1. WEATHERING & SOIL

2. Weathering  The chemical and physical alterations of rock and other Earth materials at or near earth’s surface, through the action of temperature changes, water, chemical agents, atmospheric gases, and organic materials  Basically, breaking down rocks into smaller pieces

3. Weathering v Erosion:  Weathering = changing/breaking of Earth materials  Erosion = transport of Earth materials  Examples?

4. Physical Weathering  The mechanical or physical breakdown of rock and other earth materials at or near earth’s surface into smaller pieces, called sediments  without a change in the mineral/chemical composition Break or crack in rock: is called a “JOINT”

7. Chemical Weathering  the processes by which chemicals, such as oxygen, acids, and water, break down rocks and other Earth materials  resulting in more stable new minerals (chemicals) CO 2 + H 2 O  HCO 3 (carbonic acid) main erosional agent!!

8. Rate and Type  Depends on four major variables (yes, write all of this) 1. Exposure – to air, water, and living things 2. Particle size – smaller particles = more surface area = greater weathering rate 3. Mineral composition – marble/limestone easily dissolves 4. Climate – warm, wet climate = more chemical cold, wet = more physical

9. SOIL  How does soil form? Top soil – decayed organic material, some sand and clay Subsoil – brown from settled iron oxides, contains clay and soluble materials Residual soil – parent material is the bedrock beneath it Transported soil – from moved materials (wind, streams) Parent material – material from which soil is formed (bedrock) Soil profile – cross-section of earth exposed by digging

10. Important Soil Layers http://www.seafriends.org.nz/enviro/soil/geosoil.htm ORGANIC CLAYS BEDROCK RESIDUAL & TRANSPORTED

11. 5 Factors that Effect Soil Composition 1 Time – soil formation takes decades, centuries, or millennia 2 Parent material – chemical and physical attributes of parent material influence properties of the soil formed from it 3 Plants and animals – earthworms and other burrowing animals mix and aerate soil, add organic matter, and speed decomposition Beetle grub, earthworm, fungi, cicada nymph, mites, snails, moles Plants add organic matter and affect a soil’s composition and structure

12. 5 Factors that Effect Soil Composition 4 Topography – hills and valleys affect exposure to sun, wind, and water. Steeper slopes promote runoff and erosion; also slows leaching, accumulation of organic matter, and formation of soil layers 5 Climate – soil forms faster in warm, wet climates. Heat speeds chemical reactions, weathering, decomposition, and growth of organisms. Moisture is required for many biological processes so it speeds weathering

13. Soil as a Resource FERTILITY DEPLETION Ability to grow plantslacking in nutrients Depends on minerals,cannot support life Organic material content, & water

14. CONSERVATION METHODS  Windbreaks – planting belts of trees along field edges  Contour farming – planting crops in rows parallel to land contours

15. CONSERVATION METHODS  Terraces – flattening sloped areas by forming terraces  Strip-cropping – alternating a crop that leaves bare ground between rows with a crop that covers the ground  No-till farming – doing planting, fertilization, and weed control at the same time