Rocks and Soils

Soil formation

This lesson we are going to explore what soil

is and how it is formed.

Click the above link to hear a message from Ms Green

Success criteria

We are learning to:• explain how soil is formed.

• I can state that soil is composed of different things.

• I can describe the 4 processes of soil formation.

Soil formation organic matter top soil sub soil

base rock additions losses translocations

transformations.

Key vocabulary

Keep an eye out for this key vocabulary – make a note of what they all mean as we go through and we will revisit this at the end

What is soil?

What is soil made from?

Do you know? What do you think?

Tell someone close to you what you

think soil is made from.

Go outside and find some soil –

look at it carefully, have you

changed your mind about what

it is made from?

What Is Soil Made Of?

Soil is the uppermost layer of the Earth. It is a mixture of different things.

AirSoil contains gases such as carbon dioxide, oxygen, nitrogen, methane and radon.

MineralThe minerals in soil come from finely broken down rock.

WaterAir and water fill the gaps

between particles of soil.

Organic MatterOrganic matter includes both living and decaying

animals and plants.

These are the layers of soil

Soil Formation

There are 4 main processes involved in soil formation:

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Translocations Transformations

Additions LossesThings get added to the soil

The soil is moved around

Things get removed from the soil

Things within the soil which change

Soil FormationAdditions

Rainfall adds water.

Dust adds minerals.

Animal waste adds organic matter and nutrients.

Decaying plants and animals add organic matter.

Humans add fertiliser. Fertilisers contain minerals and nutrients. Natural fertilisers are made from animal waste and organic matter. Human-made fertilisers are made from chemicals.

Photo courtesy of expansion1234 (@flickr.com) - granted under creative commons licence –

Soil FormationLosses

Water evaporates (turns into gas when hot) into the air.

Soil particles can wash away in storms.

Organic matter can turn into the gas carbon dioxide.

Nutrients and Minerals are taken up by plants and can drain into groundwater.

Photo courtesy of Walter Baxter (@geography.org.uk) - granted under creative commons licence –

Soil FormationTranslocations

Translocations are movements within the soil.

Gravity pulls water down from top to bottom.

Evaporating water draws the minerals up from the bottom to the top.

Animals living in the soil move the soil around in every direction.

Soil FormationTransformations

Transformations occur when something changes into something else.

Humus is what is left when dead leaves decompose.

Weathering causes hard rock to erode and turn into smaller and smaller pieces of rock.

Oxygen reacts with the minerals such as iron which can make the soil look a reddish, ‘rusty’ colour.

Photo courtesy of Kenneth Allen (@commons.wikimedia.org) - granted under creative commons licence –

Soil Formation – Fun Facts

All four soil formation

processes are taking place

at the same time ALL the

time!

.

Soil is formed over long

periods of time.

It takes at least 500

years to form just 2.5cm

of soil!

1 cup full of soil has

more organisms in it than

there are people on

earth!

Compost

Compost is organic matter that has been decomposed so that it can be recycled as natural fertiliser.

Many people choose to have a compost bin at home as they see it as more environmentally friendly to recycle waste food rather than throw it away.

It also means they can create their own fertiliser for soil in their garden or for plants, rather than buying it.

(@commons.wikimedia.org) - granted under creative commons licence –

Here is Ms Green’s own compost – made with a wormery – basically a layered compost heap with a LOT of worms inside!

Can you see the stages of how the food waste breaks down with the help of the worms to make compost?

Compost

You can now have a go at creating your own mini compost bin complete with worms!

You will need:

A plastic bottle, cut down with a few holes in it (round bottomed two litre bottles are best.) Thin pieces of fabric Cardboard pieces Shredded paper Fruit and vegetable scraps (cut into small pieces) Compost Small stones 5 to 6 tiger wormsScissors Plastic gloves Plant saucers Elastic bands

Make sure you wash your hands carefully after you make your compost bottle. And take great care when handling the worms

There is another version without worms in a couple of slides time if you prefer!

You can also mark the top of where your compost comes to on the side of the bottle so that you can see how much it changes.

For a version without worms see the next slide

watch this youtube clip for extra guidance

https://www.youtube.com/watch?v=kA3q07paNbE

For a version without worms:

You will need:

A clear 2ltr plastic bottle with a lid

Some garden soil- not shop bought stuff.

Some shredded paper, (not glossy stuff though)

Any of your fruit and vegetable peelings. (Not citrus and onion skin)

Some green grass clippings, hedge trimmings and leaves. Weed

pullings work too just don’t put the roots or seed heads in.

Some water

Sellotape

Sharp scissors

Permanent markers

1. First, cut around the neck of the bottle to form a wider neck hole.

2. Add a layer of garden soil to the bottom of your bottle.around 2cm – 4cm deep. This introduces the bacteria

needed to make black nutritious compost.

3. Next add a layer of peelings, anything from left over strawberries to potato peelings.

4. Add a another layer of each to your bottle.

5. Add some more soil then a layer of shredded paper.

6. Finally add another layer of soil and a layer of grass clippings or leaves. You can repeat this layering pattern

until your bottle is full.

7. Use a fine spray bottle and dampen the materials in your jar with a little water.

8. Now your bottle is ready. Tape the top of the bottle closed to keep the moisture in

9. Make a mark on the side on the bottle where the top of your bottle comes to so you can see how much it

changes.

10.Now just pop your ‘rot pot’ in a warm sunny place and let the magic begin.

In 3-6 weeks you’ll should see a big change in the contents of the bottle.

Soil formation The process by which soil is formed

organic matter The fraction of the soil that consists of plant or animal tissue which are decomposing

top soil The uppermost layer of soil, which is high in nutrients and organic matter

sub soil Subsoil is the layer of soil under the topsoil on the surface of the ground. Subsoil is

usually paler in colour than the topsoil.

base rock The rock that is underlying the other soil layers

additions The things that get added to the soil

losses The things that get removed from the soil

Translocations Movements within the soil.

transformations. Elements within the soil which change

Let’s revisit our Key vocabulary