Soil Is Mostly Not Made of Rock
Soil is the upper layer of earth where plants grow. Nearly half of it is empty space.
Soil is the upper layer of earth in which plants grow. Its composition surprises people: a healthy soil is roughly 45 percent mineral particles, 5 percent organic matter and about 50 percent pore space filled with air and water. Half of soil is gaps, and that emptiness is what lets roots breathe and water move. Compacting it kills crops as surely as drought. A separate verb *soil*, to make dirty, comes from Latin *suculus*, a little pig, through the idea of wallowing.
- Earth for growing. *Rich soil.*
- A country. *Native soil.*
- To make dirty. *Soiled clothes.*
- Topsoil. *Topsoil.*
- Old French — *soil*, ground. *The source.*
Word forms
| Form | Word | Example |
|---|---|---|
| Noun | soil | Soil. |
| Verb | soil | Soiling. |
| Adjective | soiled | Soiled. |
| Compound | topsoil | Topsoil. |
| Latin | solum | Ground. |
- The soil is heavy clay.Growing.
- Half of soil is pore space.Science.
- On foreign soil.Territory.
What soil is made of
- About 45 percent mineral particles: sand, silt and clay
- About 5 percent organic matter, living and decayed
- About 25 percent water in the pores
- About 25 percent air in the pores
- Compaction destroys the pore space and the soil with it
Old French *soil*, ground, probably from Latin *solium*, a seat, influenced by *solum*, the ground.
How much of soil is empty space?
About half. Pores filled with air and water let roots breathe and moisture move through.
Why is compacted soil bad for plants?
It destroys the pore space, so roots cannot get oxygen and water cannot drain or move.