Conserving Land and Soil
Conserving Land and Soil
• Less than a 1/4 of Earth's surface is dry land.
1.Except for the small amount added when
volcanoes erupt, new land cannot be
created.
2.All the people on Earth must share this
limited amount of land to…
– Produce their food
– Build shelter
– Obtain other resources
• Land is a precious resource!
Types of Land Use
• People use land
in many ways.
3. Three uses
that change
the land are
agriculture,
development,
and mining.
• There are many
other types of
land use
Agriculture
4. Since land is the source of most food,
agriculture is an important land use.
• New farmland must be created by clearing
forests, draining wetlands, and irrigating
deserts.
Development
• A type of land use that changes the land
even more than agriculture is development.
5.Development is the construction of
homes, stores, office buildings, roads,
bridges, and other structures.
• The process continues as what?...
6.Population grows.
7.Development not only reduces the
amount of farmland, but can also destroy
wildlife habitats.
Mining
• Mining changes the land as mineral resources
such as iron, copper, and coal are removed.
• Once land has been mined, it is often difficult to
use the land for another purpose.
The Value of Soil
8. Soil is one of Earth's most valuable
resources because everything that lives on
land depends directly or indirectly on soil.
9. It can take hundreds of years for just a few
centimeters of soil to form.
10.The thick, fertile soil may take thousands of
years to develop.
• Fertile soil is valuable because there is a
limited supply.
• Less than one eighth of the land on Earth has
soils that are well suited for farming.
Soil Damage and Loss
11.Soil is one of Earth's most important
resources.
12.But soil can be lost or damaged.
– It can become exhausted.
– Lose its fertility
– Polluted by human activities such as mining
or chemical spills.
– It can be lost to erosion by water and wind.
Soil Damage and Loss
Soil Conservation
13.Soil conservation is the management
of soil to prevent its destruction.
14.Ways that soil can be conserved
include
– Contour plowing
– Conservation plowing
– Leaving the soil to lie fallow
– Crop rotation