L‘l" ‘ mulmxllmullmxw“will 1/ LIBRARY Midiigan State University This is to certify that the thesis entitled CHARACTERIZATION OF A CONOVER-BROOKSTON SOIL MAPPING UNIT IN MONROE COUNTY,MICHIGAN presented by G. Hossein Asady has been accepted towards fulfillment of the requirements for Master Soil Sciences degree in Dr. E.P. Whiteside Major professor Datevf/c/f' / 5: /?X&7 /? 0/ 0-7639 OVERDUE FINES ARE 25¢ PER DAY PER ITEM Return to book drop to remove this checkout from your record. $.15! 1 319.94 CHARACTERIZATION OF A CONOVER-BROOKSTON SOIL MAPPING UNIT IN MONROE COUNTY,MICHIGAN BY G. Hossein Asady A THESIS Submitted to Michigan State University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Department of Crop and Soil Sciences 1980 ABSTRACT CHARACTERIZATION OF A CONOVER-BROOKSTON SOIL MAPPING UNIT IN MONROE COUNTY,MICHIGAN BY G. Hossein Asady Field studies and laboratory determinations were conducted on 16 pedons within a tentative Conover-Brookston mapping unit in Monroe County,Michigan. The purpose of this study was to characterize and evaluate the major components of this mapping unit. Field and laboratory data indicated that of the 16 pedons described in the field and sampled as Brookston and Conover,8 were truly represe- ntative of their series. Three were recognized as variants and 5 other pedons were identified as other soil series. These pedons covered the whole range of the fine-loamy family from borderline coarse loamy to borderline fine family. Only three pedons were evaluated as being deve- loped in non-uniform parent material. The pedons outside of the textural range of characteristics of the Brookston and Conover series varied significantly in other properties important to the use and management of these soils. ACKNOWLEDGMENTS The author wishes to express his sincere gratitude to Dr. E.P. Whiteside, the author's major professor for his guidance, help, and con- structive criticisms. His patience during the course of this study has been greatly appreciated. The author also wishes to express his appreciation to his other guidance committee members: Dr. L.S. Robertson, Dr. A.J. Smucker, Professor E. Kidder, and Dr. R. Kunze for their cooperation. Thanks are also extended to the personnel of the soil testing labor- atory, especially Dr. D.D. Narncke, who were very cooperative in making the materials available and carrying out some of the soil test analyses. Special thanks are also due to the University of Technology, Isfahan, IRAN, for providing the funds for the author's course of study overseas. Special thanks should go to Dr. G.D. Lemme for his useful advice and cooperation in preparation of the final draft. ii TABLE OF CONTENTS I. INTRODUCTION AND OBJECTIVES OF THE STUDY .................... II. LITERATURE REVIEW ........................................... l. Brookston series and its classification ................. A. Placement in Soil Taxonomy .......................... B. Mollisols ........................................... C. Mollic epipedon ..................................... D. Earlier profile descriptions in Michigan ............ 2. Conover series and its classification ................... A. Placement in Soil Taxonomy .......................... B. Alfisols ............................................ C. Argillic horizon .................................... D. Earlier profile descriptions in Michigan ............ III. HOW THIS STUDY WAS CONDUCTED ................................ l. Field Studies ........................................... A. Site selection ...................................... B. Sampling ............................................ 2. Laboratory Procedures ................................... A. Physical determinations ............................. a. Mechanical analyses ............................. b. Fine-clay determinations ........................ c. One-third and l5 atm. water retentions .......... B. Chemical determinations ............................. a. pH .............................................. b. Lime requirements ............................... c. Extractable phosphorus .......................... d. Extractable potassium, calcium, and magnesium... e. Organic matter .................................. f. CEC and base saturation ........... ' .............. IV. PROFILE DESCRIPTIONS ........................................ l. Tentative Brookston Pedons Sampled ...................... 2. Tentative Conover Pedons Sampled ........................ PAGE PAGE V. RESULTS AND DISCUSSIONS .................................... 40 1. Evaluation of Parent Material Uniformity ............... 4O 2. Particle Size Distribution ............................. 50 A. Brookston pedons sampled ........................... 50 B. Conover pedons sampled ............................. 56 3. Water Retention ........................................ 62 A. One-third bar percentage ........................... 62 8. Fifteen bar percentage ............................. 62 C. Available water percentage ......................... 64 4. pH and Lime Requirements ............................... 65 5. Available Nutrients .................................... 69 A. Available phosphorus ............................... 69 B. Exchangeable potassium ............................. 72 C. Exchangeable calcium ............................... 74 D. Exchangeable magnesium ............................. 77 E. Total bases ........................................ 78 F. Summary ............................................ BO 6. Organic Matter ......................................... 8l 7. Cation Exchange Capacity (CEC), Base Saturation, and Extractable Bases ................................ 84 A. Cation exchange capacity ........................... 84 8. Base saturation .................................... 87 C. Extractable bases .................................. 88 VI. CLASSIFICATION ............................................. 90 1. Individual Pedons ...................................... 9O 2. Map Units .............................................. 90 VII. CONCLUSIONS ................................................ 94 VIII. NEEDS FOR MORE INVESTIGATION ............................... 97 REFERENCES ................................................. 98 iv TABLE l0 ll l2 l3 l4 l5 l6 l7 l8 LIST OF TABLES Observed size distributions of samples filtered or not filtered, after destruction of organic matter ....... Observed size distributions, including fine-clay, when 25.0 or 50.0 ml. of calgon solution are used without and with filtering, after organic matter destruction.... Particle size distribution of non-clay fractions of tentative Brookston pedons sampled ...................... Particle size distribution of non-clay fractions of tentative Conover pedons sampled ........................ Average size distribution of tentative Brookston pedons sampled ................................................. Average size distribution of tentative Conover pedons sampled ................................................. Particle size distribution of tentative Brookston pedons sampled ................................................. Sand and silt subfractions of tentative Brookston pedons sampled ................................................. Average size distribution of six Brookston and five Conover pedons .......................................... Particle size distribution of tentative Conover pedons sampled ................................................. Sand and silt subfractions of tentative Conover pedons sampled ................................................. Hater retention percent of tentative Brookston and Conover pedons sampled .......................................... Chemical analyses of tentative Brookston pedons sampled... Chemical analyses of tentative Conover pedons sampled ..... Available nutrients of the Brookston pedons ............... Available nutrients of the Conover pedons ................. Phosphate-phosphorus recommendations for field crops on mineral soils ........................................... Potash—potassium recommendations for field crops on sandy loams and loamy sands ................................... V PAGE 20 2l 4T 42 47 48 51 53 57 58 59 63 67 68 7O 7l 73 75 l9 20 2T 22 23 24 Potash-potassium recommendations for field crops on loams, clay loams and clays .................................... 76 The average total bases of the whole pedons sampled ....... 79 Cation exchange capacity (CEC), extractable bases, and percent base saturation (8.5.) with related soil properties in sampled Brookston pedons .................. 82 Cation exchange capacity (CEC), extractable bases, and percent base saturation (8.5.) with related soil properties in sampled Conover pedons .......... l .......... 83 The average Ca lost from the soils during soil formation processes ............................................... 89 Classification of the sixteen pedons studied .............. 9l vi LIST OF FIGURES FIGURE PAGE l Location of transected areas ................................ 3 2 Location of sampled pedons .................................. 5 3 Relation of si/s ratio to clay contents of Brookston pedons sampled ............................................ 43 4 Relation of si/s ratio to clay contents of Conover pedons sampled ............................................ 44 5 Ratio of sigs in A9, and its deviation from one, in the si/s in 82 Brookston and Conover pedons sampled ...................... 46 6 Particle size distribution of tentative Brookston pedons sampled ............................................ 54 7 Particle size distribution of tentative Conover pedons sampled ................................................... 6l 8 Relation of CEC and percent clay in the sampled Brookston and Conover surfaces and subsoils ......................... 86 I. INTRODUCTION AND OBJECTIVES OF THE STUDY Brookston and Conover soil series are the poorly and somewhat poorly drained members of the Miami catena, respectively. These soils are formed under natural deciduous forest vegetation in a cool temperate, humid climate. The parent material is usually calcareous loam till and less commonly calcareous coarse clay loam till. Brookston series, the poorly drained member of this catena, is formed in level areas of till or lake plain with a relatively high water table. The somewhat poorly drained member of this catena Conover, is formed in the upper parts of an undulating to nearly level till or lake plain witha seasonal fluctuation of water table. The high water table is indirectly responsible for a higher than normal accumulation of organic materials in this mineral soil and the formation of a mollic epipedon in the Brookston series. Fluctuation of water table in the Conover pedons is responsible for formation of a thinner dark surface horizon which is not thick enough to qualify as a mollic epi- pedon, and is called an ochric epipedon. However, it is dark and thick enough to be a mollic intergrade. The humid climate has aided eluvia- tion of silicate clays from the upper parts of the solum and illuviation of them into its lower parts with formation of an argillic horizon in both series. The relatively thick layer of organic matter rich mineral, Ap horizons, their high base status, and the clay enriched subsoils have caused these soils to be fertile. However, the best productivity is conditioned by appropriate management, including drainage practices in the poorly drained member of the catena, to lower the natural water table. By characterization of pedons we can determine and measure many of the physical, chemical, mineralogical, and biological properties of soils. These measurements can only be performed on a small unit of soil, a pedon, that is representative of a larger area. Characterization of soils may be resolved into two kinds of measurements; first, field observations by which many of the observable and measureable properties of a soil are determined, and second laboratory analyses that verify the accuracy of the field observations, quantify them, and determine some other soil pro- perties as well. During the l978 mapping season in Monroe county, Michigan, the com- position of a mapping unit tentatively named "Blount" indicated that it was more likely to be dominated by fine loamy (l7 — 35% clay) rather than "fine“ (35 - 42% clay) profiles. This mapping unit was then renamed T60 (Temporary 60). This mapping unit was then transected (Figure l) accompanied by Dr. E.P. Nhiteside. It was found that from 30 point observations 27% were Conover, 2 % were Brookston, 2 % were Metamora, l3% were Celina, and l % were other soil series, (l observation of Corunna, Owosso, Pewamo, and Wasepi) each representing less than %. More observations done by the other members of the soil survey party also emphasized the necessity of renaming this unit. This percentage agreement of the series present with the name of the map unit is about the average observed to date in modern soil surveys of Michigan (E.P. Hhiteside*). In the light of these observations this mapping unit was tentatively named Conover-Brookston, and the author started describing, and sampling * Personal Communication ~ ouswgm mambo wouummcmuu mo acauwuoq 02.u2(a .4: .2. :3: the representative pedons. Finally, based on more observations in the context of the county, it was decided to name separate parts of this mapping unit Conover, Brookston, or Blount. Some parts of the first tentatively named "Blount" remained unchanged. The tentative Conover and Brookston pedons investigated in this study will be found in the following mapping units in the Monroe Co. soil survey report: Tentative Brookston pedons sampled: Bl, 82, B3, B4 and 85 appear in the Conover map unit (60 A), pedon B6 in the Brookston (6l) and B7, BB in the Blount (l3 A) map unit (Figure 2). Tentative Conover pedons sampled: All of the tentative Conover pedons are within the Conover map unit (60 A) except pedon C8 which is in the Blount (l3 A) unit (Figure 2). Characterization of the tentative Conover-Brookston mapping unit in Monroe county, Michigan, is the goal of this study. By characterization ofthesesoils several objectives can be met to: l. Aid soil scientists in correctly describing mapping units of soil in a particular area. The transects characterizing the map unit, in this case, are being evaluated by further charac- terizing the two principal soils present in the laboratory. Determine quantitatively many of the physical and chemical properties of the soils required in agricultural planning and for other uses. (Many other soil management decisions are influenced by the knowledge of soil properties such as: soil moisture management, the amount and kind of fertilizer that should be used, the degree of stability of peds useful in management and mechanization practices, the mineralogy of , 60A .82 '34 ac: «ca 083 NE 1/4 of Sec. T.6 S. R.6 E. 9 NE 1/4 of Sec. T.6 S. R.6 E. Legend 13 A 20 A 22 23 A 24 29 30 46 60 A 61 OBS , 0C2 ___...qp—- 33 scale w VI 0 "files v0 Blount loam 0-32 slope NE 1/4 of Sec. 21 T.6 S. R.6 E. 24 23A 23A 23A 23A 22 Q-Ll 60Al 13 6' ., 61 NE 1/4 of Sec. 27 T.6 S. R.6 E. Selfridge-Pewamo complex 0-22 slope Pewamo clay loam Metamora sandy loam O-ZZ slope Corunna sandy loam Colwood loam Sloan loam Ceresco fine sandy loam Conover loam O—ZZ slope Brookston loam Sampled pedons Drainage way Location of sampled pedons Figure 2 6 particles which effects fixation or availability of macro- and micro-nutrients, and liming requirements.) 3. Assist in classifying the soils correctly. 4. Aid in determining the range of characteristics of the major soils within an area. 5. Determine parent material uniformity in major soils of the mapping unit. This study was based upon the hypothesis that the Blount mapping unit would be more correctly termed Conover-Brookston, because most soils in the unit belong to the fine-loamy textural family instead of the fine textural family as is indicated by the Blount. II. LITERATURE REVIEW Franzmeier et al. (l977) have defined soil characterization as the determination and recording of important soil properties of a small soil unit that represents much larger soil bodies. It includes morphological properties, which are determined in the laboratory as well as those des- cribed in the field. l. Brookston Series, and Its Classification A. Placement in Soil Taxonomy: The National Cooperative Soil Survey (l978) has classified the Brookston series as a member of the fine-loamy, mixed, mesic family of Typic Argiaquolls, which is a Mollisol having an argillic horizon, and an aquic moisture regime. B. Mollisols: Soil Taxonomy (Soil Survey Staff l975) defines mollisols as soils having a combination of a very dark-brown to black surface horizon (mollic epipedon) that makes up more than one-third of the combined thickness of the A & B horizons or that is >>25 cm thick. and that has structure or soft consistence when dry. Mollisols characteristically form under grass in climates that have moderate to pronounced seasonal moisture deficit. A few form under marshes or on marls in humid climates. The Brookston is one of those formed under marshy conditions. C. Mollic epipedon: From the genetic point of view Soil Taxonomy (Soil Survey Staff, 1975) defines the mollic epipedon as being formed mainly by the underground decomposition of organic residues in the presence of bivalent cations, particularly, calcium. Generally a mollic epipedon is a mineral 7 8 diagnostic surface horizon which is at least 25 cm thick or at least l/3 of solum thickness, and has a color value moist of 3.5 or less (dry color 5.5 or less), a chroma of 3.5 or less, and ‘750% base saturation. 0. Earlier profile descriptions of Brookston in Michigan: Descriptions of series before l938 used no standard color chart. Texture and structure terms were less standardized than today. The range of characteristics were much broader, especially in thickness of the dark surface horizon, and the texture of the surface and subsoils. The broader range in properties of earlier established soil series resulted in the later recognized series covering only part of those properties. The following profile descriptions indicate evolution of soil survey in selected counties in Michigan. Berrien Co. soil survey report (Kerr, l922) considers the Brookston series as having, typically a dark-gray loam surface, ranging from 7 to l2 inches in depth, underlain by heavy bluish or mottled yellow and gray clay loam. The substratum is heavy calcareous till. In Ottawa Co. (Veatch. l922) Brookston consists of a dark-gray fine-sandy loam surface from 6 to l5 inches in thickness which grades into lighter gray or gray and yellow mottled soil which may be either sandy- loam or clay loam in texture. This is underlain by bluish-gray clay exhibiting yellowish or brownish mottling. Livingston Co. (Nheeting, l923) soil survey report describes the Brookston series as consisting of a layer from 2 to 4 inches thick of leaf litter or mold the lower part of which is well decomposed. The sur- face layer cfi'granular loam ranges from 8 to l2 inches in depth and varies in color from dark-gray to dark-grayish brown. There is a some- what abrupt change into the subsoil. The texture becomes heavier, the 9 structure becomes coarsely granular, with increasing clay content and the color is mottled brown, gray, and drab. It is mapped in association with Miami loam and Hillsdale loam. In Hillsdale Co. (Veatch, 1924) the Brookston consists of a surface layer with dark-gray or dark-grayish brown loam from 6 to l0 inches deep. This grades to gray or drab, more coherent, and more clayey material which in turn grades to steel-gray or bluish-gray, more plastic or sticky sandy clay mottled with yellow or brown. The substratum consists of sandy clay or alternate thin layers of sand and clay. Jackson Co. soil survey report (Veatch, l926) considers the Brookston as having a surface layer of dark-gray loam, moderately rich in organic matter and from 6 to l0 inches thick grading into gray or drab more coherent and clayey material from 6 to l0 inches thick, beneath which is steel-gray or bluish-gray more plastic or sticky sandy clay mottled with yellow or brown. The substratum is clay or alternate thin layers of sand and clay. In Lenawee Co. (Striker, et al. l947) soils of the Brookston series are dark colored and poorly drained. They formed in glacial till con- sisting of loam or clay loam. They are in the same catena as the well drained Miami, the imperfectly-drained Conover and the very poorly—drained Kokomo soils. The Brookston soils have a thinner, lighter colored surface soil than the Kokomo, and the upper part of the subsoil is predominantely gray rather than mottled. They are coarser textured than the Pewamo. After l938, profile descriptions are more standardized, the range of characteristics of series are more limited, and new soil series have been established. The new soil survey of Livingston Co. (Engberg, et al. l974, compared to the old one, Nheeting. l923) describes the Brookston series l0 as having a surface layer of very dark brown loam, l0 inches thick which has been developed in loam or light clay loam till. The upper part of the subsoil is dark-gray firm light clay loam that has dark yellow-brown and yellowish brown mottles. The underlying material consists of mottled-gray light olive-gray, dark-gray, and yellowish brown loam. The thickness of the surface layer in the Brookston series was much broader than it is today. Such as; 7-l2 inches (Berrien Co.), 6-l5 inches (Ottawa Co.) 8-l2 inches (Livingston Co.), 6-l0 inches (Hillsdale Co. and Jackson Co.). With evolution of soil survey the range of char- acteristics became narrower, and the definitions became more standardized such as in the new Livingston County soil survey report (Engberg, l974) the surface layer of the Brookston series is l0 inches thick. At the present time the surface layer of the Brookston series has to be at least l0 inches thick or l/3 of the solum thickness (Soil Survey Staff, 1975). The subsoil layers of the Brookston in Livingston Co. (l923) are somewhat heavier, and in some places are almost pure clay and silt. The substratum of clay or alternate thin layers of sand and clay has been described for the Brookston series in Jackson Co. (l926), and Hillsdale Co. (l924). These would now probably be Colwood or Lenawee series. In Ottawa Co. (l922) the subsoil texture of the Brookston ranges from sandy loam to clay loam. By l974 Brookston was described more narrowly in the new Livingston Co. soil survey, with l0 inches of dark surface, a clay loam subsoil, and a loam C horizon. In Lenawee Co. (l947) the C horizon is restricted to glacial till of loam or light clay loam textured, and Pewamo was recog- nized for the part of the former finer range of Brookston textures. The drained Brookston soil is mentioned to yield average 40 bushels ll per acre corn, g ton timothy hay, and 20-35 bushels of cats in Berrien County (l922). Excellent yeilds of corn, hay, oats, alfalfa, and sugar beets are reported for the Brookston when properly drained in Hillsdale County (l924). In Lenawee County (l947) all of the crops commonly grown in the county are grown on the Brookston loams, and yields are usually high. The available water holding capacity, and fertility of the Brookston soils are said to be high and well suited to farming particu- larly to row crops. However, they have severe limitations for many non- farm uses in Livingston County (l974). 2. Conover Series and Its Classification A. Placement in Soil Taxonomy: The National Cooperative Soil Survey (l978) has classified the Conover soil series as a member of the fine loamy, mixed,mesic, family of Udollic Ochraqualfs. Thus, it is an alfisol with an aquic moisture regime. B. Alfisols: _ Soil Taxonomy (Soil Survey Staff, l975) defines Alfisols as having unique properties of a combination of an Ochric or an Umbric epipedon, an argillic horizon, a medium to high supply of bases in the soil and water available to mesophytic plants more than half the year or more than three consecutive months during a warm season. Buol, et al. (l973) identify two prerequisites for formation of alfisols: (l) a moderate abundance of a layer lattice clay, and (2) its accumulation in the subsoil enough to produce an argillic horizon. C. Argillic horizon: Soil Taxonomy (Soil Survey Staff, l975) considers an argillic horizon as an illuvial horizon in which layer-lattice silicate clays have l2 accumulated by illuviation to a significant extent. In addition the following properties have been considered in identi- fying an argillic horizon: (l) If there is no lithologic discontinuity; a) if the eluvial horizon has ( l5% total clay, the argillic horizon has to have 3% more clay. b) if the eluvial horizon has 15 to 40% clay, the argillic horizon should have l.2 times as much clay as the eluvial horizon. c) if the eluvial horizon has ‘) 40% clay, the argillic hori- zon must have % more clay. (2) If a soil has a lithologic discontinuity, between the eluvial and the argillic horizon or if only a plow layer overlies the argillic horizon, the argillic horizon needs to have clay skins in only some parts. (3) An argillic horizon should be at least l/lO as thick as all overlying horizons.' (4) The ratio of fine clay to total clay must be more in the argil- lic horizon by l/3 or more. G.D. Smith (l978) considers an argillic horizon as a mark of the stability of the land surface for a reasonably long period of time, a matter of not hundreds but probably a few thousands or more of years. Thorp et al., (23) concluded from comprehensive investigation of a Miami soil that eluviation of clay from the A horizons and illuviation in the 82 horizons account for most of the differences in clay content of these two horizons. Mickelson (23) on the other hand concluded from weathering studies 13 of a Miami soil that little if any clay has been translocated from the surface to the subsoil even when considerable quantities of clay had been lost from the A horizons. According to H. Smith (24) the fine clay ratio has the advantage of being a more sensitive index of clay movement and is less likely to be confounded by carbonates. Alternatively the total clay ratio (carbonate - free) could serve as an argillic horizon differentia and would have the advantage of being more widely available. 0. Earlier profile descriptions of Conover in Michigan: Livingston Co. soil survey report (Nheeting, 1923) describes Conover series as consisting of: (l) forest litter and leaf mold 2 or 3 inches thick, (2) dark grayish-brown friable loam, 3 or 4 inches thick, which contains considerable organic matter near the top, (3) grayish-yellow loam, from 7 to l0 inches thick, which is not so friable as the material of the layer above, because of its lack of organic matter, (4) sticky, somewhat plastic clay loam, mottled with gray, brown, and yellow. Conover loam was developed under poor drainage conditions. In Jackson Co. (Veatch, l926) Conover loam is a moderately heavy soil which has developed under drainage conditions intermediate between those in the Miami and Brookston soils. The surface soil is brownish mel- low loam with a dark or humus color to a depth of 4 to 5 inches. This is underlain by pale-yellow or grayish friable loam which gives way, at a depth ranging from l2 to l5 inches, to moderately compact granular clay showing grayish and yellowish mottling. Lenawee Co. soil survey (Striker, et al. l947) has described Conover series as consisting of imperfectly drained, moderately dark colored soils that are nearly level to very gently sloping. The soils have 14 formed in highly calcareous glacial till of medium texture. These soils are in the same catena as the well drained Miami, the poorly to very poorly drained Brookston, and the very poorly drained Kokomo soils. The texture of the surface layer ranges from light clay loam to heavy sandy loam. Conover series in Macomb Co. (Larson, l97l) are level to gently sloping, somewhat poorly drained, medium textured soils on moraines and glacial till plains. These soils developed in loamy glacial till and are less than 42 inches deep to carbonates. The surface layer of a typical Conover is dark brown loam about 8 inches thick. The subsurface layer, about 4 inches thick, is pale-brown friable loam that contains mottles of brownish yellow. The subsoil is brown and grayish brown, firm clay loam, and is mottled with brownish yellow and grayish brown. The substratum is brown, friable, calcareous loam till with mottles of brownish yellow. In Livingston Co. soil survey report (Engberg, l974) Conover series is described as soils developed on till plains and in basin like depres- sions in the hilly moraines. -Included vfitflmthis soil in mapping are some small areas that have a heavy silty clay loam subsoil. Also included are small areas of Metea and Metamora soils that are coarser textured in the surface layer and upper part of the subsoil than Conover soil. Poorly drained Brookston soils and very poorly drained Carlisle soils are included in small, wet, depressional areas. As mentioned before, in the earlier soil survey reports of Michigan, no standard definitions have been used to describe the soil series. The colors are described as gray, dark-gray, bluish-gray, yellowish-brown, light olive-gray, light-olive-brown, steel—gray, drab and so forth. The surface layer of the Conover series is 3 to 4 inches of loam l5 overlain by 2 to 3 inches of forest litter and leaf mold, and underlain by clay loam in Livingston County (l923). In Jackson County (l926) Conover soil has 4 to 5 inches of dark surface, and in Macomb County (l97l) the surface layer is about 8 inches thick. In the l947 Lenawee Co. soil survey, the Conover series has formed in highly calcareous glacial till of medium texture and the finer tex- ture Conover were replaced by Blount series. In Livingston Co. (l974) Conover loam is mentioned as being formed on till plains and in basin like depressions. In the l974 Livingston Co. soil survey report, the variability of the Conover soils in the mapping units, that in the earlier soil survey report may have been included as variations in the series, is clearly recognized as inclusions of other series (Blount, Metea, Metamora, and Carlisle). The Conover series was developed under poor drainage conditions in Livingston Co. (l923). In Jackson Co. (l926) Conover developed under drainage conditions intermediate between those in the Brookston and Miami soils. The Conover series consists of imperfectly drained, moder- ately dark colored surface in Lenawee Co. (l947). By l97l the definition of drainage condition had been changed to somewhat poorly drained in Macomb Co. (Larson, l97l). Actually a moderately well drained soil Celina, had also been recognized in the Miami catena (see Ionia Co. Threlkeld et al. l960). The practical significance of these soils also changed with time and technology. The Conover is easily tilled and is suited to general farming, including the growing of corn, oats, hay, and sugar beets. In Macomb County (l97l) the Conover soils have high natural fertility, moderately 16 slow permeability, slow to medium runoff and moderate infiltration. In Livingston County (1974) the principle concern of management is maintaining adequate drainage. In Lapeer County (Earle, 1972) most of the Conover soils are farmed intensively, and corn, sugar beets, small grain, and forage crops are suitable crops. III. HOW THIS STUDY WAS CONDUCTED This investigation consisted of two parts: 1. Field studies and N . Laboratory analyses. 1. Field Studies Field studies included: A. Selecting the sites, and describing the soils at these sites. 8. Sampling A. Selecting the sites, and describing the soils: Site selection is one of the most important aspects of sampling that should be considered (11). Site selection varies with the objectives of the study. In this investigation to represent a soil mapping unit of the Monroe County, Michigan, soil survey area, transects of the tenta- tive Conover-Brookston mapping unit were made with supplemental pedon descriptions to find the most representative pedons in the mapping unit. Eight Conover and eight Brookston pedons, which were the most represen- tative soils comprising 53% of the tentative map unit, were chosen to be described and sampled. B. Sampling: From each pedon two samples were taken. One from the surface hori— zon or Ap, and another from the control section or 82 (the control sec- tion is subject to definition of control sections for particle size classes or their substitutes in Soil Taxonomy (26). The samples were air dried and passed through a 2 mm round hole sieve. 17 l8 2. Laboratory Procedures A. Physical determinations: a) Mechanical analyses: The pipette method of mechanical analyses was used to separate the less than 2 mm soil particles. The following modified method of analysis was employed: I 25 grams of air dry fine earth, <12 mm, was mixed with 50 m1 dis- tilled water, treated with 10 m1 of 30% hydrogen peroxide (H202), and left standing overnight. The next day, it was heated to about 90°C with additional 5 ml increments of 30% H202 until all organic matter was removed. The process of heating was continued for about an hour to be sure all excess H202 was removed. Because the samples were taken from A and B horizons, and free carbonates were not present, the samples were not treated with acid. For dispersion of particles the samples were treated with 25 ml of 5% calgon solution. The calgon solution treated samples were left over- night, and then stirred with a mechanical stirrer (milk shake type) for 15 minutes. (In a technical note titled an "Investigation of methods of mechanical analysis" by R. Laurin, 1975, good agreement was obtained between two methods of mechanical agitation; a mechanical stirrer (milk shake type) and a reciprocating shaker. So the mechanical stirrer which is less time consuming was employed.)- The other processes of measuring sand, silt, and clay percentages were based on standard methods (25, 29, 15, 8). The results reported are averages of duplicate determinations. Following the above analyses the percentages of fine clay ( < 0.2 micron) were also determined using an aliquot of the restirred suspensions as described above. 19 It should be noted that for the purpose of setting a standard pro- cedure for this investigation, some preliminary experiments were also con- ducted on several treatments of samples. One group was treated with calgon solution, after destruction of organic matter, filtered through a No. 50 Whatman filter paper, and then washed with distilled water (Treatment 1). A second group was treated with calgon solution imme- diately after organic matter destruction (Treatment II). No significant differences were observed (see Tables 1 and 2). So all the samples were subsequently treated with calgon solution, after organic matter destruc- tion, without being filtered or washed. Two levels of calgon solution were also compared in sample disper- sion; 25 m1 and 50 ml. The results showed no differences (Table 2), so the smaller amount was used subsequently. b) Fine-clay determination: Various clay fractions less than 2 micron ( .<.002 mm) have pre- viously been employed for soil characterization. Separations have been made by long setting or centrifugation (13). A centrifuge is commonly employed for the purpose of increasing the gravitational force, and hence the rate of particle sedimentation, which becomes important in the sepa- ration of small clay size particles. After sampling of silt and total clay in the pipette method of mechanical analysis, a 25 m1 portion of the suspension was transferred to a centrifuge tube. The time required for 0-2,H particles to get to the point of Sampling, 2.0 cm beneath the suspension surface, was calcu- lated using Stoke's law (27) at the appropriate temperature: R2 n log ( fif’ ) 3.81 N2 r2 ( d1 - d2 ) 20 Table 1: Observed size distributions of samples filtered or not filtered, after destruction of organic matter. Treatments Soils % clay % f. silt %ch silt % sand Total (.002 .002-.02 .02-.05 .05-2.0 mm mm mm mm I 81-1 33.6 32.5 16.0 17.9 100.0 81-2 35.5 33.6 16.2 14.7 100.0 Filtered Cl-l 13.8 16.3 9.6 60.3 100.0 C1-2 18.9 13.4 6.7 60.9 99.9 81-1 33.7 32.5 15.2 18.6 100.0 II 81-2 35.6 —‘ 34.1 13.4 16.9 100.0 Unfiltered Cl-l 13.8 16.0 8.2 61.9 99.9 C1-2 19.5 12.5 6.8 61.2 100.0 81-1 33.6 32.5 15.6 18.3 100.0 81-2 35.6 33.8 14.8 15.8 100.0 Average Cl-l 13.8 16.1 8.9 61.1 99.9 C1-2 19.2 12.9 6.7 61.1 99.9 21 Table 2: Observed size distributions, including fine clay, when 25.0 or 50.0 ml of calgon solution are used without and with filtering after organic matter destruction. Treatments Soils %f. clay % clay %f. silt %co. silt % sand Total (.0002 (.002 .002-.02 .02-.05 .05-2.0 mm mm mm mm mm I 81-1 16.0 34.2 31.3 * * * 25 ml. cal. +fi1tered C1-1 6.2 13.9 15.9 7.8 62.4 100.0 11 81-1 15.8 34.0 32.0 16.1 17.9 100.0 25 m1. cal. +unfi1tered Cl-l 6.5 14.6 15.7 9.1 60.6 100.0 III 81-1 16.3 34.7 30.7 17.6 17.0 100.0 50 ml. cal. +unfi1tered Cl-l 7.1 15.4 15.7 7.6 61.3 100.0 81-1 16.0 34.3 31.3 16.8 17.5 99.9 Average C1-1 6.6 14.6 15.8 8.2 61.4 100.0 * missed data 22 in which: t = time of sampling in seconds m = liquid viscosity in poise (temperature dependent) R1 = distance from the axis of rotation to the surface of sus- pension in cm R2 = distance from the axis of rotation to the sampling depth in cm (R1 + 2.0 cm) N = the number of revolutions per second which was 36.66 rps. (or 2200 rpm.) r = radius of particles in cm d1 = particle density = 2.65 g/cm3 d2 = liquid density in g/cm3 (temperature dependent) An International centrifuge was used, with a head carrying four 100 ml tubes. Each tube contained 25 m1 of suspension. The .(.2.H pipette sample, removed by an automatic pipette, was 5 m1 from a depth of 2 cm at a time calcuated by the above equation. c) One-third atm. and 15 atm. water retension: Less than 2 mm soil samples were placed in soil retaining rings about 1 cm high and 4 cm diameter on a porous plate. The plate was then covered with water to wet the samples from below, and left standing overnight. The excess water was removed and the plates were placed in a pressure cooker for 1/3 atm. water extraction and in a pressure membrane apparatus for 15 atm. water extraction. The required pressure was applied until no additional water was extracted. The samples were then oven dried at 105°C and moisture percentages were computed on an oven dry basis (25, 29). In this study results are average of at least 5 determinations. 23 B. Chemical determinations a) pH Five grams of air dry soil were mixed with 5 m1 of distilled water in a cup. This was shaken for 5 minutes, left standing for 10 minutes, and the pH was read with the use of a glass electrode (indicating) paired with a calomel (reference) electrode, and plugged into a reasonably good commercial pH meter. With proper standardization of the meter and using a buffer of known pH, the pH of the soil suspended in water or 0.01 M CaClz is indicated by the voltage generated between the two electrodes (19). b) Lime requirements The method by Shoemaker, McLean, and Pratt, (SMP method) was used. Ten m1 of SMP buffer solution were added to the soil samples saved from the pH measurements. This was shaken for 10 minutes and left standing 30 minutes before reading the pH (19). c) Extractable phosphorus The Bray-l soil test method for phosphorus was used. Extractable phosphorus was measured by a colorimetric method (16). d) Extractable potassium, calcium, and magnesium Extractable cations were removed from the soil with 1 N NH4OAc, pH 7, with a 1:8 soi1:solution ratio and a contact time of 5 minutes. The soil extract is diluted by a factor of 15 with a lanthanum solution (final concentration 1500 ppm La). The determination of K, Ca, and Mg was completed on a Perkin-Elmer 290 Atomic Absorption Spectrometer (37). e) Organic matter The organic matter was calculated from the organic carbon content (1.724 x O.C.). Organic carbon (O.C.) was determined by a dry 24 combustion method using an automatic carbon analyser (l). f) CEC and base saturation The cation exchange capacity was determined by saturating the exchange complex with ammonium ions (1N NH4OAc, pH 7), and extracting the absorbed ammonium. Saturation was achieved through repeated shaking and centrifuging 2 grams of soil with 20 m1 of 1N ammonium acetate, pH 7. The samples were washed 3 times each with 15 ml isopropyl alcohol after through mixing and centrifuging and then transferred to distillation flasks with acidic 10% NaCl solution. The absorbed ammonium was determined by direct steam distillation, Kjeldahl method (13, 25, 11, and 5). The percentage of base saturation was computed as follows: Ca++ + Mg++ K+ + 8.3. X 100 CEC IV. PROFILE DESCRIPTIONS The texture and reaction, in the profile descriptions, of pedons sampled within a tentative Conover-Brookston mapping unit were corrected below based on laboratory data. The new soil series or variants, different from Conover and Brookston, were identified in the light of the laboratory data. 1. Pedon 81: Classification: Tentative Brookston Pedons Sampled Pella Series fine-silty (borderline to fine), mixed, mesic, family 0f . Typic Haplaquolls. Location: Horizon Depth cms Ap 0-30 821g 30-101 822g 101-152 1320 ft. w. 1725 ft. S. of NE corner of Sec. 9, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown 10 YR 5/2 dry) dry; silty clay loam; moderate, medium, granular structure; firm; less than 5% coarse frag- ments; many fine roots; neutral to mildly alkaline; abrupt, smooth, boundary. Gray (10 YR 5/1) with common, fine, distinct, yel- lowish brown (10 YR 5/6 & 5/8) mottles; silty clay loam; moderate, fine, angular blocky structure; firm; mildly alkaline; gradual, wavy boundary. Gray (10 YR 5/1) with common, medium, distinct dark yellowish brown (10 YR 4/6) mottles; silty clay loam; moderate, fine, angular blocky structure; firm; mildly alkaline; gradual wavy, boundary. 25 C 152+ Pedon 82: Classification: Location: Horizon Depth cms Ap 0-28 II Bth 28-76 II 839 76-127 II C 127-140 Pedon 83: Classification: Location: 26 Brown (10 YR 5/3); silty clay loam; structureless, mas- sive; friable to firm; moderately alkaline to calcareous. Brookston Series fine-loamy, mixed, mesic, family of Typic Argiaquolls. 1320 ft. H.2060 ft. S. of NE corner of Sec. 9, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; sandy clay loam to loam; weak, medium, granular structure; friable; many roots; slightly acid; abrupt, smooth, boundary. Gray (10 YR 5/1) with common, fine, distinct, yel- lowish brown (10 YR 5/6) mottles; clay loam; moder- ate, medium subangular blocky structure; thin layers of brown (10 YR 4/4) clay skins on ped faces; firm; mildly alkaline; clear, wavy boundary. Gray (10 YR 6/1) with common, fine, distinct, yel- lowish brown (10 YR 5/6) mottles; clay loam; moderate, medium, subangular blocky structure; firm; moderately alkaline; gradual, wavy boundary. Brown (10 YR 5/3); loam; structureless, massive; friable; moderately alkaline to calcareous, moder- ately effervescent. Barry-variant (no argillic horizon, borderline coarse loamy) fine-loamy, mixed, mesic, family of Typic Haplaquolls. 660 ft. N. 2640 ft. S. of NE corner of Sec. 9, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. Horizon Depth cms Ap 0-28 819 28-38 829 38-76 839 76-127 Cg 127-140+ 27 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; fine sandy loam; coarse, granular structure; friable; less than 5% coarse fragments; many roots; slightly acid; abrupt, smooth, boundary. Dark gray (10 YR 4/1) with common, fine, faint, gray- ish brown (10 YR 5/2) mottles; sandy loam; weak, coarse, subangular blocky structure; friable; common, fine, roots; slightly acid; clear, wavy boundary. Gray (10 YR 5/1) with common, medium, distinct, yellowish brown (10 YR 5/6 & 5/8) mottles; fine sandy loam; moderate, medium, subangular blocky structure; friable; neutral, clear, wavy, boundary. Gray (10 YR 6/1) with common, medium, distinct, yel- lowish broWn (10 YR 5/8) mottles; sandy loam; moder- ate, medium, subangular blocky structure; friable; mildly alkaline; gradual, wavy, boundary. Light brownish gray (10 YR 6/2) with common, medium, distinct olive-yellow (2.5 YR 6/8) mottles; sandy loam; structureless, massive; friable; moderately effervescent, calcareous. Pedon 84: Brookston Series Classification: fine-loamy, mixed, mesic, family of Typic Argiaquolls. Location: 660 ft. H. 1980 Ft. S. of NE corner of Sec. 9, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. Horizon Ap A12 821tg 822tg 839 Cs page cms 0-23 23-38 38-63 63-81 81-106 106-127 28 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; moderate, medium, granular structure; friable; many roots; medium acid; abrupt, smooth, boundary. Very dark brown (10 YR 3/2) with common, fine, faint, dark gray (10 YR 4/1) mottles; loam; moderate, medium, granular structure; friable; many roots; medium acid; clear, wavy, boundary. Gray (10 YR 6/1) with many, medium, distinct, yel- lowish brown (10 YR 5/6 & 5/8) mottles;loam to clay loam; moderate, medium, subangular blocky structure; clay skins on ped faces; friable to firm; neutral; clear, wavy, boundary. Gray (10 YR 6/1) with few, fine, distinct, yellowish brown (10.YR 5/8) mottles; loam; moderate, medium, subangular blocky structure; clay skins on ped faces; friable; neutral; gradual, wavy, boundary. Gray (10 YR 6/1) with few, fine, distinct, yellowish brown (10 YR 5/8) mottles; loam; weak, medium, sub- angular blocky structure; friable; mildly alkaline; gradual, wavy, boundary. Light brownish gray (10 YR 6/2) with few, fine, faint, yellowish brown (10 YR 5/6) mottles; 10am; structure- less, massive; friable; moderately effervescent, calcareous. Pedon BS: Classification: Location: Horizon Depth cms Ap 0-30 A3g 30-46 82tg 46-91 Cg 91-101 Pedon 86: Classification: Location: 29 Brookston fine-loamy, mixed, mesic, family of Typic Argiaquolls. 2150 ft. 5. 1300 ft. w. of NE corner of Sec. 27, T.63r R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; moderate, medium, granular structure; many fine roots; friable; neutral; abrupt, smooth, boundary. Dark grayish brown (10 YR 4/2) with common, fine, distinct, yellowish brown (10 YR 5/6) mottles; loam; moderate, medium, subangular blocky structure; many fine roots; friable; neutral; clear, wavy, boundary. Gray (10 YR 6/1) with common, fine, distinct, yel- lowish brown (10 YR 5/6) mottles; clay loam; moderate, medium, subangular blocky structure; firm; clay skins on ped faces; mildly alkaline; clear, wavy, boundary. Light brownish gray (10 YR 6/2) with common, fine, distinct, yellowish brown (10 YR 5/6) mottles; loam; structureless, massive; friable; calcareous, moder- ately effervescent. Brookston-variant fine-loamy, mixed, mesic, family of Typic Haplaquolls. 2480 ft. S. 1300 ft. w. of NE corner Sec. 27, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. 30 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam to clay loam; weak, coarse, granular structure; firm; cloddy when dry; many root channels and worm castings; mildly alkaline; abrupt, smooth boundary. Gray (10 YR 5/1) with common, medium, distinct, yel- lowish brown (10 YR 5/4 & 5/6) mottles; loam; moder- ate, medium, subangular blocky structure; firm; mildly alkaline; clear, wavy, boundary. Brown (10 YR 5/3); loam; weak, medium, subangular blocky structure; friable to firm; slightly effer- vescent, calcareous; gradual, wavy, boundary. Brown (10 YR 5/3); loam; structureless, massive; friable to firm; some pebbles, (5%; moderately effervescent, calcareous. Brookston-variant fine-loamy, mixed, mesic, family 0T TYPIC Haplaquolls. 1980 ft. H. 990 ft. S. of NE corner of Sec. 33, T.65r R.6E. Dundee Twn. Monroe Co. Michigan. Horizon Depth cms Ap 0-28 82g 28-76 Cl 76-101 C2 101-127+ Pedon B7: Classification: Location: Horizon Depth cms Ap 0-30 821g 30-46 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; clay loam; moderate, coarse, granular structure; friable to firm; many fine roots; less than 5% pebbles; slightly acid; abrupt, smooth, boundary. Dark gray (10 YR 4/1) with few, medium, distinct, 31 yellowish brown (10 YR 5/6) mottles; clay loam; moderate, fine, subangular blocky structure; firm; neutral; clear, wavy, boundary. Gray (10 YR 5/1) with common, fine, distinct, yellowish brown (10 YR 5/6) mottles; clay loam; moderate, fine, subangular blocky structure; firm; neutral: gradual, wavy boundary. Gray (10 YR 5/1) with common, fine, distinct, yellowish brown (10 YR 5/6) mottles; clay loam to loam; weak, fine, subangular blocky structure; friable to firm; mildly alkaline; gradual, wavy, boundary. 104-122+ Gray (10 YR 5/1) with common, fine, distinct, yellowish Pedon 88: Classification: brown (10 YR 5/6) mottles; loam; structureless, massive; compact; friable; less than 5% pebbles; moderately effer- vescent, calcareous, some white color, strongly efferves- cent spots. Brookston Series fine-loamy, mixed, mesic, family of Typic Argiaquolls. 1320 ft. w. 660 ft. S. of NE corner of Sec. 33, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; moderate, coarse, granular structure; friable; many fine roots; neutral; abrupt, smooth, boun- dary. Grayish brown (10 YR 5/2) with common, fine, distinct, yellowish brown (10 YR 5/4) mottles; clay loam; moderate, 822tg 51—127 32 medium, subangular blocky structure; firm; a few organic dark spots; mildly alkaline; clay skins on ped faces; gradual, wavy, boundary. Grayish brown (10 YR 5/2) with many, medium, distinct, yellowish brown (10 YR 5/6 & 5/8) mottles; clay loam; moderate, medium, subangular blocky structure; firm; clay skins on ped faces; mildly alkaline; clear, wavy, boundary. Cg 127-140+ Grayish brown (10 YR 5/2) with few, fine, distinct, 2. Pedon Cl: Classification: Location: Horizon Depth cms Ap 0-23 Bth 23-66 yellowish brown (10 YR 5/6) mottles; loam to clay loam; structureless, massive; compact; friable to firm; moderately effervescent, calcareous. Tentative Conover Pedons Sampled Locke Series fine-loamy, mixed, mesic, family of Aquollic Hapludalfs. 1320 ft. w. 2390 ft. S. of NE corner of Sec. 9, T.6S: R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish-brown (10 YR 5/2) dry; fine sandy loam; weak, coarse, granular structure; friable; less than % coarse fragments; slightly acid; abrupt, smooth, boundary. Brown (10 YR 5/3) with common, fine, distinct, yel- lowish brown (10 YR 5/6) and grayish brown (10 YR 5/2) mottles; fine sandy loam; moderate, medium, subangular blocky structure; friable to firm; clay skins on ped faces; neutral; clear, wavy, boundary. 822tg 66-76 Cg 76-ll4+ 33 Gray (10 YR 5/1) with common, medium, distinct, yel- lowish brown (10 YR 5/6) mottles; sandy clay loam; dark-brown (7.5 YR 4/4) clay skins on ped faces; weak, fine, subangular blocky structure; firm; neutral; gradual, wavy, boundary. Gray (10 YR 5/1) with few, medium, distinct, yellowish brown (10 YR 5/6) mottles; sandy loam; structureless, massive; fraible; calcareous, strong effervescence. Pedon C2: Locke Series Classification: fine-loamy, mixed, mesic, family of Aquollic Hapludalfs. Location: 660 ft. w. 2310 ft. S. of NE corner of Sec. 9, T. 65.- R.6E. Dundee Twn. Monroe Co. Michigan. Horizon Depth cms Ap 0-20 A2 20-36 82t 36-66 Cg 66-1l4+ Description Very dark grayish brown (10 YR 3/2), grayish-brown (10 YR 5/2) dry; fine sandy loam; weak, medium, granu- lar structure; friable; many fine roots; neutral; abrupt, smooth, boundary. Pale brown (10 YR 6/3); loamy fine sand; structureless, single grain; very friable; neutral; abrupt, wavy, boundary. Brown (10 YR 5/3) with common, fine, distinct, gray (10 YR 6/1) mottles; fine sandy loam to sandy clay loam; weak, medium, angular blocky structure; firm; clay skins on ped faces; mildly alkaline; gradual, wavy boundary. Grayish-brown (10 YR 5/2); sandy loam; weak, medium, platy structure; somewhat compact, friable; calcareous, strong effervescence. Pedon C3: Classification: Location: Horizon Depth cms Ap 0-18 82t 18-64 Cg 64-114+ Pedone C4: Classification: Location: Horizon Depth cms Ap 0-20 81 20-38 34 Conover Series fine-loamy, mixed, mesic, family of Udollic Ochraqualfs. 660 ft. w. 1650 ft. S. of NE corner of Sec. 9, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish-brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; fine sandy loam; moderate, coarse, granular structure; friable; many worm castings visi- ble; neutral; abrupt, smooth, boundary. Yellowish brown (10 YR 5/4) with common, fine, distinct, grayish brown (10 YR 5/2) and yellowish brown (10 YR 5/8) mottles; sandy clay loam; moderate, medium, sub- angular blocky structure; firm; clay skins on ped faces; many root channels visible; mildly alkaline; gradual. wavy, boundary. Gray (10 YR 6/1) with common, medium, distinct, yellow- ish brown (10 YR 5/6) mottles; loam; structureless, mas- sive; friable to firm; calcareous, strong effervescence. Conover Series fine-loamy, mixed, mesic, family of Udollic Ochraqualfs. 1490 ft. S. 1320 ft. N. of NE corner of Sec. 21, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; moderate, coarse, granular structure; friable; neutral; abrupt, smooth, boundary. Brown to dark brown (10 YR 4/3) with few, fine, faint, 35 yellowish brown (10 YR 5/6) mottles; loam; moderate, fine, subangular blocky structure; friable; neutral; clear, wavy, boundary. Yellowish brown (10 YR 5/4) with many, fine, distinct, grayish brown (10 YR 5/2) and brown (10 YR 5/3) mottles; clay loam; moderate, fine, subangular blocky structure; firm; clay skins on ped faces; mildly alkaline; gradual, wavy, boundary. Grayish-brown (10 YR 5/2) with common, medium, dis- tinct, yellowish brown (10 YR 5/6) mottles; loam; structureless, massive; friable; less than 5% pebbles; calcareous, moderately effervescent. Conover Series fine-loamy, mixed, mesic, family of Udollic Ochraqualfs. 1820 ft. S. 1320 ft. N. of NE corner of Sec. 21, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. 82t 38-64 Cg 64-ll4+ Pedon C5: Classification: Location: Horizon Depth cms Ap 0-23 II 82t 23-64 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; fine sandy loam; moderate, medium, granular structure; friable; many fine roots; less than 5% pebbles; mildly alkaline; abrupt, smooth, boundary. Yellowish brown (10 YR 5/4) with many, fine, distinct, grayish brown (10 YR 5/2) and yellowish brown (10 YR 5/6) mottles; clay loam; brown (7.5 YR 4/4) clay skins on faces of peds; moderate, fine, angular II 83 64-81 II C 81-114+ 36 blocky structure; firm; moderately alkaline; gradual, wavy, boundary. Yellowish brown (10 YR 5/4) with many, coarse, dis- tinct, grayish brown (10 YR 5/2) mottles; clay loam; weak, fine, angular blocky structure; firm; slightly effervescent; gradual, wavy, boundary. Brown (10 YR 5/3) with common, fine, distinct, grayish brown (10 YR 5/2) mottles; loam; weak, medium, platy structure; compact, friable; calcareous, moderately effervescent. Pedon C6: Conover Series Classification: fine-loamy, mixed, mesic, family of Udollic Ochraqualfs. Location: 1490 ft. 5. 660 ft. N. of NE corner of Sec. 21, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. Horizon Depth cms Ap 0-23 81 23-36 Bth 36-64 Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; weak, fine, granular structure; friable; slightly acid; many roots; abrupt, smooth, boundary. Dark brown (10 YR 3/3) with many, fine, faint, yel- lowish brown (10 YR 5/4)nmttles;loam; moderate, medium, subangular blocky structure; friable; slightly acid; clear, wavy, boundary. Brown (10 YR 5/3) with many, fine, distinct, grayish brown (10 YR 5/2) and yellowish brown (10 YR 5/4) mottles; clay loam; moderate, medium, subangular 37 blocky structure; clay skins on faces of peds; firm; neutral: clear, wavy boundary. Grayish brown (10 YR 5/2) with common, fine, distinct, yellowish brown (10 YR 5/4) and brown (10 YR 5/3) mottles; clay loam; moderate, medium, subangular blocky structure; clay skins on ped faces; firm; neutral; gradual, wavy, boundary. Grayish brown (10 YR 5/2) with common, fine, distinct, yellowish brown (10 YR 5/4) mottles; loam; structure- less, massive; friable; calcareous, strongly effer- vescent. Conover - variant fine-loamy, mixed, mesic, family of Aquic Eutrochrepts. 1820 ft. S. 1300 ft. w. of NE corner of Sec. 27, T.6S.- R.6E. Dundee Twn. Monroe Co. Michigan. 822tg 64-81 Cg 81-127+ Pedon C7: Classification: Location: Horizon Depth cms Ap 0-25 82 25-51 C 51-89+ Description Dark grayish brown (10 YR 4/2), light brownish gray (10 YR 6/2) dry; clay loam; moderate, medium, granular structure; firm; many roots; some worms; less than 5% pebbles; neutral; abrupt, smooth, boundary. Brown (10 YR 5/3) with many, fine, distinct, grayish brown (10 YR 5/2) and yellowish brown (10 YR 5/6) mottles; clay loam; moderate, medium, subangular blocky structure; firm; less than 5% pebbles; mildly alkaline; clear, wavy, boundary. Brown (10 YR 5/3) clay loam: structureless, massive; Pedon C8: Classification: Location: Horizon Depth cms Ap 0-20 II Bth 20-38 II 822t 38-69 II Clg 69-81 38 finn; less than 5% pebbles; moderately effervescent, calcareous. Kibbie - variant fine-silty, mixed, mesic, family of Aquollic Hapludalfs. 1980 ft. N. 660 ft. S. of NE corner of Sec. 33, T.6S.- R.6E. Summerfield Twn. Monroe Co. Michigan. Description Very dark grayish brown (10 YR 3/2), grayish brown (10 YR 5/2) dry; loam; weak, fine, granular structure; friable; neutral to slightly acid; abrupt, smooth, boundary. Brown (10 YR 5/3) with common, medium, distinct, yel- lowish brown (10 YR 5/4 & 5/8) mottles; silty clay loam; moderate, medium, angular blocky structure; firm; clay skins on ped faces and in root channels; mildly alkaline; clear, wavy, boundary. Brown (10 YR 5/3) with common, medium, distinct, yel- lowish brown (10 YR 5/4) and light brownish gray (10 YR 6/2) mottles; silty clay loam; moderate, med- ium, angular blocky structure; firm; clay skins on ped faces; mildly alkaline; clear, wavy, boundary. Grayish brown (10 YR 5/2) with few, medium, distinct, light yellowish brown (10 YR 6/4) mottles; silt loam; weak, fine, angular blocky structure; friable; small lenses of shells are present; slightly effervescent; abrupt, wavy, boundary. 39 III CZg 81-101+ Grayish brown (10 YR 5/2); clay loam; structureless, massive; firm; strongly effervescent, light color of free lime visible. V. RESULTS AND DISCUSSIONS 1. Evaluation of Parent Material Uniformity Investigation of uniformity of the parent material in the tentative Conover-Brookston mapping unit indicated that lithologic discontinuities were present either in the field observations or in the laboratory data for pedons 82, C5, and C8. A common manipulation in assessing lithologic discontinuity is to compute sand and silt separates on a clay-free basis (i.e., percent fine- sand divided by percent sand plus silt, times 100, etc.) (Tables 3 and 4). Clay distribution, because of illuviation and eluviation, is subject to pedologic change and may mask inherited lithologic differences (20). The relationship between the ratio of si/s and percentages of clay in the surface and subsoil of each pedon is plotted in Figure 3 for the Brookston and Figure 4 for the Conover pedons sampled. This relationship indicates that with increasing si/s ratio, the clay percentages increase. However, the clay percentage increase is more at low si/s ratios than at the higher ratios. The dashed line passed through Ap points is on the left side, and the dashed line through the 82 points is on the right side of the average solid line, indicating coarser textured Ap's and 82's in the Brookston and Conover pedons sampled with given si/s ratios. The criteria of the ratio of silt/sand in the Ap horizon relative to that of the subsoil ( si/Sin Ap/si/S in 82) (Tables 3 and 4, col. 9) seems to be the best test of initial uniformity of materials, because it relates the non-clay size distribution in each horizon to the other hori- zon in each pedon. In other words, it relates two major non-clay size classes in each horizon in each pedon. If the material in the Ap and 82 are originally uniform, then the ratio of si/S in Ap/si/S in 82 tends to 40 41 mm..H mmmcm>< .cocma some cw Pwomazm co .:o~wco; mm any m? m- new .:o~wco; mumwezm so a< .cmxwp 3o_a ecu m? P. .coumxoocm mo umpaEmm mcovma an» ace .oum mm ._m« ©¢_.n «mm. me. N.N ¢.o m.o_ N.mm ~.—P ¢.m_ m.mm miwm pom. ~.N ¢.m m.a m.mm w.mp F.NP ~.om Puma vmo.u mum. ¢Q.F m._ N.¢ m.m o.q~ m.F_ ¢.mp c.¢¢ Nukm om.~ o.m ¢.¢ m.m m.mp _.N— ¢.mp P.¢¢ —-mm mP.+ mp._ mmx. ¢.N m.m n.v m.~_ o.~m m.m— m.mm miom Cum. ~._ P.m m.m ~.m_ _.mm ©.mp m.om Flam ppm.u owe. mm.~ ~.m o.m m.v m.—P o.m— ~.N— o.¢¢ mimm wa. m._ m.N m.~ N.NP m.¢m m.—P _.mm —-mm cm.+ qm.~ moo. m. N.m ¢.m m.mm m.om o.mp N.¢m mucm mpm. o. o.m o.m m.mm m.w_ m.mp F.~m Flam mm.+ mm._ NQm. o. m.m _.P— o.om m.mm m.m o.m_ Nimm mwm. o. ~.m —.o— m.mm m.mm m.m _.m_ pamm mmm.u Pow. mN.— N.~ ~.N v.v m.o_ m.mp m.©— m.wm Nimm pwm. m. N.N 0.x ©.mm ©.NN ¢.op m.©m anm .u .wa. mo.m o. c.~ ¢.— m.w P.N_ m.mm m.mm Nupm map om.m m. ¢.~ m.~ m.m o.mp m.mm m.wv _-_m 55 SE 55 55 55 :z. ==_ sm__om mm.m\_m mm.m\wm .hW o.mn— o._um. 0m.-mm. mm.uo—. o_.1mo. mo.umo. No.1Noo. Pu m<.m\wm Q& .m.ou& .m.umEN .m.mw .mw.>x upwm.oofi upwm.m& 11 op m w u o m e m N — .w:sz_ou umFQEmm mcouwa :oywxoocm m>wumucmu mo meowuumcw >m_u-:o: mo :o_u:nwcumwc QNPm mpowpcmd m m4m< .cm>o:ou mo empasmm mcouma 8:» men .oum Nu ._uk _oN.- mom. mm.~ N._ m.~ o.m _.m m... N.mm m.oc N-muHH mmm. m._ m.¢ ¢.m m.~— m.mm ¢.m_ w.cm _-mu mop.- Nmm. Pm.~ m._ m.m w.m o.m_ _.m_ m.¢_ ¢.N¢ Niko mo.~ m. m.~ m.e _.m_ m._m q.m_ 0.0m _-Nu meo.- .mm. Fo._ ~._ N.¢ m.m ¢.m_ m.m_ m.o. m.mm N-©u Foo. N.” m.m ~.m N.m_ m.op m.m_ o.om F-ou mom.- mmo. Now. ~.m m.~ ¢.o_ ¢.o_ N.e_ N.m_ o.mm NimuHH mom. m.N N.“ «.mp m.mm o.N_ o.m_ ~.P~ _-mu .. . «ma. m._ w.m w.m F.NP o._m m.m_ m.mm m-eu mac sea saw. m.. N.s a.“ m.m_ N.om N.m_ _.om _-su NNm.- mme. 0.0. c. m.m w.“ o.mm m.~m m.o. _.NN N-mu mmm. m.— N.m m.__ o.Pm m._m q.m ¢.m_ _-mu mmm.- Fax. emm. e. o.m m.m m._¢ m.om e.“ _.N_ NINU oqm. e. N.m ¢.m m._¢ m.mm m.o o.m_ _-Nu m~.+ mN.P mum. m. m.m N.¢p m.mm o.o_ ¢.w o.o_ N-_u mam. m. ¢.m v.~_ o.mm m.o_ m.m m.m_ _-Pu E: E: 5:. EE 5:. EE 5:. r m _. .P om -Nm.m\wm mm.m\wm 1m. o.~-_ o._-m. om.-m~. mm.-op. op.-mo. mo.-mo. No.-moo. p Q<.m\wm awdwxwm .m .m.oo.>w .m.ou& .wmnumea .m.e& .wmwwwm pgvm.ooN wwwwm.e& III- III. ‘4- III I o. a m A a m a m N _ .mmamaau umpasmm mcouma cm>ocou m>_pmu:mp mo mcowpomcm zmpo-:o: mo :o_uznwcgmwn mem m_u_ucmd v m4m

1 ”1819311)’ finer Ap than 132 n u = + " <11 " coarser " " " n 11:: — " 05 1 ( ea 37 '4’ 9 oz 1 2 T o p as 0.2 I "1’ )01 ‘fiO-——— ___. -—O&) 0C 9' 009’ 0C )0: 6 .c 9' 0'8' 0.2 i o 04’ 68 ‘03 .l' ‘ 7"? a? 0.5» 06 éa 04 06 03. 6 07 0‘2 (l8 0" 0.9 09 81 82 8‘3 ‘ ‘ I ’ “ B‘ ‘ 1° _ 84 BS 86 7 88 Cl 92 C3 C4 cs C6 C7 ca Sampled Brookston pedons e Sampled Conover pedons o Non-uniform bv field criteria f True Brookston or variant 9; True Conover or variant oc Si/S in A? kston S si/sfin 82 and its deviation from one in the Brcc Figure 5 (deviation from 1 ) - l p SCI oils in Ag 31 s in 82 never pedons sampled 47 TABLE 5 Average size distribution of tentative Brookston pedons sampled. Horizon or atio Size Plow layer, Subsoil BZ/Ap class or ratio\ Ap 32 ratio Z 40.2 36.7 .91 .3 Sand * 38.8 37.4 .96 2 .0 m Z 34.6 34.7 1.00 H D. g Silt * 35.4 33.8 .95 CO d) .3 Z 25.2 28.5 1.13 .2 3 Clay * 25.7 28.7 1.11 Texture L CL - * L CL — Z 52.7 50.4 .95 03 '8 Sand * 51.2 51.2 1.00 m .2 3‘ z 47.3 49.6 1.05 H U E Silt * 48.7 48.7 1.00 o z: Si/S .89 .98 l.l0 * .95 .95 1.00 *Averages of those pedons considered as uniform parent material. 48 TABLE 6 Average size distribution of tentative Conover pedons sampled. ‘ Horizon or Plow layer Subsoil BZ/AP Ap 82 ratio Z 51.3 40.5 .79 0! 13 Sand * 51.8 44.8 .86 <0 .0 0) r4 Z 30.9 32.7 1.05 a. E , g Silt * 29.7 29.6 .99 G) H 0 Z 17.7 26.7 1.51 “:5. Clay * 18.4 25.6 1.39 Texture L-SL L-CL - * L-SL L - Z 61.7 54.4 .88 CD '3 Sand * 62.7 59.4 .95 <0 .0 :~ Z 38.2 45.6 1.19 r-4 9 Silt * 37.3 40.6 1.08 c o z Si/S .62 .84 1.35 * .59 .68 1.15 *Averages of those pedons considered as uniform parent material. 49 the pedons studied for the tentative Brookston and Conover. For the) Brookston soils sampled, the ratio of sand in 82/Ap averaged .96 for the uniform pedons and .91 for all the pedons (Table 5). This ratio was even closer to one when on a clay-free basis. The ratio of sand in 82-Ap (clay-free basis) was equal to .95 for all the pedons, and 1.00 for the uniform pedons. Similar data for Conover are shown in Table 6. The average ratio of si/s in 82 horizon relative to the Ap horizon (Tables 5 and 6) is equal to 1.00 for those sampled Brookston pedons con- sidered as in uniform parent material, and 1.10 for all the Brookston pedons sampled. For the Conover these ratios are 1.15 and 1.35, respec- tively. These values for the Conover pedons sampled indicate thay are in relatively less uniform parent material, on the average, than the Brook- ston pedons sampled. Indeed looking again at the individual pedon values (Tables 3 and 4, col. 10) it is evident that the uniform Brookston values vary from +.34 to -.31 while the uniform Conover values vary from -.049 to -.37 (all negative). Thiinndicates that the Conover pedons are usually developed from coarser materials in their Ap than in their 82 horizons. However, Brookston pedons are sometimes developed from coarser materials (85, 87, and B8) and sometimes from finer materials (84 and 86) in their surfaces. To emphasize these relationships a C or 8 has been entered beside the true Conover and Brookston pedons (or their variants) in Figure 5. Summary: (a) Parent materials vary considerably within this map unit, from pedon to pedon, and from the surface to the subsoil of pedons normally considered from field observations to be within each 50 series. (b) The Conover pedons sampled usually have Ap's developed in coarser materials than their 82's. (c) These parent material variations need to be considered when genetic relationships among the soils and mong each soil's horizons are discussed. 2. Particle Size Distribution Particle size and minerological composition are fundamental criteria for grouping series into families of mineral soils (12). Those composi- tional data are averaged over a discrete thickness of soil, usually the upper 0.25 to 1.0 m (10 to 40 in.), or the upper 50 cm of the argillic horizon, referred to as the control section. As pointed out in Soil Taxonomy (26), families and series, serve pur- poses that are largely pragmatic, particularly when their phases are con- sidered. The pragmatism of soil series lies, in part, in their use as important components of the basic mapping unit names appearing on pub- lished soil survey maps in the United States. From the particle size distribution (11) one can learn about the origin and mode of deposition of the parent material and make predictions of water holding capacity, permeability, erosiveness, power requirements for tillage, engineering classifications, and other soil interpretations. Of sixteen pedons described in the field, and sampled within a ten- tative Conover-Brookston mapping unit in Monroe county, Michigan, 8 were identified as Brookston and 8 as Conover. A. Brookston pedons sampled: The results of the particle size distribution of the tentative Brookston pedons sampled are shown in Table 7. In all—uoucou uo couuasvhum«c wu_m afloauuza h ma=-888888888 8.8 6.6 6.6 6.88 8.88 6.6 8.88 8-88 N.H n.~ n.~ m.HH n.- c.HH c.- 81cm I u.N w.m n.n a.~ o.NH ~.m m.a~ mum: : n.- a. m.~ ~.H a.m c.n~ ©.w N.m~ _-mn N. o.~ H.s H.~N o.m~ m.a m.w~ mien :Oum 008 mu 8 8 6. 8.8 6.8 8.68 8.88 8.88 6.88 8-88 m. N.N H.m o.a~ 5.0“ $.m N.m~ Nimm u8888a>lzuusm . m. A.m m.m H.m~ o.o~ m.~ ~.oa 81m: o. m.H N.m m.- m.qH ~.~H ~.wm NINn__ ecumxooum e. H.N 0.9 m.m~ Q.NH. ~.m ~.o~ _I~n m.h a. o.~ a. m.m w.~ m.¢~ m.mn ~a_: . a u 8 8 88 6 8. 6. 8.8 6.8 6.6 8.88 8.86 8-88 El . If as BE 38 as as m8.V ad o.Nto.H °.Hton. On.ln~. n~.|ca. c~.uno. mo.i~o. ~o.u~oo. 8.858 as 8886 u a. .88 .> .8 .88 .8 .88: .8.8 .8.8.> 8888 .88 8888 8 .. can 838850: N N N N N . N N a u e m c m N m:E:—38 _ .1 comaaem eccvoa coumxooum c>8ucuzeu no mecwuomuunsm 888m 1:: team w m4m<fi 54 88888.6 :8 28:28.8 8.: 8.2.8.828 88.82888... 88888888 888 11W 8.6.8. mod-8.8.. 8288 58.8 886 111v 0. ON on 2880.. .530. .5248 x -- --488 .0: 80808 mm.Hfiomnan .vo8aauu «cocoa ecumxooun a<.ouuu8:m o>8888888 uo :owuanwuuaqv o~8m mau8uuwm o ahauwm 55 clay ratio are the concurrent result of the processes involved in the genesis of an argillic horizon. These data (Table 7 col. 10) suggest that in the investigated soils the ratio probably is set too high because clay films were found to be present but the ratio of fine-clay to total clay were not one-third or more. These results agree with those found by Laurin (18) working on similar soils in the region. Four soils studied by Laurin having a total B/A clay ratio more than or equal to 1.2 no soil had a ratio of fine-clay to total clay in the B horizons greater than the A horizons at least by one-third. A fine-clay ratio of greater than or equal to 1.2 between the 8 and A horizons seems to be more suitable than the fine-clay to total day ratio of one-third or more in these Michigan soils. This criterion would be consistant with the total clay ratio presently used in the definition of an argillic horizon and would still reflect illuviation of fine-clay as does the present fine-clay to total clay ratio. Based on this criterion and other requirements cited for argillic horizons, including field observations of clay skins in the 82, four of the tentative Brookston pedons sampled have an argillic horizon. These are pedons 82, 84, 85, and 88 (Table 7). Based on laboratory analyses and field observations, these Brookston pedons were in the fine-loamy, mixed, mesic, family of Typic Argiaquolls, and are truly representative of the Brookston series. Two others (86 and 87) were in the fine-loamy, mixed mesic, family of Typic Haplaquolls, a Brookston-variant without argillic horizons. The two borderline pedons, 83 and 81 have been identified as: fine-loamy (borderline to coarse loamy). mixed, mesic, family of Typic 56 Haplaquolls, a Barry-variant (without an argillic horizon) and fine-silty, mixed, mesic, family of Typic Haplaquolls, the Pella series, respectively. So far our discussions were about all the Brookston pedons sampled which refer to all eight of the tentative Brookston pedons. From here onward any discussion under Brookston will refer to only those six pedons identified as Brookston or Brookston-variant. The average size distribu- tions of all these Brookston pedons and those from uniform parent material are shown in Table 9. B. Conover pedons sampled: The particle size distribution of the eight tentative Conover pedons sampled are shown in Table 10. In all the Conover pedons sampled, as in the Brookstons, the fine- and very fine-sand and the fine-silt predom- inated in the sand and silt fractions (Table 11). In contrast to the Brookston pedons sampled, all of the tentative Conover pedons (except pedon Cl, where they are nearly equal), the percentage of sand decreased with increasing depth. The distribution pattern of silt in the profiles also differs from the Brookston pedons sampled, such that 62.5% (5/8) of the sampled Conover pedons have higher percentages of silt in the subsoil than in the plow layers. The distribution pattern of the clay particles indicate that more translocation of clay has taken place in the sampled Conover profiles (Table 10, col. 4) than in the Brookston profiles (Table 7, col. 4). The percentages of fine-clay (Table 10, col. 5) also indicate that more fine- clay is translocated from the surface to the subsoil in the Conover pedons sampled relative to the Brookston pedons (Table 7, col. 5). The percen- tages of fine-clay in the total clay is also usually greater in the sub- soil of the Conover pedons (Table 10, col. 9) than in their surface .musmwum>luo>o:oo cam Icoumxooum azaw=HUCH+ .mamfiuoums uamuma Show8cs w:8>m; mm cohovwmcoo mcouma @8058 no mwwmum>¢w 57 68.8 86. 68. 88.8 86. 86. 8 8\88 v 88.8 86. 88. 88.8 66. 88. m . 88.8 8.88 8.88 88.8 8.88 8.88 8 p 8888 .m 88.8 8.88 8.88 88.8 8.68 8.88 8 n8 9 86. 8.88 8.88 66. 8.88 8.88 8 m 8888 s 68. 8.88 8.88 86. 8.88 8.88 8 - 88 8 - 88 8 8888886 I AU A I do A n m. 88.8 8.88 8.88 88.8 8.68 8.88 8 6888 mm 88.8 8.68 8.88 88.8 8.68 8.88 8 m . .m 88.8 8.88 8.88 86. .6.88 8.88 8 8888 "n 88.8 8.88 8.88 88.8 8.88 8.88 8. m S 88. 8.88 8.88 86. 8.88 8.88 8 8888 a. 66. 6.88 8.88 88. 8.88 8.88 N 88888 88 68 88888 88 88 6<\88 8888888 88688 3888 8<\~8 8888888 88688 3886 +uo>ocoo +coumxooux no conwuoz mconoa Ho>ocou m>8m can coumxooum K88 mo ceausswuumav @888 wmmuo>< m mqm<8 58 .5088; some :8 Haomnam uo .conauon «a 8:8 88 ml was .couwuon ouamuam no Q< .8888“ 3088 may 88 8- .uo>ocoo mo vuaasmm mcouma 8:8 mum .888 N0 .80 « 8.88 8888 8.88 8.88 8.88 6.88 8-8888 88 8 8.68 88 8 88 8 8 8.8 8.88 8.88 6.88 8-88 8.88 88 6.88 6.88 8.68 6.68 8-88 86 8 8.88 88 8 88 8 88 8.88 8.88 8.88 8.88 8-88 8.88 88 8.88 8.88 8.88 8.88 8-88 86 8 8.68 88 8 88 8 8 8.88 8.88 8.88 6.88 8-88 8.88 88 8.88 8.68 8.88 8.88 8-8888 88 8 8.68 68 8 88 8 88.8 8.8 8.88 6.88 8.88 8-88 8.88 88 8.88 8.88 8.88 8.88 8-88 . . O . 88 8 8.88 88 8 88 8 8 8.6 8.88 8.88 8.88 8-88 88.88 8-888 8.88 8.88 8.88 8.88 8-88 88 8 8.88 86 8 88 8 88.8 8.8. 8.88 8.88 6.88 8-88 8.88 88.8 8.6 6.88 8.68 8.88 8-88 88 8 8.88 88 8 68 8 88.8 8.8 8.88 8.88 8.88 8-88 8.88 88.8 6.88 8.68 8.68 8.88 8-88 88 8 8.88 88 8 88 8 88.8 8.8 8.88 8.88 8.88 8-88 HI Noe. as as EE EH SE 8888. 888 888.. 8.88898 8 8:888“v 8 888.V 888.V 888.88. 8.8-8.8 8888 I moo. SE NIN8H8.u N Nlnwmu N muauxmh >888.m >888 8888 8:88 4 . 8888. 8888. 8 8 8 8 Owumu 88 6 8 8 8 8 8 8 8 8 8888588 850803 uw>o=oo u>wumucou mo :ofiusnauunav 8888 888888;; 0a mqm¢e 8665808 o.a m. N.N m.N c.m m.N «.mm ¢.N~ N-mu~_ usmNum>uufinANx c.~ 0.0 m.¢ w.cH m.¢~ H.0fl n.- Hume a. m.H . e.N m.H~ n.NH ¢.a m.a~ also ucmwum>luu>occu .. h. m.~ H.m H.ma w.m~ N._~ c.c~ disc ~.H m.m H.o m.- H.HH m.- «.mw . Nico um>ocoo . m.H N.c o.h o.m~ ¢.~H o.¢~ ¢.MN alco o.~ m.m m.m m.~H O.CH o.m o.n~ Numu- uw>ocoo m.~ ©.o o.oH «.ma n.¢~ m.- H.m~ Almu ~.~ ~.N H.q ~.N~ ¢.mH n.~H N.¢N Nico Lm>ocou ¢.H h.m m.m m.¢~ o.c~ e.nH o.m~ Maco m. ~.~ . m.m a.c~ ¢.ma ~.m ~.o~ mnmo um>ccoo H.H m.q N.oH m.o~ H.ma. H.~ 0.6H Hamo m. c.~ m.¢ «.mm m.- o.o m.m~ NINU mxuoa c. w.~ n.m N.~n m.m~ m.n ~.HH Humo m. o.m m.- A.~N ¢.n~ m.c a.~H NIHU waved m. n.h ~.oH m.m~ ~.¢H m.m m.mH dado . B:— E:— 55 .5: EE E:— .5: ma V.uu c.Nto.H O.H!¢m. On.lmN. n~.IoH. OH.lno. no.1No. No.tNoo. m~«om ES oihn .u .00 .> .a .00 .n .vma .u.m .m.u.> 93m .0“. ”Sand 28 3353 N N N N N N N a h o m c m N .mzszfic: — caaafiqz «canon uo>o=co o>uumucou uo acoauuauwnao uHHm cam team AH mqm4h 60 horizons. However in no case is this ratio 1.33 as suggested by Soil Taxonomy for argillic horizons (see Table l0, col. 10). The ratio of total clay and fine-clay in the 82 horizons compared to those of the Ap horizons (Table l0, col. 7 and 8 respectively) is l.20 in all of the sampled Conover pedons except pedon C7. Based on these criteria and other requirements cited for argillic horizons, including field observation of clay skins on faces of peds, all of the sampled Conover pedons, except pedon C7, met requirements of an argillic horizon. There is a possibility that pedon C7 may have been somewhat eroded. As indicated in Figure 7, the tentative Conover pedons sampled covered nearly the whole range of the fine-loamy family. Correlation of field observations and laboratory data has classified the eight Conover pedons sampled as follows: Pedons Cl and C2 were in a fine-loamy, mixed, mesic, family of Aquollic Hapludalfs, the Locke series. They have more sandy profiles than Conover. Pedons C3, C4, C5 and C6 were in a fine-loamy, mixed, mesic, family of Udollic Ochraqualfs, and are truly representative of the Conover series. Pedons C7 was in a fine-loamy, mixed, mesic, family of Aquic Eutrochrepts, a Conover-variant; and pedon C8 was in the fine-silty, mixed, mesic, family of Aquollic Hapludalfs, a Kibbie-variant, which is more silty in the control section (82t) than Conover or Kibbie. So far we were dealing with the eight tentative Conover pedons sampled, but from here onward Conover pedons will refer to only those four pedons identified as Conover and a Conover-variant. As far as the degree of fineness of the Conover pedons is concerned, the average composition of the Conover pedons are as shown in Table 9. It is concluded that, the particle size distribution patterns of the 61 324-: 43..» 20:23 m2» 3:22; @5255 .2538: e: oilv “semenwdéfl 2:5. 53 E On 0m 2. ow ~ unhpnu —J~vfl /8. .1...... a/li/i .. \.. ON. ...... .... .... 8 ~ I. .... Q. .. 24°... 5’44“. .. >._..:m . 310.. >140 :ozdm iniymiawona $8,. .. i . aw... .zlvxov%r ’ .. .23... ...,mflmm \ J. . 1w 0" \ ,‘0 $ DV'O al.! III .\\ cm I”. x . . 4.. . .. .. ..U a. N \ GO A... 84...... 2. o 9. .. we .0: cocoa / ... .W. N. o 4 fl. 0 NnJfiomnam no. \ 6013.3 25qu um>ocou . o n< @0325 «.5335; no .3323:an 03m 303.25 h and «m 62 Brookston and Conover pedons indicate the following: (a) The Conover pedons averaged coarser than the Brookston profiles in their Ap horizons. (b) Excess of moisture (poor drainage) in the wet part of the land- scape, the Brookston pedons, has reduced translocation of clay from the surface to the subsoils. (c) Conditions of somewhat poor natural drainage in the Conover pedons favored movement, and accumulation of clay in the subsoil. They occur in that portion of the landscape which had somewhat deeper water tables that are subject to considerable seasonal fluctuations. 3. Water Retention A. One-third bar percentage: It has been found experimentally that the water percentage of many medium textured soils at the moisture equivalent corresponds closely to a water potential of -33 joules/kg (l/3 bar equivalent suction) (29). The amount of water held at l/3 bar equivalent suction has been recognized as the upper limit of available water (Table l2) at field capacity. 8. Fifteen bar percentage: As water infiltrates the soil and moves into dry zones some of it is also used in the process of evaporation or transpiration. Since these processes continue after infiltration ceases, water continues to be lost from the soil. As each increment of water is lost from the soil, the work that must be done to remove the next increment increases (29). Because the extracting power of plant's cells for water is limited, when this negative force get to l5 bar equivalent suction, the plant cells can not keep up with their needs and plants wilt. The wilting point is a range 63 TABLE 12 Water retention percent of tentative Brookston s Cnnnvcr pedons sampleda 1/3 atm. 15 urn. 1/3-15 atm. Fhickncss* Ava. mots. \va. mole. Soils H2” “20 "2” cu cm cu Remarks 1 I Z 3°192. to 68 cu 81-1 38.7 16.5 22.2 30 8.1 63.6 8.1 19.1 Pella 81-2 35.0 16.9 18.1 122 35.3 11.0 82-1 29.6 11.7 17.7 28 6.0 32.6 6.0 16.7 Brookston 1182-2 29.2 12.6 16.8 99 26.6 10.7 83-1 25.0 9.2 15.8 28 6.6 29.1 6.6 15.6 Barry-variant 83-2 21.7 . 7.8 13.9 99 22.7 9.2 86-2 25.9 9.9 16.0 68 17.6 7.7 85-1 30.5 12.6 18.1 30 6.6 21.7 6.6 16.0 " 85-2 30.2 16.7 15.5 61 15.1 9.6 86-1 32.7 ‘13.6 19.1 28 6.5 6.5 18.8 16-7 Brookston-variant 86-2 27.9 11.9 16.0 68 12.3 10.2 37-1 33.6 1601 19.5 30 701 25.8 7.1 16.7 '9 87-2 31.5 15.7 15.8 76 18.7 9.6 88-1 27.6 11.3 16.3 25 5.0 35.6 5.0 15.8 Brookston 88-2 29.6 13.9 15.7 102 30.6 10.8 01-1 26.5 8.6 16.1 23 5.6 18.1 5.6 16.2 Locke 01-2 22.9 8.5 16.6 53 12.5 10.6 02-1 19.6 6.1 13.3 20 6.0 16.5 6.0 16.9 Locke 02-2 22.5 8.6 13.9 66 10.5 10.9 03-1 .22.3 7.7 '16.6 18 6.0 15.3 6.0 16.3 Conover 03-2 26.2 11.2 ' 15.0 66 11.3 12.3 06-1 28.7 10.8 17.9 20 5.6 16.3 5.6 17.3 Conover 06-2 28.6 13.2 15.2 66 10.9 11.9 65-1 22.7 8.1 16.6 23 5.1 20.2 5.1 16.8 " 1105-2 29.3 13.6 15.9 58 15.1 11.7 06-1 28.8 11.7 17.1 23 6.0 20.5 6.0 17.3 n 06-2 28.6 13.3 15.3 58 16.5 11.3 07-1 31.5 13.8 17.7 25 6.7 13.6 6.7 17.8 Conover-variant 07-2 29.5 13.7 15.8 26 6.7 11.1 08-1 22.6 7.5 16.9 20 5.1 19.6 5.1 19.3 Kibbie-variant 1108-2 31.7 16.2 17.5 69 16.5 16.2 .Avorngo of I replicates 'Thickness of A and B horizons. 64 or water content, and permanent wilting is usually in the vicinity of 15 bar equivalent suction (Table 12). C. Available water percentage: The difference between the percentage of moisture held at 1/3 bar and 15 bar equivalent suctions (Table 12) is the percentage of available water. The available water percentages are higher in the plow layer than the subsoil in all of the Brookston pedons and in most of the Conover pedons (C4, C6 and C7). Because of lack of information about bulk density in this study, the average bulk density of some other pedons from Michigan have been used in calculating available moistures in the solums as follows: Bulk density Soils A9 82 Sources Brookstons and a Pella 1.22 1.60 Average of two pedons studied by Dr. Erickson. Barry-variant 1.45 1.65 Averages of 3 pedons, two ' from Lapeer and one from Ingham Co. Conovers and Lockes 1.52 1.64 Averages of 2 pedons, one from Dr. Erickson's study and one from Ohio. Kibbie-variant 1.64 1.73 Averages of 3 pedons, 2 from Monroe, and Nashtenaw Co. Michigan and one from Ohio. The thickness of available moisture held in the whole solum (A + B horizons) was greater in the Brookston (26.7 cm, 10.5 in.) than in the Conover (17.1 cm, 6.7 in.) pedons. This was largely because of the deeper solum in the Brookston than in the Conover soils. If the available mois- ture depth of the Brookstons and Conovers was calculated for the average 65 solum depth of the Conover pedons (68 cm) these numbers were very com- parable (Table 12). The average depth of available water in the Brookston pedons was then 16.3 cm (6.4 in.), and inthe Conover it remained 17.1 cm (6.7 in.). The Brookston average available water to 68 cm was more than that of the coarser Barry-variant (15.6 cm, 6.1 in.) and less than that of the finer Pella series (191. cm, 7.52 in.) (Table 12). The average depth of available water to 68 cm depth in the Conover pedons, 17.1 cm (6.7 in.), was more than that of the coarser Locke series, 15.55 cm (6.13 in.), and less than that of the finer Kibbie-variant, 19.3 cm (7.6 in.). In the Kibbie and Bella, the existence of more silt seemed to be responsible for the higher available water retention, and in the Barry-variant and Locke, the coarser sandier textures were responsible for less available water retention. 4. pH and Lime Requirements Soil reaction is expressed in terms of "pH" which measures the hydro- gen ion activity in the soil solution. It shows the environment in which plant roots exist, and characterizes the acidity of the soil solution that could cause corrosion of pipes in the soil (11). A soil having a pH of 7.0 is neutral, neither acid nor alkaline. A soil having a pH of 6.0 is mildly acid, a pH of 5.0 is 10 times more acid. On the other hand, pH 8.0 is mildly alkaline. Most well-drained Michigan soils, in their natural state have a pH lower than 7.0. This is desirable from the standpoint of availability of most nutrients (36). ‘ Liming, as the term applies to agriculture, is the addition to the soil of any calcium or calciwn—andnmgnesium-containing compound that is capable of reducing acidity. Lime strictly refers only to calcium oxide 66 (CaO), but practically the term almost universally includes such materials as calcium carbonate, calcium-magnesium carbonate, and calcium silicate slag (31). The estimated lime requirements of acid soil samples is determined by measuring the total soluble and exchangeable hydrogen and aluminum content. The degree of acidity is reported as the "lime index." This method of determining the lime requirement is more precise than estimates made from soil pH measurements alone, since it measures total acidity instead of just the active acidity of the soil. The results of pH measurements and lime indices for the Brookston and Conover pedons are shown in Tables 13 and 14, columns 1 and 2 respec- tively. In both soils the Ap horizon is more acid than the subsoils. Three of the Brookston pedons need liming in their Ap horizons (Table 13, columns 11 and 12). One of the Conover pedons needs liming (Table 14, columns 11 and 12). The maximum lime recommendation in any season is 5 tons per acre. If the lime index (BpH) is less than 6.5 the soil should be retested two years after application for additional lime needs (36). The amount of lime needed dependscwithe desired pH. In Tables 13 and 14, columns 11 and 12, lime requirements for two pH's (6.5 and 6.8) are calculated for the depth of the plow layers. In all of the pedons studied the pH results indicate that the coarser-textured surface layers tended to have lower pH levels than finer-textured surface layers. Thus, the median (not the mean, because pH is logarithmic) pH of the Brookston pedons are 6.7 for the surface, and 7.4 for the subsoil; compared to those of the finer-textured, Pella which are 7.3 for the surface and 7.7 for the subsoil, and those of the coarser- textured, Barry-variant which are 6.1 for the surface and 7.3 for the subsoil (Table 13, col. 1). Similarly, the median pH of the Conover pedons were 7.02 for the plow 67 .Aa1=oumNoocN No.N coHN oc.NN oN. ON. com. ooN N N.N Nlom No.6 Ne N NN.¢N NN. NNN NNNN NNN NN 6.N NleN N6.N No.N NN.NN NN. NNo NNNN ooN N N.N NlNN : NN.N NN.N No.NN «N. Nae NNNN NNN Ne N.N N1NN eobmxooum «NH NNHN oNHNN NN. . New NN.. qu N o.N Nlcm N.N N.N NN N No N NN N NN. .NNN oNNN NNN oNN 8.6 N.N N-¢N ucaNua>1N6uaN NNH NN.N oo.N NN. NNN NNNN NNN N N.N N-NN N.N N.N NN N NN.N NN.N NN. NON NNNN NNN om N.o N.N N-NN caumxooum NN.N oN.N NN.NN NN. NNN Noe. cNN N ..N N-NNN_ N.N NN. No.6 No.N oN.NN NN. NN. oeqm NNN NN N.e N.N N-NN .NNoN NN.N NN.N NN.NN NN. NNN NNNN omN N N.N N-NN NN.. NN.N NN.NN NN. «NN NNNN NNN NNN N.N N-NN NN NN oN N N N o N c N N N maesNou mxcasmm N.o za 0. N.o EN 68 .z.o m: so a N: no N N zmm za mNNoN <\a <\N N NeoNNNus QNNmaN #J—od 8.8.4 womxm UHQQUUQHUXH QUCQEOHM QHSQUUQHUKN voanano cacao; souuxooun o>Nuaucou uo ooahduca HauNaozo nu u4n<fi .Aalounnux . . . . . NN N N. N N. N NN NNN NNNN NNN NN N.N N.N N-NN NN.N NN.N NN.NN NN. NNN NNNN NNN N N.N N-No unauum>luo>ocoo NN.N NN.N NN.NN NN. NNN NNNN NNN NN N.N N1Nu NN. NN.N NN.NN NN. NNN NNNN NNN N o.N NlNN uo>ocoo . . - N N N N NN.N NN.N NN.NN NN. No. NNNN NNN NNN N.N o.N N-Nu NN.N NN.N. NN.NN NN. NN. NNNN NNN N N.N NamuNN uo>ocou . NN.N NN. NN.NN NN. NNN NN.N NNN oN N.N N-NN NN.N NN.N NN.NN NN. NNN NNNN NNN N N.N N-Nu uo>ocoo NN.N NN.N NN.NN NN. NNN NNNN NNN NN N.N N-NN NN. NN.N NN.NN NN. NNN NNNN NNN N N.N N-Nu uo>ocoo . NN.N NN.N NN.N NN. .. NN. NNNN NNN NN N.N NlNN NN.N NN.N NN.NN NN. NNN NNN. NNN N N.N N-Nu 0x004 NN.N NN.N NN.N NN. NNN NNNN NNN NN N.N N-No oxooN NN.N NN.N NN.NN NN. NNN NNo. NNN N N.N N-No N N. NN.N NN.N NN.N NN. NNN NNNN NNN NN N.N N.N N-No NN NN oN N N N N N c N N N messmmw quNaoN N.N Na 06 N.N mm 08 .z.o N: No N N: no N N NNN NN mN_:N <2. <2. N N 8:3... 63...: i.¢..~ {J76— mmmam Odo-muomuuxm mucmaadm cannuumuuxm uoHQEuu acovoa uo>ocoo m>wuaucmu mo momxdmsm Nuuqaozu «a mqa<9 69 layer and 7.5 for the subsoil: compared to 6.5 in the surface and 7.1 in the subsoil of the coarser-textured Locke, and 6.6 in the surface and 7.4 in the subsoil of the finer-textured Kibbie-variant (Table 14, col. 1). The same trends were found in the previously reported study of Michigan corn fields (22). 5. Available Nutrients Available phosphorus and potassium are being measured by soil testing methods in soil testing laboratories. In addition to indicating the nutrient status of the profile, phosphorus values sometimes show the location of buried horizons in which phosphorus accumulated at one time by biocycling (11). In conversion of extractable nutrients (meq/lOOg) to available nutrients (lbs/ac) it was assumed that an acre of surface soil weighs 2 million pounds. A. Available phosphorus: The available phosphorus of the Brookston pedons ranged from 49 lbs/ ac. to 120 lbs/ac. in the surface and was only 2 lbs/ac. in the subsoil (Table 15, col. 1). Their average available phosphorus in the plow layer was 76 lbs/ac. and 2 lbs/ac. in the subsoil (Table 15, col. 1). The available phosphorus level of the Conover pedons ranged from 52 lbs/ac. to 169 lbs/ac. in the plow layer and from 2 to 3 lbs/ac. in the subsoil (Table 16, col. 1). The average available phosphorus of the sur- faces and subsoils were 90 lbs/ac. and 2.4 lbs/ac., respectively. The range of available phosphorus in the plow layers of the Brookston and Conover pedons were within the range of available phosphorus levels for the SMG 2.5, formerly studied by L.S. Robertson et al. for Michigan corn fields (22). The available phosphorus in the Pella series was 139 lbs/ac. in the 70 .N:N\N NV so N.NN No Nuaau oz“ uoN. NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN N N: mm. o NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN NN N- .. >< NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN N N-NN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN oNNN NNN NN NlNN NN.NN NN.N NN.NN NN.N NN.NN oN. NNN NNNN NNN N NuNN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN NN N-NN NN.NN NN.N NN.NN NN.N NN.NN oN. NNN ooNq NNN N NsNN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN NN N1NN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN N N-NN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN Ne N-NN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NN.N NNN N N-¢N NN.NN NN.N NN.NN NN.N NN.N NN. NNN oNNN NNN NNN quN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNN. NNN N N-NNNN NN.NN NN.N NN.NN No.N NN.NN NN. NNN NN.N NNN NN N-NN OH m m h o m e m N H mcazaou woo~\wos um\mn~ N: N .man.:oxm N2 no N N: 80 N N NNNoN N N moc~\aoa momma wanwmucmsuxm om\mp~ momma oNnmwucmzoxm oanmanmaum>< Nauoa «acovon :Ouoxooun onu mo nucoNuuac QHAQNN6>< nH HAQ< NN NN oN N NN NN NN N No NN NN NNN NNNN NNN oN N- NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN N NuNu NN.NN NN.N NN.NN NN.N NN.NN NN. NNN oNoN NNN NN NINN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN N NINN NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN NNN NuNu NN.NN NN. NN.NN NN.N NN.NN NN. NNN NNNN NNN N NlNNNN NN.N NN.N NN.NN NN. NN.NN NN. NNN NNNN NNN oN Nlmo NN.NN NN.N NN.NN NN.N NN.NN oN. NNN. NNNN NNN N NlNo NN.NN NN.N NN.NN NN.N NN.NN NN. NNN NNNN NNN NN N-No NN.NN NN.N NN.NN NN.N NN.NN NN. NNN oNNN NNN N NlNN NN.NN NN.N NN.NN NN.N NN.N NN. NNN NNNN NNN NN N-NN oN N N N N N N N N N messNou N Nw um NNN N: N .NmmNAquN N: no N N2 «o N NN NNNoN N N HauOH moo~\woe mmmmm wanmcwcmcuxm um\ma~ momma manmowcmzowm maanNm>< cmcovoa uo>oaoo ozu no mucowuuac manmdum>< 0H mandh 72 surface and 2 lbs/ac. in the subsoil layer. These figures were 80 lbs/ac. and 2 lbs/ac. for the Barry-variant surface and subsoil, respectively (Table 13, col. 3). The available phosphorus in the surface and subsoils of Locke series or Kibbie-variant were 85 lbs/ac. and 2.5 lbs/ac. (ave.) or 36 lbs/ac. and 2 lbs/ac., respectively (Table 14, col. 3). The recommendations for application of phosphorus were based on soil tests, crop to be grown and the yield goal as shown in Table 17 for Michigan soils. 8. Exchangeable potassium: The exchangeable potassium of the Brookston pedons ranged from 184 lbs/ac. to 296 lbs/ac. in the plow layer and from 144 lbs/ac. to 232 lbs/ac. in the subsoil (Table 15, col. 2). The average exchangeable potassium was 237 lbs/ac. in the plow layer and 186 lbs/ac. in the subsoil of the Brookston pedons (Table 15, col. 2). The exchangeable potassium content of the Conover pedons ranged from 152 lbs/ac. to 264 lbs/ac. in the surface soil and from 136 lbs/ac. to 192 lbs/ac. in the subsoil (Table 16, col. 2). The average exchangeable potassium content was 195 lbs/ac. in the plow layer and 163 lbs/ac. in the subsoil in the Conover pedons (Table 16, col. 2). The exchangeable potassium, average values in the Brookston pedons (Table 15, col. 2) were between those of the finer textured Pella profile (with 352 lbs/ac. in Ap and 280 lbs/ac. in 82) and the coarser textured, Barry-variant (with 176 lbs/ac. in Ap and 128 lbs/ac. in 82) as shown in Table 13, col. 4. The average values of exchangeable potassium in the Conover pedons (Table 16, col. 2) were more than those of the coarser tex- tured profiles, Locke (with 144 lbs/ac. in Ap and 128 lbs/ac. in 82) as shown in Table 14, col. 4. The Kibbie-variant (non-uniform material) had 136 lbs/ac. potassium, exchangeable in the Ap and 168 lbs/ac. in the 73 TABLE 17. Phosphate—phoSpliorus recommendations for field craps on mineral soils.(35) POUNDS PER ACRE ANNUALLY RECOMMENDED Arelleble Soil Phosphorus-pan ML! of Phosphorus (1’) per acre Pro: 1' N9 250 l 10 039 40-79 200 38 40-59 - 80-99, 150 56 0-19--—-—- 60-79———-100-l 19 125 55 0-19 20-39—--— 80-99——°--l20-133 100 - :3 0-19 -—-—--—20-39 ----—-- 40-59—-—--—100-1 19 140-159 75 4.13 0-19 20-39 -———--40-59 -—----- 50-79--—-—-—1 510-139 1130-179 50 22 2039MO-59 ——----60-79 80-99—-—-—1-lO-159 180-199-—-«-—- 25 11 40+ -----—60+ ----—~SO+- 100+ ----—160+ --—-—-200+ 0 W0 Alfalfa 3-6'1' Alfalfa 5-5'1' _ Alfalfa 74- '1' Com' Sugar beets' Potatoes‘ topdressing topdressing topdressing 130+ bu 24-28‘!’ 300-500 cwt Buckwheat Alfalfa 34'1" Alfalfa 5+ '1" Corn silaze‘ Potatoes“ Clover seeding seeding 204301 180-239 curt Com‘ Barley ‘ Barley Sugar beets 5089 bu 40-59 bu 70-100 bu 13-231' Cover crops Blrdst’oot Corn‘ \t’hcat' Field beans' Trefoil 1201-19 bu 6.5+ bu 1529 bu Cornl Corn silaze‘ c3333" €09,223; “11:1,” To us. am 3.51.. loolt for 11.. N99 to b.- (unimproved) 10,141- 4055 bu (Town 811ng the yield potential near- Crosses Field beans' est your expected yield goal. Then find Timothy. Or- 3050 bu the position of the soil test range in the dud. Brome (19.30 cwt) overlying column of figures. To deter- ndney beans' Kidney beans‘ mine the phosphate (PaOs) needed. fol- 1529 bu 3060 bu low dashed line to the appropriate (9'13 W0 “9’30 CW" column on the right side. ..1.“ °::..... ”W 5.2:: ‘2?:.:'::";::::': ”'79 b“ “"5“” Soil nix—23 pounds or m. 23:59,", 5012;“:3 B--- “"‘“:: 50 pounds of P30; ‘ 2040 bu Sudangrass Wheat' 2539 ha Mending 2.5 lb hOJA will stimulate early plant growth, but null not necessarily tnereeu yield. 74 82 horizons (Table 14, col. 4). The current potassium recommendations in Michigan are shown in Tables 18 and 19 for different profile texture classes. The Brookston, Conover and Kibbie pedons belong to the loams group; the Locke and Barry pedons are in the sandy-loams group. C. Exchangeable calcium Calcium, an essential part of plant cell wall structure, provides for normal transport and retention of other elements in the plant. Cal- cium is also thought to counteract the effect of alkali salts and organic acids within a plant. Calcium is absorbed as the ion Ca++ and exists in a delicate balance with magnesium and potassium in the plant. Too much of any of these three elements may cause insufficiencies of the other two (35). Well limed soils are rich in calcium. Even soils needing lime, to correct acidity, generally contain sufficient calcium for most plants. The poor growth of plants on acid soil is usually due to excess soluble manganese, iron/or aluminum. Research at Purdue University found the calcium content of water for Indiana varied from 8 to 450 ppm and aver- aged 30 ppm. Assuming a ratio of 400 to l as the amount of water needed to produce one pound of dry matter, even the lowest reading of 8 ppm would supply sufficient calcium to plant roots (36). Taking a look at the amounts of exchangeable calcium in the plow layers and subsoils (Table 15 and 16, col. 3) indicate that all the Brookston and Conover pedons have sufficient Ca for plant growth. Less than 50 lbs/ac. of calcium is utilized in the production of a lOO-bu corn crop (21). The average exchangeable calcium values of the Brookston pedon surfaces and subsoils (5244 and 5368 lbs/ac. respectively, Table 15, 75 TABLE18. Potash—potassium recommendations for field crops on sandy loams and loamy sands.‘ 35) POUNDS PER ACRE ANNUALLY RECOMMENDED Available soil potassium—pounds of K per acre K20 K 0-59—-—----—-300 249 0-59 60-1 19- «250 208 0-59——--—-~ 60-119 120-179—-----—200 165 0-59--—--- 60-119 ---—----120-169 oml80-239 150 125 0-59---«-—-- 60-1 l9--—----120-169 - 170-209 “240-279 100 _ 33 60-119 ...—......) 20-169 170-209 ”210-239 ”280-309 75 62 120-169 170-209 210-239 ------2-10-269 -—-—---~3 10-339 50 '22 170-209 --—----—210-239 m~240269 m-270-299 MiG-359 25 2 1 210+ 240+ 270+ o---—-—-.300+ ---——-——360+ e 0 Barley Barley Alfalfa 8-4'1' Alfalfa 581' Alfalfa 7+ '1' 40-69 bu 70-100 bu seeding seeding topdresstng Buckwheat Clover Alfalfa 341' Alfalfa 5-61' Potatoes Corn Corn topdressing topdresstng 300-500 cwt 6059 bu 90-119 bu Birdsfoot Trefoil Corn Cover crops Corn silage Corn 150+ bu Field beans 10-14'1‘ 120-149 bu Corn silage 15-29 bu 1" teld beans Corn silage 2030'? (9-18 curt) 80-50 bu 15-10‘1' Potatoes Crass pasture (19-80 ewt) Sugar beets 150-299 out (unimproved) Kidney beans 18-23 T Sugar beets Grasses 30-50 bu Wheat 24.28'1‘ Timothy, Or- (19430 cwt) 65+ bu chard, Brome Oats Kidney beans 80-120 bu 15-29 bu Soybeans (9-18 cwt) 40+ bu Millet Sorghum Oats Sudangrass 50-79 bu Wheat Rye 40.85 bu Soybeans 20-40 bu Wheat 25091»: 76 TABLElQ. Potash—potassium recommendations for field crops on lonms, clay loams and clays.(36) POUNDS PER ACRE ANNUALLY RECOMMENDED Available soil ;:“ ’ — ,- “‘ oIK per acre K20 K 0-59---—-—- 0119 300 249 0-59 60-119 120-169m200 166 0-59----—-- 50-1 19 M-120-159 -------- 70-209 150 125 0-59-------- 60-119---- 120-159 -----—--—170-209 “210-239 -- ' -100 83 60-119 120-159 160-199 -----—-«2 10-2-10 -—-—-240-279---——-—- 60 50 120-179 160-203 “200-239 --~—-——-—250-269 250-299 “...... 30 25 180+ 210+ ...-240+ - 270+ -——-—--—-.300+ e 0 Barley Barley Alfalfa 341' Alfalfa 5-6‘1' Alfalfa 7+ '1' 40-69 bu 70-100 bu seeding seeding topdressing Buckwheat Clover Alfalfa 3—4‘1' Alfalfa 5-6'1’ Potatoes orn Corn topdressing topdressing 300-500 ewt 60-89 bu 90-119 bu Birdsfoot Trefoil n Cos-er crops Corn silage Corn 150+ bu Field beans 10-141‘ 120-149 bu Corn silage 15-29 bu Field beans Com silage (9-18 ewt) 210-50 bu 1519'1' Potatoes Crass pasture (150-30 cwt) Sugar beets 150-299 M (unimproved) Kidney beans 18-23'1' Sugar beets Grasses 3050 bu Wheat 24-28‘1' Timothy. Or- (1900 wt) 65+ bu chard. Brome Oats Kidney beans 80-120 bu 15-29 bu Soybeans (9-18 curt) 40+ bu Millet Sorghum Oats Sudangrass 50-79 bu Wheat Eye 4065 bu Soybeans 20-40 bu Wheat 25-39 bu 77 col. 3) were between those of the finer textured Pella profile (with 7573 lbs/ac. in Ap and 6187 lbs/ac. in 82) and the coarser textured Barry-variant (with 3733 lbs/ac. in Ap and 3627 lbs/ac. in 82) as shown in Table 13, col. 5. The average calcium content of Conover surfaces and subsoils (4800 and 6059 lbs/ac. respectively, Table 16, col. 3) were more than the average values of the coarser textured Locke profiles (with 3191 lbs/ac. in Ap and 4106 lbs/ac. in 82) as shown in Table 14, col. 5. The Kibbie-variant had much higher calcium in the 82 than Ap horizon (2987 and 7467 lbs/ac. respectively, Table 14, col. 5), because it was developed from non-uniform materials. The calcium content of the Conover-variant was higher in its surface than any of the other Conover pedons studied. D. Exchangeable magnesium Magnesium is a part of the chlorophyll in all green plants and essen- tial for photosynthesis. It also helps activate many plant enzymes needed for growth. Magnesium is a relatively mobile element in the plants. It is absorbed as the ion Mg++ and can be readily translocated from older to younger plant parts in the event of a deficiency (35). Magnesium defi- ciency is most likely to occur in acid soils with a sandy loam, loamy sand or sand plow layer with a subsoil as coarse or coarser than the plow layer, and in similar soilslimedwfith calcitic limestone or marl. Pre- sent soil test criteria for recommending magnesium in Michigan are: (1) if the exchangeable magnesium level is less than 75 lbs/ac. or (2) if as a percent of total bases (calcium plys magnesium plus potassium expressed as meg/100 9 soil), potassium exceeds magnesium or (3) if the soil magne- sium (as a percent of total bases)is less than 3 percent (36, 21). Based on the above criteria and the data in Table 15, columns 4, 9, 78 10 and Table 16, columns 4, 9, 10 none of the Brookston and Conover pedons showed magnesium deficiency. The exchangeable magnesium ranged from 394 lbs/ac. to 886 lbs/ac. in the plow layer and from 480 lbs/ac. to 665 lbs/ac. in the subsoil of the Brookston pedons (Table 15, col. 4). The average exchangeable magne- sium was 560 lbs/ac. in the plow layer and 566 lbs/ac. in the subsoil (Table 15, col. 4). The average values of magnesium in Brookston are between that of the finer textured Pella profile (with 714 lbs/ac. in Ap and 751 lbs/ac. in 82) and the coarser textured, Barry-variant (with 309 lbs/ac. in Ap and 369 lbs/ac. in 82) as indicated in Table 13, col. 6. In the Conover pedons, the exchangeable magnesium ranged from 183 lbs/ac. to 566 lbs/ac. in the plow layer and from 480 lbs/ac. to 714 lbs/ ac. in the subsoil (Table 16, col. 4). The average magnesium content was 393 1bs/ac.irlthe plow layer, and 583 lbs/ac. in the subsoil (Table 16, col. 4). The average values in Conover are more than those of the coarser textured, Locke (274 lbs/ac. in Ap and 480 lbs/ac. in 82, Table 14, col. 6). The Kibbie-variant has much more exchangeable magnesium in the sub- soil than the Ap as a result of the non-uniformity of its parent material (Table 14, col. 6). E. Total bases The average total bases have been calculated for the whole pedons sampled as shown in Table 20. These figures indicated that the total exchangeable bases for the average thicknesses of surfaces and subsoils were more in the Brookston than in the Conover pedons. The total bases of the Brookston pedons were in between those of the finer textured Pella series and the coarser textured Barry-variant (see Table 20). In the Conover pedons the average exchangeable bases were more than those of the 79 TABLE 20 The average total bases of the whole pedons sampled g Average Average Average Average Soils 3 thickness total bases* total bases for total bases ‘3 cm lbs/ac the ave.th1ckness in Ap+82 horizons =3 lbs/ac lbs/ac (or tons) -1 28.0 4,218. 6,988. 15 260 Barry-variant ' (7,6) ' -2 3800 4,1240 9,2720 . -1 28.5 6,041. 10,187. Brookston %{glzg' -2 58.0 6,120. 21,003. ° -1 30.0 8,639. 15,335. Pella 73347;. -2 122.0 7,218. 52,106. ' -1 21.5 3,564. 4,535. 16 112 Locke (8’1) ' -2 41.5 4,714. 11,577. ' -1 22.0 5,388. 7,014. 21 912 Conover (11 0). -2 37.0 6,805. 14,898. ° -1 20.0 3,468. 4,104. Kibbie-variant lllagg. -2 49.0 8,410. 24,384. ' * For the thickness of 16.9 cm ( 6 2/3") 80 coarser textured Locke series. The Kibbie variant had almost 5 times as much exchangeable bases in its subsoil as in its plow layer. F. Summary (a) Based on the current soil nutrient interpretations (11), the surface layer of both the Brookston and Conover pedons were very high ( 7771 lbs/ac.) in P, and their subsoils were very low (0-10 lbs/ac.) in P. The exchangeable potassium was more uniform in the profiles of both Brookston and Conover pedons. These values were mainly in the medium (151-210 lbs/ac.) to high (211/310 lbs/ac.) range. The Brookston pedons contained more exchangeable bases in their solums than the Conover pedons, largely because of their greater thicknesses. The average total exchangeable bases in the Brookston pedons were in between those of the finer textured Pella series and the coarser textured Barry-variant. The average total exchangeable bases in the Conover pedons were more than those of the coarser textured Locke series. The Kibbie series had a substantially greater amountcfi’exchange- able bases in its subsoil than in its plow layer (non-uniform material). The available nutrients found in this study were within the range of the available nutrients found in soils of the same soil management group in Michigan corn fields by L.S. Robertson et al. (21 and 22). However, these values show a narrower range in values than those in the soils formerly studied. 81 6. Organic Matter Soil organic matter is composed of plant and animal residues in various stages of decomposition along witilthe'living micro-organisms that are decomposing these materials. Some soils, called peat or muck are composed largely of organic material (29). Organic carbon is a component of soil organic matter. Organic mat- ter percentages are usually estimated by multiplying organic carbon per- dentages by 1.724 (11). The result of organic matter determinations in the Brookston and Conover pedons sampled are shown in Tables 13 and 14, col. 10. The average organic matter percentages of the Brookston and Conover pedons are indicated in Tables 21 and 22. These values are 3.81% and 1.20% in the Brookston, and 3.34% and 1.07% in the Conover, surfaces and subsoils, respectively. The Brookston pedons are better supplied with organic matter. Organic matter commonly exerts a profound influence upon the physi- cal properties of soil, such as its structure, water percolation rate and water retention. Decomposing organic materials provide substances which cause soil particles to stick together into aggregates. Hydrogen bonding between clays and carboxyl groups of organic matter has been shown to occur (29). Ionic bonding of carboxyl groups to exchange sites and physical absorption are also known to occur. Additions of organic matter to soil improves many of the soil pro- perties related to plant growth. It is a major source 0f nitrogen, through both nitrogen fixation (by legume green manures) and nitrifica- tion, and barnyard manure may supply many of the essential trace elements. The intermediate decomposition products of organic matter increase the 82 .mucmauo> ecumeOHm weavaaucHa u H.~m ~.a~ o~.~ «.58 Ho.oa m.m~ N- no“. ooh w ~.moH m.m~ Hm.m a.am ma.ma s.o~ Haw .33 a m u a.nm n.m~ mH.H «.8o ~5.ma o.m~ N- e c.5ofi ~.n~ ow.m s.an oa.na m.o~ ..mcoeaa 544 m «.8» a.on an.~ H.no mm.aa a.o~ mime aouuxooum .moa n.n~ oo.m m.mn mo.n5 n.m~ 2-»: “.ma o.nn s~.~ 8.5e ms.aa m.m~ ~lae .. «.ma m.mm no.3 m.~o em.aa ~.am alas H.mm e.n~ ao.a “.mo o~.sa e.a~ ~le: a“ Hfl>l~u0u m OOH a a x m .moa m.o~ No.3 H.mo am.mH o.o~ aloe o.~m ~.~m nq.fl q.oa am.ma 4.8N Nine .moH ~.e~ Ha.~ «.mm Ha.nfl m.w~ H-nm 8.8m m.n~ «a. , “.mo ma.qa o.o~ Nism acumxooum .oaa “.ma N~.n o.om ma.oa ~.H~ Hues 3.3a 8.53 mm. ~.me.. ma.oH c.ma ~lmm ucowum>lauuom .HNH “.ma m~.m o.an mm.oH c.aa Hume o.m~ o.- -.H o.me om.sa m.H~ «-maaa coumxooun .eod ¢.H~ No.3 8.5“ ha.ma m.- Hume m.om ”.mn m~.H m.me sa.m~ m.m~ ~-am madam . . . . . . aoa c an as a o so an «N N am alum undo w03~\coa woo~xcoa uxuaaom woo~\umo Adam R .:.o N .mwm N momma omu mafiom manauumuumm «cocoa ecumxooum voaasom ca mowuuoaoun Haow woumfiou sag: A.m.mv coauouaumm omen ucoouoa one woman uqnmuuouuxo.Aomov Auuomacu owzmsuxo coHumo AN m4m uo>ocou ma«u=~uc~s - 5.88 8.85 58.5 8.55 55.55 8.85 5- v 5.885 5.85 88.8 5.88 88.85 5.55 5- «acasoeou m l 8.88 5.85 85.5 8.55 88.85 8.85 5- e - a 8.855 5.55 88.8 5.58 88.55 5.85 5- 88888 558 m 5.88 8.88 88.5 8.88 88.55 8.85 5-8855 u :6 u Q>IQ 5 58855 8.88 . 8.85 58.5 5.88 88.8 8.85 5-88 8.88 8.88 88.5 5.85 58.85 5.85 5-58 ucowun>luu>ocoo .855 8.55 88.8 5.58 88.55 8.88 5-58 8.58 8.88 58. 8.88 85.85 5.85 5-88 uu>ocoo 8.88 8.85 55.8 5.88 88.55 8.55 5-88 8.88 5.85 88.5 8.55 55.85 8.85 5-8855 uo>ocoo .855 5.85 55.8 8.58 88.85 8.55 5-88 8.88 5.85 58.5 5.88 58.85 8.85 5-88 uoaocoo .885 5.85 88.8 5.88 88.85 8.55 5-88 8.58 8.85 88. 5.85. 88.55 8.85 5-88 uo>ocou . .885 8.85 58.8 5.58 88.85 8.85 5-88 5.88 8.85 85.5 5.85 88.55 8.55 5-58 0x005 .585 8.85 58.5 5.58 88.5 , 5.85 5-58 85885 .885 5.85 88.5 8.58 85.55 8.85 5-58 .885 8.85 88.8 8.58 58.85 5.85 5-58 undo woo5\coe woo5xvma 8558888 88855888 5858 5 .z.o 5 .8.8 5 88888 888 85588 oanmuumuuxm acovoa uo>ocoo voaasnm c8 muuuuogoum Huow uoum5ou 2583 A.m.mv ceauouauam omen acouuma new momma manouumuuxo.aomov >5fiucamu owcmsoxo cowuao NN mqm-8588_5 88 8 8.5 858888888588 85888 .= = = . = . . 888,885-8as8888 58 a m 0N 3 3 3 3 3 3 3 3 3 Lm>ocou WU D m o N 3 3 3 3 3 3 3 3 3 LQ>OCOU mo a m o N 3 3 3 3 3 3 3 3 3 Lw>ocou V0 8 m.~ 88588885580 855588: = = 8 = = 8 = cm>o=ou mu a O .m = .. : : : : : : : wv—UOA NU . 8885888 2 O M m% PMUJ Pam: Ur _._.035< : : : .. : : 5A. PLOOQ Hmz3meOm QXUO-d _.U U m.N m—POSUMPUL< UwQX-r : : : : : : : COHmv—OOLm mm U moN 3 3 3 3 3 3 3 3 3 HEMPL6>ICOHWXOOLQ NM— U m.N mPFODUm FQGI Own—5AM. : : .. : : : : chwsw>lcoumeOLm om U m . N : .. : : : : : .. .. : COHmv—OOLm mm 8 8.5 85588885888 85885 = = = z .. .. .. 885858888 88 U O.m mPPOJUGPQmI UPQXP .. z : : : : : wcme©>l5ALme mm 8 m.N 8558888588< 05885 88 855588 .85882 .8mxwa .85885-8855 8 885858888 58 - . 8 8888 88 0588 o m o m N 855588 .owmms .voxwe .58858 8» m:_ “mueomv mupwm-wcww 8885888 858888 85588 5m 885558888 8588 02m 88558058588850 88885888 mmwcmm 888888 5888582 8888858 888888 :mwuxwm 8:5 88 88558858588850 8N m4m<8 92 These data illustrate that 50% of the observations were naturally somewhat poorly drained, and 32% were poorly drained. The dominant pro- file texture was loam (SMG 2.5 a+b+c, 56%). Because 57% of the observa— tions are Metamora, Brookston and Conover, the most suitable name for this mapping unit would have been Brookston-Matemora-Conover, based on the field and laboratory evidence. In the final field legend, approval in the final field review of Monroe Co. Michigan, 22 out of the 30 point observations in the tentative Conover-Brookston mapping unit studied, were within the new Conover map unit. One was in the Brookston and seven were in the Blount map unit, from which the Conover-Brookston was originally separated. Hence, the composition of the newly established Conover mapping unit, in the light of this study was as follows: Profl]e\ Nat. % w.d. and % Somewhat % text. drain. mod. w. drained p. drained P. drained Total no. class x a a b b-s c c-s l.5 CL ' Pewamo 5 5 2.5 Loam Celina Conover* Brookston l8 23 14 55 3/2 SL/L Owosso Metamora 5 l8 23 3.0 SL Locke Barry-variant 9 5 l4 4.0 L5 Wasepi 5 Total 23% 55% 24% l02% * Including its variant. These results indicate that the portion of the tentative 93 Conover-Brookston map unit that is now in the newly established Conover mapping unit was dominantly (55%) somewhat poorly drained, including 4l% Conover and Metamora. Thus, Conover-Metamora seems to be the most suit- able name for that portion of this mapping unit. In comparing the above composition of the tentative Conover-Brookston map unit (revised with the aid of the laboratory studies; ll/30 = 37% Conover + Brookston) with those based on field work alone (16/30 = 53% Conover + Brookston) it is evident that the transects of the map units, after their delineation, are over-optimistic as to their homogenity. However, both transects to more quantitatively characterize the map units on modern soil surveys, and additional studies of the component pedons of individual series are needed to approach truly quantitative soil surveys for modern land use planning purposes. VII. CONCLUSION This study was carried out to characterize the major components of the Blount mapping unit in Monroe county, Michigan. 0n the basis of transect observations it was determined that the major soils of the unit were Conover and Brookston instead of Blount. It was also concluded that; parent materials varied considerably from pedon to pedon and from the sur- face to the subsoils of pedons recognized in the field to be in the same soil series. The Conover pedons sampled had apparently been developed from coarser materials in their Ap's than in their 82's. The Brookston pedons averaged finer than the Conover pedons in the Ap horizons. The poorly drained conditions in the Brookston pedons sampled was responsible for reducing the clay translocation from the surface to the subsoil. The somewhat deeper water table in the sampled Conover pedons have favored translocation of clay from the surface to the subsoil. The l6 pedons sampled covered the whole range of the fine-loamy family from coarse-loamy to borderline to-the fine to fine-silty family. The solum depth was greater in the poorly drained pedons than in the somewhat poorly drained pedons. Consequently the amount of available water held in the solum was greater in the Brookston than in the Conover pedons. The depth of available moisture was also greater in the pedons finer than the Brookston or Conover, and less in the pedons that were coarser. The coarser-textured pedons had lower surface pH's than the finer- textured pedons, such that, in the sampled tentative Brookston pedons, the pH increased from Barry ----> Brookston --—-+ Pella, and in the sampled tentative Conover pedons it increased from Locke ----> Conover 94 95 ----+ Kibbie. 0f the l6 pedons, only 6 pedons had lime requirements in their surfaces. The surface horizons of the Conover and Brookston pedons were rich in available phosphorus content but their subsoils were very low in avail- able phosphorus. Their exchangeable K levels were medium to high and the exchangeable K was uniformly distributed in the profiles of the sampled Brookston and Conover. The available base levels increased from the coarser-textured to the finer-textured pedons, and those bases were pre- dominantly Ca and Mg. The organic matter content was somewhat greater in the poorly drained Brookston pedons than the somewhat poorly drained Conover pedons. The cation exchange capacity of the Brookston pedons was greater than in the Conover pedons, and it also increased from the coarser- textured to the finer-textured pedons sampled for each series. The base saturation was more than 50% in all the pedons studied, and the Conover pedons were somewhat more saturated with basic cations than the Brookston pedons. However, the Brookston pedons had more extractable bases (per acre) in their solums. Classification of the l6 pedons studied indicated that only 8 pedons were truly representative of the Brookston and Conover series. Three more pedons were identified as variants of these series, and 5 others were representative of other soil series. In the light of this study the most suitable name for this mapping unit would have been Brookston-Metamora- Conover. The results of this study indicated that the field transects of the map units after their delineation are over-optimistic as to their homogeneity. For truly quantitative soil surveys, additional studies of the component pedons of the individual series are also needed for modern land use planning. 96 VIII. NEEDS FOR MORE INVESTIGATION In the results of this study it was found that the translocation of clay and fine-clay was less than generally believed to be representative of the poorly drained Brookston and the somewhat poorly drained Conover soils. Only 4 of the 6 Brookston pedons and 4 of the 5 Conover pedons studied contained an argillic horizon based on their total clay contents. None of the Conover or Brookston pedons sampled had a ratio of fine-clay to total clay in the subsoil more than one-third greater than that of the surface layers. Soil Taxonomy (26) recognizes this as a criterion for an argillic horizon. Hence, more work is needed to investigate the process of clay translocation particularly under poor natural drainage conditions. The validity of the proposed alternative criterion, that the ratio of fine-clay to total clay in the subsoil needs only to equal or exceed that of the surface layers of Michigan soils, needs more general testing for possible use in Soil Taxonomy. 97 LI ST OF REFERENCES TO. IT. 12. 98 LIST OF REFERENCES Belo, J. A. O. 1970. Determination of total carbon by dry combus- tion and its relation to forms of soil nitrogen as measured in the laboratory and in the greenhouse. Unpub. Ph.D. Dissertation, Michigan State University, East Lansing. Bremner, J. M. 1965. Inorganic forms of nitrogen. In C. A. Black (ed.), Methods of Soil Analysis, Part II. Agr. No. 9. Madison, Wisconsin. pp. ll9l-ll95. Broadbent, F. E. and J. B. Ott. 1957. Soil organic matter-metal complexes: 1. factors affecting retention of various cations. Soil Sci. 83:4l9-427. Buol, S. W., F. D. Hole and R. J. MacCracken. l973. Soil Genesis and Classification. The Iowa State Univ. Press. Ames, Iowa. Chapman, H. D. 1965. 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D. 1974. Determination of extractable potassium, cal- cium and magnesium. Michigan State Univ. soil testing lab. mimeo. Dept. of Crop and Soil Sciences. Wheeting, L. C. 1923. Soil survey, Livingston Co., Michigan. USDA. Bur. of Chemistry and Soils. U.S. Govt. Printing Office. Wash. D.C. MICHIGAN STATE UNIV. LIBRARIES 1111111111111 1111111111 11111111 “I111 11111 11111111111111 31293100643265