Exam 4

Question 0

Acid in terms of chemistry

Answer 0

A substance which gives off h+ ions, and is a solid

Question 1

Under what climatic condition are you likely to have more soil acidification?

Answer 1

High rainfall areas

Question 2

What does ph indicate?

Answer 2

The degree of acidity or alkalinity of the soil.

Question 3

What does ph measure in terms of chemistry?

Answer 3

The quantity of H+ ions

Question 4

What is the precise difference in H ion concentration between a soil with a ph of 4 and one with a ph of 6

Answer 4

4=10 to the 4th
6=10 to the 6th
Equals 100x difference

Question 5

How is an acid soil neutralized?

Answer 5

A base must be added

Acid+ Base = water + salt

Question 6

Name the 3 major causes for the development of soil acidity

Answer 6

Al compounds
Loss of basic cations (by leaching)
Plant removal

Question 7

Natural sources of acids

Non-natural sources of acids

Answer 7

Natural
Acid rain
OM
Clays
Oxidation of n & sulfur compounds
Release of AL from exchange sites and oxides
Non-natural
Fertilizers
Acid rain

Question 8

Discuss the connection between the release of al compounds and ph in the soil?

Answer 8

There is more H+ to be released

Question 9

Fertilizers that increase soil acidity?

Answer 9

Nitrogen and sulfur containing fertilizers

Question 10

What is the target range for most plants?

Answer 10

6.2-6.8

Question 11

Wh might a low ph be bad for plants?

Answer 11

Changes the form of nutrients which makes them unavailable to plants

Question 12

Effects of acid soils.
Microorganisms
Macronutrients
Micronutrient

Answer 12

Microorganisms-are inhibited
Macronutrience- are all reduced in availability
Micronutrients-malibdumum & boron have low availability. Copper cobalt manganese iron zinc become extra available= toxic

Question 13

What are other effects of increased al solubility in acid soils?

Answer 13

Interferes with plant development harms microbes

Question 14

What is lime?

Answer 14

Compound that neutralizes soil acidity

Question 15

2 ways lime reduces acidity?

Answer 15

Release oh negative which binds with h+

Calcium pushes h+ off cec

Question 16

Effects of over liming

Answer 16

Soil structure collapse

Question 17

5 liming materials

Answer 17

Calcium carbonate 
Calcium oxide Best
Calcium hydroxide
Dolomite
Slag 
Marl 
Ash

Question 18

Effects neutralization of lime

Answer 18

Purity

Fineness

Question 19

Indicators of liming needs

Answer 19

Ph

Base saturation

Question 20

Selection of liming material

Answer 20

Cost
Effectiveness
Nutritional value
Other nitriances
Ease of using
Water content low

Question 21

Reduce effectiveness of low ph

Answer 21

Not altering the ph
Gypsum
-reduce al
Add nutrient

Question 22

Soil characteristics effecting om

Answer 22

Cec
Whc
Soil aggregation
Nutrient supply
Microbes habitat

Question 23

What is dry matter composed of?

Answer 23

90-95% c h and o

5-10 comes from soil

Question 24

Organic compounds in soil

Answer 24

Carbohydrates*

Question 25

Decomp of om

Answer 25

1 enzyme oxidation 2 nutrients are releases 3 biomass is resistant to future degradation

Question 26

Effects of low air and cold o2

Answer 26

Will slow decomp

Question 27

4 aspects of organic residue quality

Answer 27

Composition Location Particle size C/N rationp

Question 28

C and N connected in residue

Answer 28

Microbes consume carbon but need n to do so

Question 29

C/N ratio groups

Answer 29

10/1 humus 20-30/1sufficient n in s for decomp 30/1+ n from soil is required for decomp

Question 30

Decomp process

Answer 30

``` Om added to soil Micobes eat Nitrate in soil drops Co2 rises C/N r drops Om is consumed microbes die co2 drops nitrate released 4-8 weeks ```

Question 31

Comprises om

Answer 31

Everything living + formerly living

Question 32

Humus

Answer 32

Compounds created from organic compounds created by microbes

Question 33

Benifits of om in soil

Answer 33

``` Release of nutrients Cec increase Better soil structure Buffer ph change (if on soil reduce erosion) ```

Question 34

Why om bad?

Answer 34

Allelopathy

Question 35

Global carbon cycle needs

Answer 35

330 kg ha yr

Question 36

Effect c in soil

Answer 36

Vegetation type Climate Texture Cultivation

Question 37

What form of n so plants prefer | What is second best?

Answer 37

Nitrate | No3- no2-

Question 38

Ultimate source of n

Answer 38

Atmosphere

Question 39

4 sources of n

Answer 39

Biological fixation Climatic Natural fertilizers Synthetic fertilizers

Question 40

N conversion of biological fixation?

Answer 40

N2-NO3

Question 41

How much does nit fix provide?

Answer 41

50-80% | rest from soil

Question 42

Free living n fixing organisms

Answer 42

Blue-green algae Azospirullium Azotobactor

Question 43

Symbiotic n fixing organization

Answer 43

Bacteria living in plant roots (legumes only)

Question 44

% of n from inorganic form?

Answer 44

2-5% of total n

Question 45

Mineralization? | Immobilization?

Answer 45

Mineralization - nitrate or no4+ | immobilization - organic *** bad

Question 46

Process of nitrification

Answer 46

NH3-NO2- -NO3- | Microbe cause reaction through activity

Question 47

Process of denitrification

Answer 47

NO3- -NO2-NO-N2O-N2 bad | Microorganisms cause reaction

Question 48

6 forms of n are connected

Answer 48

``` NH3 NO2 NO3 NO N2O N2 ```

Question 49

What causes change in forms of n to occur?

Answer 49

Microbes activity

Question 50

Use of sulfur in plants

Answer 50

Enzyme and vitamin production | Part of photosynthesis

Question 51

How sulfur enter plant? What chemical form?

Answer 51

SO2 leaves | SO4- roots

Question 52

6 pools of sulfur

Answer 52

``` Organic compounds Primary minerals Elemental sulfur Clay compounds Soil solution as so4- Atmospheric ```