Soil

Front 1

Alfisols

Back 1

Soils with clay B horizons and a high base status
• Moderately leached forest soils that have relatively high native fertility
• These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer)
• Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons)
• Found in Mississippi Valley and east Texas

Front 2

Aridisols

Back 2

Soils of arid regions
• Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development
• They are characterized by being dry most of the year
• They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated
• They are used mainly for range land, wildlife, and recreation
• Because of the dry climate in which they are found, they are not used for agricultural production unless irrigation water is available

Front 3

Entisols

Back 3

Recently formed soils
• Soils of recent origin
• The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon
• All soils that do not belong in any of the other orders belong here
• They are characterized by great diversity, both in environmental setting and land use
• Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world
• Most extensive soil order, occupying 16.2% of the world’s ice-free land area

Front 4

Histosols

Back 4

Peats
• Soils that are composed mainly of organic materials
• They contain at least 20-30% organic matter by weight and are more than 40cm thick
• Bulk densities are often quite low
• Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time
• They are ecologically important because of the large quantities of carbon that they contain
• These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes
• They are mined for fuel and horticultural products
• Swamps, marshes, bogs

Front 5

Inceptisols

Back 5

Soils without contrasting horizons (new soils)
• Soils that exhibit minimal horizon development
• They are more developed than Entisols, but still lack the features that are characteristic of other soil orders
• Inceptisols are widely distributed and occur under a wide range of ecological settings
• They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials
• Many are found in mountainous areas and are used for forestry, recreation, and watersheds

Front 6

Mollisols

Back 6

Soils with mull humus
• Soils of grassland ecosystems; soils of the north America plains
• They are characterized by a thick, dark surface horizon
• Fertile surface horizon results from the long-term addition of organic materials derived from plant roots
• Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S.
• Mollisols are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose

Front 7

Oxisols

Back 7

Sesquioxide-rich, highly weathered soils
• Very highly weathered soils that are found primarily in intertropical regions of the world
o Thick O-Horizon
• These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals
• These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity
• Most nutrients in oxisol ecosystems are contained in the standing vegetation and decomposing plant material
• Despite low fertility, oxisols can be quite productive with inputs of lime and fertilizers

Front 8

Spodosols

Back 8

Soils with iron and hums in the B horizon
• Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron
• These photogenic soils typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown spodic horizon
• Spodosols often occur under coniferous forests in cool, moist climates
• Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally

Front 9

Ultisols

Back 9

Soils with clay B horizons and low base status
• Strongly leached, acid forest soils with relatively low native fertility
• They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes
• Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils
• Ultisols have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides
• Because of favorable climate regimes in which they are typically found Ultisols often support productive forests
• Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. Ultisols are poorly suited for agriculture without the use of fertilizer and lime

Front 10

Vertisols

Back 10

Shrinking and swelling clay soils
• Clay-rich soils that shrink and swell with changes in moisture content
• During dry periods, the soil volume shrinks, and deep wide cracks form
• The soil volume expands as it gets wet
• The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons.
• Vertisols occupy 2.0% of the US land area and occur primarily in Texas

Front 11

Gelisols

Back 11

• Soils of very cold climates that contain permafrost within 2 meters of the surface
• These soils are limited geographically to high-latitude polar regions and high mountain elevations
• Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly
o Holds a lot of organic material
• Gelisols store large quantities of organic carbon
• They surpass swamps and marsh ecosystems

Front 12

Andisols

Back 12

• Soils that have formed in volcanic ash and other volcanic ejcta
• These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials
• Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus

Front 13

Engineering Properties of Soils

Back 13

1. Soil strength
2. Soil sensitivity
3. Soil Compressibility
4. Erodibility
5. Hydrualic Conductivity
6. Corrosive Potential
7. Ease of Excavation

Front 14

O - Horizon

Back 14

-Organic horizon, or Humus
-Dead and decaying organic materials
-This layer, in tropical forests, supports the vegetation

Front 15

A - Horizon

Back 15

(True 1st layer of soil) – Oldest soil most altered from its parent material
-Zone of Leaching
-Residue – non dissolvable material
-Principally affected by chemical weathering

Front 16

B - Horizon

Back 16

-Zone of Accumulation
-Beginning form as soil-proper
-Chemical and physical weathering

Front 17

C - Horizon

Back 17

-Partially decomposed parent material
-Mainly physical decomposition

Front 18

D/R - Horizon

Back 18

No longer soil
-Unaltered parent material

Front 19

E - Horizon

Back 19

Root resistant layer either too hard or burns the roots
-Light colored layer
-Present in some soils as part of the Zone of Leaching
-Composed of clay, calcium, magnesium, and iron
An E – Horizon – Specially adapted trees (cedars) or just grass and shrubs; found in dryer environments

Front 20

Contour Plowing

Back 20

o Plow perpendicular to the slope
o Each rill serves to keep water, and sediment from running downhill
o One of the most widely used methods

Front 21

No-till Agriculture

Back 21

o Eliminates plowing, which loosens the soil and makes it more susceptible to erosion
o This method may include “punching holes” in the soil and injecting the seeds at the same time
o This is part of an integrated plan to control weeds and pests

Front 22

Terracing Slopes

Back 22

o Producing a flat surface on a slope and adding a lip
o Water collects on each of the terraces. If it overruns the lip of the terrace, it will be trapped on the next level
o This methods has been used for hundred (or more) years in the mountains of the Far East

Front 23

Polyculture Agriculture

Back 23

o There are row crops (corn, wheat, etc.) and cover crops (strawberry, melons, etc.)
o Row crops protect from the wind, but they tend to leave the ground exposed to water erosion
o Cover crops protect from the water, but not as much from the wind.
o By planting several types of crops, ether in the same area, or in alternating strips, you get the best of both worlds
o Of course, leaving the ground alone would be the best method

Front 24

• Moderately leached forest soils that have relatively high native fertility
• These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer)
• Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons)
• Found in Mississippi Valley and east Texas

Back 24

Alfisols

Front 25

• Moderately leached forest soils that have relatively high native fertility

Back 25

Alfisols

Front 26

These soils are well developed and contain a subsurface horizon in which clays have accumulated (E horizon – clay rich layer)

Back 26

Alfisols

Front 27

Mostly found in temperate humid and subhumid regions of the world (wet and dry seasons)

Back 27

Alfisols

Front 28

Found in Mississippi Valley and east Texas

Back 28

Alfisols

Front 29

• Soils that have formed in volcanic ash and other volcanic ejecta
• These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials
• Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus

Back 29

Andisols

Front 30

Soils that have formed in volcanic ash and other volcanic ejecta

Back 30

Andisols

Front 31

These soils differ from those of other suborders in that they are typically dominated by glass and poorly crystalline colloidal (gell) materials

Back 31

Andisols

Front 32

Possess many unique chemical and physical properties including high water-holding capacity and the ability to fix large quantities of phosphorus

Back 32

Andisols

Front 33

• Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development
• They are characterized by being dry most of the year
• They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated
• They are used mainly for range land, wildlife, and recreation
• Because of the dry climate in which they are found, they are not used for agricultural production unless irrigation water is available

Back 33

Aridisols

Front 34

Are calcite-containing soils of arid regions that exhibit at least some subsurface horizon development

Back 34

Aridisols

Front 35

They are characterized by being dry most of the year

Back 35

Aridisols

Front 36

They contain subsurface horizons in which clays, calcium carbonate, silica salts, and/or gypsum have accumulated

Back 36

Aridisols

Front 37

They are used mainly for range land, wildlife, and recreation

Back 37

Aridisols

Front 38

Because of the dry climate in which they are found, they are not used for agricultural production unless irrigation water is available

Back 38

Aridisols

Front 39

• Soils of recent origin
• The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon
• All soils that do not belong in any of the other orders belong here
• They are characterized by great diversity, both in environmental setting and land use
• Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world
• Most extensive soil order, occupying 16.2% of the world’s ice-free land area

Back 39

Entisols

Front 40

Soils of recent origin

Back 40

Entisols

Front 41

The central concept is soils developed in unconsolidated parent material with usually no genetic horizons except an A-Horizon

Back 41

Entisols

Front 42

All soils that do not belong in any of the other orders belong here

Back 42

Entisols

Front 43

They are characterized by great diversity, both in environmental setting and land use

Back 43

Entisols

Front 44

Many are found in steep, rocky settings, however Entisols of large river valleys provide croplands and habitat for millions of people of the world

Back 44

Entisols

Front 45

Most extensive soil order, occupying 16.2% of the world’s ice-free land area

Back 45

Entisols

Front 46

• Soils of very cold climates that contain permafrost within 2 meters of the surface
• These soils are limited geographically to high-latitude polar regions and high mountain elevations
• Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly
• Store large quantities of organic carbon
• They surpass swamps and marsh ecosystems

Back 46

Gelisols

Front 47

Soils of very cold climates that contain permafrost within 2 meters of the surface

Back 47

Gelisol

Front 48

These soils are limited geographically to high-latitude polar regions and high mountain elevations

Back 48

Gelisol

Front 49

Low soil temperatures cause soil-forming processes such as decomposition of organic materials to proceed very slowly

Back 49

Gelisol

Front 50

Store large quantities of organic carbon

Back 50

Gelisol

Front 51

They surpass swamps and marsh ecosystems

Back 51

Gelisol

Front 52

• Soils that are composed mainly of organic materials
• They contain at least 20-30% organic matter by weight and are more than 40cm thick
• Bulk densities are often quite low
• Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time
• They are ecologically important because of the large quantities of carbon that they contain
• These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes
• They are mined for fuel and horticultural products
• Swamps, marshes, bogs

Back 52

Histosols

Front 53

Soils that are composed mainly of organic materials

Back 53

Histosol

Front 54

They contain at least 20-30% organic matter by weight and are more than 40cm thick

Back 54

Histosol

Front 55

Bulk densities are often quite low

Back 55

Histosol

Front 56

Most form in settings where restricted drainage inhibits the decomposition of plant and animal remains, allowing these organic materials to accumulate over time

Back 56

Histosol

Front 57

They are ecologically important because of the large quantities of carbon that they contain

Back 57

Histosol

Front 58

These are often referred to as peats and mucks and have physical properties that restrict their use for engineering purposes

Back 58

Histosol

Front 59

They are mined for fuel and horticultural products

Back 59

Histosol

Front 60

Swamps, marshes, bogs

Back 60

Histosol

Front 61

• Soils that exhibit minimal horizon development
• They are more developed than Entisols, but still lack the features that are characteristic of other soil orders
• Widely distributed and occur under a wide range of ecological settings
• They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials
• Many are found in mountainous areas and are used for forestry, recreation, and watersheds

Back 61

Inceptisol

Front 62

Soils that exhibit minimal horizon development

Back 62

Inceptisol

Front 63

They are more developed than Entisols, but still lack the features that are characteristic of other soil orders

Back 63

Inceptisol

Front 64

Widely distributed and occur under a wide range of ecological settings

Back 64

Inceptisol

Front 65

They are often found on fairly steep slopes, young geomorphic surfaces, and on resistant parent materials

Back 65

Inceptisol

Front 66

Many are found in mountainous areas and are used for forestry, recreation, and watersheds

Back 66

Inceptisol

Front 67

• Soils of grassland ecosystems
• They are characterized by a thick, dark surface horizon
• Fertile surface horizon results from the long-term addition of organic materials derived from plant roots
• Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S.
• They are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose

Back 67

Mollisol

Front 68

Soils of grassland ecosystems

Back 68

Mollisol

Front 69

They are characterized by a thick, dark surface horizon

Back 69

Mollisol

Front 70

Fertile surface horizon results from the long-term addition of organic materials derived from plant roots

Back 70

Mollisol

Front 71

Occur primarily in middle latitudes and are extensive in prairie regions, such as the Great Plains of the U.S.

Back 71

Mollisol

Front 72

They are among some of the most important and productive agricultural soils in the world and are extensively used for this purpose

Back 72

Mollisol

Front 73

• Very highly weathered soils that are found primarily in intertropical regions of the world
o Thick O-Horizon
• These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals
• These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity
• Most nutrients in oxisol ecosystems are contained in the standing vegetation and decomposing plant material
• Despite low fertility, they can be quite productive with inputs of lime and fertilizers

Back 73

Oxisol

Front 74

Very highly weathered soils that are found primarily in intertropical regions of the world
o Thick O-Horizon

Back 74

Oxisol

Front 75

These soils contain few weatherable minerals and are often rich in iron and aluminum oxide minerals

Back 75

Oxisol

Front 76

These soils are characterized by extremely low native fertility, resulting from very low nutrient reserves, and high phosphorous retention by oxide minerals, and low cation exchange capacity

Back 76

Oxisol

Front 77

Most nutrients in this ecosystems are contained in the standing vegetation and decomposing plant material

Back 77

Oxisol

Front 78

Despite low fertility, they can be quite productive with inputs of lime and fertilizers

Back 78

Oxisol

Front 79

• Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron
• These photogenic soils typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown horizon
• They often occur under coniferous forests in cool, moist climates
• Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally

Back 79

Spodosol

Front 80

Acids oils characterized by a subsurface accumulation of humus that is complexed with aluminum and iron

Back 80

Spodosol

Front 81

Typically form in coarse-textured parent material that have light-colored E-Horizon overlying a redish-brown horizon

Back 81

Spodosol

Front 82

They often occur under coniferous forests in cool, moist climates

Back 82

Spodosol

Front 83

Many support forests, but because they are naturally infertile, they require additions of lime in order to be productive agriculturally

Back 83

Spodosol

Front 84

• Strongly leached, acid forest soils with relatively low native fertility
• They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes
• Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils
• They have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides
• Because of favorable climate regimes in which they are typically found they often support productive forests
• Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. They are poorly suited for agriculture without the use of fertilizer and lime

Back 84

Ultisol

Front 85

Strongly leached, acid forest soils with relatively low native fertility

Back 85

Ultisol

Front 86

They are found primarily in humid temperate and tropical areas of the world, typically in older, stable landscapes

Back 86

Ultisol

Front 87

Intense weathering of primary minerals has occurred, and much of the ca, Mg and K has been leached from these soils

Back 87

Ultisol

Front 88

They have a subsurface horizon in which clays have accumulated, often with strong yellowish or reddish colors resulting from the presence of iron oxides

Back 88

Ultisol

Front 89

Because of favorable climate regimes in which they are typically found they often support productive forests

Back 89

Ultisol

Front 90

Because of their acidity and relatively low quantities of plant-available Ca, Mg and K. They are poorly suited for agriculture without the use of fertilizer and lime

Back 90

Ultisol

Front 91

• Clay-rich soils that shrink and swell with changes in moisture content
• During dry periods, the soil volume shrinks, and deep wide cracks form
• The soil volume expands as it gets wet
• The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons.
• Occupy 2.0% of the US land area and occur primarily in Texas

Back 91

Vertisol

Front 92

Clay-rich soils that shrink and swell with changes in moisture content

Back 92

Vertisol

Front 93

During dry periods, the soil volume shrinks, and deep wide cracks form

Back 93

Vertisol

Front 94

The soil volume expands as it gets wet

Back 94

Vertisol

Front 95

The shrink/swell action creates serious engineering problems and generally prevents the formation of distinct, well-developed horizons.

Back 95

Vertisol

Front 96

Occupy 2.0% of the US land area and occur primarily in Texas

Back 96

Vertisol