Table Of ContentAgricultural Science A
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S O I L S E SS OO II LL SS
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in NATURAL LANDSCAPES
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In any complete investigation of terrestrial ecosystems, rocks and I
soils must be considered. Soils are essential resources, providing L
LLAANNDDSSCCAAPPEESS
water and nutrients for vascular plants, and mitigating the flow of
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water from the land. In addition, soil diversity is critical for biotic
diversity. Although there are many references on the agricultural
perspective of soils, there is a need for a basic soils book for those i
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concerned with natural landscapes and ecosystems. Soils in E A R L B . A L E X A N D E R
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Natural Landscapes fills this niche, providing a thorough introduc-
tion to the physics, chemistry, and biology of soils and their roles A
in local to global systems.
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The book begins by describing the field of soils and the major roles U
of soils in natural landscapes. The chapters that follow cover a
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range of topics:
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• Soil parent material • Soil landscapes
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• Architecture of soils • Plant nutrition
• Temperature and soils • Soil organisms
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• Water, air, and climate • Organic matter in soils
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• Classification of soils
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The author also discusses global issues such as water and
carbon cycles, global warming, and acid rain. He addresses land D
management for different uses, soil quality, and soil degradation.
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Using an interdisciplinary approach, this book provides practical
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insights for the evaluation of soils in natural environments and
their non-intensive management. A
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K20663
S O I L S
i n
N A T U R A L
LANDSCAPES
EARL B. ALEXANDER
Boca Raton London New York
CRC Press is an imprint of the
Taylor & Francis Group, an informa business
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© 2014 by Taylor & Francis Group, LLC
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No claim to original U.S. Government works
Version Date: 20130830
International Standard Book Number-13: 978-1-4665-9436-4 (eBook - PDF)
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Contents
Preface ix
about the author xi
chaPter 1 SoilS, landScaPeS, and ecoSyStemS 1
1.1 Concepts of Soils 2
1.2 Soil from the Bottom Up and from the Top Down 4
1.3 Soils, Landscapes, and Ecosystems 6
1.4 Global Perspective 8
1.5 Land Use 9
1.6 Land Management 9
Questions 10
Supplemental Reading 12
chaPter 2 Soil Parent material, Weathering, and
Primary ParticleS 13
2.1 Parent Material 13
2.2 Weathering 16
2.3 Primary Soil Particles 18
2.3.1 Particle Size 18
2.3.2 Particle Size Distribution (Soil Texture) 19
2.3.3 Particle Shape 20
2.3.4 Particle Composition 22
2.4 Clay 22
2.4.1 Clay Minerals 22
2.4.2 Clay Properties 26
2.4.3 Clay Mineral Distribution 28
2.5 Ion Exchange and the Soil Solution 28
© 2010 Taylor & Francis Group, LLC iii
iv Contents
Note on Units of Measure 30
Problems 31
Questions 32
Supplemental Reading 32
chaPter 3 Soil architecture—Structural unitS
and horizonS 35
3.1 Soil Structure 35
3.2 Soil Pores and Soil Density 39
3.2.1 Note on Units of Measure 41
3.3 Soil Strength 41
3.4 Ecosystem Effects of Soil Structure 42
3.5 Soil Horizons and Pedons 43
3.5.1 Soil Horizons 43
3.5.1.1 Organic Layers in Well-Drained Soils 45
3.5.1.2 Organic Layers in Wet Soils 45
3.5.1.3 A Horizons 46
3.5.1.4 E Horizons 46
3.5.1.5 B Horizons 46
3.5.1.6 C Horizons 47
3.5.1.7 R Layers 47
3.5.1.8 Soil Horizon Suffix Designations 47
3.5.2 Pedons and Soil Description 47
3.5.2.1 Pedon Definition 47
3.5.2.2 Pedon Description 48
Problems 49
Questions 50
Supplemental Reading 50
chaPter 4 heat and Soil temPerature 53
4.1 Sources of Heat and Heat Transfer at the Surface
of Earth 53
4.1.1 Variations in Energy Flow to and from Earth 57
4.1.2 Latitudinal and Slope Effects 59
4.1.3 Ground Cover and Soil Color 60
4.1.4 Heat Exchange in Soils 60
4.2 Soil Temperatures 61
4.3 Soil Temperature Regimes 63
4.4 Soil Temperature Effects 64
Note on Units of Measure 65
Questions 65
Supplemental Reading 66
chaPter 5 Soil Water, air, and climate 67
5.1 Infiltration of Water into Soils 68
5.2 Energy Status and Disposition of Water in Soils 69
© 2010 Taylor & Francis Group, LLC
Contents v
5.3 Water Storage and Air in Soils 70
5.3.1 Field Capacity 70
5.3.2 Wilting Point 70
5.3.3 Saturation 71
5.3.4 Aeration Porosity 71
5.3.5 Available Water Capacity 71
5.3.6 Solute, or Osmotic, Potential 73
5.3.7 Some Management Implications 74
5.4 Movement of Water and Air in Soils 75
5.4.1 Soil Permeability 76
5.4.2 Saturated Hydraulic Conductivity 76
5.4.3 Direction of Flow 77
5.4.4 Water Tables 78
5.5 Evaporation and Transpiration 78
5.6 Composition of Air in the Soil Atmosphere 79
5.7 Landscape Perspective 80
5.8 Global Patterns of Precipitation 82
Problems 85
Questions 87
Supplemental Reading 88
chaPter 6 Soil claSSification—KindS of SoilS 89
6.1 Organization of the USDA System, Soil Taxonomy 90
6.2 Diagnostic Horizons 91
6.2.1 Epipedons 91
6.2.2 Subsurface Diagnostic Horizons, or Layers 93
6.3 Soil Temperature and Moisture Regimes 94
6.3.1 Soil Temperature Regimes 94
6.3.2 Soil Moisture Regimes 95
6.4 Order and Lower Levels of Soil Taxonomy 96
6.4.1 Orders of Soil Taxonomy 97
6.4.2 Suborders, Groups, and Subgroups 97
6.4.3 Soil Families and Series 98
6.5 World Reference Base (WRB) 99
6.6 Features of Soils in the Twelve Orders of Soil Taxonomy 99
6.6.1 Gelisols 100
6.6.2 Histosols 100
6.6.3 Spodosols 101
6.6.4 Andisols 101
6.6.5 Oxisols 103
6.6.6 Vertisols 103
6.6.7 Aridisols 105
6.6.8 Ultisols 106
6.6.9 Mollisols 106
6.6.10 Alfisols 107
6.6.11 Inceptisols 108
6.6.12 Entisols 108
© 2010 Taylor & Francis Group, LLC
vi Contents
6.7 Global Distributions of Soils 108
6.8 Hydric Soils 109
Questions 109
Supplemental Reading 110
chaPter 7 SoilS and landScaPeS 111
7.1 Lithology and Stratigraphy 111
7.2 Landforms and Topography 113
7.3 Climate 117
7.4 Biota (Plants, Animals, and Other Living Organisms) 123
7.5 Plant Communities and Ecosystems 124
7.6 Soils and Time 124
7.7 Soil and Ecological Landscape Maps 127
Questions 130
Supplemental Reading 132
chaPter 8 Primary Production and Plant nutrition 133
8.1 Primary Productivity 133
8.2 Plants in the Physical Environment and Photosynthesis 134
8.3 Role of Soils in Plant Nutrition 137
8.3.1 Nitrogen 138
8.3.2 Phosphorus 140
8.3.3 Sulfur 143
8.3.4 Sodium and Potassium 144
8.3.5 Calcium and Magnesium 144
8.3.6 Boron 145
8.3.7 Chlorine 146
8.3.8 Transition Elements 146
8.4 Potential Plant Productivity 150
Questions 152
Supplemental Reading 152
chaPter 9 Soil organiSmS: life in SoilS 155
9.1 Faunal and Microorganism Habitats 156
9.2 Viruses 157
9.3 Main Kinds of Organisms Living in Soils 158
9.3.1 Archaea 160
9.3.2 Eubacteria 160
9.3.3 Protoctists 163
9.3.4 Algae 164
9.3.5 Fungi 164
9.3.6 Animals (Animalia) 166
9.3.7 Plants 173
9.4 Soil Ecology 175
Questions 176
Supplemental Reading 177
© 2010 Taylor & Francis Group, LLC
Contents vii
chaPter 10 Soil organic matter 179
10.1 Sources of Organic Matter and Its Composition
in Plant Tissues 179
10.2 Decomposition of Organic Matter 183
10.3 Composition of Soil Organic Matter 184
10.4 Distributions of Soil Organic Matter 188
10.5 Functions of Soil Organic Matter 191
Problems 192
Questions 193
Supplemental Reading 194
chaPter 11 SoilS and global ProceSSeS 195
11.1 Crust of Earth 195
11.2 Free Water Balance 199
11.3 Carbon Cycle 202
11.4 Ancient Climates, Plants, Weathering,
and Atmospheric CO and Methane 207
2
11.5 Nitrogen Cycle 209
11.6 Sulfur Cycle 211
11.7 Acid Rain, Water, and Soils 213
11.8 Phosphorus Cycle 215
11.9 Nutrient Cycling and Plant (Site) Productivity 217
Questions 218
Supplemental Reading 220
chaPter 12 land management and Soil Quality 221
12.1 Types of Use and Management for Different Lands 221
12.2 Water 223
12.3 Soil Degradation 224
12.3.1 Loss of Organic Matter 226
12.3.2 Compaction 226
12.3.3 Erosion 229
12.4 Diversity of Plants and Animals 231
12.5 Soil Quality 232
12.5.1 Aspects of Soil Quality 232
12.5.2 Indicators of Soil Quality and Soil Condition 233
12.6 Degraded Landscapes and Soils 235
Questions 237
Supplemental Reading 238
gloSSary 239
aPPendix a: extenSive and intenSive ProPertieS
and floW of heat, air, and Water in SoilS 245
aPPendix b: formS of life 247
aPPendix c: noteS on the elemental nutrition
of living organiSmS 253
© 2010 Taylor & Francis Group, LLC
viii Contents
aPPendix d: rocK claSSification for nongeologiStS 255
aPPendix e: naming the SuborderS, great grouPS,
and SubgrouPS in Soil taxonomy 267
aPPendix f: taxonomic nameS of the PlantS 273
referenceS 277
© 2010 Taylor & Francis Group, LLC
Preface
Rocks and soils are integral parts of terrestrial ecosystems. They must
be considered in any complete investigation of terrestrial ecosystems.
Vascular plants, which are the primary producers in terrestrial eco-
systems, cannot thrive without roots in soils from which they extract
water and nutrients. Biotic diversity is highly dependent on soil diver-
sity, and soils are essential for mitigation of the flow of water from
the land. Without soils, flash flooding would be a rule rather than
an exception. Soils are essential resources, and all who are involved
in land resource management should be able to recognize how soils
affect the resources and how management affects soils.
There are many good books on soils from an agricultural perspec-
tive, for example, Brady and Weil (2008), Gardiner and Miller (2008),
and Singer and Munns (2006), and several books on forest soils.
Missing are basic soil books for those who are concerned with natural
landscapes and ecosystems. This book was written to fill that niche.
It is a thorough introduction to the physics, chemistry, and biology of
soils and their roles in local to global systems. Although the emphasis
is on soils, an appendix summarizes basic information on the rocks
that are most important for describing landscapes and understanding
ecosystem functions. Some of the figures in this book can be down-
loaded in color at the CRC Press website: http://www.crcpress.com/
product/isbn/9781466594357.
© 2010 Taylor & Francis Group, LLC ix
