Soil is A loose mixture of small minerals and rock fragments, organic material, water, and air.

What’s in soil?

Soil The kind of soil in an area is determined by: Parent rock or bedrock Climate of region

Soil properties 1. Texture (grain size) Gravel Sand Silt Clay Each has advantages and disadvantages so its best with a mixture.

2. Structure- how evenly mixed the nutrients &textures are 3. Fertility- how much nutrients are in the soil, how good it is for growing.

Soil forms very slowly but it will eventually form layers Litter Humus rich (Topsoil) Clay & mineral rich (Subsoil) Weathered rock Bed or Parent Rock

Soil is important because:

How soil is made The solid bedrock is weathered by acids from water and living things mainly into smaller pieces...

Over time this forms the C horizon, a layer of weathered rock. Eventually enough poor soil builds up that simple plants and animals move into the area.

Weathering continues to make the rock fragments smaller and smaller As living things die they add humus to the soil.

As humus is mixed with the poor soil the A horizon forms. Then larger plants and animals can move in further adding to the litter and humus. Rain water helps the B horizon separate out.

The role of organisms and decomposers mix it making room for water and air. Make humus from litter (mostly Fungi Bacteria, and worms)