soil. The pH values of the original soils varied from 5.6 for warsaw loam to 8.1 fer Wisner clay loam. Organic matter content of the mineral soils expressed on per cent basis ranged from 0.90 for Kalkaska sand to 11.2 for Thomas sandy loam. Clay contents varied.between 3.8 per cent for Kalkaska sand to 37.6 per cent for'Wisner clay loam. In Table II, values are given for exchange capacity, total exchangeable bases, and exchangeable calcium, magnesium, and potassium contents of the surface and subsoil at the start of the experiment. The exchange capacity of the mineral soils from.the 0-6 inch layer varied between 1.68 milliequiva- lents per 100 grams for Oshtemo loamy sand to 28.52 milliequivalents for Thomas 22. ea.0H No.0 0m.ea 00.NN 00.mNH 00.HmH N.0 0 n 0 goes dopameea 04.nm NH.0 em.HN em.m m0.aN 00.0H 0.0 NH . 0 Hm.0H mH.0 me.0N 0m.N 00.NN 0H.eH H.0 0 u 0 aeoH aeHo neanHe NN.m0 0m.0 00.a eH.0 Hm.0H Ne.NH 0.0 NH . 0 HN.NH 0m.0 0H.HH a0.H mH.eH we.mH N.a 0 - 0 aaeH aaHe seem 00.am mH.0 0m.e 0a.m NH.0 00.0H 0.m NH . 0 Nm.0m NH.0 mH.0 HN.N m0.m 00.0 0.0 0 u 0 aeoH heath eaeua Na.Hm aH.0 aa.HH am.0 em.0H 00.NH 0.0 NH . 0 0a.NH mN.0 mm.HH H0.m 0m.0H 0H.0N a.0 0 u 0 aaeH eaHe doehxooam 00.mN NH.0 em.e me.H m0.0 .0m.0 N.m NH a 0 Ha.mH mH.0 0m.0 me.H mH.0 we.0H m.0 0 u 0 aeoH oHHn aHHooanH 40.2H 4H.0 4N.m H0.H . 00.0 0m.NH H.m NH . 0 4N.mH mH.0 0:.N 00.N 0N.HH 0m.mH 0.m 0 u 0 adoH henna; Na.0H 0H.0 0H.0 ma.H 00.0 Hm.0H 0.m NH . 0 ea.NH mH.0 0a.m 00.H 0H.a Nm.0 N.0 0 u 0 aaeH henna woe mm.ee m0.0 0m.H 0H.H Nm.m 04.N 0.0 NH - 0 NH.mN 00.0 H0.H ea.0 0;.N 0N.m m.0 0 n 0 ante aaeoH 0HeHeeHeHa 00.0H 00.0 Na.N eN.0 0H.m 00.0 m.0 NH a 0 NH.NH 00.0 0m.m Na.0 mm.0 0m.N m.0 0 u 0 aaoH evade posse am.NN mH.0 mm.0 aa.H ma.a Na.0 a.0 NH . 0 am.mm 0H.0 mH.0 0a.0 m0.» 00.H a.» 0 u 0 acme aeaoH oedeeh0 0H.a m0.0 am.0 mN.0 N0.H Nm.m N.m NH u 0 Nm.eH 00.0 m0.0 He.0 H0.H 0H.N 0.0 0 u 0 anew axnexHae m0.mH e0.0 Nm.eH 0m.m 0N.HN 0m.mN e.a NH u 0 0H.0N 0H.0 0e.0H mN.m 0m.0N Nm.0N H.N 0 u 0 adoH heath masons M to ME .25 00a pom .30 00a 0.50 no.» 6.: mommm new 6.: 3065 0030.8me .96 00a mom 6.: oanmomswmo 00.000000 5 was 00030.0 manmowcwnounm Iwmr depots? omcwnoxm mm 5.08 0%! Show Naeem mmeomzmmme may a0 amaem may 94 mHHom may a0 zeHmmaeoa 02a .zeHoaao .zeHmmzea: Egezamoa 02a .mmmam mamamezamea .52. £984.20 wages .2032? HHS HH «35.9 23. sandy loam. The high cation exchange capacity value for the latter soil is due to its high organic matter content. The exchange capacity of the subsoils from the 6-12 inch layer ranged from 3.52 milliequivalents per 100 grams for Oshtemo loamy sand to 25.30 milliequivalents for Thomas sandy loam. A general positive relationship between the cation exchange capacity, organic matter, and clay contents of the mineral soils is apparent. Houghton muck had a high exchange capacity of 131 milliequivalents per 100 grams of air dry soil. The content of exchangeable magnesium of'the mineral soils from the 0-6 inch layer varied between O.h1 milliequivalents per 100 grams for Kalkaska sand to 3.61 for Brookston clay loam. The subsoils contained exchangeable magnesium from 0.25 milliequivalents per 100 grams for Kalkaska sand to 8.1h milliequivalents for Kent clay loam. In general, the subsoils contained more exchangeable magnesium than the surface soils, the exceptions being Thomas sandy loam, Kalkaska sand, Emmet sandy loam, and Plainfield loamy sand. The exchangeable magnesium, calcium, and potassium contents of Houghton muck were 22.00, 7h.58, 0.62 milliequivalents per 100 grams, respectively. The magnesium saturation of these soils varied from a low of 7.10 per cent for Kalkaska sub- soil to a high of 65.22 per cent fer Kent clay loam subsoil. The values for per cent magnesium saturation of these soils furnish a partial index to the mag- nesium-supplying powers of these soils. 0f the surface soils, all thirteen soils had more than 10 per cent of their exchange capacity satisfied by magne- sium. 0f the thirteen subsoils, all but one soil, namely, Kalkaska, had more than 10 per cent of the exchange capacity satisfied by magnesium. It is also evident that there is no correlation between magnesium saturation percentage and soil reaction in the case of these thirteen soils. 2h. wflmoewwernmmpom mo opmHHSm me mamas when :0 no eoflamdm omz Mo mesdoa op mammoma 0m.Hw mm.m 00.0 0m.Hm mm.:H ww.0 0m.Hw 00.:H mm.0 0m.am m5.ma mm.0 x055 coezwsom MN.0 00.HN a0.m mN.0 om.HN m0.m MN.0 mH.0N NH.e mN.0 0m.eH 40.: eeOH aaHe henna; mN.0 00.0H 0m.0 mN.0 m0.mH Na.N NN.0 00.0H eN.N mN.0 mH.0H mN.0 aeoH aaHo 000m a0.0 00.0H a0.0 e0.0 0m.NH 00.0 a0.0 0H.NH 00.0 e0.0 0H.NH 00.m aaoH aeaae HaaHa 0N.0 ma.NH 0N.m 0N.0 ma.aH 00.0 aN.0 05.NH 00.0 0N.0 00.NH 00.0 aaeH aaHo eoenxeoam a0.0 0H.m 00.0 a0.0 0a.: 0a.; a0.0 om.m 0a.: 0H.0 00.0 00.m aaOH pHHm eHHeeanH a0.0 0N.0 0a.m e0.0 00.0 Na.N e0.0 00.0 Na.N a0.0 00.a mN.H aaeH amends a0.0 0N.0 mH.m a0.0 0a.: mH.m e0.0 00.: 0a.N HH.0 00.m Na.N aeoH aeaan woa 00.0 ma.H Na.N m0.0 me.H Na.N 00.0 0N.H. mN.0 m0.0 0m.H ma.0 ache aaaoH 0HeHaaHeHm m0.0 mN.m 0N.m 00.0 0m.m 0m.N m0.0 0N.m 0N.N 00.0 0e.m mN.H aaoH aeaan posse 00.0 0©.m mm.m 00.0 05.m mm.m 50.0 00.0 mm.m 50.0 05.0 m5.H comm hamoa 0509300 m0.0 0N.0 0N.N 00.0 0H.0 ma.H 00.0 0H.0 Ne.0 00.0 mH.0 00.0 00am aseaxHae mH.0 0m.NH H0.e mH.0 00.0H 0e.m NH.0 0m.NH 00.m NH.0 mH.NH m0.m saoH aeaea neaoae a e0 02 a 00 we a a0 02 a a0 m2 002.00N omauoNH 002-00 H002-0 HHOW .HO mEdhO OOH pom .o.z ca meowpwo mammomcmnoxm mama HHom ho Hzmezoo Ememdeom Qz¢ NEDHoqdo NEDHmmzo¢z mqmdmcz mBH3,GmHAmmDm QHOm 25. The exchangeable calcium.of the surface layer of mineral soils ranged from 0.3h milliequivalents per 100 grams for Kalkaska sand to 20.h5 milli- equivalents for'Wisner clay loam. The CaeMg ratio of the original soils ranged from 1.1 for Kent subsoil to 8.9 for Wiener surface soil. The exchangeable potassium content of the mineral soils ranged from 0.05 milliequivalents per 100 grams for Kalkaska sand to 0.3 milliequivalents for Kent clay loam. Data of the exchangeable magnesium, calcium, and potassium contents of the soils at the end of the greenhouse experiment are listed in Table III. The amount of exchangeable magnesium at the end was found to be generally slightly higher than that found at the beginning of the experiment in all the four series, namely, O-MgO, 60-Hg0, lZO-MgO, and 2h0-Mg0. It is possible that this increase may have come from the subsoils, and also from added mag- nesium. In Fox sandy loam, magnesium at the end of the experiment at the o—wgo level was higher than at the start of the experiment, even though the subsoil was lower in exchangeable magnesium. The same was true for Isabella, Brookston, Miami, and Emmet soils. In cases where the exchangeable magnesium is higher at the end than at the beginning, it is likely that magnesium has been released from the soils as a result of cropping. And where exchangeable magnesium at the end is lower than at the beginning, it is probable that the exchangeable magnesium has been reduced.by cropping or added magnesium has been fixed by the soil. Yields of Crops on Different Soils Data presented in Tables IV through VI show the dry weight yields of soybeans, millet, and.wheat, respectively, grown on the thirteen soils in the greenhouse, while in Tables VII through IX is listed the per cent increase 26. 3080300300 no 3.0.3.50 no 333 93.. 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Ion-z 3.0 3% 91m 8.m 9% .33 has.» ”8h «3" 8.; 8A 3.4 mm.m Ban 53 Sodflfim £6 8.: m}. ofim RS .33 P5» 33 86 2.6 86 em.» 36 E: 3.3 2838 RA 82m 8:. 8....” on; as: 3.9385. mm.“ 83 8.: 26 2:. .33 has 8.8a. an um omzuofi owxnofi 3.78 Hows... «on 8m .25 add «.8?» m 55$ «0 .33» 23.2 b: 85. do» 6292 he mgfia Band» HE gnaw mAHOm madman 24%on SEE no nun—OS E IH 56mm g3 EHH BNEHE HP as 29. or decrease in yields of soybeans, millet, and wheat, respectively, due to applications of 60, 120, and 2&0 pounds of NgO per acre. Thegattern of yield response in each of the three crops is shown graphically in Figures 1 through 13. Results of the yield responses of the three crops for each soil are presented below: Thomas sandy loam. Data shown in Tables IV and V and in Figure l for yields of soybeans and millet grown on Thomas sandy loam indicate there was no response from added magnesium. The same is true for the dry weight yields of wheat as shown in Table VI and Figure l. {oreover, the dry weight yields of wheat plants tended to be depressed, as magnesium ad- ditions were increased. Since this soil contained more magnesium in the surface layer than any soil except Houghton muck, it is quite likely that no growth response could be expected. Kalkaska sand. Increases in dry weight of soybeans from added mag- nesium were not significant, although the lZO-Mgo series showed a 28.9 per cent increase in dry weight over the checks, as shown in Table IV. Data for yield increases in millet were found to be significant for this soil as shown in Table V. The greatest dry weight yields and most vigorous plants were found in the lZO-NgO series. No yield responses from added mag- nesium for wheat were noted. This soil contained less than 0.5 milliequivalents of magnesium in both the surface and subsoil of the original samples, although magnesium saturation was slightly less than 20 per cent in the surface soil. However, since crop yields were equal to those found with most of the soils, greater response to magnesium might have been expected. 30. Oshtemo loamy sand. There was no significant response in yields of soybeans or wheat to magnesium treatments applied to this soil as shown in Tables IV and VI. However, a significant decrease in yield was found for millet when the lZOéMgO level was compared with the O-NgO treatments. No explanation can be given for the apparent depression in growth when such a condition was not evident with the 2hO-Ng0 level. Emmet sandy loam. No significant response in yields of soybeans, millet, or wheat is evident according to data in Tables IV, V, and VI. This soil contained 0.92 and 0.7h milliequivalents magnesium in the original surface and subsoils, respectively, and had a magnesium saturation of 12.17 per cent in the surface layer. Yield increases from added magne- sium might be expected from this soil. However, as shown in Tables IV, V, and VI, crop yields on this soil are distinctly lower than those obtained on other soils. It is possible that the decreased yield is due to physio- logical disorders brought about by additions of large amounts of magnesium. Plainfield loamy sand. No response from added.magnesium was noted in the yields fbr soybeans or wheat as shown in Tables IV and VI. There was a significant decrease in dry matter produced.by millet. The surface and subsoil in this case contained 0.7h, and 1.10 milliequivalents exchangeable magnesium, respectively, per 100 grams, although the magnesium saturation of the surface soil was 23.12 per cent. However, as in the case of Emmet sandy loam, here also crop yields fall far below those obtained on most other soils. This situation is rather strange, because one would expect a favorable yield response to magnesium additions by‘a light-textured soil like Plainfield loamy sand, provided no other nutrient is a limiting factor in growth. 31. Fox sandy loam. There was no significant increase in yields of soybeans, millet, or wheat from added.magnesium, as shown in Tables IV, V, and VI. This soil contained 1.06 and 1.93 milliequivalents exchangeable magnesium in the surface and subsoils, respectively, and, in fact, there was an increase in the exchangeable magnesium content of the soil at the end of the experiment, particularly in the O-NgO series. However, crop yields were similar to those obtained from most other soils. 'Warsaw loam. No significant increase in yields of soybeans or millet was Obtained from added magnesium as shown in Tables IV and V. There was a significant decrease in dry weight of wheat plants, as shown in Table VI. The surface layer of this soil contained 2.06 milliequivalents exchangeable magnesium per 100 grams, and had a magnesium saturation of 13.2h per cent. It is likely that there would not be any growth response to added magnesium. In the case of wheat, a peculiar nutritional disorder set in, with the plants becoming lean, spiny, and yellowish, and most plants withered off. This condition was responsible for the depressed yields. Isabella silt loam. There was no significant increase in dry matter production from added.magnesiumszr soybeans, millet, or wheat, as shown in Tables IV, V, and VI. The surface and subsoil both contained 1.93 milli- equivalents of exchangeable magnesium per 100 grams of soil, with a magnesium saturation of 18.h1 per cent in the surface layer. If values above 15 per cent magnesium.saturation are considered adequate, then no yield increases would.be expected from soluble magnesium added to this soil. Brookston clag'loam. A significant decrease in yields of soybeans grown on this soil was obtained when the highest rate of magnesium was applied, as seen in Table IV. Millet yields were significantly increased by magnesium, 32. as shown in Table V, while the data in Table VI show that there was no significant increase in yields of wheat from any rate of added magnesium. Since this soil contained 3.61 and 6.59 milliequivalents of exchangeable magnesium content per 100 grams of soil in the surface and subsoil layers, respectively, and the respective magnesium saturation values were 17.96 and 51.97 per cent, any response to added magnesium would be unlikel . However, no explanation can be given for the significant increases in millet yields on this soil. Fiami sandy loam. Magnesium additions brought about significant in- creases in the yield of soybeans as shown in Table IV, while for millet and wheat, no significant response is recorded in Tables V and VI. This soil has an exchangeable magnesium content of 2.71 milliequivalents per 100 grams in the surface layer and 3.90 milliequivalents in the subsoil, and the mag- nesium saturation values are 30.52 per cent and 39.00 per cent, respectively. It is quite likely that no growth response could be anticipated. This sit- uation is true for millet and wheat yields obtained on this soil. However, the soybean crop, which is quite responsive to magnesium additions, does show significant increases in yields from added magnesium on this soil. Kent clay loam. Iry'weight yields of soybean plants were not signifi- cantly increased, as shown in Table IV. However, magnesium additions sig- nificantly increased the yields of millet and wheat, as seen in Tables V and VI. This soil had 1.89 milliequivalents of exchangeable magnesium per 100 grams of soil in the upper six inches, and a magnesium saturation per cent of 12.21. It is rather likely that millet and.wheat, which have a shallower root system than soybeans, would show significant response to added magnesium. 33. 030.33 3385. no.3”: 95¢.on 230.85 33.85 .853 3.380." 3033.39." 3.3» «a noon .5 0.8 need: a fiuongngom no 38.?- 3 363 one. no no eon—”and on: no uneven 3 cannon .n 9.8 + 8.8 28 .. 8A a 8..“ + 2.8 .. :8- 58:8 88 + 8.” .. 8.8 23 + 8.... .. 86 .. .83 53o .55: 2....v + 5.2 + 3.3 a 2.8 a 2.... - 8.2. a 83 3. as. 85 + 8.0 + 8.3 + 8.... + 8.8 + 38 .. .33 he... in. on.» .. 8.2. - 8; .. 2.8 .. 8.2. .. 88 .. l3 .2? ass—88 8.3 a 88 + 8.3 + 2......" 4 88 a 8.... a 83 3:. 333.3 8.8 .. 88 .. 8.3 .. 88 u 8.3" u 8.3 .. 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Tables X, XI, XII contain data for magnesium.and potassium expressed as milliequivalents per 100 grams of dry matter, and the MgeK ratios for soy- beans, millet, and wheat, respectively. In Tables XIII, XIV, and XV are re- ported values for the magnesium and calcium expressed as milliequivalents per 100 grams of dry matter, and the NgeCa ratios for soybeans, millet,and wheat, respectively. A discussion of the experimental results on this aspect for each crop is presented below: Sgybeans. The amount of'magnesium in soybeans for the 13 soils where no magnesium was applied ranged from 25.66 milliequivalents per 100 grams of dry matter for Kalkaska sand to hh.75 milliequivalents for Thomas sandy loam. The potassium contents varied.between 26.82 milliequivalents per 100 grams of dry matter for Wisner clay loam to 59.56 milliequivalents for Houghton.muck. The Mng ratios in soybeans varied between 0.66 fer Houghton muck to 1.56 fer Thomas sandy loam. The amount of calcium in soybeans grown on the different soils ranged from 21.h0 milliequivalents per 100 grams of dry matter for Kalkaska sand to 36.00 milliequivalents for Thomas sandy loam. The MgeCa ratios in soybeans varied between 0.8h for Warsaw loam to 1.h3 for Houghton muck. In the 60-Mg0 series, the amount of magnesium in soybeans ranged from 29.h2 milliequivalents per 100 grams of dry matter for Kalkaska sand to h7.66 milliequivalents for Houghton muck. The amount of potassium ranged from 23.23 milliequivalents per 100 grams of dry matter for Isabella silt loam to h9.23 milliequivalents for Houghton muck. The Mng ratios varied.between 0.63 for Plainfield loamy sand to 1.62 fer Thomas sandy loam. It can be seen from Figure 1 that potassium content of soybeans was greatly increased as magnesium hS. application to the soil was increased. Calcium in soybeans grown in soils treated with 60 pounds of magnesium expressed as the oxide ranged from 18.h0 milliequivalents per 100 grams of dry matter for Kalkaska sand to 35.00 milliequivalents for Thomas sandy loam, as shown in Table XIII. The MgtCa ratios of this crop ranged from 1.00 for Warsaw loam to 1.67 for Houghton muck. In the 1204Mg0 series, the amount of magnesium.in soybeans varied between 29.83 milliequivalents per 100 grams dry matter for'Warsaw loam to 5h.00 for Houghton muck, as seen in Table X. The potassium content ranged from.25.31 milliequivalents per 100 grams dry matter for Emmet sandy 10am to 5h.51 milliequivalents fer Houghton muck. The MgeK ratios varied between 0.67 fer Warsaw loam to 1.72 for Thomas sandy loam. The amount of calcium in soybeans on this series ranged from 21.50 milliequivalents per 100 grams dry matter for Kalkaska sand to 39.50 milliequivalents for Thomas sandy 10am. The Mg+Ca ratios varied between 0.92 for Warsaw loam to 2.03 for Houghton muck. In the 2h0-Mg0 series, the content of magnesium in soybeans ranged from 32.50 milliequivalents per 100 grams of dry matter fer Oshtemo loamy sand to 53.h2 milliequivalents for Houghton muck. The amount of potassium content ranged from 27.69 milliequivalents per 100 grams of dry matter for Thomas sandy loam to 52.56 milliequivalents for Houghton muck. The MgeK ratios varied.between 0.69 for Plainfield loamy sand to 1.h2 for Thomas sandy loam. The content of calcium in soybeans on the 2h0-Mg0 series ranged from 17.30 milliequivalents per 100 grams of dry matter fer Kalkaska sand to 36.12 milli- equivalents fbr‘Wisner clay loam. The NgeCa ratios ranged from 1.12 for Thomas sandy loam to 2.1h for Houghton muck. h6. In summarizing the nutrient composition of soybeans grown on the dif- ferent soils in the O-figO, 60-Ng0, l20-Mg0, and 2h0-Mg0 series, it was found that the magnesium content initially increased with added magnesium, and then decreased when 120 and 2h0 pounds of MgO were applied. The content of potassium increased appreciably as the rate of'magnesium application was increased. So far as the uptake of calcium is concerned, a gradual decrease in calcium content occurred as the amount of added magnesium.was increased. £21132, The amount of'magnesium.in millet on the O-MgO series varied between b.66 milliequivalents per 100 grams of dry matter for Kalkaska sand to 30.83 milliequivalents for Houghton muck. The amount of potassium varied between 28.20 milliequivalents per 100 grams dry matter for Houghton muck to 62.56 milliequivalents for Isabella silt 10am. The MgeK ratios ranged from 0.08 fbr Kalkaska sand to 1.09 for Houghton muck. The content of cal- cium in millet on this series varied.between h.b0 milliequivalents per 100 grams of dry matter for Warsaw loam to 5.90 milliequivalents for Wisner clay loam. The thCa ratios ranged from 0.95 for Kalkaska sand to 5.71 for Houghton muck. In the 60-Mg0 series, the amount of magnesium in millet ranged from 8.33 milliequivalents per 100 grams of dry matter for Kalkaska sand to 38.92 fer Houghton muck. The amount of potassium varied between 35.90 milliequivalents per 100 grams of dry matter fbr Houghton muck to 69.h9 milliequivalents for Fbx sandy loam. The MgeK ratios ranged from 0.12 for Kalkaska sand to 1.08 for Houghton muck. The calcium content varied between 3.28 milliequivalents per 100 grams of dry matter for Kent clay loam to 5.88 milliequivalents for'Wisner clay loam. The Mnga ratios ranged from 2.13 for Kalkaska sand to 7.85 for Miami sandy loam. h7. 0n the 120-Mg0 series, the magnesium content in millet varied between 10.66 milliequivalents per 100 grams of dry matter for Oshtemo loamy sand to 36.33 milliequivalents for Emmet sandy loam. The potassium content ranged from 2h.69 milliequivalents per 100 grams of dry matter for Kalkaska sand to 68.20 milliequivalents for Oshtemo loamy sand. The NgeK ratios in this crop ranged from 0.15 for Oshtemo loamy sand to 0.95 for Kalkaska sand and Plain- field loamy sand. The amount of calcium varied between h.00 milliequivalents per 100 grams of dry matter for Miami sandy loam to 5.75 milliequivalents for Emmet sandy loam. The NgeCa ratios ranged from 2.21 for Oshtemo loamy sand to 7.52 for Miami sandy loam. 0n the 2h0-Mg0 series, the amount of‘magnesium in millet varied between 9.h2 milliequivalents per 100 grams of dry matter for 0Shtemo loamy sand to 39.66 milliequivalents for Houghton muck. The amount of potassium varied between 29.23 milliequivalents per 100 grams of dry matter for Kalkaska sand to 68.66 milliequivalents for Fox sandy loam. The HgtK ratios varied between 0.28 for'warsaw loam to 1.16 for Emmet sandy loam. The calcium content of A millet on this series ranged from 3.16 milliequivalents per 100 grams of dry matter for Kalkaska sand to 5.91 milliequivalents for Thomas sandy loam. The MgeCa ratios ranged from 1.81 for Oshtemo loamy sand to 8.92 for Miami sandy'loam. The above data of the magnesium, calcium, and potassium contents and their ratios in millet indicate that the quantity of potassium was increased to a very great extent as magnesium application to the soil increased. The high potassium content of the plants seems to be associated with low yields. The NgtCa ratios are very wide, very low amounts of calcium being absorbed in h8. comparison to the amounts of magnesium absorbed by millet. It is a well known fact that magnesium cannot replace calcium in the nutrition of plants and the rather low absorption of calcium by millet may account for the low yields. E2232, 0n the O-MgO series, the amount of magnesium absorbed by spring wheat plants varied between 8.16 milliequivalents per 100 grams of dry matter fbr Brookston clay loam to 30.66 milliequivalents for Thomas sandy loam. The amount of potassium found in the same crop ranged from h9.23 milliequivalents per 100 grams of dry matter for Emmet sandy loam to 76.66 milliequivalents for Brookston clay'loam. The NgtK ratios of the plant tissue ranged from 0.10 for Brookston clay loam to 0.66 for Houghton muck.' The calcium.content of wheat on this series ranged from 5.93 milliequivalents per 100 grams of dry matter for Isabella silt loam to 13.30 milliequivalents for Houghton muck. The NgeCa ratios ranged from 1.65 for Kalkaska sand to 2.81 for Fox sandy loam. 0n the 604Mg0 series, the magnesium content of wheat plants varied from 12.08 milliequivalents per 100 grams of dry matter for Kent clay loam to h0.l6 milliequivalents for Thomas sandy loam. The amount of potassium ranged from h2.38 milliequivalents per 100 grams of dry matter for Houghton muck to 69.h9 milliequivalents for'Warsaw loam. 'With this crop the NgeK ratios ranged from 0.1h forBrookston clay loam to 0.75 for Houghton muck. The amount of calcium ranged from 5.30 milliequivalents per 100 grams of dry matter for Kalkaska sand to 12.90 milliequivalents for Thomas sandy loam. The NgtCa ratios varied from 1.h8 for plants grown on Kent clay loam to 3.11 for those grown on Thomas sandy loam. h9. On the 120-Mg0 series, the amount of magnesium in.wheat plants varied between 10.75 milliequivalents per 100 grams of dry matter for Kent clay loam to 33.83 milliequivalents for Thomas sandy loam. The potassium content varied between 33.59 milliequivalents per 100 grams of dry matter for Emmet sandy loam to 79.h9 milliequivalents for Brookston clay loam. Magnesium to potassium ratios of from 0.15 to 0.91 were found for Kent clay loam and Emmet sandy loam, respectively. The amount of calcium varied between 5.00 milliequivalents per 100 grams of dry matter for Isabella silt loam to 11.55 milliequivalents for Thomas sandy loam. The Mg+Ca ratios in this crop ranged from 1.53 for Kent clay loam to b.20 for Emmet sandy loam. 0n the 2h0-Mg0 series, the amount of magnesium in wheat varied between 10.75 milliequivalents per 100 grams of dry matter for Brookston clay loam to 37.h1 milliequivalents for Thomas sandy loam. The quantity of potassium varied between 38.72 milliequivalents per 100 grams dry matter for Houghton muck to 81.79 milliequivalents for Kalkaska sand. The NgeK ratios ranged from 0.1h for Brookston clay loam to 0.76 for Houghton muck. The amount of calcium varied between 5.91 milliequivalents per 100 grams of dry matter fer Kalkaska sand to 10.90 milliequivalents for Thomas sandy loam. The ngCa ratios ranged from 1.55 for Kent clay loam to b.62 for Kalkaska sand. As in the case of millet, the increase in the uptake of potassium as in- creasing amounts of magnesium were added to soils appears to have caused de- creased yields. Further, calcium absorption was depressed below the level of magnesium, and this probably resulted in physiological disturbances, which ac- count for the low yields and even a depression of growth on some soils. «a +~ +— 4-—~ 4. 4e ~+~ +— —+- we : +4~~~+~4.—s-1——:4-+-~+— +-+—: SO. «mom- amen New scam- swam mam sees assesses asma+ mama Hod Jama+ OQNH 20H awed mean gonna: NQHm+ maom med Hems+ omfls Hma sees aeae seem mmem+ mamm mam ammm+ comm sea sees asses ages: seas+ new: mma aaam+ ewe: ama seed seas eesexeesm 80$ 83 SN :33 0me 42 50a flaw eflopemH map + mam mas pea . oom med eeeH sense: Hama+ seas mas eaom+ mama mmfl seeH asses x0e am + New mos me + om mos seem hseeH eHeaesHeHm oaNH+ mmaa was oeeH+ cam mm seoH asses pessm Hama+ maaa mma mafia» one med seem sewed aseseeo Ha: - New mas mafl e Hsz mas seem exeesase «amen mama Nam mafia- mesa saw sees asses essesa .mema .meE .msms .meE .meE .mEME 90m mofidmono spam mmnfidmono meoso m an gem assessmez seems use seem mmeoeo m an emposmm mo ommmaom Iem soammcmwz emboamm EdHMmcwmz, no commmxfih, ea coachemman‘ sofimmcwmz weeeeem omzuo hem sdfimmowmz umpm< new show mo mmwmamm umm Edfimmcmwz no eomvwxwm ewlmocmpmmmwn, eefieem omw-oe some seem Edmmslmz¢ «BMAHHZ «mz¢mmwom Mm UZHmmomo Q2¢ :DHmmzwdzwmmcm¢ mo mBZDOZ¢ OZHME; Mm mmeoflmm< m4 339m mmbomzmmmo mme ,mo Bow Mm. 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The exchangeable potassium, calcium, and magnesium contents of the greenhouse soils after cropping are presented in Table III. These data indicate that exchange- able magnesium.after cropping was slightly higher than that of the surface soil at the start of the experiment, as shown in Table II. It is difficult to tell whether this increase was entirely due to release from non-exchangeable sources or to a mixing of the surface and subsoil increments at time of sampling at the end of the experiment. It is also likely that some magnesium may have remained in the roots not harvested. The data in Table XVI refer to the total amount of magnesium removed by soybeans, millet, and wheat, the difference in magnesium in the soils before and after cropping, and fixation or release of magnesium expressed as milli- grams per pot in all the four series, namely, o-mgo, 60-Mg0, 120-Mg0, and 2hO-Mg0. The values for the "difference in magnesium before and after cropping"‘ were calculated as follows: The quantity of exchangeable soil magnesium before cropping plus the amount of'magnesium added per treatment, minus the exchangeable soil mag- nesium after the harvest of the three crops. The colums headed, "Fixation or release of magnesium per pot" show positive and negative values, indicating both release and fixation. The values for magnesium fixation or release in the different soils are obtained from the following relation: 53. Amount of exchangeable magnesium in the soils at the beginning of the experiment plus the amount of magnesium added per treatment, minus the total amount of magnesium.removed by the three crops, plus the amount of magnesium left in the soil at the end of the experiment. Several criteria can be used for evaluating the need of soils in general fer magnesium fertilization. These are, the absolute yields with- out added.magnesium, the response of crops on the application of magnesium to the soil, the content of exchangeable magnesium of the original soils, and the extent to which their reserve magnesium is released. In the O-MgO series, where no magnesium was added, three soils, namely, Thomas sandy loam,'warsaw loam, and Houghton muck, fixed.magnesium. The soils on the O-MgO series can be arranged in order based on the total amount of magnesium removed by all three crops: Thomas sandy loam, Houghton muck, Miami sandy loam, Wisner clay loam, Oshtemo loamy sand, Brookston cldy loam, Kent clay loam, Fox sandy loam, Isabella silt loam, Kalkaska sand, warsaw loam,and Emmet sandy loam. As regards the ability of the soils to release magnesium, the soils can be arranged in the following order based on the greatest or lowest amounts of’magnesium released: Brookston clay loam, Kent clay loam, Miami sandy loam, Isabella silt loam, Fox sandy loam,'Wisner clay loam, Emmet sandy loam, Oshtemo loamy sand, and Kalkaska sand. The soils in the order of increasing fixation of magnesium on the O-MgO series are: ‘Warsaw loam, Thomas sandy loam, and Houghton muck. In the 60-Mg0, 120-Mg0, and 2h0-Mg0 series, three soils, Thomas sandy loam, Kalkaska sand, and Houghton muck fixed magnesium, the last soil showing the highest fixation of all the soils in the three series. Sh. The greatest release of magnesium.occurred.with Brookston clay loam, followed by lower values from Kent clay loam,'Wisner clay loam, Isabella silt loam, and finally lowest values from the coarse textured soils. SUI‘II-L‘LRY AND CONCLUSIONS This study was undertaken in order to evaluate the magnesium-supplying powers of some Michigan soils for certain crops. Twelve mineral soils and one organic soil, representing different soil types, were used in a pot cul- ture experiment . . Magnesium was the only fertilizer element varied. Four rates of this element corresponding to 0, 60, 120, and 2h0 pounds of‘MgO were applied on an acre basis as Sul-Po-Mag, a water-soluble, double sulfate of potash-mag- nesia. All other nutrients, including nitrogen, phosphorus, potassium, and certain nicronutrients, were added at what was believed to be optimum rates. Soybeans, millet, and wheat were grown as the test crops. Yield and chemical composition of the crops were determined. The plants were analyzed for potassium, calcium, and magnesium. The last two elements were deter- mined on the Beckman DU flame spectrophotometer, while potassium was analyzed on the Perkin-Elmer flame spectrophotometer. The soils were analyzed for pH, per cent organic matter, per cent sand, silt, and clay, exchange capacity, total exchangeable bases, and exchangeable magnesium, calcium, and potassium at the start of the experiment. Exchange- able magnesium, calcium, and potassium were determined on the soils after cropping. Yield of soybeans was significantly increased in only one of thirteen soils, 3 Miami sandy loam, while in Brookston clay loam, soybean yields were significantly decreased due to magnesium additions. 56. Yield of millet was significantly increased using three soils - Kalkaska sand, Brookston clay loam, and Houghton muck, while a significant decrease in yield was found using Oshtemo loamy sand, Plainfield loamy sand, and Kent clay loam. A significant increase in wheat yield was registered in only one soil, namely, Kent clay loam, while the growth of wheat on Warsaw loam was signifi- cantly decreased upon use of supplemental magnesium. Results of chemical analysis of the three crops showed that, in general, magnesium uptake increased only up to the 120-Mg0 level in all soils except Emmet sandy loam,'Warsaw loam, and Houghton muck. Increasing amounts of mag- nesiwm reduced uptake of magnesium beyond the l20-Mg0 level, but in contrast, increases in the uptake bf potassium were found for most of the soils, especial- Ly in the case of millet and wheat. The increase in potassium uptake was as- sociated with decreased crop yields. The NgeK ratios for a given crop were not very consistent for the dif- ferent magnesium treatments in the case of most soils. Particularly the MgeCa ratios in millet and.wheat were very wide. It appears that supplemental additions of calcium to the soil would.have been of decided benefit to these crops, as it is recognized that excessive amounts of magnesium without calcium might reduce crop yields. It has also been recognized that if:magnesium ex- ceeds calcium in plants by a very wide margin, toxic conditions result, which, in turn, would affect growth. This point emphasizes the importance of the proper balance of these three cations in the soil. 'With the soils used in this study, no magnesium deficiency was noted. Neither were visual symptoms of toxicity apparent. However, the total amount of magnesium removed by the three crops was only a small fraction of the quantity S7. of exchangeable magnesium in the original soils. The yield data, especially indicate that an application of 2h0 pounds of Ego as the sulfate was too high. It seems likely that all the soils used in this study had adequate amounts of exchangeable magnesium, and it is apparent that much response to added magne- sium.would not be forthcoming. Since these soils were collected from farmer's fields, it is possible that some had received dolomitic limestone, it would be necessary to conduct further experiments on a wide range of soil types, where exchangeable magnesium was known to be low, in order to show magnesium defi- ciency with Michigan soils. Since the total amount of magnesium removed by the three crops was only a small fraction of the quantity of exchangeable magnesium in the original soils, it would be necessany to increase the crop- ping period. The following conclusions can be made from this investigation: 1. No visible magnesium deficiency was feund in several field crops grown on the soils used in this greenhouse study. 2. There was no definite correlation between the dry matter production of crops and the exchangeable magnesium content of the soils studied. 3. The increased uptake of magnesium by plants did not necessarily indicate increased yields in all cases. h. The uptake of potassium was markedly influenced by supplemental magnesium, the larger the amount of magnesium in the soil, the higher was the content of plant potassium, especially in the case of millet and wheat. 5. Response to applications of magnesium was influenced by its ratio to other cations in the exchange complex, especially those of calcium and potassium. 58. 6. There was no cation constancy relationships in the crops as grown. 7. It is likely that 60 to 80 pounds of MgO in the form of a soluble salt is adequate to meet the magnesium needs of crops. 8. The ideal amount of exchangeable magnesium of a Soil has been sug- gested to be equivalent to about 10 per cent of the total exchange capacity. In this study it was found that most of the soils had exchangeable magnesium far in excess of this amount, hence, any response to applications of magne- sium in the soluble form would be unlikely. 9. Magnesium fixation occurred only in three soils, namely, Thomas sandy loam, Kalkaska sand, and Houghton muck, the first and the last soils showing high fixation values. All other soils released magnesium, the largest release occurring in the heavier soils. It is possible that some magnesium remained in the roots of the crops, especially the final one, and on this basis, the values for release might be even higher than recorded. Dry plant weight in gus. per pot Nutrient uptake by crop in mgms. per pot 59. r SB - Soybeans M - Millet 30 W — Wheat 25 _ 20 _ 15 r 5 L—\\\’ i 1 1 _L 4 g o 60 120 2b( i MgO Application in Pounds Per Acre 1 ..l_. 3180 _ She , I 5 uzo 3150 _ ’ - } 88 I120 _ 3’“ _‘\. ; aa1,SB l i 90 _ Magnesium 270 _ Potassium M 30 ' I 1 J ._J 1 1 J l o 60 120 2ho o 60 120 2&0 MgO Application in Pounds Per Acre Fig. l. The effect of varying amounts of added Magnesium on the yield and uptake of Magnesimn and Potassium by soybeans, millet, and wheat grown on Thomas sandy loam. Dry plant weight in gas. per pot Nutrient uptake by crop in mgms. per pot SB — Soybeans M - Millet 33 r_ w _ Wheat 25 ;. SE 2.1) _ 15 _ 10 _ M 5 4+ _. w J l l g 0 60 120 2&0 M50 Application in Pounds Per Acre 180 r Sho _ 150 .. hSo _ J J J l l l J 0 60 120 2h0 0 60 120 EL M30 Application in Pounds Per Acre Pig. The effect of varying amounts of added Magnesium on the yield and uptake of Magnesiun and Potassium by soybeans, millet, and wheat grown on Kalkaska sand. 5. per pot P bind t in r-\ L {’1 J r plant “78in A L. 61. SE; - So;,rbeans M-——1 10 m - Millet -- _ W - Wheat 20 L 15 F 10 \ M J—v 5 Ta. w 1 1 ‘ J o 60 120 3L0 ”g0 Application in Pounds Per Acre 180 , 5“°~ 150 _ “50 ~ 120 ___..SB Potassimn 90 Magnesium l g 1 J J 1 l _J c 60 120 2&0 o 60 120 2H0 MgO Application in Pounds Per Acre Fig. 3. The effect of varying amounts of added Ma nesium on the yield and uptake of Xagnesium and otsssi millet, and ’heat grown on Oshtemo loamy sand. 1b in gas. per pot ,1 bl y plant weiv Dr Nutrient uptake'by crop in mgms. per pot --_m___._._ HF?» (‘ a": a- - QUJI Gt? d.» :8 .. r3 t !'; '7" ”J. - llkL-L.LC*U r. W -- In LC at 1! 58 L. n— 4—0 Li / I L- *+ . :. 5‘9 1 l 1 J O 60 190 2&0 MgO Application in Pounds Per Acre 1:0 1 540 _ SB 1? e O p 200 Potassium 90 - 270 7- 53 1 . ,a 60 _ hagnesium. 150 P a“ r A M 30 ... 70 ,-_ I :‘W Aw 1 1 L, J 1 1 1 all 0 {o 120 22; o 50 12 2.1.0 M30 Application in Pounds Per Acre Fix. h. The effect of varying amounts of added Magnesium on the yield and uptake of Magnesiun and Potassium by soytears, millet, and wheat grown on Emmet sandy loan. 63. per pot ." J15. in ht ’Y L) Dry plant wei ’J c. 20 15 10 \J‘. "I: ‘ ~1- » a. . 1.3.) - bf); “‘81:..13 ' If: 1 .1. J. -- mlh F3 '1; A — ‘1’310 at 1 1 1 1 M50 Apalication in Pounds Per Acre o If? 1U r- II‘QO [- 13c L 115.0 _ —. 5:3 120 36;} __ (r. 0 k; ,3 O ‘fr-n.‘ . muJHQSlum Potassium — b y.— I... L— 2Lo c- :30 logo mo .1 ca ion in Pounds Per Aer F\' m‘ “I." ‘jro C '}"D pv‘mc‘ .t *5). ’0 a...’ ‘4‘-.. . a a1 a? . C‘ .' 1 .1 ' .1 _ J. 0"“ ' 11?); .L1 L (I, CEJ'L'J. ‘ ‘.'— . e I ' ‘ ' Y ' ‘7"'.'" Y‘"' fv-w Mac-t r‘ vp his” "1 “v. .‘7‘ v r "n-J Orr—'1- LI 4.: ‘\'.) Li- . ml.‘ \J‘ A .‘O ‘(l L ak.‘ ‘ {.414 ‘0. J. . 46.-' l‘. -‘A LT-j C a A r/ n --’... x 1 - f‘, I.)\ a" W\ li'i'a‘, .\o:.‘ ~1h‘. O" {1‘ 1.; 11101,,er‘l. , L”, ,,..;.|-‘,- ,. . 1L; 5: =»J'.1.. 1: L 'I.l y! y L)'_‘ 1 x; (I .u' A W wheat grown on Plainzield loamy sand. gms. per pot i I. . 11’ I O11?- n t. w (3. 'v I L. y P "I b er pot Q or. a v 1 ' .Ls}. 17'. in A @305 n by 4 r ‘ ‘ 41.1.. 1‘V\ ks? e. I F-Ht a . er 3 ._‘\ J r) 'n p— ~—‘o 88 . C TO HrO Applicition 1 in Poruds Per Acre ' ) F) (v C 1...: \j“ C) H FJ ‘3 ~‘ (Err; _ 11 N Magnesium J ,— r «"2‘w So in *‘O QT} .44 L- Potassium b l ‘11 :3><;>-—<= 11 1 1 1 1J C 6 '1“ 1." 1'"? C .' , (“‘- ifi"'* r"l p F ' s I. 4.1.8 9- AL?“ V .. SA- 9'14 ’7'" & P.. . fieli and uptake of Miqresium m3: 7 ‘3? I.,.. ,5. I", 9 effect of varyinr amounts and Wheat grown on Fox sandy of added MagnGSWum on tit and Potassium by soyfwins loam. Dry'plant weight in gms. per pot Nutrient uptake by crop in mgms. per pot 65. SB - Soybeans ,A M - Millet ”’ v w _ Wheat :5 g __,___ .__. 58 MD _ I + 3 M S - _ ___.__¥ fit ’ “v 1 1 1 J O 60 120 2&0 MgO Application in Pounds Per Acre 180, 5110- 150- 1150- 120_. 360_ SB Magnesium Potassium SB 90- 27c- 30 91;}. ‘ ~—-o ' f "“$ 11 113 W' 1 1 1 120 2110 o 60 120 MgO Application in Pounds Per Acre 4 2L0 Fig. 7. The effect of varying amounts of added Magnesium on the yield and uptake of Magnesium and Potassium by soybeans, millet, and wheat grown on Warsaw loam. Dry plant weight in gms. per pot Nutrient uptake by crop in mgms. per pot SB - Sc foe 51.-as K - Millet J. P W - Wee at 4—; SB ”,‘f‘ »,I L 1(1- +- a——oli + r 9 s ——3v-* :::t::* ““" 1' 4 L J 0 60 1'20 2110 21:50 implication in Pounds Per Acre 180 Sto r 150 hi _ 120 390 ~ as '\ AS} 90 270 _ 6O _ Magnesium 130 L Potassium 14W 90 ‘M I .. 1— 33 n NW L J 1 _ J 1 1 1 J o 60 120 at o 50 120 2L0 1150 Application in Pounds Per Acre Pig. 8. The effect of varying amounts of added Magnesium on the yield and uptake of‘ Magnesium and Potassium by soyb ,ans, millet, and wheat grown on Isabella silt loam. Dry plant weight in gms. per pot in mgms. per pot ‘- :e by tree 5 Nutrient uptak 67. 30”‘ 1::- lOr— M s T— 4+ W + 1 -ML 1 A l) 63 120 2g“ MgO Application in Pounds Per Acre A P \ le’ ”- 51,3 W- 150 .— L..', 3 Jr- 88 i 120 SB 4 i“ M A 300 4" i 1 ;U L magnesium ;‘Q t Potassimn K- L on M ' 5"“? 1 ‘J\.:' >— WT M t i W J l a , ,1 L J __'_1 c o 120 aka 0 6.0 120 m0 ”60 Application in Pounds er Acre Fi' 9. The effect of varying atounzs of added leanesium on the ‘ield and u take of Marnesiun and Potassinn b' SO”L€&HS J J . J 9 millet, and wheat grown cc Broomston cley' loam. 68. 1 y plant- Dr S} - Soybean 18 M — Millet ’In .. — H 119. at ‘T \ h- /\ hr- ‘1- r- ) I - 1tmuih.ler Acre per pot , 15. n.'(' Ul‘ r—n op in m y- A e by C r A 1 A utrient up to. x N H (D O 1 ‘V b 150 O h- F. :. SB fin .- ‘H—I t— .j "9 1— 9: Ci ‘ v ' 2 O K‘- I 4- . * refineSium - IotaSSium 6C) 1. 19.5 /.\7 a M W M (I ‘I V . I ‘- I- N 1 1 _J 1 1 1 _J O 33 120 2;? C CO 120 2‘0 K50 Application in Pounds Fer Acre v“) k.) —-_ -. —-———.——_-—'---_‘_.- v-1: -_ .1 , N“_‘ , ’\ s — '-—-—. .5 .x a v . - :- —‘. 1.1 ‘ 'r . ' -‘ O x p ’ r * I :-;. i0. LAG cfi~c of varying ¢.01Lts of augfid mabflfibidn uJ one vrfi‘r 1 (an a - r P \ y'v .‘ '-V.- .‘o fi ‘1- I. . i " N ~‘v;-. ‘\ ‘ J LL) L11 wlxi ur) take Ur 11nd,); .11 f- 4.1. 11.. {d to 1.'LS:3 1.111. by 12‘ 1.1.)" u .s-r 2). 1L1, ., £ 1, + .. H: . .- ‘ lilict, and wheat grown on miami sanuy loam. fi‘ v 13"; an t. W. Jl‘ 'r' V , per pot -'. v‘ rv‘ ’vmf'} .LAL AJ-L’.4-LI O 5. at 1‘3“” 0 69. on — soybeans ‘1 T-.‘, ‘1 " .~ 1. in -' ¢u.:...~.L\.;u 1‘. .. J- ,. u - :ulCdo p h— p— D I: 1. CW 1 L 1 1 J x f- \ "’\_" (,"1‘" C uu ‘9‘} ugu I . ~ A '1 ' ' '5... . p, M 1") ‘Llu’lJA--\.'1L__\)l‘al- o.-- Lq‘14:;‘-:.’ llrr 4.. ‘hl... .— - r"'n I - ', ' ° .L/‘v _ JagneSimn In») _. PotasszLum 1 Hr .LL- .' .5 I ,. y r- )1}...— SR EB y w, ,_ C. ‘ '41— ::\‘ P ‘ .42. ,'\ I b M 7" t ‘ T, P“! I “ V"'v\'r'"‘ )‘.. . - v ‘ A - :4” ‘lr“ -- '-'o: m. .- 1‘. rib. 3.1. £1153 Of; 0013 Oi 11m 'y 1.3 (mm m US of dducd magnum; 11 m v.18 7": ' 1 ‘ 1" I ’1’ ' "'.‘ . ,‘I , IV r-\‘,. -4--.;-: ’v.‘ .«.‘_—;. . ”‘3. J J-UJ.d 41111 1}) Lit-.8 Of “‘“6‘ lei); 11.11 dud I’O 1.19.004. «A?! by DbJuCQAoJ, \-"‘. '. r., “if“- .. v, .t .. 1% MLLG u, cU‘ul VulUdt :51 Huh \211 ALT“: Clay 4.0613. ght in Ems. per pot Ery'plant'wci ,r pot Nutrient uptake by crop in mgms. 70. SS — Soy-beans M - Millet 3° ,. w .. Wheat A 33 25 ‘1F—‘ «——o——e 20 _ 15 _ 10 _ —-01M 5 W . A w l I l A O 60 120 240 MgO Application in Pounds Per Acre 180 .. She r' 190 L— LSO .. ‘ SB SB Magnesium Potassium 60 .. 180 _ N M 30 .. 90 r. W MI 1:: a w J l 1 _J l l _L J o 60 120 21:0 0 60 120 22,0 MgO Application in Pounds Per Acre The effect of varying amounts of added Magnesium on the yield and uptake of Magnesium and Potassium by on millet, and wheat grown on Wiener cLay Ivan- 71. pot H ‘L 'ms. pe k.) ;. Dry plant weight in 10 I o“ 1°C V Mgo Application in Pounds Per Acre 1 L 1 A_J #51 c4 utrient uptake by'crop in mgms. per pot Y 0 5‘ \ 180 120 90 Potassium ‘W W 90 _ 1 1 i4 1 1 i_J C . 2:0 (I :Q E) O J- .T. a .u-J n) O icstien in Pounds or Acre effect 01 varying amounts 0: added Magneslu" .h¢ su,tnmins, 1i and uptake of Magnesimn and Potassium by et, and wheat grown on chgnton muck. «y\ k (1-1 tug l. 2. 3. he 9. 10. 12. 13. LITERATURE CITED Bear, F. E., Editor, Soil Chemistry, American Chemical Society MonOgraph, Reinhold Publishing Corporation, New York. 1955. Prince, A. L., Toth, S. J., and Purvis, E. R. Magnesium in Wants and $0118. No Jo Agri. EXP. Sta. B111. 760. 19510 and Malcolm, J. L. The potassium-supplying powers of twenty N. J. soils. Soil Sci. 58:139-lh9. 19hh. Beeson, K. C. Mineral composition of crops with particular reference to the soils in which they were grown. U. S. Dept. Agri. Misc. Pub. 369. 1mm. Blair, A.'W., Prince, A. L., and L. E. Eisenmenger. Effect of applications of magnesium.on crop yields and on the percentages of calcium and magne- sium oxides in plant material. Soil Sci. h8259-73. 1939. Boynton, D., and Compton, O. C. Studies on the control of magnesium.defi- ciency in New York apple orchards. Amer. Soc. Hort. Sci. hézl-S. 19h5. . Leaf analysis in estimating the potas- sium, magnesium, and sodium needs of fruit trees. Soil Sci. 59:339-353. 19h5. Bouyoucos, G. J. Directions fer making mechanical analyses of soils by hydrometer method. Soil Sci. h2:225-229. 1936. Bradfield, R., and Peach, M. The effects of lime and magnesium on absorption of potassium. Soil and Plant. Amer. Part. 9?, No. 6, 20. 1mm. Bray, R. H., and Wilhite, F. M. The determination of total replaceable bases in soils. Ind. Eng. Chem. Anal. Ed. lzlhh. 1929. Carolus, R. L. Some factors affecting the absorption of magnesium by the potato plant. Proc. Amer. Soc. Hort. Sci. 303h80-h8h. 1933. Clarke, F3 W. Composition of the earth‘s crust. U. S. Geol. Survey Prof. Paper. 127. l92h. Cooper, H. P. Certain factors affecting the availability, absorption, and utilization of magnesium.by plants. Soil Sci. 60:107-11h. 19hS. 16. 17. 18. 19. 20. 21. 22. 23. 2h. 25. 73. Daniel, H. A. The magnesium content of grasses and legumes and the ratios between this element, and the total calcium, phosphorus, and nitrogen in these plants. Jour. Amer. Soc. Agron. 27:922-927. 1935. Davis, J. F., and McCall, W. W. Occurrence of’magnesium deficiency in celery on the organic soils of’Kichigan. Mich. Agri. Exp. Sta. Quart. Bul. 35(3):32h-329. 1953. Eisenmenger, W} S., and Kucinski, K. J. Relationships of seed plant development to the need of magnesium. Soil Sci. 63:13-19. 19b7. Ponder, J. F. Variation in the potassium content of alfalfa due to stages of growth and soil type and the relationship of potassium and calcium in plants grown upon different soil types. Jour. Amer. Soc. Agron. 21:732-750. 1929. Graham, E. R. Magnesium as a factor in nitrogen fixation by soybeans, Missouri Agri. Exp. Sta. Bul. 288. 1938. Harmer, P. H., and Benne, E. J. Sodium as a crop nutrient. Soil Sci. 60:137-lh8. 19h5. Hunter, H. S. Yield and composition as affected by variations in the Caohg ratio in the soil. Soil Sci. 67:53-62. 19h9. Jenny, H. Simple kinetic theory of ionic exchange I. Jour. Phys. Chem. hO:SOl-l7. 1936. Joffe, J. S., Kardos, L. T., and Mattson, S. Laws of soil colloidal behavior XVII. Mg-silicate - its base-exchange properties. Soil Sci. 10:255-268. 1935. Johnson, K. E. E. Some chemical aspects of the control of magnesium deficiency in celery grown on the organic soils of’Michigan. Ph.D. thesis. Michigan State Univ. Library, East Lansing. 1955. Kardos, L. T. and Joffe, J. S. Preparation, composition and chemical behavior of the complex silicates of’Fg. Ca, Sr, and Ba. Soil Sci. h53293-307. 1938. Lawton, K. A study of the relation between the supply of potassium and other nutrient elements in several Michigan soil types and the growth of alfalfa and field beans. Ph.D. thesis. Michigan State Univ. Library, East Lansing. 19h5. 26. 27. 28. 29. 30. 31. 32. 33. 3h. 35. 36. 37. 38. 7h. Lucas, R. E., and Scarseth, G. D. Potassium, calcium, and magnesium and their reciprocal relationships in plants. Jour. Amer. Soc. Agron. 39:887'950 19h7o MacIntire, W. R., Young, J. B., and Robinson, B. Magnesium.retention in soils in relation to the forms and rates of additions. Soil Sci. Soc. Amer. Proc. 6:233-37. l9hl. , Shaw, W. H., and Robinson, B. The dis- tinction between magnesium absorbed and that exchangeable from four years lysimeter incorporations of carbonates and oxides. Soil Sci. 37:289-303. l93ho Mattson, S. Laws of soil colloidal behavior. XI. Electrodialysis in relation to soil processes. Soil Sci. 36:1h9-63. 1933. Nehlich, A., and Reed, J. F. The influence of the degree of saturation, potassium level, and calcium additions on the removal of Ca, Mg, and K. Soil Sci. Amer. Proc. 10:87-93. 1985. Obenshain, S. S. Effect of different concentrations of nutrient supplies in sand cultures on the chemical composition of the expressed sap of the corn plant. Va. Acad. Sci. Proc. 7h: l9hh. Peech, M. Determination of exchangeable cations and exchange capacity of soils. Soil Sci. 59:25-h8. 19h5. Piper, C. S. Soil and Plant Analysis. Interscience Publishers, Inc. Prince, A. L. Magnesium-supplying powers of twenty N. J. soils. Soil Sci. 63:69-78. 19h7. Rabinowitch, E. I. Photosynthesis and related processes. Vol. I. Interscience Publications, Inc., New York. 19h5. Southwick, L. Some results in correcting magnesium deficiency in apple orchards. Amer. Soc. Hort. Sci. Proc. hhz8-lh. l9hh. Wallace, T., Croxall, H. E., and Pickford, P. T. H. Field experiment on the fertilizing of potatoes. Agri. Hort. Res. Sta. Long Ashton, Bristol Ann. Rpt. 38-83. l9h2. Walsh, T., and Clarke, E. J. Chlorosis of tomatoes with particular reference to potassium-magnesium relations. Proc. Royal. Irish. Acad. 503:2h5-263. 19h5. 39. ho. 111. 1:2. 75. Welsh, T., and O'Donohoe, T. F. Magnesium deficiency in some crop plants in relation to the level of potassium nutrition. Jour. Agri. Sci. 35:2Sh-263. l9h5. Webb, J. R., Ohlrogge, A. J., and Barber, S. A. The effect of'mag- nesium upon the growth and the phosphorus content of soybean plant. Soil Sci. Soc. Amer. Proc. 18(h):h58-h62. l9Sh. Wiegner, G., and Jenny, H. On base exchange. Abs. Proc. Ist Inter- nat'lo Cong. SOil SCio 23’46-510 1927. Zimmerman, M. Magnesium in plants. Soil Sci. 6331-13. 1987. a w Date Due R813: 113E £9.31 Demco-293 4-... .__f 96 I 8 III III I'- I'll l I I'll Illl ll] '11 I_||II 1'" III III ll'l. 'II III 93 03169 34 3 1 # i lllllmilili\llll'llllUllll