Soil Horizon

Horizon Horizon is a side profile of the layers of soil Soil usually has 3 main layers, and one above and one below (5 total)

Soil Horizons Diagram Copy this into your notes O Horizon: LitterN A Horizon: Topsoil B Horizon: Subsoil C Horizon: Parent Material R Horizon: Bedrock

O Horizon: Litter Not really a layer of soil It’s on top of the first layer of soil Contains grass, plants, and animals

A Horizon: Topsoil 1st layer of soil Darkest layer of soil (dark brown or black) Contains humus which is decayed plants and animals The darker the soil, the more nutrients it contains

B Horizon: Subsoil 2nd layer of soil Reddish brown in color; contains a lot of clay Fewer nutrients and water Limited plant growth

C Horizon: Parent Material 3rd layer of soil Lightest in color (gray) No nutrients, animals, or plant growth Contains weathered rock and sediment

R Horizon: Bedrock Below the last layer of soil Solid rock – no soil Has not been weathered or broken down yet

Properties of Soil Texture – determined by the size of the weathered rock particles it contains Sand – largest Silt – smaller Clay - smallest Color – most come from iron content and humus Pore Space – how much air and water it can hold pH – how acidic is the soil