The Changing Landscape. Different types of soil Soil is made of four parts: 1) Sand 2) Silt 3)Clay 4)Humus. The Changing Landscape. Sand, Silt and Clay are inorganic. Sand is the largest particle in the soil. When you rub it, it feels rough. This is because it has sharp edges. .
Silt feels smooth and powdery. When wet it feels smooth but not sticky.The Changing Landscape
Clay is the smallest of the particles. Clay is smooth when dry and stick when wet.
Soils high in clay content are called heavy soils.The Changing Landscape
Clay can also hold lots of nutrients, but doesn’t let air and water through it well.
Nutrients are food for living things.The Changing Landscape
Humus is organic matter. Organic means naturaland made from living things.
It is made of decayed or dead plants and animals. Humus contains the most nutrients.The Changing Landscape
Soil is classified by the amount of sand, silt, clay, and humus it contains.
This is sandy soil.The Changing Landscape
Sandy soil has the largest pieces. It also has a lot of air spaces between the pieces.The Changing Landscape
Sandy soils have good drainages but they do not hold water and nutrients well.The Changing Landscape
Clay soil is heavy. It has few spaces between the pieces so drainage is not good. It holds nutrients well but doesn’t allow water and air to pass through.The Changing Landscape
Loam soil has a lot of organic matter. It has a good mixture of sand, silt, clay and humus. It has good drainage and plenty of nutrients.The Changing Landscape
Plants need air, water, and nutrients from soil. Loam has all of these things so it is the best for growing plants.The Changing Landscape
Some plants use humus for nutrients. Small animals eat the plants and bigger animals eat the small animals.
Humus is an important part of the food chain.The Changing Landscape
Homework: complete the handout with a partner. Fill in the blanks using page 27, 28 and 29The Changing Landscape