| A | B |
|---|
| Soil | Many plants grow in it and it provides support and nutrients for the plants. |
| Nutrients | Materials that plants and animals need to live and grow |
| Stuff in soil | Rock, clay, silt, sand, and humus |
| weather, water, and living things | These break down rocks into soil |
| Topsoil | upper soil surface layer |
| Subsoil and bedrock | layers of soil under the topsoil |
| Humus | Decayed plant and animal matter in the topsoil, adds nutrients to soil |
| Clay | Contains tiny particles of soil that hold water well and provides nutrients |
| Sand | Made up of small grains of worn-down rock, has few nutrients, and does not hold water well. |
| Silt | made up of very small broken pieces of rock. Its particles are larger than clay and smaller than sand. |
| Erosion | Water and wind carry topsoil away. Plants and trees hold soil in place and prevent it. |
| Why conserve soil? | Soil takes a long time to form from rocks. |
