Transcript of SOIL AND AGRICULTRE Environmental Science Chapter 12.
- Slide 1
- SOIL AND AGRICULTRE Environmental Science Chapter 12
- Slide 2
- THE CENTRAL CASE Possible Toxic Maize in Oaxaca, Mexico How can
we balance our growing demand for food with our need to protect the
environment??
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- SECTION 1 Objectives 1. Explain 3 processes by which soil
forms. 2. Describe the horizons that make up a soil profile. 3.
List the four characteristics used to classify soil.
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- SECTION 1 What percent of the Earths land surface do you think
is used for agriculture? How would you describe the difference
between soil and dirt?
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- SECTION 1 __________ : a complex plant-supporting system made
up of ________________________,
___________________________________, _________, ____________,
______________, and ________________________. Soil is a
__________________ resource. Figure 1
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- SECTION 1 Soil forms through __________________,
______________, and __________________. Soil consists of 45 %
_________________, 5% ____________________, and 50%
____________________________.
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- SECTION 1 __________________________; the geological material
in a particular location may be made up of ______________, rock or
sediment deposited by ____________, ________________, ___________,
____________, ______________, or _________________. ______________:
the continuous mass of solid rock that makes up the Earths
crust
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- SECTION 1 __________________ is the first process in soil
formation. It describes the ____________ and __________ processes
that break rocks and minerals into smaller pieces.
________________: the natural break up of rock without chemical
reactions. ____________ and ____________ are the 2 main causes.
But, ___________________, _____________, and _____________ also
contribute.
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- SECTION 1 ________________: breaking down rocks by chemical
processes.
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- SECTION 1 _____________________: the dropping of eroded
material at a new location. _______________________: the breakdown
of organic material. ________________: dead leaves and vegetation.
_____________: partially decomposed organic mater. Both add to the
fertility of the soil.
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- SECTION 1 ____________________: the distinct layers of soil.
___________________: the cross-section of all the soil horizons of
a specific soil. There are 6 major soil horizons: O, A, E, B, C,
and R Soils differ from location to location, and few soils have
all 6 horizons. Figure 4
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- SECTION 1 A horizon: ______________. This horizon has the most
plant nutrients available. Gets much of its potential from the O
horizon, _____________, The A horizon is fragile. It must be
protected in order for it to last.
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- SECTION 1 As you move lower through the horizons the particle
size _____________. E horizon: ___________. Particles suspended in
liquid are transported to another area
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- SECTION 1 Soil Characteristics ____________, ______________,
_____________, _________ _____________ Dark soil: Pale soil:
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- SECTION 1 __________________ Based on particle size __________:
particles 0.002 mm or smaller __________: particles between
0.002-0.05 mm __________; particles between 0.05-2 mm
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- SECTION 1 Sand particles do not stick to each other Clay
particles do stick to each other Most soils are a combination of
clay, silt, and sand. When there is a relatively even mixture of
the three the soil is called ______________.
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- SECTION 1 The texture of the soil influences its
_________________; how easy it is to plant in and harvest from. It
also determines its _________; the size of the air spaces between
the particles.
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- SECTION 1 Structure Describes the arrangement of the soil
particles pH Can be either ____________ or ______________.
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- SECTION 2 Objectives 1. Describe some practices that can lead
to soil erosion and some that can prevent it. 2. Identify the
causes and effects of desertification. 3. Discuss the activities of
US and international agricultural organizations. 4. Explain how
irrigation and pesticide use can cause soil pollution.
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- SECTION 2 Studies show that the most productive soil is
____________, with a _____________ pH. It is _______________,
contains _____________, and holds _____________. Human activities
can cause ___________, __________________, and ____________ that
make soil less productive.
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- SECTION 2 The deterioration of the soil characteristics needed
for plant growth or other ecosystem services is called ___________
________________. This can be devastating to ecosystems. Lets look
at how this can occur
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- SECTION 2 Erosion Can be a problem because it usually occurs
____________ than the rate at which soil is formed. Erosion can
also ____________ soils Ex:
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- SECTION 2 Today, human activity cause more erosion than do
natural events. More than ___________acres of the worlds croplands
now suffer from erosion and other forms of soil degradation.
Reasons: _______________________, ______________________, and
________________________.
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- SECTION 2 In the US erosion rates are now declining due to
_______________ _______________. Figure 7 Farming Practices
______________________: planting different crops of mixed
arrangements. ____________________: alternating crops grown in a
field ____________ ______________
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- SECTION 2 ______________________ _________________: rows of
trees of other tall perennial plants that are planted along the
edges of fields to slow the wind. _________________: The turning
over of soil before planting. Makes soil more susceptible to
erosion. _____ ___________ ______________: planting right back into
a field with the residue left from previous crop.
______________-_____________: turning the soil slightly.
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- SECTION 2 _________________: transforms steep slopes into a
series of steps like a staircase ____________ ___________: plowing
sideways along a hillside allowing the land to conserve soil and
water. Ranching Practices ___________________: when too many
animals eat too much of the plant cover, impeding regrowth.
Effects: __________________, _________________, and
_____________.
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- SECTION 2 Forestry practices _____________ ____________ can
lead to severe erosion. _____________ __________: lead to less
erosion Desertification The loss of more than 10% of productivity
due to erosion, soil compaction, forest removal, overgrazing,
drought, salt buildup, climate change, depletion of water.
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- SECTION 2 Some scientists suggest _______ of Earths land area
is affected by desertification. THE DUST BOWL In the late 1800s and
early 1900s settlers in OK, TX, KS, NM, and CO began tilling up the
grasslands. Between _______ and ______ the farmed area of the Great
Plains increases ______%
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- SECTION 2 Soil Conservation Policies In response to the
________ ________ soil conservation practices were being explored
______: the U.S. Congress passed the ________ _________________
______ establishing the _______ _________________ _________ (SCS)
In _______ it was renamed to ______ _________ ______________
___________ and was expanded to include __________ __________ and
_______ _____.
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- SECTION 2 U.S.Policies: ____________ _________ __________ (CRP)
was part of the _________ farm bill requiring farmers to put in
place a conservation plan before they got their subsidies. It is
estimated the for each dollar invested in this program saves nearly
1 ton of topsoil.
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- SECTION 2 International Policies: ________ ______ ____________
(FAO) ____ _____ ____ ____ (FARM)
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- SECTION 2 Soil Pollution _________________: providing water to
crops other than precipitation ________________: the build up of
salts in upper soil horizons. Can be made worse through irrigation
How? Solutions:
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- SECTION 2 Pesticides Residual chemicals could remain in the
soil for long periods of time and may be toxic to humans. Chemicals
can get into the groundwater contaminating it We are not sure of
the long-term effects of some pesticides. Broad-spectrum pesticides
may kill a wide variety of insects, some of which may be helpful to
the soil.
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- SECTION 3 Objectives 1. Discuss the beginnings of agriculture
2. Explain the importance of industrial agriculture and the green
revolution 3. Identify different types of pest control 4. Explain
the importance of pollinators to agriculture
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- SECTION 3 Agriculture began about ____________ years ago when a
warmer global climate allowed humans to plant seeds and raise
livestock. This change was called the _________ ___________. Figure
13 ____________ ____________: planting seeds only from plants whose
fruit has desirable qualities.
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- SECTION 3 ____________ ______________: faming with hand tools
and worker animals without the use of fossil fuels. Soon bigger
fossil-fueled machines replaces worker animals. _____________
____________ replaced traditional agriculture.
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- SECTION 3 ________________ ________________:
________________________: large areas planted with a single crop.
Benefits: Drawbacks:
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- SECTION 3 ___ _________ ______________: a movement in the
mid-to late 1900s in which scientists from developed countries
introduced new technology, crop varieties, and farming practices to
the developing countries. Technology: Environmental Effects:
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- SECTION 3 _______: something that damages plants that are
valuable to us. _______: a plant that competes with our desired
crops. How do we control them? __________________ _________
________ __________: controlling pests and weeds with organisms
that eat or infect them Figure 16
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- SECTION 3 Biological Pest Control ______: Bacillus
thuringiensis a naturally occurring soil bacterium that produces a
protein that kills many caterpillars and the larvae of some flies
and beetles. ________________________: combining the most useful
aspects of chemical and biological pest control
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- SECTION 3 Pollinators: _______________: The process by which
male sex cells of a plant (pollen) fertilize female sex cells of a
plant. Some plants are pollinated by the wind, while others rely on
_______________: animals, such as insects and hummingbirds that
pollinate flowers.
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- SECTION 3 Pollinator populations have ______________. Ex:
_______________
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- SECTION 4 Objectives 1. Explain why the world needs to grow
more food and grow it sustainably. 2. Discuss genetically modified
food 3. Describe the advantages and disadvantages of industrial
food production. 4. Discuss sustainable agriculture
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- SECTION 4 Each year the Earth gains 75 MILLION people and LOSES
12-17 MILLION acres of productive cropland. In addition ________
_____, or land suitable for farming is running out. Since 1961 we
have increased our food production by _________________,
___________, _________, ________, ____________, ______________.
Despite these efforts ____________ people globally are still
hungry.
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- SECTION 4 _________ ____________: the guarantee of an adequate
and reliable food supply for all people at all times. In _______,
the government classified _______ Americans as food insecure.
____________: a shortage of nutrients the body needs, as a result
of poor quantity and quality of food.
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- SECTION 4 _______________: occurs when a person does not get
enough protein. ________________: a condition that causes wasting
of the muscles and other physical and mental problems.
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- SECTION 4 Genetically modified organisms _________________: any
process in which scientists directly manipulate and organisms DNA
____________________: organisms that have undergone genetic
engineering. Produced by a process called __________________.
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- SECTION 4 ______________________: the use of genetic
engineering to introduce new genes into organisms to produce more
valuable products. The US grows about _______ of the total global
GM crops. Risks: Benefits:
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- SECTION 4 Industrial Food Production _______________:
Advantages: Disadvantages: ____________________:
__________________: Losses: Preservation:
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- SECTION 4 __________________: agriculture that does not deplete
soil faster than it forms. _________________: food-growing
practices that use no synthetic fertilizers, insecticides,
fungicides, or herbicides, but rely on biological approaches.
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- SECTION 4 ______________________: supporting local, small-scale
agriculture.