Soil

Question 1

Soil is any solid earth material that can be removed without blasting.

This is a definition by?

Answer 1

Engineers

Question 2

Soil is a solid earth material that has been altered by physical, chemical, and organic processes such that it can support rooted plant life.

This is a definition by?

Answer 2

Scientists

Question 3

Soil involves the combination of _____, _____, ______, and ________ _________

Answer 3

rock, air, water, and organic material

Question 4

Soil Component:
disintegrated and decomposed rock

Answer 4

Mineral matter (~45%)

Question 5

Soil Component:
a complex solution containing many soluble nutrients

Answer 5

Water (~25%)

Question 6

Soil Component:
source of oxygen and carbon dioxide

Answer 6

Air (~25%)

Question 7

Soil Component:
decayed remains of plants and animals

Answer 7

Humus (Organic Matter) (~5%)

Question 8

Physical and chemical breakdown of rocks and the first step in soil development

Answer 8

Weathering

Question 9

Weathered rock is further modified by the activity of _____ _______

Answer 9

soil organisms

Question 10

Controls of Soil Formation

Answer 10

1. Parent Material
2. Slope
3. Time
4. Climate
5. Plants and Animals

Question 11

[Parent Material]
Source of the mineral matter; can either be:

Answer 11

Bedrock (residual soil)
Unconsolidated sediment (transported soil)

Question 12

[Slope]
Poorly developed soils
✓ Low moisture content
✓ Accelerated erosion

Answer 12

Steep Slope

Question 13

[Slope]
Average Soils
✓ Some drainage
✓ Less erosion

Answer 13

Gentle Slope

Question 14

[Slope]
Great Soils
✓ Good drainage
✓ Minimum erosion
✓ Sufficient infiltration of water
✓ Optimum terrain for soil development

Answer 14

Flat to undulating upland

Question 15

The longer the soil has been forming, the thicker it becomes, and the less it resembles the parent material

Answer 15

Time

Question 16

Most influential control of soil formation

Answer 16

Climate

Question 17

Temperature and precipitation

Answer 17

Climate

Question 18

Controls the type of plant and animal life

Answer 18

Climate

Question 19

Decay → organic acid = ?

Answer 19

hastens weathering

Question 20

Strong influence on the chemical and physical properties of the soil

Answer 20

Plants and Animals

Question 21

Furnish organic matter

Answer 21

Plants and Animals

Question 22

amount of organic matter present

Answer 22

Soil Fertility

Question 23

vertical cross-section from the surface down to the parent material

Answer 23

Soil Profile

Question 24

distinct layers formed in well-developed soils

Answer 24

Soil Horizons

Question 25

A well-developed soil profile indicates that the environmental conditions have been relatively stable over an extended period and that the soil is _________.

Answer 25

mature

Question 26

By contrast, some soils lack horizons. Such soils are called _________.

Answer 26

immature

Question 27

Soil development has been going on only for a short time (e.g., steep slopes).

Answer 27

immature

Question 28

[Soil Profile Development] topmost layers, where organic matter decompose forming humus

Answer 28

O horizon

Question 29

[Soil Profile Development] where seeds are grown; rich in nutrients

Answer 29

A Horizon (topsoil)

Question 30

[Soil Profile Development] eluviation layer; contains dead soil, no nutrients

Answer 30

E Horizon

Question 31

[Soil Profile Development] hard and compact; only roots of old and big plants reach this; rich in mineral deposits and clay

Answer 31

B Horizon (subsoil)

Question 32

[Soil Profile Development] weathered parent material; no plant or organic matter

Answer 32

C Horizon (regolith)

Question 33

[Soil Profile Development] unweathered parent material

Answer 33

R Horizon (bedrock)

Question 34

[Soil Particle Size] if you can see individual grains

Answer 34

Sand

Question 35

[Soil Particle Size] if you can see the grains with a 10x hand lens

Answer 35

Silt

Question 36

[Soil Particle Size] if you cannot see the grains with such a hand lens

Answer 36

Clay

Question 37

[Soil Texture] gritty

Answer 37

Sand

Question 38

[Soil Texture] feels like baking flour

Answer 38

Silt

Question 39

[Soil Texture] cohesive

Answer 39

Clay

Question 40

The Soil Texture Triangle is developed by?

Answer 40

US Dept. of Agriculture

Question 41

good for plant life due to better moisture characteristics and nutrient storage capacity in comparison to soil consisting predominantly of clay or coarse sand

Answer 41

Loam Soil

Question 42

[Soil Type] highly leached soil rich in oxides of Fe and Al; hard, nutrient poor soil

Answer 42

Laterite

Question 43

[Soil Type] rich in calcite; less fertile, low amounts of organic matter.

Answer 43

Pedocal

Question 44

[Soil Type] rich in Al clays and Fe oxides; very fertile, dark brown or black soil

Answer 44

Pedalfer

Question 45

Environmental Problems of Soils

Answer 45

* Soil Pollution * Desertification * Urbanization * Use of Off-Road Vehicles