Chapter 12

Question 1

Agricultural operations can cause modifications to the C Horizon

Answer 1

False

Question 2

Soils in wet tropical regions tend to have high organic matter and distinct profiles

Answer 2

False

Question 3

Weathered rock can be a source of essential minerals for plants

Answer 3

True

Question 4

Plants with low C:N ratios decay rapidly

Answer 4

True

Question 5

Sawdust added to the soil can cause nitrogen deficiency

Answer 5

True

Question 6

Organic matter has a positive charge

Answer 6

False

Question 7

Higher earthworm populations are achieved in conventional tillage in comparison to no-till

Answer 7

False

Question 8

Plants infected with mycorrhizal fungi can absorb phosphorus better than noninflected plants

Answer 8

True

Question 9

Productive soils are densely packed

Answer 9

False

Question 10

A plant will extract water at field capacity until it reaches the permanent wilting point

Answer 10

True

Question 11

Sandy soils darin at a faster rate than clay soils

Answer 11

True

Question 12

Soils that are fertile and hold nutrients will have a low cation exchange capacity

Answer 12

False

Question 13

The pH of a soil is important because it influences the availability of plant nutrients

Answer 13

True

Question 14

Most crops grow well in soils with high salinity

Answer 14

False

Question 15

Crop yields will increase indefinitely in response to increasing fertilizer

Answer 15

False

Question 16

Synthetic fertilizers are used to provide organic matter to the soil

Answer 16

False

Question 17

Geologic erosion occurs at a faster rate than soil formation

Answer 17

False

Question 18

Erosion can leave behind less fertile subsoils

Answer 18

True

Question 19

How thick does the soil layer tend to be in agricultural regions? 
       A. 3 to 4 inches 
       B. 4 to 12 inches 
       C. 3 to 4 feet 
       D. 4 to 12 feet

Answer 19

C. 3 to 4 feet

Question 20

A vertical section through the soil extending from the surface to the unweathered rock is best described as the: 
       A. Crust
       B. Horizon 
       C. Profile 
       D.Core

Answer 20

C. Profile

Question 21

The topsoil is also known as the: 
       A. A horizon 
       B. B horizon 
       C. C horizon 
       D. O horizon

Answer 21

A. A horizon

Question 22

The subsoil is also known as the: 
       A. A horizon 
       B. B horizon 
       C. C horizon 
       D. O horizon

Answer 22

B. B horizon

Question 23

Which horizon has the highest amount of organic matter? 
       A. A horizon 
       B. B horizon 
       C. C horizon 
       D. O horizon

Answer 23

D. O horizon

Question 24

Which of the following is one of the most important soils in agriculture production? 
       A. Aridisol 
       B. Mollisol 
       C. Gelisol 
       D. Spodosol

Answer 24

B. Mollisol

Question 25

``` Which is the predominant parent material for soils? A. Igneous Rock B. Sedimentary rock C. Soil aggregation D. soil texture ```

Answer 25

D. Soil texture

Question 26

``` The fineness or coarseness of a soil is called: A. Soil field capacity B. Soil structure C. Soil aggregation D. Soil texture ```

Answer 26

D. Soil Texture

Question 27

``` Sand and silt are chemicals composed mostly of: A. Silica B. Potassium C. Aluminum D. Magnesium ```

Answer 27

A. Silica

Question 28

``` Which soil particle contributes most to pant nutrition? A. Sand B. Silt C. Clay D. Silica ```

Answer 28

C. Clay

Question 29

``` The clustering of soil particles into various shapes is called: A. Soils Field capacity B. Soil structure C. Soil Salinity D. Soil Texture ```

Answer 29

B. Soil Structure

Question 30

``` The pH range that most field crops grow best at is: A. 4-5 B. 5-6 C. 6-7 D. 7-8 ```

Answer 30

C. 6-7

Question 31

``` Which of the following is an index that rates the soils for intensive agriculture production on a 0 to 100-value scale? A. Crop Agriculture Index B. Crop Productivity Index C. Crop Parameter Index D. Crop Suitability Index ```

Answer 31

B. Crop Productivity Index

Question 32

``` One distinction between organic and inorganic fertilizers is that organic fertilizers contain: A. Carbon B. Nitrogen C. Potassium D. Lime ```

Answer 32

A. Carbon

Question 33

``` Which of the following fertilizer nutrients is NOT obtain for mining? A. Phosphorus B. Nitrogen C. Potassium D. Lime ```

Answer 33

B. Nitrogen

Question 34

``` Limestone is applied to soil to: A. Increase organic matter B. Add potassium C. Add phosphorus D. Increase soil pH ```

Answer 34

D. Increase soil pH

Question 35

The biochemically weathered uppermost portion of Earth's crust is called _______

Answer 35

Parent Material

Question 36

The layers seen within a soil profile are called ______

Answer 36

Horizons

Question 37

The number of elements essential for plant growth is _______

Answer 37

17

Question 38

_________, ___________, and _________ are three essential elements that plants can obtain from the air

Answer 38

Carbon, oxygen and hydrogen

Question 39

___________ is the portion of the soils that includes animal and plant residues

Answer 39

Organic matter

Question 40

The soil water that drains through the soils within 48 hours of irrigation or rainfall is called ____________

Answer 40

Gravitational Water

Question 41

The soil water content after drainage of gravitational water is called __________

Answer 41

Field Capacity

Question 42

The three soils particles are _______, ________ and ________

Answer 42

Sand, Silt and Clay

Question 43

The property too having beneficial qualities relating to crop plant growth is soil ________

Answer 43

Tilth

Question 44

The concentration of hydrogen ions in a soil is the ______

Answer 44

Soil Reaction (pH)

Question 45

The three terms used to describe soils salinity are ______, ________ and ________

Answer 45

saline, sadoic, and saline-sodic

Question 46

A material applied to the soil to promote plant growth is called a ________

Answer 46

Fertilizer

Question 47

Plants that are grown and plower under while green in order to provide organic mater and nutrients to the soils are known as ________

Answer 47

Green Manure

Question 48

Commercial nitrogen fertilizers are made through the _________ process

Answer 48

Habor-Bosch

Question 49

Erosion is the accelerated loss of soils through the action of ________ or _______

Answer 49

Wind or Water