soil

2. -defined as a top layer of the earth’s crust
-a mixture of mineral grains, organic
materials, water, and gas.
- Provides support and nutrients
for plant growth

3.  Thin layer of loose, unconsolidated, weathered
material that overlies bedrock.
 Some earth scientists and engineers use the
terms regolith and soil interchangeably
 Soil scientists include soil as only the upper
layers of regolith.

4.  breaks down rocks to create soil. It can be
caused by weather, water, or living things

5.  Minerals
 Organic matter
 Water
 Air

6. Humus is made of leaves, twigs, small animals, or
other decayed substances.
Humus adds many nutrients to the soil.
Humus is in the topsoil.

7.  Clay holds water well. It is sticky and can be
shaped when it is wet. But, it is very hard
when dry.
Clay is used for adobe or brick houses.

8.  Silt is very small, broken pieces of rock. It is
larger than clay, but smaller than sand. It is
powdery when dry.

9.  -most fertile soil
 mixture specially rich in sand and silt with
generous amounts of organic matter

10.  Sand is tiny grains of worn down rock. It
doesn’t hold water or have many nutrients.

12.  Parent rock
 Climate
 Rates of plant growth and decay
 Slope aspect and steepness
 Time
 Transport of soil materials