Soils exam 1

Question 0

Is reduction good for plants?

Answer 0

No

Question 1

Oxidation if pyrite produces extreme acidity and soluble iron and sulfur

Answer 1

Acid mine drainage

Question 2

What happens if Eh falls below .32 volts

Answer 2

A soil is devoid of o2 and other elements are used for microbial metabolism

Question 3

The ability if soils to bind chemical substances depends on these 3 things:

Answer 3

Chemical characteristics if substance

Characteristics if soil

Question 4

Oxygen concentration does what as soil depth increases?

Answer 4

Decreases

Question 5

Preferential or bypass flow

Answer 5

Transports chemicals to groundwater more rapidly via macro pores

Question 6

What is mass flow?

Answer 6

Physical movement if air due to fluctuations in moisture content

Question 7

What is biological 0?

Answer 7

5 degrees centigrade

Question 8

What 3 factors affect soil aeration and Eh?

Answer 8

Drainage and nacroporosity

Respiration rates

Soil heterogeneity

Question 9

What happens to microbial activity as temperature rises?

Answer 9

It doubles for every 10 degrees and dies around 50 or 60

Question 10

What can anaerobic conditions in soil lead to?

Answer 10

Production of reduced nitrogen gases, methane gases, hydrogen sulfide, ethylene

Question 11

What does water do to diffusion?

Answer 11

Slows it because it moves 10000 times slower

Question 12

What is aspect?

Answer 12

The direction of slope of a surface

Question 13

Loss of electrons in a substance

Answer 13

Oxidation

Question 14

What is albedo?

Answer 14

The fraction of sunlight reflected?

Question 15

Anaerobic decomposition can lead to…

Answer 15

Toxins

Question 16

What is the electron receptor for respiration?

Answer 16

Oxygen

Question 17

What is a veal action process?

Answer 17

Seeds needing cold treatment to germinate

Question 18

The measure in volts of how aerobic or anaerobic a system is. A measure of electrical potential of a substance to give up electrons

Answer 18

Redox potential

Question 19

What is the more important form of soil gas exchange?

Answer 19

Diffusion

Question 20

When does run off occur

Answer 20

When accumulation exceeds rare if infiltration or soil storage capacity

Question 21

What is the partial pressure gradient?

Answer 21

A difference in every potential of gas concentration

Question 22

Provides maximum opportunity for soils to bind chemicals:

Answer 22

Matrix flow

Question 23

Why does diffusion occur?

Answer 23

Concentration gradients

Question 24

What 2 things regulate o2 availability?

Answer 24

Soil macro porosity and water content

Question 25

Greatly decreases the ability if a soil to bond chemicals

Answer 25

Macropore flow

Question 26

High saturation levels does what to o2 content?

Answer 26

Lowers it

Question 27

What kinds if soils are under frequent reducing conditions?

Answer 27

Wetland soils ---> histosols

Question 28

What two ways does soul gas exchange?

Answer 28

Mass flow and diffusion

Question 29

What are concentrations of co2 like beneath the soil surface.

Answer 29

It can be 10 to 100 times greater and be toxic

Question 30

At what percentage air porosity dies microbial and root respiration cease?

Answer 30

10

Question 31

Eutrophication

Answer 31

Excess nutrients (phosphorus) that leads to excessive aquatic growth and ultimately oxygen depletion

Question 32

Material that reduces evaporation and controls weeds

Answer 32

Mulch

Question 33

Interception

Answer 33

Precipitation that never reaches soil due to vegetation

Question 34

The gain of electrons

Answer 34

Reduction

Question 35

1:1 type composed of which sheets

Answer 35

1 tetrahedra, 1 octahedral

Question 36

Tetrahedral sheet is composed of:

Answer 36

4 oxygen | 1 silicon at center

Question 37

1:1 clay type example

Answer 37

Kaolinite

Question 38

2:1 clay groups without shrinking and swelling:

Answer 38

Fine grained micas(ilites) and chlorites

Question 39

Examples of 2:1 clays

Answer 39

Smectites

Question 40

Octahedral sheet is made of which atoms

Answer 40

6 oxygen/hydroxyl | With an aluminum/magnesium at center

Question 41

Eutrophication

Answer 41

Excess nutrients (phosphorus) in fresh water leading to excessive aquatic growth and ultimately oxygen depletion

Question 42

2:1 type made if which sheets

Answer 42

2 tetrahedra, 1 octahedral

Question 43

2:1 type shrinking and swelling clay groups

Answer 43

Smectites | Vermiculites

Question 44

Important silicate clays

Answer 44

Phyllo silicates

Question 45

Difference between anions and cations

Answer 45

Anions are negative cations are positive

Question 46

What happens when a soil accepts H

Answer 46

It lowers the soils ph

Question 47

What is CEC?

Answer 47

The amount of cations a soil can contain

Question 48

If you increase CEC, what happens to plants ability to store nutrients?

Answer 48

Increases

Question 49

What 3 factors raise CEC?

Answer 49

Amount of clay Amount if organic matter Increase in soil ph

Question 50

How do soils acidify?

Answer 50

Respiration in roots and microbes creating co2 that reacts with water to create weak acids

Question 51

What is a very toxic element to plants?

Answer 51

Al3+

Question 52

What are the 3 pools of soil acidity?

Answer 52

Active acidity Exchangeable acidity Residual acidity

Question 53

What determines active acidity?

Answer 53

Ph

Question 54

What determines exchangeable acidity?

Answer 54

Cation exchange?

Question 55

What determines residual acidity?

Answer 55

Ph buffered extractent

Question 56

When do herbicides become soluble?

Answer 56

At high ph

Question 57

When do metals become soluble?

Answer 57

At low ph

Question 58

When little or no mg is in a carbonate it is

Answer 58

Calcitic

Question 59

When a carbonate has increasing amounts if mg it becomes

Answer 59

Dolomitic

Question 60

On what 4 things does a lining requirement depend?

Answer 60

Change in ph required Buffering capacity Type of lime used The fineness of lime

Question 61

What is cce?

Answer 61

The neutralizing value of lining material

Question 62

How is salinity measured?

Answer 62

Electrical conductivity

Question 63

How is sod ivory measured?

Answer 63

Exchangeable sodium percentage