Weathering & Soil Vocab. Chap 7
Weathering- mechanical or chemical surface processes that break rock into smaller and smaller pieces.
Mechanical weathering- physical processes that break rock apart without changing its chemical makeup; can be caused by ice wedging, animals, and plants.
Ice wedging- mechanical weathering processes that occur when water freezes in cracks of rocks and
expand, causing the rock to break.
Chemical weathering- occurs when chemical reactions dissolve or alter the minerals in rocks or change
them into different minerals. This type occurs at or near the earth’s surface.
Oxidation- Occurs when some Materials are exposed to Oxygen and water over time. Ex: Iron = Rust
Climate – Pattern of weather that occurs in a particular area over many years.
Soil – A mixture of weathered rock, decayed organic matter, mineral fragments, water and air. Soil can take
1000’s of years to form.
Humus – Dark colored, decayed organic matter that supplies nutrients to plants and is found mainly in
Topsoil.
Horizon – Each layer in a soil profile – Horizon A (top layer), Horizon B (middle layer), Horizon C (bottom
layer).
Soil Profile – Vertical section of soil layers, each of which is a horizon.
Litter- twigs, leaves, and other organic matter that help prevent erosion and hold water and
may eventually be changed into humus by decomposing organisms.
Leaching – Removal of minerals that have been dissolved in water.
No- Till Farming – Method for reducing soil erosion; Plant stalks are left in the field after harvesting and
the next year’s crops are planted within the stalks without plowing.
Contour Farming – Planting along the natural contours of the land to reduce soil erosion.
Terracing – Farming method used to reduce erosion on steep slopes.