Vocab
Weathering that breaks rock into smaller pieces without changing its chemical composition.
Mechanical Weathering
Horizon B contains a lot of humus.
False- it has clay and minerals but little humus.
Name two types of mechanical weathering.
Ice wedging, Abrasion, Plant growth, or Animal actions
This is the solid layer of rock beneath the soil.
Bedrock
Name two farming methods that prevent soil erosion today.
Contour plowing and conservation plowing
The grinding away of rock by rock particles carried by wind, water, or ice (give an example)
Abrasion (example: rocks tumbling in a river)
Soil rich in humus is usually dark.
True- Humus is made of decayed matter that darkens soil color.
Name five types of chemical weathering.
Water, Oxygen, Carbon dioxide, Living organisms, and Acid rain
This is a soil layer that differs in color and texture from the layers above or below it.
Soil Horizon
Name the 1930s soil disaster that hit the Great Plains.
The Dust Bowl
The dark organic material formed from decaying plants and animals. State why it is important to soil.
Humus- it makes soil fertile by holding nutrients and moisture.
Water is the only agent in both chemical and mechanical weathering.
False- ice wedging, oxygen, carbon dioxide, and organisms also play roles.
Compare mechanical and chemical weathering. What is one similarity and one difference?
Mechanical = physical breakdown, Chemical = chemical changes
Name the method of plowing fields along the curves of a slope and explain why it is useful.
Contour Plowing- It reduces water runoff and erosion.
What caused the Dust Bowl?
Drought and poor farming practices that removed topsoil.
The soil type made of equal parts clay, sand, and silt. State why this is the best for growing plants.
Loam- it is rich in nutrients, holds water well, and drains well.
Horizon C is made of partly weathered rock.
True- it’s the transition between bedrock and soil, providing material.
Name what type of weathering is faster in hot, wet climates and explain why.
Chemical Weathering- heat speeds reactions, water is what the reaction happens in.
This soil conservation practice leaves the soil and plants mostly undisturbed.
Conservation Plowing
Why is the Dust Bowl an example of the importance of soil conservation?
It showed how neglecting soil care leads to massive erosion and crop failure.
Organisms that break down plant and animal remains. Name three examples.
Decomposers (examples: bacteria, fungi, worms)
Chemical reactions happen faster in higher temperatures. And what does this mean for tropical regions?
True- warm, wet climates have rapid chemical weathering.
Give an example of both mechanical and chemical weathering happening to the same rock.
Ice wedging cracks the rock (mechanical) while acid rain dissolves minerals (chemical).
Name three ways animals and plants contribute to soil formation.
Plants add litter and roots; animals burrow/mix soil; decomposers recycle nutrients.
During the Dust Bowl, many farmers abandoned their land and moved west. How did this migration affect both the people who moved and the regions they moved to?
It caused severe hardship for the farmers who faced poverty, discrimination, and tough working conditions in places like California. The regions they moved to struggled with overcrowding, job competition, and strained resources.