Transcript Soil: Foundation for Land Ecosystems

Soil: Foundation for Land
Ecosystems
Chapter 8
Soil
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Soil texture and proportions
• Loam: 40% sand, 40% silt, 20% clay
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Affects fertility and workability
Soil profiles and different horizons
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O horizon
A horizon
E horizon
B horizon
C horizon
Different Classes of Soil
Plants and Optimal Growth
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Enough mineral nutrients, oxygen and
water
• pH and salinity important
• Use of fertilizers
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Water-holding capacity
Contribution to soil enrichment by:
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Detritus
Soil organisms
Humus
Top soil
Degradation
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Erosion
• Desertification
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Formation and expansion of degraded soils and
vegetation in seasonally dry areas
Causes
• Overcultivation
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Countour strip cropping
• Overgrazing
• Deforestation
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Irrigation
Salinization
Conservation
Individual Land owner vs. Public
Policy
 Public Policy
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• Subsidies
• Farm Bills
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Individual Land Owner
• Education
• Sustainability
Homework
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#3 and #4 in Thinking Environmentally
pg. 217
Read introduction Chapter 9 pg 219-221
Read ethics pg 234
Read Global Perspective pg 236
Read section 9.3 and 9.4