weathering and soil formation chapter 6. warm-up #1 the breaking down of rocks and other materials...
TRANSCRIPT
weathering and erosion
• Weathering – the process that breaks down rock and other substances at the Earth’s surface.
• Erosion – forces of erosion carry the pieces away…..weathering and erosion work together to break down and carry away rocks on Earth’s surface.
MECHANICAL WEATHERING
• Mechanical weathering – weathering where the rock is broken into smaller pieces….each piece is still the same composition….mechanical weathering is a slow process
EXAMPLES
• Freezing and thawing, release of pressure, plant growth, actions of animals, abrasion
• Abrasion – grinding away of rocks by rock particles carried away by wind, water, ice, or gravity
• Ice wedging – water seeps into cracks – expands when it freezes – ice is like a wedge that breaks the rock apart
Chemical weathering
• Process that breaks down rock through chemical changes………..causes are the action of water, oxygen, carbon dioxide, living organisms, and acid rain.
VOCABULARY
• Oxidation – when iron combines with oxygen in the presence of water………….rust
• Permeable – rock that is full of tiny holes…allows water to seep through easily….permeable rocks will weather quickly when exposed to chemical weathering.
VOCABULARY
• Soil – loose weathered material on Earth’s surface where plants can grow• Bedrock – solid layer of rock below
the soil• Humus – decayed organic material in
soil
VOCABULARY
• Fertility – measure of how well the soil supports plant growth• Loam – soil made up of equal parts
of sand, clay and silt• Soil horizon – is how the soil
develops into layers ………the layers differ in color and texture
WARM-UP #11
• The movement of rock pieces and other materials on Earth’s surface is called ____________________________.
WARM-UP#12
• The kind of weathering that breaks rocks into smaller pieces is _____________weathering.
TOPSOIL AND SUBSOIL
• Topsoil – is horizon A ….crumbly, dark brown soil that is a mixture of humus, clay and other mixtures• Subsoil – is horizon B….clay and
other particles washed down from horizon A…little humus
LITTER AND DECOMPOSERS
• Litter – is what is left of the plant before it adds to humus…..leaves, roots, and the plant itself when it dies.• Decomposers – organisms that break
down the remains of dead organisms into smaller pieces and digest them with chemicals.
WARM-UP#13
• The scraping of rock by wind-blown pieces of rock is called __________________________.
VOCABULARY
• Sod – thick masses of tough roots at the surface of the soil……..keeps the soil in place and held onto moisture.• Natural resource – anything in
the environment that humans use
VOCABULARY
• Dust Bowl – ruined farmland on Oklahoma and parts of the surrounding states…..caused by years of droughts and lots of plowing tuned the top soil to dust and it blew away.• Soil Conservation – management of
the soil to prevent it’s destruction.
PLOWING
• Contour Plowing – plow the fields along the curve of the slope….slows runoff and preserves the soil from erosion.
• Conservation Plowing – disturb the plant cover and soil as little as possible…dead weeds and stalks are left in the ground to help return soil nutrients.
CROP ROTATION
• Farmers plant different crops in the field each year………helps maintain the nutrients in the soil