What’s in the soil?. And why is it important?. Sand. Drains well but can not hold onto nutrients. Sand is a large particle. Form lightweight, free-draining soils. Sand is an important part of the soil because it provides drainage. Silt.
And why is it important?
decaying animals and plants, and waste from animals.
Living Organisms (Biota)
Soil scientists use the capital letters O, A, B, C, and E to identify horizons (layers). Most soils have three major horizons -- the surface horizon (A), the subsoil (B), and the substratum (C). The letter E is used for subsurface horizons that have a significant loss of minerals.
Soil horizons show different properties of soil such as color, texture, structure, and thickness.