SOIL COMPOSITION

Soil

A thin layer of natural material formed from weathering and erosion

A vital resource

They contain nutrients for plants to grow

Most important factor in soil formation

Climate

How long does soil formation take?

400 years for 1cm

Soil Composition

Mineral Matter, Air, Water, Humus, Living Organisms

45%

Mineral Matter

25% each

Air and Water

5%

Organic Matter (Humus)

Mineral Matter consists of

Sand, silt, stones and clay

Mineral Matter is derived from

Parent rock that has been weathered and eroded

Dissolved minerals are

Absorbed by plant roots – providing nourishment

Eg. Limestone produces

Calcium-rich soil which produces calcium-rich vegetables

Air & Water are located

In the pores in soil’s mineral particles

It supplies

Oxygen and nitrogen to the soil

Humus

A dark jelly-like substance that is rich in nutrients and is key for fertility

How is humus formed?

As plant litter and dead creatures decay, they are further broken down by microorganisms

Plant litter

Plant material (leaves, twigs, needles etc) that fall to the ground

Living Organisms consists of

Living creatures such as earthworms and various bacteria