Renaissance Academy
4th Grade
Immersion
Mrs. Wyatt
Miss Zhou
soil 土壤
Objective
1. I know the basic components of soil.
2. I can relate the soil components to plant growth.
4.1 Components of Soil 土壤的成分
Organic Material: living or once-living material.
Example: twig, bug, hair, pine needle, leaves, grass, roots, decaying animals, worms.
Inorganic Material: non-living material.
Example: rocks, shell, clay, sand, silt, minerals.
4.2 Soil Layers 土壤层
Humus 腐殖质
Topsoil 表层土
Subsoil 底土
Bedrock 基岩
Humus: This is the very top layer. It includes leaf litter and other decomposing organic material such as dead animals and plants.
Topsoil: It is made of both organic and inorganic material. It is where the roots of the plant grow.
Subsoil: It is made up of mostly clay and has few nutrients for plants.
Bedrock: The layer under the subsoil. Mostly solid rock.
4.3 Three Types of Soil
Sand: sand is made up of tiny fragments of rocks, does not hold water well, and has very few nutrients.
Silt: sand and soil that has been washed by water and collects at the bottom of rivers and streams is called silt.
Clay: clay is made up of tiny particles of rock and decayed plant material. It holds water well and is often sticky.