The Ground Beneath Our Feet · The Ground Beneath Our Feet S6E5. Obtain, evaluate, and communicate information to show how Earth’s surface is formed. d. Ask questions to identify

The Ground Beneath Our Feet

S6E5. Obtain, evaluate, and communicate information to

show how Earth’s surface is formed.d. Ask questions to identify types of weathering, agents of erosion and transportation, and environments of deposition. (Clarification

statement: Environments of deposition include deltas, barrier islands, beaches, marshes, and rivers.)

h. Plan and carry out an investigation to provide evidence

that soil is composed of layers of weathered rocks and

decomposed organic material.S6E6. Obtain, evaluate, and communicate information about the uses and

conservation of various natural resources and how they impact the Earth.

b. Design and evaluate solutions for sustaining the quality and supply of

natural resources such as water, soil, and air.

Directions

•Read each slide. Some slides are just facts, look

for the bold and

underlined words to complete the notes

Precious Soil

You step on it. You stomp on it. You walk all

over it. Soil doesn’t seem very precious. But

it is. Without soil, which is a mixture of

weathered rock and humus, there would be

no plants. Without plants, we would have no

food to eat and no oxygen to breathe. Soil is

very precious to our way of living. Some

people spend their entire careers studying

soil.

• Why don’t you give it a try?

Explain this quote after you

complete the notes

“The nation that destroys

its soil, destroys itself.”

What Is Soil Made Of?

Start Here (Copy on chart)

How is soil formed???Soil is a MIXTURE of

•weathered rock/mineral pieces

•organic material (decayed plants and

animals—thanks to fungus, lichen & bacteria)

(called HUMUS)

•water and air

•. It may take hundreds to thousands

of years for one inch of soil to form.• soil is NONrenewable because it takes thousands

of years to make

Read this: Soil begins to form

when bedrock is broken apart

into small pieces of minerals

(rock). The agents rain, ice,

wind, freezing, and thawing can

do this breaking. Chemical

changes can do this , to rock.

continue reading: Plants and animals that

live in small rock pieces help break

apart rocks. As plant roots grow down,

they pry apart rocks. Burrowing

animals, such as earthworms and ants,

create tunnels between rock pieces.

Some of these tunnels fill with air and

water. Water expands as it freezes,

further breaking apart the rocks.

Read: How Soil Forms

Humus becomes mixed with the rock pieces. Finally, a material that can be called soil is produced. Soil is a mixture of tiny rock particles, minerals, humus, water, and air. Soil takes a long time to form. It may take hundreds to thousands of years for one inch of soil to form. So it’s nonrenewable), so it needs to be protected (conserved)

Bacteria and fungi also help create soil. They

decompose dead plants and animals for energy.

The leftover plant and animal matter is called

humus.

SOIL Texture• Definition: the soil quality that is based on the

proportions of soil particles.

• Affects the soil’s consistency

– The soil’s ability to be worked and broken up for

farming

• Influences infiltration

– Ability of water to move through the soil

– Also known as percolationLargest particle

Smallest particle

Soil Properties: Soil Structure

O Definition: the arrangement of soil

particles

O Often one type of soil particles will clump

in one area, which can block the flow of

water through the soil affecting soil

moisture.

Soil Properties: Soil FertilityODefinition: Soil’s ability to hold

nutrients and to supply nutrientsto a plant

OSoils vary in the amount of

nutrients it contains. Plants need

nutrients (such as IRON) to

grow.

Soil Properties: Soil pHO Soils can be acidic or basic pH scale

O Used to measure how acidic or basic a soil is and

ranges from 0 to 14.O The midpoint 7 is neutral. Above 7= basic. Below 7=

acidic.

O The pH of a soil influences how nutrients

dissolve in the soil.

Types of Soil

O Sorted by their properties:

~Texture or size of particle

~Structure or arrangement of

particle

~Fertility or ability to hold

and supply nutrients

Loam is soil — best rich soil — that is a mix

of sand, clay, and various organic materials.

Food for thought:

Explain this cartoon!

The importance of soil

• Soil provides minerals and other

nutrients for plants.

• All animals get their energy from

plants, either by eating plants or by

eating animals that have eaten

plants.

• Soil stores water for plant use

• Soil also prevents water run off

Soils develop as a result of the interplay of 5 factors; Parent material,

climate, organisms, relief and time.

Parent material

Organisms: vegetation,

fauna and soil biota

Relief (landforms and

topography)

ClimateTime

Soil Forming Factors

SOIL

FORMING

FACTORS

Parent Material

This is the material from which the soil has

developed and can vary from solid rock to

deposits like alluvium and boulder clay. It has

been defined as ‘the initial state of the soil

system’.

Jenny H (1941) Factors of soil formation. McGraw-

Hill Book Co Inc pp281.

The parent material can

influence the soil in a number of ways:

• color

• texture

• structure

• mineral composition

• permeability/drainage

This soil has developed on Old Red Sandstone and

so has derived its distinctive color from its parent

material.

Climate

This is probably the most important factor

(soils produced from the same parent

material under different climates contrast).

Climate governs the rate and type of soil

formation and is also the main determinant

of vegetation distribution.

Soil climate has two major components;

moisture (precipitation) and temperature,

influencing evaporation. When precipitation

exceeds evaporation, leaching of the soil will

occur.

Temperature determines the rate of

reactions; chemical and biological decay and

so has an influence on weathering and

humification.

Organisms : vegetation, fauna and soilmicrobes

Organisms influencing soil development range form

microscopic bacteria to large animals including man. Micro

organisms such as bacteria and fungi assist in the

decomposition of plant litter. This litter is mixed into the soil

by macro organisms (soil animals) such as worms and

beetles.

Soil horizons are less distinct when there is much soil

organism activity.

Higher plants influence the soil

in many ways. The nature of the soil

humus is determined by the vegetation

cover and resultant litter inputs. Roots

contribute dead roots to the soil, bind

soil particles together and can

redistribute and compress soil.

Relief (landforms and topography)

Relief is not static; it is a dynamic system (its study is called

geomorphology). Relief influences soil formation in several ways:

• It influences soil profile thickness i.e. as angle of slope

increases so does the erosion hazard

• it has an effect on climate which is also a soil forming factor

• gradient affects run-off, percolation and mass movement

• it influences aspect which creates microclimatic conditions

In this photograph soils are thin

on the glacially eroded rock

outcrops but are much deeper

on the raised beach deposits in

the foreground.

Time

This soil profile shows a recent soil inCulbin Forest which has formed on sand

overlying an ancient buried profile

Recent soil

Buried soil

Soils develop very slowly. In Britain it

takes about 400 years for 10mm of soil to

develop.

Young soils retain many of the

characteristics of the parent material.

Over time they acquire other features

resulting from the addition of organic

matter and the activity of organisms.

The soils of Britain are relatively

young because they are largely post-

glacial.

An important feature of soils is that they

pass through a number of stages as they

develop, resulting in a deep profile with

many well differentiated horizons.

Uses of soil: How do Humans (people) use the land (soil)?

• Agriculture

• Development-Construction of homes,

stores, office buildings, etc.

• Mining-Removal of iron, copper, and coal

Harm to Soil: Damage and loss

• Soil can be damaged from overuse by

poor farming techniques or by over

grazing.

• Deforestation: Cutting large masses

of trees leaving bare forest land

• Overuse– soil loses its nutrients• Overgrazing– animals eat (destroy) plants

and leave the soil bare and exposedto erosion.

DEFORESTATION

clear cutting the trees

DEFORESTATION

clear cutting the trees

WHAT ABOUT THE ANIMALS?

Where and how will they live?

pasture

pasture

Over grazing

Over grazing leads to ???

Overgrazing

SOIL POLLUTION chemicals being

carried in water from field to river

Soil Movement: Erosion

• Erosion is the process by which wind,

water or gravity transport soil and

sediment from one location to

another.

• Plant roots anchor the soil and keep

it in place

• By taking care of the plants you also

take care of the soil.

EROSION

Leaching• Wherever rainfall exceeds evaporation and

there is free downward movement of water

through the soil pore system, soluble

minerals are leached or removed from the

soil profile.

• Continual leaching tends to impoverish the

upper mineral horizons by removal of basic

cations (cations are ions having a a positive

electrical charge e.g. Ca2+).

• Leaching is most active in sandy

soils with high porosity and is least

in fine-textured soils such as clays

which have restricted pore spaces.

A soil with small soil peds or crumbs and

high porosity leading to free drainage and

active leaching

DUST BOWL wind erosion

When you are finished with your

notes go back to the soil food

diner.

Select any Dust bowl link to help

you answer the questions watch

the video clips, and look at the

images.

How do we SAVE OUR SOIL!

•Predict three ways that

soil can be conserved?