| A | B |
|---|
| humus | decayed vegetation & animals |
| loam | soil containing humus, clay, and sand |
| best soil for growing plants is | loam |
| aerated soil | soil needed for healthy plants |
| what aerates soil? | micro & macro organisms |
| what are horizons | the name for layers of soil |
| "O" horizon | organic matter |
| "A" horizon | humus/sediment |
| "E" horizon | found under pine tree/acidic soil |
| "B" horizon | clay subsoil |
| "K" horizon | found in deserts |
| "C" horizon | bedrock |
| chemical agents of weathering | acid rain; carbonic acid; fire |
| physical agens of weathering | pressure; freezing rain |
| soil profile | all soil's horizons from a sample |
| what are factors contributing to soil profile? | time; mineral content of underlying bedrock; types of plants & animals in area; climate;sloped of land |
| minerals | naturally occuring, non-living substances found in earth w/ definite chemical structure |
| how many common minerals | 20 |
| how many minerals | more than 3500 |
| igneous rock | (look up) |
| sedimentary rock | (look up) |
| metamorphic rock | (look up) |
| eatth's crust | solid rock; oceanic crusts |
| mantle | rock denser than crust |
| inner mantle | soft, pliable rock |
| outer mantle | solid rock |
| outer core | liquid metal (iron and nickel) because of heat |
| inner core | solid metal because of pressure |
