Lab Introduction
This activity will help you visualize some of the physical properties of soils. Specifically, you will investigate:
- Texture: Texture relates the amounts of sand, silt, and clay-sized particles in a soil sample. Sandy soils are coarse-textured, and they feel gritty between your fingers. A soil made mostly of silt is medium-textured; it feels smooth like flour between your fingers. A clayey soil is fine-textured and it will feel sticky between your fingers. Most soils are a mixture of sand, silt, and clay and are a type of loam. Depending on where you live and the environmental conditions around you, your local soil may be sandy, silty, clayey, or loamy.
- Color: Color is usually a result of the soil’s parent material, though it can also derive from local environmental conditions. Red, yellow and orange colors in a soil usually indicate the presence of iron. Grey colors are sometimes associated with soils that are water-saturated for much of the year. Soils very high in organic matter are usually dark brown or black.
- Porosity and Permeability: Porosity describes the number of open spaces, or pores, between individual soil particles. Permeability describes how connected those pores are and how well water can move downward through the soil. A soil that drains water very quickly must have high porosity and permeability. On the other hand, a soil with very slow drainage (meaning that water has a hard time moving downward through it) will have low porosity and/or permeability.
You will need the following as you work through this lab:
