Soil isn't just dirt! It is born when parent rock breaks down and dead plants and animals decay — a process that can take hundreds of years.
🪜Looking Inside the Soil
A soil profile, top to bottom
Topsoil — dark, humus-rich layer where most plant roots grow.
Subsoil — minerals & clay wash down here; less humus.
Bedrock — solid, unweathered parent rock at the bottom.
What is soil made of?
🪨Rock & minerals Tiny bits of weathered parent rock.
🍂Humus Decayed plants & animals; rich in nutrients.
💧Water Fills tiny spaces; roots drink it up.
🫧Air In the gaps so roots & bugs can breathe.
⛏️How Soil Forms (Very Slowly!)
Weathering
Rock breaks into smaller pieces.
→
Erosion
Water & wind move the pieces.
→
Deposition
Pieces settle & build new soil.
🐛 It can take 500+ years to make 1 inch!
Tiny decomposers — worms, fungi, and bacteria — break dead plants and animals into humus, slowly turning broken rock into living soil.
🔑Key Terms
🌱SoilA loose mix of rock fragments, organic matter, water, and air.
🪨Parent RockThe rock that breaks down to form a soil's mineral pieces.
🍂HumusDark, decayed organic matter that makes soil rich.
🧱WeatheringThe breaking down of rock into smaller pieces.
🌊ErosionThe MOVEMENT of weathered rock & soil by water, wind, or ice.
🤝StewardshipResponsibly managing resources — like protecting soil from erosion.
⭐Remember: soil forms slowly as parent rock weathers and humus builds up — but erosion can wash it away fast, so we must protect it with good stewardship!