| A | B |
|---|
| weathering | the process that breaks down rock and other substances |
| decomposers | breakdown the remains of dead organisms into smaller pieces and digest them with chemicals |
| uniformitarianism | processes that exist today also existed in the past |
| mechanical weathering | the physical breakdown of rock particles |
| abrasion | the grinding away of rock by rock particles carried by water, wind, ice, or gravity |
| bedrock | solid layer of rock beneath the soil |
| chemical weathering | breaks down rock through chemical changes |
| oxidation | iron combines with oxygen in the presence of water causing rust |
| permeable | matter is full of tiny connected air spaces allowing water to seep through it |
| soil | loose, weathered material on earth's surface in which plants can grow |
| ice wedging | when water freezes and refreezes causing cracks in rocks to increase and eventually break |
| soil | a mixture of rock particles, minerals, decayed organic material, water and air |
| humus | the decayed organic material in soil |
| loam | equal parts of clay sand and silt |
| fertility | a measure of how well soil supports plant growth |
| soil horizon | a layer of soil that differs in color and texture from the layers abovew and below it |
| topsoil | crumbly soil made from humus, clay, and other minerals |
| subsoil | consists of clay and other particles washed down from topsoil |
| litter | a loose layer of dead plant material on the surface of soil |
| erosion | the removal of rock particles by wind, water, ice, or gravity |
| sod | the thick mass of tough roots at the surface of soil |
| natural resource | anything in the environment that humans use |
| uniformitarianism | processes that exist today also existed in the past |
| soil conservation | the management of soil to prevent its destruction |
| contour plowing | farmers plow their fields along the curves of a slope |
| conservation plowing | farmers desturb the soil and its plant cover as little as possible. |
| dust bowl | in 1930 a long drought turned soil into dust in parts of the Great Plains. |
