Soil Resources

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Soil Resources
Chapter 15
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What is Soil?

• Composed of
• mineral matter
• organic matter
• Modified by
• weather
• water
• organisms

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What is Soil?

• How Soils are Formed
• From parent material
• Formation time varies (200 1000 years)
• Depth varies (thin film to 10 ft)

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What is Soil?

• Soil Composition

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What is Soil?

• Soil Composition
• Other components

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What is Soil?

• Soil Composition
• Other components

Pore space (wet soil)
Pore space (dry soil)
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What is Soil?

• Soil Horizons

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What is Soil?

• Soil Organisms

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What is Soil?

• Nutrient Cycling

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What is Soil?
(alternate slide)

• Nutrient Cycling

Organic matter in soil
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Soil Properties and Major Soil Types

• Soil Texture Sand, Silt, and Clay

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Soil Properties and Major Soil Types

• Availability of nutrient minerals in clay

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Soil Properties and Major Soil Types

• Soil Properties Affected by Soil Texture

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Soil Properties and Major Soil Types
pH scale

• Soil Acidity

0
7
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Soil Properties and Major Soil Types

• Major Soil Groups

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Soil Properties and Major Soil Types

• Major Soil Groups

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Soil Properties and Major Soil Types

• Major Soil Groups

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Soil Problems

• Soil Erosion
• Caused by water, wind, and ice

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Soil Problems

• Case-in-Point The American Dust Bowl

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Black Blizzard History Channel
Take a front row seat on a period of U.S. history
from 1930-1940 when America's heartland was
ravaged by a weather phenomenon that became known
as a "black blizzard." Watch as scientists and
special effects experts recreate the black
blizzards in amazing detail and reveal that this
was a man-made disaster. Discover how these
phenomena form, what they're made of, and how
they affect people's health and the environment.
Learn how a black blizzard emerged so ferociously
that it seemed like a moving mountain range
creating enough static electricity to power New
York City. Hear the story of the people who
refused to leave their land and learn the history
of the Great Plains and how it came to be settled
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A wall of dust approaches a Kansas town, as shown
in "Effect of Dust Storms on Health," U.S. Public
Health Service, Reprint No. 1707 from the Public
Health Reports 50(40) October 4, 1935. (Image
courtesy of the
http//video.pbs.org/video/1311363860/
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Soil Problems

• Nutrient Mineral Depletion

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Soil Problems

• Soil Problems in the United States
• Cultivated soils in southern Iowa, northern
  Missouri, western and southern Texas, eastern
  Tennessee have greatest erosion
• 25 of agricultural lands lose more topsoil
  than formed

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Soil Problems

• World Soil Problems
• Mineral depletion in tropical rainforest soils
• Degradation in the African Sahel

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Massive Dust Storm from Sahel Region.
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Soil Conservation and Regeneration

• Conservation Tillage

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Soil Conservation and Regeneration

• Crop Rotation

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Advantages of crop rotation -Prevents soil
depletion -Maintains soil fertility -Reduces
soil erosion -Controls insect/mite pests. Crop
rotation as a means to control to insect pests is
most effective when the pests are present before
the crop is planted have no wide range of host
crops attack only annual/biennial crops and do
not have the ability to fly from one field to
another. -Reduces reliance on synthetic
chemicals -Reduces the pests' build-up
-Prevents diseases -Helps control weeds
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Soil Conservation and Regeneration

• Contour Plowing, Strip Cropping, and Terracing

Strip cropping contour plowing
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Soil Conservation and Regeneration

• Preserving Soil Fertility
• Organic fertilizers
• e.g., manure, compost
• slow release, but nutrient content varies
• Commercial inorganic fertilizers
• e.g., typical bagged fertilizer
• exact nutrient content known, but prone to
  leaching

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Soil Conservation and Regeneration

• Soil Reclamation
• increasing productivity on eroded land