| crystal | | characteristic of a material full of tiny, connected air spaces that water can seep through |
| oxidation | | mixture of humus, clay, and other minerals that forms the crumbly, topmost layer of soil |
| soil | | natural inorganic solid with a crystal structure and definite chemical composition |
| ore | | dark-colored organic material in soil |
| sediment | | chemical and physical processes that break down rock at Earth's surface |
| smelting | | type of weathering in which rock os physically broken into smaller pieces |
| fertility | | plowing fields along the curves of a slope to prevent soil loss |
| basic | | area of the Great Plains where wind erosion caused soil loss during the 1930s |
| metamorphic rock | | word used to describe a substance that feels slippery and changes red litmus paper blue |
| conservation plowing | | natural resource that is not replaced in a useful time frame |
| permeable | | loose, weathered materials on Earth's surface in which plants can grow |
| abrasion | | process that breaks down rock through chemical changes |
| loam | | loose layer of dead plant leaves and stems on the surface of the soil |
| humus | | process that splits rock when water seeps into cracks, then freezes and expands |
| nonrenewable resource | | measure of how well soil supports plant growth |
| chemical weathering | | anything in the environment that humans use |
| sod | | anything in the environment that humans use |
| sedimentary rock | | planting of different crops in a field each year to maintain the soil's fertility |
| natural resource | | rock that contains a metal or useful mineral |
| litter | | type of rock that forms from the cooling of molten rock at or below the surface |
| decomposer | | thick mass of grass roots and soil |
| soil horizon | | rich, fertile soil that is made up of about equal parts of clay, sand, and silt |
| natural resources | | series of processes on the surface and inside Earth that slowly changes rocks from one kind to another |
| mineral | | describes a substance that reacts strongly with metals and changes blue litmus paper red |
| weathering | | geologic principle that the same geologic processes that operate today operated in the past to change Earth's surface |
| topsoil | | small, solid pieces of materials from rocks or organisms; earth materials deposited by erosion |
| contour plowing | | management og soil to prevent its destruction |
| uniformitarianism | | layer of soil that differs in color and texture from the layers above or below it |
| bedrock | | grinding away of rock by other rock particles carried in water, ice, or wind |
| erosion | | solid rock beneath the soil |
| Dust Bowl | | process by which water, ice, wind, or gravity moves weathered rock or soil |
| igneous rock | | solid in which the atoms are arranged in a pattern that repeats again and again |
| ice wedging | | type of rock that forms when particles from other rocks or the remains of plants and anumals are pressed and cemeted together |
| subsoil | | rock that forms when a rock is changed by heat, pressure, or chemical reactions |
| rock cycle | | process by which ore is melted to seperate the useful metal from other elements |
| soil conservation | | soil conservation method in which the dead stalks from the previous year's crop are left in the ground to hold the soil in place |
| crop rotation | | organism that breaks down wastes and dead organisms |
| mechanical weathering | | layer of soil beneath the topsoil |
| acidic | | chemical change in which a substance combines with oxygen |
