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You see soil every day. But have you ever wondered exactly what
it’s made of? Here’s your chance to find out.
The recipe for onemeasuring cup—8ounces (240milliliters)—
of average soil is:
• 3.5 ounces (105 ml) of broken-up rock
• 2 ounces (60 ml) of water
• 2 ounces (60 ml) of air
• 0.5 ounces (15 ml) of
humus
—rotting bits of plants
and animals
There may not be much humus in soil. But it has an important
job to do. It’s food for lots of little creepy crawlies. Earthworms,
beetles, and centipedes live in soil. So do fungi and
bacteria
.
Even plants get nutrients from humus.
The Secrets
of Soil
