Weathering and Soil Test Study Guide Ali White Core1

1-5 0 The process that breaks down rocks into smaller and smaller pieces is called weathering. 0 Mechanical weathering is the break up of rocks by physical forces that doesn’t change the rock. 0 Mechanical weathering includes: ice wedging, pressure release, plant root growth, abrasion 0 Chemical weathering occurs more in a wet-tropical climate. 0 Mechanical weathering occurs more in

6-9 0 Ice wedging is when water seeps into cracks in rocks then freezes and expands. 0 Chemical weathering is the breakdown of rocks by chemical reactions that change the rock’s composition and make-up 0 How fast a rock weathers depends on surface area, rock composition, and location, climate. 0 Abrasion is the process of wearing down rocks by friction

What causes exfoliation or onion skin weathering? Pressure release 0 Humus is the decayed organic matter in soil that gives nutrients to plants. 0 What can humus contain? Decayed organic matter 0 When do rock fragments become soil? When plants and animals live in them.

Give some things that effect soil formation: the kind of rock in an area, the area’s climate or overall weather pattern, the landforms in an area, animals and other organism, and time 0 What is litter? Any organic matter 0 Describe the A horizon: called topsoil, seeds germinate and plant roots grow in it, made up of humus mixed with mineral particles.

Describe the C horizon: regolith; slightly broken bedrock, plant roots don’t penetrate, very little organic matter found in this layer, the most weathering occurs. 0 Most soils are a mixture of sand, silt, and clay 0 Tell the 3 main types of soil and their sizes: sand: largest, silt: to small to see without a microscope, clay: smallest

Give some properties that soil has: texture, color, pore space, and chemistry. 0 When farmers change the crops that they grow in a field each year it is called crop rotation. 0 When farmers reduce the number of times he tills and plows his field he is practicing the conservation technique called conservation tillage.

Farming leads to soil loss-true/farming has harmful effects on the environment-true/farms are important because they provide food for the world’s people-true 0 Cows and sheep overgraze near dry regions of the world, causing the size of the deserts to increase. This process is called desertification. 0 What are some conservation practices used by farmers to reduce soil loss? Crop rotation, conservation tillage, terraces, contour plowing, and windbreaks.

Soil Profile

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