SNC 1D
Ecosystems & Soil
All life depends on soil. Terrestrial plants need it for nutrients, minerals and support. Without terrestrial
plants, all land based food webs would collapse. So, soil is as important to us as oxygen, or water. Health
of an ecosystem can be determined by examining the state of soil in the area.
SOIL is a mixture of small, weathered pieces of rock and decomposing
plant/animal matter. It includes all of these particles as well as the
spaces that hold air and water. The characteristics of soil depend on
the nature of the bedrock, the weather and the plants that were
established first. Soil can be examined as a series of layers, each of
which can be easily identified by its distinct colour and texture.
Litter – top layer composed of partially decomposed
leaves and grasses. Maintains the temperature of the
soil and reduces H2O evaporation
Topsoil – consists of small rocks mixed with HUMUS
(black soil rich with minerals and nutrients). Filled with
oxygen and water for microbes, and best suited for
plant growth.
Subsoil – consists of more rocks and small organic
matter. It is lighter in colour (no humus) and contains
large amounts of aluminum, iron and phosphorus.
Bedrock – final layer of soil, consisting of large
masses of rocks.
Soil Types
Loam Soil
- various sizes of rock particles
- large pockets that hold air or water
- lots of humus; plants grow well (most fertile)
Clay Soil
- particles are extremely small
- packed tightly together (no air pockets)
- poor drainage & limited plant growth
Sandy Soil
- composed of sand particles
- large pockets allow water to drain nutrients away
- low plant fertility
SNC 1D
Ecosystems & Soil
All life depends on soil. Terrestrial plants need it for nutrients, minerals and support. Without terrestrial
plants, all land based food webs would collapse. So, soil is as important to us as oxygen, or water. Health
of an ecosystem can be determined by examining the state of soil in the area.
SOIL is ________________________________________________
______________________________________________________.
It includes all of these particles as well as the spaces that hold air and
water. The characteristics of soil depend on the nature of the bedrock,
the weather and the plants that were established first. Soil can be
examined as a series of layers, each of which can be easily identified
by its distinct colour and texture.
Litter –
Topsoil –
Subsoil –
Bedrock –
Soil Types
Loam Soil
Clay Soil
Sandy Soil
SNC 1D