3rd Grade SOL 3.7 Soil Matchup Tools A B Soil Provides support and nutrients for the plants. Nutrients Plants and animals need these to live and grow Rock, clay, silt, sand, and humus What's in soil? 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. Soil takes a long time to form from rocks. Why conserve soil?