Soil

Soil Litter - decomposing but recognizable leaves and other organic material on the surface of the soil. Humus - the organic component of soil, decayed organisms.

Soil Topsoil - the top layer of soil, often defined as the “organic layer”. Organic and inorganic mixed Subsoil - inorganic layer beneath topsoil that contains many soluble nutrients.

Soil Moisture Organic material, humus, absorbs water and can hold onto it. Sandy soil drains quickly. Clay soil retains water. Mix of humus, sand and clay determines soil moisture characteristics.

Soil Nutrients Nitrogen - necessary for making proteins Phosphorus - used in making the cell membrane of all cells Potassium - in animals very important for nerve impulses

Soil Nutrients How do nutrients get into a soil? From the rock or “parent material” that the soil is derived from. Fixed nitrogen Sulfur from volcanoes How could nutrients be lost from soil?