Schimmel Soil Study Guide Soil is loose material that covers much of the Earth’s surface. Soil is made up of bits of rock, minerals, and material that was part of once living things. Soil forms when rocks are weathered. Humus Humus is decayed remains of plants and animals. Humus has lots of nutrients in it which makes it easy for plants to grow. Large amounts of humus are found in forests. Soil Layers Topsoil Top layer Plants grow best here Large amounts of humus Subsoil Bottom layer of soil Contains little humus Contains small pieces of rock Bedrock Solid unweathered rock Below the subsoil

If you had a jar full of the 3 types of soil Sandy Soil Largest particles Water passes through it easily Silt Soil Particles are smaller than sandy soil, but larger than clay soil. Clay Soil Smallest particles Water does not pass through it easily Soaks water like a sponge If you had a jar full of the 3 types of soil Sandy soil would be at the bottom because the particles are bigger and water passes through them easily. Silt would be in the middle because the particles are smaller than sandy soil but larger than clay soil. Clay soil would settle last because the particles are so small they fall very slowly. Relative soil particle sizes SAND CLAY SILT . Invisible at this scale