SOIL

Definitions Bedrock – Solid, un-weathered base rock Regolith – Broken up rock particles

4 Components of Soil

Rock Material in Soil Sand - Largest component (2mm – 0.06mm) Composition (parent material) = Quartz Source = Mechanical weathering

Rock Material in Soil Silt (0.06mm-0.002mm) Composition - feldspar & quartz Source - mechanical weathering

Rock Material in Soil Clay - less than 0.002mm Composition (parent material)– feldspar Source – chemical weathering

Which soil is best? Sandy Soil? Pro vs. Con Silty Soil? Clay Soil?

Soil Sizes Sand (largest) Silt Clay (smallest) Loam (mix of all 3)

Soil Texture

TAKE OUT YOUR OBJ. NOTES Pick up your papers from back

Soil Profile A cross section of soil showing the different layers (horizons) Horizons A (O) B (E) C DRAW THIS

SOIL PROFILE A- HORIZON: Organic material B-HORIZON: area where nutrients from A are “leaching” down. C-HORIZON: mostly parent bedrock, unweathered material.

SOIL HORIZONS A- horizon top soil rich in organics humus- decaying leaves B- horizon plant roots anchor here C- horizon bedrock

Tropical - Rainforest Thin A + B lots of chemical weathering, but nutrients are used quickly why?

Desert Climate thin A + B little nutrients little weathering why?

Polar soil thin A + B few nutrients little chemical weathering why???

Temperate Climate Thick A + B lots of nutrients good farmland lots of chem. + phys. weathering why?

Importance of soil Food chain Filters groundwater 1 cm = 1,000 years formation Providing resources for world to survive.