Laboratory Tests for Soils

Dirt, ground, earth, and soil are remarkably useful loose stuff that forms at the interface of earth’s rocky crust and the atmosphere. The term soil is a layer of weathered, unconsolidated material on top of bedrock (a term used for rock beneath soil). Soil is a mixture of mineral particles, organic matter, chemicals, air, and water that supports life. The texture of the soil is determined by the proportions of sand, silt, and clay; the term “loam” refers to a medium-textured soil composed of sand, silt, and clay as well as organic matter. Loamy soils are usually well drained and fertile.