Download Soil

Name: __________________
Quiz- Tuesday, November 9, 2010
Study Guide Checklist
Be able to define each of our soil vocabulary words.
Be able to explain how organisms help develop soil.
Be able to identify the correct sequence of events in which soil
forms.
Be able to identify & describe at least two farming practices that
reduce soil loss.
Be able to correctly label & describe each horizon in our soil
profile diagram. (Which layers have the most/least humus, rocks?)
For Extra Credit:
Be able to explain why soil profiles contain layers or horizons.
Be able to correctly identify & describe at least 3 organisms in
our soil ecosystem diagram.
Name: _____________________________
Date: ______________________________
Study Guide for Quiz: Tuesday, November 9, 2010
Soil Vocabulary Words:
 Soil: A mixture of weathered rock, organic matter, mineral
fragments, water, & air.
 Humus: Dark-colored, decayed organic material (plants &
animals) found in soil.
 Soil Profile: A vertical view of soil layers (horizons).
 Horizon: Layers of soil that differ in color and texture from the
layers above and below. Most areas of the Earth have 3 basic
horizons (A, B, & C).
 Leaching: Process that occurs when soil materials dissolved in
water are carried down through the soil layers.
 Bedrock: The solid layer of rock beneath the 3 major soil layers.
 Decomposers: Organisms that break down the remains of dead
plants and animals.
 Litter: The loose layer of leaves or plant remains on the ground.
 Erosion: The process by which wind, ice, water, or gravity moves
weathered rock or soil.
 Nutrients: Chemical substances in soil that plants and animals
need in order to live.
How do organisms help soils develop?
 Lichens, moss, and fungus begin to grow on the rock. As they decay,
they create humus. This additional soil allows more plants to grow.
 Animal organisms move in and their waste adds organic matter to the
soil.
 When these animal organisms decay, they add humus to soil.
 Animals also move through the soil mixing the humus with the particles
of rock.
 This movement allows spaces for air and water between the particles.
The correct sequence of events when soil forms:
1
Rock is weathered.
2
Plants grow.
3
Worms & insects move in.
4
Humus develops.
5
Humus mixes with weathered rock.
6
Soil is formed.
What farming practices reduce soil loss?
No-till Farming: The soil is not plowed each time a new planting takes place. The
roots of the previous planting continue to hold the soil in place until the next
planting.
Strip Cropping: A crop that covers the ground such as wheat is planted in strips
around crops such as corn that leave a lot of soil exposed. When crops are grown
in strips, it helps to keep the soil in place.
Planting Shelter Belts: Planting trees around the edge of fields reducing wind
erosion. When the wind hits the trees, it slows down. This reduces wind erosion.
Terracing: When planting on steep slopes, farmers create step-like terraces to
reduce erosion. These step-like terraces slow water as it is flowing down the slope.
Grazing Instead of Plowing: In very dry areas, farmers graze animals on the land
instead of plowing the soil and planting crops. Grazing reduces the need for
plowing the soil.
Soil Profile Diagram:
In a sentence or two, describe each horizon in our typical soil profile. Tell me
which layers have the most/least humus. Tell me which layers have the
most/least rock material.
Layer O:
Layer A:
Layer B:
Layer C:
EXTRA CREDIT:
Soil Ecosystem Diagram:
In the picture above, identify & describe at least 3 organisms that are
helping to create soil.
1)
2)
3)
Why do soil profiles contain layers or horizons?
 As soil evolves, layers form.
 The least evolved layer is the bottom or C horizon.
 As this gradually changes, a B horizon develops on top.
 Finally an A horizon forms above that.