Earth Science Chapter 8 – Weathering And Soil Formation

Earth Science Chapter 8 – Weathering and Soil Formation

Weathering – _____  Includes heat, cold, water, ice, and gasses in the atmosphere (oxygen and carbon dioxide)  Can be seen anywhere there is rock  2 types _____ and _____  weathering is a slow process Erosion – _____  Weathering and erosion work together to wear down and carry away the rocks at Earth’s surface  Uniformitarianism – _____ The same processes that we see today are the ones at work millions of years ago that formed rocks, mountains, valleys, etc that we see now.

Mechanical Weathering  Rock _____  Pieces have the same composition as the rocks they came from  Freezing and thawing (water gets in cracks, expands as it freezes, and makes the cracks bigger) called _____  Abrasion – _____ (think of sand at the beach wearing grinding on your feet in the water)  Release of pressure –_____  Animal actions – moles, etc that burrow break rocks apart  Plant growth – _____

Chemical Weathering  process that _____  can produce new minerals as it breaks down rock  creates holes or soft spots so it can break apart more easily  water – _____  oxygen – iron combines with oxygen in the presence of water in the process called _____, creating _____  carbon dioxide – _____  living organisms – plant roots produce _____  acid rain – _____

Rate of weathering  type of rock – rocks made of minerals that dissolve easily in water weather quickly  permeable – _____ weathers chemically quickly because holes _____  climate – weathering occurs faster in _____ climates  human activities are also important (creating acid rain…) Soil – _____. It is a mixture of _____.  Bedrock – _____. Once exposed to the elements, it weathers into small particles that are the basic ingredient of soil.  Humus – _____, helps create spaces in soil for air and water plants need  Fertility of soil is measure of how well the soil supports plant growth. Lots of humus = high fertility. Soil Texture  Depends on _____  Clay, silt, sand, gravel small to large  Loam – _____ Soil Formation  Soil formation is always occurring, takes a long time  Soil horizon – layer of soil that differs in color and texture from the layers around it  A horizon – _____  B horizon – _____  C horizon – _____  Bedrock Soil types  Based on climate, plants, and soil composition  Tundra, northern forest, prairie, mountain, southern forest, desert, tropical Organisms  Litter – _____  Decomposers – _____  Worms and burrowing mammals _____

How do we keep soil in place, preventing erosion from moving it? Sod – _____ Natural resource – anything in the environment that humans use, including soil

Causes of damage and loss  Overuse by 1 crop takes out nutrients  Wind and water take topsoil away if no plant cover

Conservation  Contour farming/step or terrace farming – _____  Conservation plowing – _____  Crop rotation – _____  Step farming – _____