SOL 3.1 & 3.7
Soil provides support and nutrients for plant growth
EROSION is the movement of sediment and rock to new places.
Weathering breaks down rocks to create soil. It can be caused by weather, water, or living things
There are five components of soil: 1. Rock 2. Sand 3. Silt 4. Clay 5. Humus Can you match each type of soil to its picture?
Rock is solid and made of minerals
Sand Sand is tiny grains of worn down rock. It doesn’t hold water or have many nutrients.
Sand ------------Silt---------------Clay Silt is very small, broken pieces of rock. It is larger than clay, but smaller than sand. It is powdery when dry. Sand ------------Silt---------------Clay (smaller particles) (larger particles)
Clay is used for adobe or brick houses. Clay holds water well. It is sticky and can be shaped when it is wet. But, it is very hard when dry. Clay has many nutrients. Clay is used for adobe or brick houses.
Humus Humus is made of leaves, twigs, small animals, or other decayed substances. Humus adds many nutrients to the soil. Humus is in the topsoil.
Soil Composition and Texture Soil is a mixture of rock particles, minerals, decayed organic material, air, and water Humus – the decayed organic material in soil; helps create spaces in soil for air and water; rich in elements that plants need Loam – soil made up of about equal parts of clay, sand, and silt; ideal for most plants
3 Layers of Soil Topsoil (The layer on TOP) Subsoil (The prefix SUB means under) Bedrock (It’s hard as rock down there!)
Life in Soil Some soil organisms mix the soil and make spaces in it for air and water. Other soil organisms make humus, which makes soil fertile. Litter – the loose layer of dead plant leaves and stems on the surface of the soil Decomposers – organisms that break down dead organisms and digest them
Natural Resources Made by NATURE Cannot be replaced Must be conserved (saved)!
Ways to Conserve Soil Plant trees Plant grass Healthy farming Plant gardens to grow crops What else can you do to conserve soil?
Soil of North America