Soil provides…

nutrients for plant growth.

Soil comes from:Rocks

MineralsDecaying Organic Matter

EROSIONis the movement of sediment and

rock to new places.

Weatheringis the breaking down of rocks to create soil. It can be caused by wind, water, ice, or living things

There are five components of soil:

• 1. Rock

• 2. Sand

• 3. Silt

• 4. Clay

• 5. Humus

• Can you match each type of soil to its picture?

RockRock is solid and made of minerals

Sand

Sand is tiny grains of worn down rock. It doesn’t hold water or have many nutrients.

Properties of Sand

• Color: white, tan, darker brown, an assortment

• Texture: gritty, coarse

• Capacity to retain water: water drains through sand quickly

• Ability to support plants: sand is not a fertile soil

Silt

Silt is very small, broken pieces of rock. It is larger than clay, but smaller than sand.

It is powdery when dry.Sand ------------Silt---------------Clay

(larger particles) (smaller particles)

Properties of Silt

• Color: rich dark brown

• Texture: larger than clay, but smaller than sand; smooth and slippery when wet

• Capacity to retain water: retains water well

• Ability to support plants: fertile for plants

CLAYClay holds water well. It is sticky and can be

shaped when it is wet. But, it is very hard when dry.

Clay has many nutrients.

Clay is used for adobe or brick houses.

Properties of Clay

• Color: shades of gray• Texture: sticky and plastic-like when wet;

spreads into ribbons when squeezed; very fine texture

• Capacity to retain water: holds too much water, becomes water-logged & drowns plants

• Ability to support plants: not a fertile soil for plants

HumusHumus is made of leaves, twigs, small animals, or other decayed substances.

Humus adds many nutrients to the soil.

Humus is in the topsoil.

Note: clays are microscopic in size !

Formation of soils over time…

Oldest Layers

Youngest Layers

4 Layers of Soil

1. Undecayed Layer (The layer that contains the humus)

2. Topsoil (The layer on TOP)

3. Subsoil (The prefix SUB means under)

4. Bedrock (It’s hard as rock down there!)

Undecayed

Layer

Oldest layers

Youngest layers

Natural Resources

• Made by NATURE

• Cannot be replaced

• Must be conserved (saved)! When soil is left without anything holding

it down, it can easily be

washed away by erosion!

Ways to Conserve Soil

• Plant trees

• Plant grass

• Healthy farming

• Plant gardens to grow crops

• What else can you do to conserve soil?

The plant’s roots hold the soil in place. This prevents water erosion!