The document discusses the major biomes of the world and the soils typically found within each one. It describes the key biomes as tropical rainforests, temperate forests, boreal forests, grasslands, tundra, deserts, shrublands, and wetlands. Each biome is defined by its climate, vegetation, and characteristic soil orders that form as a result of the particular environmental conditions within that biome.

1. Chapter 7
Soils and Biomes

2. A biome is a large
geographic region with
a similar environment
that contains distinctive
plant and animal
communities
soils4teachers.org/KSKL Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
What is a Biome?
Fig. 7-1. World biomes.

3. Climate
• Temperature
• Precipitation
• Soil temperature
• Soil moisture
soils4teachers.org/KSKL Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
What factors influence
how biomes form?
Fig. 7-3. Soil temperature
regimes.
Fig. 7-4. Soil moisture regimes.

4. Four types
• Tropical rainforests
• Temperate rainforest
• Temperate forest
• Coniferous/boreal forest
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Forests

5. Located near equator
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Fig. 7-1. World biomes.
Tropical Rainforest
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-5. A rainforest in Costa Rica.

6. • Characterized by:
• Warm temperatures year-round
(hyperthermic, see Fig. 7-3)
• Very wet (udic moisture regime,
see Fig. 7-4)
• Dense Vegetation
• High biodiversity
• Soils
• Oxisols and Ultisols
• Highly weathered, low nutrient
availability
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Tropical Rainforest
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-6. Oxisols. Fig. 7-7. Utisols.

7. • Located
• Only 0.3% of land surface (not even
shown on Fig. 7-1)
• Pacific Northwest U.S., Chile, Japan,
New Zealand, southern Australia,
Norway, U.K.
• Characterized by
• High levels of precipitation
• May have cooler temperatures than
tropical rainforest
• Soils
• Andisols, Spodosols, and Alfisols.
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Temperate Rainforest
Fig. 7-11. Spodosols. Fig. 7-9. Alfisols.
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-2. World
soil orders.

8. • Located
• Regions that receive more
than 100 cm rainfall/year
• Characterized by
• Dormant season when trees
drop their leaves
• Soils
• Cool regions
• Alfisols, Inceptisols
• Warmer regions
• Ultisols, Spodosols
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Temperate
Deciduous Forest Right: Fig. 7-10.
Inceptisols.
Left: Fig. 7-9.
Alfisols.
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Right: Fig. 7-11.
Spodosols.
Left: Fig. 7-7.
Utisols.

9. • Located
• Eastern Canada, Alaska, Europe,
Asia, Russia
• South of tundra
• Characterized by
• Evergreen forests, often with large
areas of a single tree species
• Soils
• Spodosols dominate in sandy areas
• Inceptisols and Entisols in other
areas
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Coniferous/ Boreal Forest (AKA taiga)
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-12. Entisols.
Fig. 7-11.
Spodosols.
Fig. 7-10. Inceptisols.

10. Two types
• Tropical savannahs
• Temperate grasslands
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Grasslands

11. • Located
• Largest area is in East Africa
• Characterized by
• Tall grasses with occasional
trees and shrubs
• Soils
• Highly weathered
• Alfisols, Ultisols, and some Oxisols
• Low fertility due to heavy rainfalls
and high levels of decomposition
during rainy season
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Tropical Savannahs
Fig. 7-9. Alfisols.
Fig. 7-7. Utisols
Fig. 7-6.
Oxisols.
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012

12. • Located
• U.S. Great Plains, Russia,
Brazil
• Transition between forest
and prairie
• Characterized by
• Grasses dominate
vegetation
• Occasional trees or
shrubs
• Soils
• Predominantly Mollisols,
with organic matter
contents dependent upon
the type of dominant
grass
• Some Alfisols in sandy
areas
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Temperate Grasslands
Fig. 7-13. Prairie
expanse in Kansas.
Fig. 7-14(a).
Mollisol from
tall-grass prairie.
Fig. 7-14(b).
Mollisol from
short-grass prairie.
Fig. 7-15. Grassland Alfisol has
sandy texture and lighter colors.
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012

13. soils4teachers.org/KSKL
Tundra
Two types
• Arctic tundra
• Alpine tundra

14. • Located
• Far northern latitudes
• Characterized by
• Permafrost, strong
winds, short growing
season, shallow soils
• Soils
• Gelisols, which have
permafrost within 1.0 m
of soil surface.
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Fig. 7-17. Alaskan tundra showing patterned
ground which forms from annual freeze-thaw
cycles in upper portion of the soil and permafrost.
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Arctic Tundra
Fig. 7-18. Gelisols are
slow to decompose
organic matter due to
cold temperatures.

15. • Located
• High elevations
• Characterized by
• Diurnal (daily) freeze-thaw cycle, rather than seasonal cycle seen in
arctic
• Diverse climatological and vegetation features, depending primarily on
elevation and location on a mountain face
• Soils
• Generally young and not well-formed
• The exception, Spodosols and Andisols, whose parent materials
(Andisols) and organic acids (Spodosols) may lead to greater levels of
soil formation
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Alpine Tundra

16. • Located
• Every continent
• Characterized by
• Low precipitation
• May be hot or cold
• Soils
• Primarily Aridisols, soils which are generally not well-formed and which contain
accumulations of clay, carbonates, gypsum, and/or sodium and clay
• Occasionally Entisols, slightly more developed soils which may have some horizonation
formed under previous climates
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Deserts
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-22 . Deserts from US
Southwest (left), and dry valleys
of Antartica (right).
Fig. 7-1. World biomes.

17. • Located
• West coast of N. America, S. America, Australia, S. Africa, and the
Mediterranean coast
• Characterized by
• Evergreen, fire tolerant shrubs, with interspersed grasses in between
• Soils
• Mollisols and Alfisols
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Shrublands

18. • Located
• Worldwide
• Interfaces between fresh and salt water
bodies
• Characterized by
• Saturated soil in upper 20 cm
• Vegetation adapted to saturated,
oxygen-poor soils
• Freshwater wetlands have less than 1%
salt content
• Soils
• Histosols, which are characterized by
high levels of organic matter
accumulation
• Anaerobic, reducing conditions lead to
little horizon formation
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Aquatic Biomes (Wetlands)
Image Credit: Know Soil Know Life, D. Lindbo, D. Kozlowski, and C. Robinson - Editors, © 2012
Fig. 7-30. Histosols.
Fig. 7-29 . Presence of
redoximorphic features.

19. • Soil and plants evolve together
• Biomes are influenced by weather and climate as well as soils
• Not just a one-way interaction; soils and soil formation
are also strongly influenced by climate (“C” in CLORPT)
and plant communities (“O” in CLORPT).
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Key Points