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Land, Air, and Water Resources
Ms. De Los Rios
7th Grade
Ch. 8.1 Conserving Land and Soil
Essential Question:
How Do People use Earth’s Resource?
How do People Use Land?
Why is Soil Management Important?
What are the Effects of Deforestation and
Urbanization?
Pgs. 252-259
Vocabulary
1. Natural resource- is anything that occurs
naturally in the environment and is used by
people.
2. Litter- top layer of leaves and grass
3. Topsoil- the next layers is a mixture of rock
fragments, nutrients, water, air, and
decaying animal and plant matter.
(absorbed by roots)
4. Subsoil- contains rock fragments, water,
and air but has less animal and plant matter
than the topsoil.
5. Bedrock- this is the rock that makes up the
Earth’s crust.
6. Erosion- the process by which water, wind,
or ice moves particles of rocks or soil.
Vocabulary
7. Nutrient depletion- when the soil becomes less
fertile.
8. Fertilizer- nutrients that help crops grow better.
9. Desertification- The advance of desertlike
conditions into areas that previously were fertile.
10. Drought- A period when less rain than normal
falls in an area.
11. Land reclamation- the process of restoring an
area of land to a more productive state.
12. Deforestation- people cut down woodlands to
harvest timber or clear the land for farms or
ranches.
13. Urbanization- large areas of land are developed
as more and more people move to cities and
suburbs.
How Do People Use the Land? Pg. 252
Less than a quarter of Earth’s
surface is dry, ice-free land.
All people on Earth must share this limited
amount of land to produce their food, build
shelter, and obtain resources (r. 1 p.)
.
Natural Resources
(anything that occurs naturally in the environment and is used by
people.)
Land, air, and water
Three uses that change the land
are agriculture, mining, and
development.
3 Uses that Change the Land
Agriculture- Less than a third of Earth’s
land can be farmed. People create new
farmland by clearing forests, draining
wetlands, and irrigating deserts. Land can also
be use for grazing livestock or growing food for
animals, or growing crops such as cotton.
Mining- is the removal of nonrenewable
resources from the land. Strip mining exposes
soil and causes erosion. (r. p.)
Development- people settle in areas
with good soil near fresh water. As pop. grew,
the settlements became towns and cities.
Assess your Und.
Pg. 253
Why is Soil Management Important? Pg. 254
Soil contains the minerals and nutrients
that plants need to grow.
The structure of fertile soil contains
layers including:
Litter
Topsoil
Subsoil
Bedrock.
Because it can take hundreds of years
to form just a few centimeters of new
soil, it is important to protect Earth’s soil.
Without soil, most life on land
could not exist.
The structure soil contains layers
Litter, topsoil, subsoil and bedrock
1. Litter- top layer of leaves and grass
2. Topsoil- the next layers is a mixture of rock
fragments, nutrients, water, air, and
decaying animal and plant matter.
(absorbed by roots)
3. Subsoil- contains rock fragments, water,
and air but has less animal and plant matter
than the topsoil.
4. Bedrock- this is the rock that makes up the
Earth’s crust.
Soil Use Problem pg. 255
Poor soil management can result in
three problems: erosion, nutrient depletion,
and desertification.
When plants are removed during logging,
mining, or farming, the soil is exposed and soil
particles can easily move. The process by
which water, wind, or ice moves particles of
rocks or soil is called erosion.
If a farmer plants a field with the same crops
year after year, the soil becomes less fertile, a
situation called nutrient depletion. When soil
becomes depleted, farmers usually apply
fertilizers, which include nutrients that help
crops grow better.
Desertification Pg. 256
If soil in a once-fertile area becomes
depleted of nutrients and moisture, it
can become like a desert. The advance
of desert-like conditions into areas that
previously were fertile is called
desertification.
One cause of desertification is
drought, a period when less rain than
normal falls in an area.
The process of restoring an area of land
to a more productive state is called land
reclamation.
Apply IT!!Conserving Land and Soil
pg. 256
Desertification
Desertification affects many areas
around the world.
1.
Which continent has the most
existing deserts?__________
2. Where I the US is the greatest risk of
desertification?______________
3. Is desertification a threat only in
areas wehre there is existing
deserts? Explain. Circle an area on
the map to support your answer.
________________________________
________________________________
4. If an area is facing desertification,
what are some things people could
do to possibly limit its effects?
____________________________
____________________________
Fig. 4 Conserving Land and Soil pg. 257
Land Reclamation
These pictures show land before and after it was mined. Write a story about what
happened to the land.
Deforestation pg. 258,259
2 Human processes that are changing
Earth’s environment greatly:
Deforestation
urbanization
r. D & U
Deforestation, the cutting down of
woodlands, affects soil, the flow of water,
biodiversity and Earth’s climate.
Urbanization, the development of land to
support people moving to cities, impacts land,
air, and water. It decreases the amount of land
available for farming, wildlife, and flood control
and increases pollution of air and water
.
Fig. 5 Conserving Land and Soil pg. 259
Costs and Benefits of Urbanization
Identify what are the costs and benefits of urbanization?
Assess your Und.