THE CHANGING LANDSCAPE

THE CHANGING LANDSCAPE Different types of soil

Soil is made of four parts: 1) Sand 2) Silt 3)Clay 4)Humus

THE CHANGING LANDSCAPE Sand, Silt and Clay are

inorganic.

Sand is the largest particle in the soil. When you rub it, it feels rough. This is because it has sharp edges.

THE CHANGING LANDSCAPE Sand doesn’t hold many

nutrients. Sand is good for drainage.

THE CHANGING LANDSCAPE Silt is a soil particle whose size

is between sand and clay.

Silt feels smooth and powdery. When wet it feels smooth but not sticky.

THE CHANGING LANDSCAPE Clay is the smallest of the

particles. Clay is smooth when dry and stick when wet.

Soils high in clay content are called heavy soils.

THE CHANGING LANDSCAPE Here is some red clay when its

wet.

THE CHANGING LANDSCAPE Here is some clay we use to

make pots.

THE CHANGING LANDSCAPE Clay can also hold lots of

nutrients, but doesn’t let air and water through it well.

Nutrients are food for living things.

THE CHANGING LANDSCAPE What is this?

Clay

THE CHANGING LANDSCAPE What is this?

Silt

THE CHANGING LANDSCAPE What is this?

Sand

THE CHANGING LANDSCAPE If a particle of sand was the size

of a basketball

Sand

THE CHANGING LANDSCAPE Then silt would be the size of a

baseball.

Silt

THE CHANGING LANDSCAPE And clay would be the size of a

golf ball.

Clay

THE CHANGING LANDSCAPE Which is the biggest?

THE CHANGING LANDSCAPE So which is the biggest?

THE CHANGING LANDSCAPE Humus is organic matter.

Organic means natural and made from living things.

It is made of decayed or dead plants and animals. Humus contains the most nutrients.

THE CHANGING LANDSCAPE Soil is classified by the amount

of sand, silt, clay, and humus it contains.

This is sandy soil.

THE CHANGING LANDSCAPE Sandy soil has the largest

pieces. It also has a lot of air spaces between the pieces.

THE CHANGING LANDSCAPE Sandy soils have good drainages

but they do not hold water and nutrients well.

THE CHANGING LANDSCAPE This is clay soil.

THE CHANGING LANDSCAPE Clay soil is heavy. It

has few spaces between the pieces so drainage is not good. It holds nutrients well but doesn’t allow water and air to pass through.

THE CHANGING LANDSCAPE This is Loam soil.

THE CHANGING LANDSCAPE Loam soil has a

lot of organic matter. It has a good mixture of sand, silt, clay and humus. It has good drainage and plenty of nutrients.

THE CHANGING LANDSCAPE So which soil is

the best for growing plants?

A. Sandy Soil B. Clay Soil C. Loam Soil

THE CHANGING LANDSCAPE Plants need air, water, and

nutrients from soil. Loam has all of these things so it is the best for growing plants.

THE CHANGING LANDSCAPE Some plants use humus for

nutrients. Small animals eat the plants and bigger animals eat the small animals.

Humus is an important part of the food chain.

THE CHANGING LANDSCAPE Homework: complete the

handout with a partner. Fill in the blanks using page 27, 28 and 29