FINAL Flashcards

1
Q

Plants take up potassium in what form?

A

K+

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2
Q

Name the forms of potassium commonly found in soils.

A
  1. Mineral
  2. Non-exchangeable
  3. Exchangeable
  4. Solution (taken up by plants)
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3
Q

What are the relative amounts of potassium found in soil?

A

Least to greatest plant availability…

Mineral: 90 - 98% (5,000 - 25,000 ppm)
Non-exchangeable: 1 - 3% (50 - 750 ppm)
Exchangeable / Solution: 0.2 - 2% (40 - 600 ppm … 1 - 10 ppm)

Pssst! % = ppm / 10,000 !

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4
Q

Draw the K cycle!

A

Doodle time.

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5
Q

Discuss K fixation.

A
  • Micas (CEC=0 cmolc/kg) release K when introduced to water / weathering…
  • As this process continues, illite (CEC=30-50 cmolc/kg) begins to form. Particles become smaller and more K+ is released.
  • Soil ‘degrades’ into vermiculite (CEC=150 cmolc/kg) with much more available K+ than before.
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6
Q

In what clays does K fixation occur?

A

micas, vermiculite

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7
Q

In which soil situations can K leaching be a concern?

A

Only sandy soils.

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8
Q

What are the basic functions of K in a plant?

A

NOT a component of biological compounds!

Function related to ionic strength in cells… regulation of turgor pressure

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9
Q

What is the relationship between K and stomates?

A

K provides osmotic ‘pull’… opens stomates with influx of K.

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10
Q

What is the K content in plant tissue (dry matter basis)?

A

1 - 3%

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11
Q

Define organic fertilizer.

A

With C

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12
Q

Define inorganic fertilizer.

A

Without C.

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13
Q

Define soluble fertilizer.

A

Readily available for plant use.

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14
Q

Define slow release fertilizer.

A

Nutrients metered out over time…

two types!

  • physically slow-release
  • chemically slow-release
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15
Q

What’s the difference between chemically-slow and physically-slow release fertilizers?

A

Chemical composition ‘resists’ degradation.

Physical coatings prevent excessive solution.

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16
Q

Define guaranteed analysis.

A

% nutrient content and source of said nutrients.

This MUST be on the product to be considered a fertilizer (AL state law).

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17
Q

Discuss the Haber-Bosch process… what is produced? from what?

A

#

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18
Q

Formula / nutrient content of ammonium sulfate?

A

(NH4)2SO4 … 21-0-0

sometimes reported as 21-0-0-24(S)

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19
Q

Formula / nutrient content of ammonium nitrate?

A

NH4NO3

… 34-0-0

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20
Q

Nutrient content of UAN?

A

urea ammonium nitrate

… 28~32-0-0

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21
Q

Formula / nutrient content of DAP?

A

diammonium phosphate – (NH4)2HPO4

… 18-46-0

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22
Q

Formula / nutrient content of MAP?

A

monoammonium phosphate – NH4H2PO4

… 11-52-0

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23
Q

Formula / nutrient content of urea?

A

CO(NH2)2

… 46-0-0

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24
Q

What is the most widely used N source in the world?

A

Urea! (NH4+ / NH4- forming)

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25
Q

What are biurets and why do we care?

A

Chain of NH2-CO-NH2-CO… etc. Phytotoxic byproducts from manufacture of urea.

Citrus is sensitive, but generally not an issue with most crops(1.5 - 2% okay).

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26
Q

Physical state of UAN?

A

Liquid.

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27
Q

Physical state of anhydrous ammonia when transported?

A

Liquid only under pressure.

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28
Q

How is anhydrous ammonia applied?

A

Applied to surface as a gas… knifed in. Slits must close or gas escapes.

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29
Q

What are some safety issues with anhydrous ammonia?

A

Very irritating to lungs, eyes, skin. Can blow up. Used in meth manufacture.

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30
Q

Formula / nutrient content of anhydrous ammonia?

A

82-0-0 … highest N content of any fertilizer!

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31
Q

What is aqua ammonia?

A

NH3 in H2O

Usually locally made (too heavy to transport due to water content)

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32
Q

Where are ammonium chloride and ammonium bicarbonate used more?

A

Asia, esp. China

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33
Q

UF / MU stands for…

A

urea formaldehyde … shorter chain, faster release

methylene urea … longer chain, slower release

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34
Q

What makes UF / MU slow release?

A

chemically slow release … longer chains take longer to degrade!

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35
Q

How is N availability controlled in UF / MU?

A

Microbial activity

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36
Q

What is a triazone?

A

Circular MU … not a chain!

Foliar, slow-release source of N.

37
Q

Give some examples of physically slow-release fertilizers. What makes N slow release?

A

Coated with sulfur, resin, wax, or other components to SLOW degradation process.

Sulfur coat urea (SCU)
Polymer coat urea (PCU)

38
Q

Urease inhibitors slows down what process?

A

stops urease from forming… helps prevent volatilization losses!

39
Q

Nitrification inhibitors slow down what process?

A

affects enzymatic activity of Nitrosomonas…

40
Q

What are the two common nitrification inhibitors mentioned in class?

A
  • Nitrapyrin

- Dicyandiamide

41
Q

Is rock phosphate suitable to use within a cropping year? Why or why not?

A

NO. Takes a while to degrade and become available.

Rose growers

42
Q

Nutrient content of Triple Super Phosphate (TSP)?

A

0-46-0

43
Q

Nutrient content of ammonium polyphosphate (APP) … two different kinds.

A

10-34-0

11-37-0

Both are liquids!

44
Q

Formula / nutrient content of potassium chloride?

A

KCl … highly soluble

0-0-60 to 0-0-63

45
Q

Potassium chloride, aka…

A

muriate of potash (KCl)

46
Q

Formula / nutrient content of potassium sulfate?

A

K2SO4 … 0-0-50

47
Q

Formula / nutrient content of potassium magnesium sulfate?

A

“K Mag”

… 0-0-22-22(S)-11(Mg)

48
Q

Formula / nutrient content of potassium nitrate?

A

KNO3 … specialty crops

13-0-44

49
Q

Formula / nutrient content of potassium thiosulfate?

A

K2S2O3 … liquid, foliar apps

… 0-0-25-17(S)

50
Q

Formula / nutrient content of potassium carbonate?

A

K2CO3 … foliar

?

51
Q

What is the salt index, and why do we care?

A

Ratio of increase in osmotic pressure produced by fertilizer to that produced by same weight of NaNO3

52
Q

If a fertilizer has a high salt index, what damage can be done?

A

reduced germination, inhibited seedling growth, foliar burn

53
Q

Fertilizer with highest salt index?

A

Muriate of potash … KCl

54
Q

P fertilizers have high or low salt indexes?

A

Low.

55
Q

What can we do with P fertilizers that we cannot do with most N and K fertilizers?

A

Overapply without worry!

56
Q

The salt index uses which fertilizer as its comparison? (100)

A

NaNO3

57
Q

Draw the S cycle!

A

Doodle time.

58
Q

In the soil, what percentage of S is in the organic form?

A

~90%

59
Q

In which forms do plants take up S?

A

SO4 2-

60
Q

What is the role of S in plants?

A

Important in N relations… amino acid conversion to plant proteins.

61
Q

In what soil situation do sulfides exist?

A

Compacted, waterlogged soils.

62
Q

Until the Clear Air Act, how was a lot of our needed soil S applied?

A

Blanket deposition

63
Q

Formula / nutrient content of ammonium sulfate?

A

21-0-0-24S

64
Q

Is gypsum a liming source? Why or why not?

A

No! No carbonates.

65
Q

What Ca / Mg sources are used when soil pH is low?

A

Lime!

66
Q

Plants take up Ca in what form?

A

Ca2+

67
Q

Plants take up Mg in what form?

A

Mg2+

68
Q

When no lime is needed, what Ca sources are used?

A

CaSO4
Ca(NO3)2 … calcium nitrate, specialty crops
CaEDTA … synthetic chelate

69
Q

What is grass tetany?

A

specialized Mg issue… low Mg in forages -> low Mg in blood of grazing animals… twitching, staggering, nervous.

High rates of NH4+ or K+ fertilizer can depress Mg uptake.

70
Q

How do we fix grass tetany, economically?

A

Add supplement (SweetLicks)

71
Q

When no lime is needed, what Mg sources are used?

A

Epsom salts (MgSO4) … 0-0-0-13(S)-10(Mg) … rose growers.

magnesium nitrate, Langbeinite in horticulture

72
Q

Discuss examples of specialty situations where we apply micronutrients. (four)

A
  1. very sandy soils
  2. high pH *
  3. early in season with cold, wet soils *
  4. specialty crops
  • = typically together
73
Q

What is a chelate?

A

latin for ‘claw’ …

inorganic / organic structure which holds metal ions within it. Makes ion plant available.

74
Q

Is Zn deficiency an issue anywhere in the world?

A

HUGE issue in many parts of the world, but not in US.

Commonly seen in cool, wet weather, early in the season.. then disappears.

75
Q

Why do we talk about K as a nutrient for stress?

A

Related to water relations, charge balance, osmotic pressure in cells, and membrane continuity

76
Q

Factors of K availability

A
  1. clay minerals and CEC
  2. exchangeable K
  3. environment
  4. K leaching
77
Q

Why are nutrient contents (N-P2O5-K2O) reported in different forms than what plants uptake?

A

Old vestige - nutrients reported on oxide basis.

78
Q

%N in UF/MU?

A

~38%

79
Q

%N in IBDU?

A

~31%

80
Q

IBDU stands for…

A

isobutylidene diurea

81
Q

How is N availability controlled in physically slow release fertilizers?

A

Microbial activity and water content

82
Q

Most commonly applied micronutrient in turf?

A

Iron! via chelates… gives green without excess growth associated with N application

83
Q

How are chelates normally applied?

A

Foliar spray at low rates

84
Q

Plants take up Fe in what form?

A

Fe2+ or Fe3+

85
Q

Plants take up Zn in what form?

A

Zn2+

86
Q

Plants take up Cu in what form?

A

Cu2+

87
Q

Plants take up Mn in what form?

A

Mn2+

88
Q

Plants take up B in what form?

A

H3BO3+ … can be taken up as anion, but not typical.

89
Q

Plants take up Mo in what form?

A

MoO4 2-