GEOG 1290 Lecture Notes - Lecture 23: Clay Minerals, Soil Texture, Silt
Document Summary
Soil - the uppermost natural layer of the land surface that contains living matter and can support plants. Soil consists of matter in all three states (liquid, solid and gas) Soil varies from place to place dependent upon a variety of factors. Important as soil determines how much vegetation will grow and therefore, how much life the area can support (including humans) Parent material (mineral matter upon which the soil forms) Note: physical weathering breaks up material but chemical weathering is needed to alter mineral to make the available to plant life. Humus (partially decomposed organic matter) found at the surface and mixed into soil. Also air and water (contains dissolved substances) Soil colour (important factor to identify soil) Humus: dark brown to black e. g. , black prairie soils. Iron: red or yellow e. g. , moist tropical soils tend to be red.