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Chapter 12 Soil and Agriculture

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Soil and Agriculture Mr. Manskopf Class Web Site Http://www.manskopf.com ... Soil composition is influenced by climate, organisms, landforms, parent material, ... – PowerPoint PPT presentation

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Title: Chapter 12 Soil and Agriculture


1
Chapter 12 Soil and Agriculture
  • Mr. Manskopf
  • Class Web Site
  • Http//www.manskopf.com

2
Essential Questions Covered
  • What are the components of the soil?
  • How is soil formed?
  • What are some of the effects of soil erosion on
    the land?
  • Describe the impact of human activities on the
    land.
  • How do recycling and composting programs affect
    the soil?
  • What impact do pesticides have on the soil?
  • What affect do fertilizers have on the nitrogen
    cycle?

3
Who Cares About DIRT?
4
How is my food choice impacting the environment?
5
How come not everyone has enough food?
6
About 38 of Earths land surface is used for
agriculture.
7
Section 1 Soil
  • Explain how soil is formed.
  • Describe the different layers (horizons) of soil.
  • List four characteristics used to classify soil.

8
What is soil made of?
  • Soil is made up of minerals, organic matter, air,
    and water.
  • Soil composition is influenced by climate,
    organisms, landforms, parent material, and time

9
Soil Composition
  • Soil is a thin layer over most land that is a
    complex mix of rock, nutrients, decaying matter,
    water, air and billions of organismsmany
    microscopic decomposers

10
Why is soil important
  • Renewable resourceSLOW
  • Depends upon climate (1cm in 15yrs.)
  • Basis of life
  • Filters water
  • Water storage
  • Habitat

11
Simplified Soil Food Web
12
Soil Formation
  • Weathering Physical and chemical breaking of
    rocks and minerals into smaller pieces
  • Erosion and deposition Pick-up, transport, and
    drop-off of material from one place to another
  • Decomposition Breakdown of waste, organisms, and
    organic material into simple molecules

13
Weathering of PARENT MATERIAL (ROCK)
14
Decomposition
15
Leaf Litter
16
Different Biomes Different Parent Material,
Climate, Organic Matter Different Soil
17
Soil Horizons
  • Soil horizons are distinct layers of soil.
  • A cross-section of soil horizons is a soil
    profile.
  • A Most Critical

18
Did You Know? In general, organic matter is
concentrated in the O and A horizons, making them
the most critical for agriculture.
19
Is All DIRT The Same?
20
Soil Characteristics
  • Soil groups are further classified according to
    properties such as color, structure, pH, and
    texture.
  • Soil texture is based on particle size.

21
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22
Topsoil Color a Great Quick Indicator
Dark, loamy, neutral pH are some of best soils
for farming Dark color often means lots of
decayed material (nutrients)
23
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24
Section 1 Review
  • Explain how soil is formed.
  • Describe the different layers (horizons) of soil.
  • List four characteristics used to classify soil.

25
Section 1 Quiz
  • 1) After a catastrophe, soil formation is the
    first step in
  • A. primary succession.
  • B. secondary succession.
  • C. a climax community.

26
2) Most of the nutrients in soil come from A.
chemical weathering. B. mechanical
weathering. C. erosion.
D. decomposition.
27
3) A farmer interested in raising healthy crops
should look for a A. heavy clay soil with a high
pH and a dark color. B. loamy
soil with a low pH and a light color. C. loamy,
clumpy soil with a neutral pH and a dark color.
D. sandy soil with a high pH, no clumps,
and a light color.
28
4) An example of a soil parent material is A.
humus. B. volcanic rock.
C. leaf litter. D. topsoil.
29
5) As a farmer, you would be most concerned with
the quality of the soil in the A. O horizon.
B. A horizon. C. E
horizon. D. R horizon.
30
6) A rancher interested in the quality of the
soil in her pasture might use which aspect of
soil as a quick indicator of the pastures
overall fertility? A. color B. smell
C. structure D. pH E. Taste
31
7) Short Answer If you were to travel to the
desert in Arizona, you might find Horizon Layer O
and A missing. Why?
32
8) Short Answer What determines how quickly
Horizon O and A form?
33
Some estimates predict that 50 million people
could be displaced in the next 10 years due to
desertification, a form of soil degradation.
34
Section 2 Soil Degradation and Conservation
  • What causes soil erosion?
  • How serious of a problem is it?
  • What are ways that farmers, ranchers and forestry
    lead to soil erosion?

35
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36
Causes of Soil Erosion
  • Wind
  • Water 1
  • People

37
Soil Erosion
  • Often occurs faster than soil is formed,
    depleting fertile topsoil
  • Crops, trees, and other plant communities protect
    soil from erosion.

38
Did You Know? More than 19 billion hectares (47
billion acres) of the worlds croplands suffer
from erosion and other forms of soil degradation
resulting from human activities.
39
Impacts of Soil Erosion
  • Loss of soil fertility
  • Sediment runoff causes problems in surface water
    (pollution, clog ditches, boat channels,
    reservoirs)
  • 1 source of U.S. water pollution
  • Renewable only on LONG timeframes (200-1,000yrs.
    for 1 inch)

40
What time of year do you think most farm fields
in U.S. are vulnerable to erosion?
41
On Ag. land in U.S. today, soil is eroding 16
times faster than it is created
42
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43
Farming Practices That Reduce Erosion
  • Intercropping Different crops mixed together
  • Crop rotation Crops are alternated.
  • Shelterbelts Tall plants block wind.
  • Conservation tillage Soil turnover is reduced.
  • Terracing Steep slopes turned into steps

44
Tillage vs. Conservation Tillage
45
Contour and Strip Cropping
46
Ranching Practices
  • Ranching is the raising and grazing of livestock.
  • Overgrazing causes and worsens many soil
    problems.
  • Range managers encourage grazing limits and
    enforce them on publicly owned land.

47
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48
Forestry Practices
  • Forestry practices, such as clear-cutting, can
    increase erosion.
  • Today, practices that reduce soil erosion, such
    as selective logging, are increasingly common.

49
Soil Pollution
  • Too much, or carelessly timed irrigation can
    waterlog crops and lead to salinizationa buildup
    of salts in upper soil horizons.
  • Toxic pesticides can remain in soil for a long
    time, eventually filtering to groundwater.

50
Desertification
51
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52
Soil Salinization
53
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54
Soil Pollution
55
Section 2 Review
  • What causes soil erosion?
  • How serious of a problem is it?
  • What are ways that farmers, ranchers and forestry
    lead to soil erosion?

56
Humans have been practicing agriculture for about
10,000 years.
57
What is that?
58
Aldo Leopold
  • There are two spiritual dangers in not owning a
    farm. One is the danger of supposing that
    breakfast comes from the grocery store, and the
    other that heat from the furnace.

59
Section 3 Agriculture
  • Describe the history of farming.
  • Analyze the costs and benefits of the Green
    Revolution
  • What are some ways farmers control weeds and
    pests?
  • Why are pollinators important to farmers?

60
The Beginnings of Agriculture
People were hunter-gatherers through most of
human history, until agriculture developed about
10,000 years ago.
61
Why 10,000 years ago?
62
Agriculture History
  • In early agriculture, people began planting seeds
    from plants they liked most
  • Agriculture and livestock provided a stable food
    supply, which allowed the development of modern
    civilization.

63
Types of Agriculture
  • Traditional Agriculture

Industrial Agriculture
64
The Green Revolution
  • Introduced new technology, crop varieties, and
    farming practices to the developing world in the
    mid- to late 1900s
  • Benefits
  • Increased crop yields and saved millions of
    people from starvation in India and Pakistan
  • Prevented some deforestation and habitat loss by
    increasing yields on cultivated land

65
Green Revolution
  • Costs
  • Led to a 7000 increase in energy used by
    agriculture
  • Worsened erosion, salinization, desertification,
    eutrophication, and pollution

66
Pests and Weed Control (Farmers Enemies)
  • Chemical pesticides Effective and cheap, but can
    lead to resistance

67
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68
Pests and Weed Control
  • Biological pest control Permanent solution, but
    can harm nontarget organisms
  • Integrated pest management Increasingly popular
    solution, combines chemical and biological
    pest-control methods

Cactus moth larvae are used to control prickly
pear cactus, but also threaten many rare, native
cacti around the world.
69
Pollinators
  • Agriculture relies on pollinators, such as
    insects.
  • Native and domesticated pollinator populations
    have declined due to pesticide use, parasites,
    and other as-of-yet unknown causes

70
Section 3 Review
  • Describe the history of farming.
  • Analyze the costs and benefits of the Green
    Revolution
  • What are some ways farmers control weeds and
    pests?
  • Why are pollinators important to farmers?
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