SOIL
The soil is the source of life,
creativity, culture, and real
independence.
David Ben Gurion (1886-1973),
Hazon VeDerek, 1951
Just What Is Soil?
 It is where life and life processes begin on
land.
 It is the material that constitutes the
outermost solid layer of our planet.
 It is a naturally-occurring mixture of
minerals, air, water and organic
ingredients.
 It is formed by the dynamics of chemical
and physical weathering.
Soil Composition
 Soil is composed of four major
components:
 Minerals or rock particles – 45%
 Water – 25%
 Air – 25%
 Organic matter such as leaves –
5%
Soil Components
Minerals 45%
Water 25%
Air 25%
Organic Matter 5%
The Soil’s Ecosystem
 Soil is a home for many
living things such as worms
and many microorganisms
that you cannot always see
with your eye.
 The soil’s ecosystem is a
source of food for the
organisms that live there.
 The soil’s ecosystem is a
protective area.
Soil Properties
 How do soils differ?
 Composition
 Texture
 Color
 Porosity – the ability to retain water
 Permeability – the ability of water to
move through the soil
 Nutrients – the ability to support
plant growth
Soil Composition
 Observing the sample with a
hand lens
 Touching the dry sample
 Rolling the moist sample
 Smearing
 Settling
Soil Texture
 The way soil “feels” is called the soil
texture.
 Soil’s texture depends on the amount of
each component and the size of its
particles:
 Sand are the largest particles and they feel
gritty
 Silt are medium-sized and they feel soft or
silky like flour
 Clay are the smallest-sized particles and they
feel sticky and hard to squeeze.
Soil Texture
 In the Classroom
 Coffee Grounds, Flour and Modeling Clay
 In the Environment
 Sand, Silt and Clay
 Dichotomous Key
 Guide to Soil Texture by Feel
Relative Size Comparison of Soil
Particles
Barrel
Sand
(feels gritty)
(2.00 - 0.05 mm, USDA)
(2.00 - 0.02 mm, ISSS)
Plate
Silt
(feels floury)
(0.05 - 0.002 mm, USDA)
(0.02 - 0.002 mm, ISSS)
Coin
Clay
(feels sticky)
(< 0.002 mm, USDA)
(< 0.002 mm, ISSS)
Soil Texture Triangle
Soil Colors
Hue
Value
 Degree of lightness
or darkness of a
color
 Black: 0/
 White: 10/
 Gray: halfway
between black and
white 5/
Water Relationship
 Porosity – the ability of soil to hold
water
 Permeability – the ability of water to
move through the soil
 Dependent on soil particle size
 The larger the particle size the more
movement
 Saturation Rate – the point where no
more water can be absorbed or
moved through the soil
Soil Provides Nutrients
 Washed down from the O and A
horizons.
 Held in the B Horizon by presence
of clay
 Absorbed by the plant’s roots to
provide food to the plants.
Soil Profile
 A soil profile is a slice of earth
several feet deep.
 By studying soil profiles, scientist
learn about the soils
characteristics and how to use
and protect it.
 Soil profiles are made up of
several layers called horizons each with their own job.
The Soil’s Horizons
 The surface layer or the O Layer is made up of
organic material like leaves and grass.
 The A horizon is a mixture of decayed organic
material and minerals.
 The B horizon is the most active layer. It is
where the nutrients and moisture is stored.
 The B horizon is also called the root horizon.
This is where plants’ roots reach out and pull
nutrients and water into the plants.
 The C horizon is the area of parent material
that helps to make the soil.
Types of Existing Bedrock – the
solid rock beneath a layer of soil
Soil is Formed by Weathering
 Physical/Mechanical:




Freezing water
Wind
Running water
Frost
 Chemical:
 Acid rain
 Minerals are
dissolved
 Biological:
 Roots of plants
 Lichen
 Burrowing and
digging by
animals and
insects
What are the ingredients???
Soil Conservation
 Apple Demonstration
 Soil Stories
 Soil Is Not Trivial
 Enviroscape
 Cookie Mining
 From Apple Cores to Healthy Soil
 Composting (Presented by Solid Waste
Management Authority)
Respect the Soil
Once you step out
onto a piece of
ground, you step out
onto something that is
alive. Soil is not just a
piece of dirt. Soil is
made up of living and
nonliving material
spread as a very thin
layer over the entire
surface of the planet
we call Earth.
OMS science teachers thank the following
for their assistance with this unit.
Summit County Educational Service Center Standards-Based Science Curriculum Includes:
Model Curriculum-Content Statement(s)
Model Curriculum-Content Elaboration Concepts
Model Curriculum-Visions Into Practice (V)
A Framework for K-12 Science Education: Practices , Crosscutting Concepts, and Core
Ideas (F) → Next Generation (Next Gen) Science Education Standards
Strategies for Teaching and Learning
•
Missi Zender-Sakach
Science Consultant
Summit County Educational Service Center
•
Sandy Barbic
Education Specialist
Summit Soil & Water Conservation District
•
Debbie Rohr
Consultant
Summit County Educational Service Center