Biology / Unit 11 Bio 2577 short lesson, about 20 seconds
Soil Composition: Four Major Components
Captions available
The idea
Soil consists of four components by volume: inorganic mineral matter, organic matter called humus, and water and air together occupying roughly half of a soil's volume.
In practice
Humus, made of decaying organisms and plant matter, improves soil structure and water and nutrient retention.
Where people slip
Particle size, not nutrient content, defines sand, silt, and clay — a loam mixes all three with no dominant size.
Your place on the trail
Every lesson rests on earlier ones and opens later ones. Tap any to jump.
Unlocks
Something wrong in this lesson? Flag it · Sources for Biology