| A | B |
|---|
| Weathering | The chemcial and physical processess that break down rock at Earth's surface. |
| Mechanical Weathering | The type of weathering in which rock is physically broken into smaller pieces. |
| Chemical Weathering | The process that breaks down rock through chemical changes. |
| Bedrock | The solid layer of rock beneath the soil. |
| Litter | The loose layer of dead plant leaves and stems on the surface of the soil. |
| Humus | Dark-colored organic material in soil. |
| Soil | The loose, weatherd material on Earth's surface in which plants can grow. |
| Soil Horizon | A layer of soil that differs in colr and texture from the layers above or below it. |
| Conservation Plowing | Soil conservation method in which the dead stalks are left in the ground to hold the solid in place. |
| Soil Conservation | The management of soil to prevent its destruction. |
| Crop Rotation | The planting of different crops in a field each year. |
| Contour Plowing | Plowing fields along the curves of a slope to prevent soil loss. |
| decomposers | An organism that breaks down wastes and dead organisms. |
| desertification | The advance of desertlike conditions into areas that previously were fertile. |
| Dust Bowl | The area of the Great Plains where wind erosion caused soil loss during the 1930s. |
| land reclamation | The process of restoring land to a more natural state. |
| topsoil | Mixture of humus, clay, and other minerals that forms the crumbly, topmost layer of soil. |
