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Soils of Iowa: an Examination of Three Pedological Assumptions Jenny Richter Iowa State University

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Soils of Iowa: an Examination of Three Pedological Assumptions Jenny Richter Iowa State University Iowa State University Capstones, Theses and Graduate Theses and Dissertations Dissertations 2016 Soils of Iowa: An examination of three pedological assumptions Jenny Richter Iowa State University Follow this and additional works at: https://lib.dr.iastate.edu/etd Part of the Soil Science Commons Recommended Citation Richter, Jenny, "Soils of Iowa: An examination of three pedological assumptions" (2016). Graduate Theses and Dissertations. 16003. https://lib.dr.iastate.edu/etd/16003 This Dissertation is brought to you for free and open access by the Iowa State University Capstones, Theses and Dissertations at Iowa State University Digital Repository. It has been accepted for inclusion in Graduate Theses and Dissertations by an authorized administrator of Iowa State University Digital Repository. For more information, please contact [email protected]. Soils of Iowa: An examination of three pedological assumptions by Jenny L. Richter A dissertation submitted to the graduate faculty in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY Co-majors: Soil Science (Soil Morphology and Genesis); Environmental Science Program of Study Committee: C. Lee Burras, Major Professor Tom Loynachan Tom Sauer Janette Thompson Richard Cruse Iowa State University Ames, Iowa 2016 Copyright © Jenny L. Richter, 2016. All rights reserved. ii TABLE OF CONTENTS Page LIST OF TABLES ................................................................................................... v LIST OF FIGURES ................................................................................................. vi LIST OF ACRONYMS AND ABBREVIATIONS ............................................... x ACKNOWLEDGMENTS ....................................................................................... xii ABSTRACT .............................................................................................................. xiii CHAPTER 1. GENERAL INTRODUCTION ...................................................... 1 CHAPTER 2. HUMAN IMPACTED CATENAS IN NORTH-CENTRAL IOWA, USA: RAMIFICATIONS FOR SOIL MAPPING .................................. 2 Abstract ...................................................................................................................... 2 Catenas and Soil Mapping ......................................................................................... 3 Iowa Catenas: The Des Moines Lobe ........................................................................ 5 Clarion-Nicollet-Webster Catena .................................................................. 5 Historic Catena Research .............................................................................. 6 Agricultural Land Use: Agent of Soil Change ........................................................... 7 Subsurface Drainage ..................................................................................... 9 Erosion and Sedimentation ............................................................................ 10 Soil Organic Carbon ...................................................................................... 12 Soil Amendments ............................................................................................ 12 Soil Taxonomy ................................................................................................ 13 Case Study: Modern Catenas on the Des Moines Lobe ............................................. 14 Materials and Methods .................................................................................. 14 Results and Discussion .................................................................................. 16 Soil pH .................................................................................................. 16 Thickness of mollic colors .................................................................... 18 Soil organic carbon ............................................................................... 20 Geometric mean .................................................................................... 22 iii Bulk density .......................................................................................... 24 Ramifications for soil mapping ............................................................. 25 Conclusions .................................................................................................... 26 References .................................................................................................................. 27 CHAPTER 3. PARTICLE DENSITY OF SOME IOWA SOILS ....................... 57 Abstract ...................................................................................................................... 57 Introduction ................................................................................................................ 57 Materials and Methods ............................................................................................... 58 Results and Discussion .............................................................................................. 60 Particle Density with Depth ........................................................................... 60 Particle Density and Particle Size ................................................................. 62 Particle Density across Catenas .................................................................... 63 Particle Density and Soil Taxonomy.............................................................. 67 Soil Porosity ................................................................................................... 68 Conclusions ................................................................................................................ 69 References .................................................................................................................. 69 CHAPTER 4. PROFILE VARIABILITY OF FOUR IOWA SOILS: AN EXAMINATION OF SOIL HORIZONS ....................................................... 95 Introduction ................................................................................................................ 95 Materials and Methods ............................................................................................... 96 Results and Discussion .............................................................................................. 97 Soil pH ........................................................................................................... 97 Total Soil Carbon ........................................................................................... 98 Bulk Density ................................................................................................... 99 Soil Morphology............................................................................................. 99 Conclusions ................................................................................................................ 100 References .................................................................................................................. 101 CHAPTER 5. GENERAL CONCLUSION ........................................................... 119 iv APPENDIX A. SOIL DESCRIPTIONS FOR CATENA SOILS ........................ 121 APPENDIX B. LABORATORY DATA FOR CATENA SOILS ........................ 149 APPENDIX C. SOIL DESCRIPTIONS FOR INDIVIDUAL PEDONS ............ 162 APPENDIX D. LABORATORY DATA FOR INDIVIDUAL PEDONS ............ 186 APPENDIX E. SOIL PEDON SUMMARY (ID, LOCATION, CLASSIFICATION) ................................................................................................ 211 v LIST OF TABLES Page Table 2.1. Characteristics of the soil series commonly found along the Clarion- Nicollet-Webster catena in north-central Iowa ......................................... 40 Table 2.2. Taxonomic classification for soils typically found along the Clarion- Nicollet-Webster catena ............................................................................ 40 Table 2.3. Distribution of the Clarion-Nicollet-Webster catena by land area ........... 41 Table 2.4. Average erosion and sedimentation rates for closed basins on end moraines of the Des Moines Lobe, Iowa .................................................. 42 Table 2.5. Characteristics of the four catena study sites in north-central Iowa ......... 42 Table 2.6. Current soil taxonomic classification and drainage class across catenas at four study sites in north-central Iowa ................................................... 43 Table 3.1. Recent particle density values found by other scientists. ......................... 76 Table 3.2. Particle densities of some common soil minerals ..................................... 76 Table 3.3. Location and taxonomic classification of sampled pedons ...................... 77 Table 3.4. Particle density with depth in 41 Iowa pedons ......................................... 78 Table 4.1. GPS locations, taxonomic classification, and parent material for four pedons in Iowa .......................................................................................... 103 Table 4.2. Soil pH (1:1 and 2:1) and total carbon for four Iowa pedons using 3-cm and standard horizons ............................................................................... 104 Table 4.3. Comparison of soil description data for 3-cm vs. standard horizons, and variability within 3-cm samples from a given depth corresponding to standard horizons .................................................................................
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