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Final Soil Fertility > Plant Nutrients > Flashcards

Plant Nutrients Flashcards

1
Q

How many elements known to be essential

A

17

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2
Q

Photosynthesis

A
  • Light Energy used, H split off of water
  • H combined w/ C and O to make CO2 (diffused through leaf stomata)
  • Results in CHO + other organic _______?___________
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3
Q

Macronutrients

A

Needed to supply plant so large amounts are needed:

  • N
  • P
  • K
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4
Q

Secondary Nutrients

A
  • Ca
  • Mg
  • S
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5
Q

Micronutrients

A

Minuscule amounts needed but so critical if below amount needed then it can cause major problems:

  • B
  • Cl
  • Cu
  • Fe
  • Mn
  • Ni
  • Zn
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6
Q

Mechanisms of Nutrient Uptake

A
  • Nutrients reach root surfaces by three mechanisms
  • Absorption of Nutrients into roots
  • Absorption through leaves
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7
Q

Nutrients reach root surfaces by three mechanisms

A
  • Mass flow
  • Diffusion
  • Interception
  • all three in constant operation but shift in priority as move through growing season
  • root hairs primarily responsible for the uptake
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8
Q

Mass flow

A

movement of nutrients in water flowing towards the root

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9
Q

Diffusion

A

movement down a concentration gradient from high to low

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10
Q

Interception

A

roots explore new soil areas containing unused soil nutrients

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11
Q

Absorption of nutrients into roots

A

Mechanism not well understood (hard to see below ground)

  • Movement through cell wall easy
  • movement into cytoplasm much harder
  • nutrient must go through passageway or bond w/ carrier to get through cell membrane
  • some actively pulled into cell
  • Electrical balance also involved
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12
Q

Absorption through leaves

A

Leaf Stomata

  • Exchange of H20, )2, CO2
  • Some soluble elements can be absorbed in small amounts
    * Mostly micronutrients
    * Marcos typically need in too high quantities to foliage needs
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13
Q

Soil N gains and transformations

A
  • N is the key nutrient in plant growth management
  • Most Soil N isn’t in a form that can be absorbed
  • Unique Nutrient
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14
Q

N is the key nutrient in plant growth management

A
  • Most commonly deficient nutrient
  • controlling factor in plant growth
  • Constituent of: proteins, chlorophyll, nucleic acids
  • Plants w/ sufficient N have thinner cell walls and are more succulent plants
  • N deficiency= poor plant yields
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15
Q

Most soil N isn’t in a form that can be absorbed

A

-Most immobile in organic matter
-N2 gas in the atmosphere
-Must be fixed bu soil bacteria
first

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16
Q

Unique Nutrient

A

-Can be absorbed soluble organic form
-NH4, NO3
-Soluble, mobile, easily
leached
-can be easily denitrified by
soil microbes

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17
Q

2 forms of N available to plants

A
  • NH4

- NO3

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18
Q

N deficiency symptoms

A
  • poor
  • spindly
  • stunted growth
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19
Q

NH4 & NO3 are not necessarily interchangeable

A
  • NH4 saves the plant energy (easier for plant to use)

- NO3 is more stable in the soil

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20
Q

NH4

A

Ammonium

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21
Q

NO3

A

Nitrate

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22
Q

Fixation of N gas (N2)

A
  • Primary source of soil N
  • Taken by soil microbes, converted to NH4
  • Wide variation in how much N is fixed
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23
Q

Wide variation in how much N is fixed due to:

A
  • soil
  • fertilizers used
  • crops
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24
Q

In very productive soil and high amounts of N plants don’t have a relationship with

A

N fixing bacteria, no nodules form on the roots

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25
Q

Mineralization of N

A

-Release of N from decomposition of organic materials

-Conversion of organic N to NH4 form
-Soil OM contains ~5% N
-Only small % of OM
decomposes each year

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26
Q

Nitrification of Ammonium

A
  • oxidation of ammonium to nitrate by bacteria and other organisms
    • Rapid microbial transformation (1-2 days)
    • Most is complete w/in 1-2 weeks
  • Some absorbed, some absorbed quickly
  • Slowed by anaerobic conditions, dry, cold, toxic chemicals
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27
Q

Other Fixation reactions involving Soil N

A

immobilization

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28
Q

immobilization

A

soluble N held in plant materials or microbes

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29
Q

in immobilization N…..

A
  • is not available to plants
  • can be fixated to clay particles
  • can be consumed by decomposing microbes and held until they die
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30
Q

N losses from the system

A
  • leaching of soil N

- nitrification inhibitors

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31
Q

Leaching of soil N

A

NO3- readily leached form of N, toxic to young mammals

  • Nitrate lost due to negative charge
  • Ammonium held due to positive charge
  • leaching rates
  • losses from crop covered soils usually low
  • losses from heavily fertilized, wet soils high
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32
Q

Leaching rates _____ as _______ increase, when plant growth rates aren’t quick enough to keep up with N production

A

increase

percolation rates

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33
Q

Nitrification inhibitors

A
  • chemicals used to inhibit nitrification
  • N-Serve, DCD, ATC
    - Inhibit the first step of nitrification, slow the release of N to the soil
    • N-serve more volatile and can evaporate slowly
    • DCD, ATC stable, easy to handle, can be applied as coatings to granules
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34
Q

What effect does Nitrification inhibitors have and what options does it allow producers?

A

Completely altering ecosystem, lost of N-fixing microbes which eliminate the process to nitrify in the soil, reliant on the addition because we have eliminated natural bacteria populations from the ecosystems

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35
Q

N losses from the system

A
  • leaching of soil N
  • nitrification inhibitors
  • Gaseous losses of soil N
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36
Q

N losses from the system

A
  • leaching of soil N
  • nitrification inhibitors
  • Gaseous losses of soil N
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37
Q

Gaseous losses of soil N

A

Denitrification: change by bacteria of NH4 to N gas

  • biological process
  • can be most extensive gaseous N loss (esp. with poorly aerated/wet soils)
  • rapid process
    • substantial N loss can occur in
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38
Q

N losses from the system

A
  • leaching of soil N
  • nitrification inhibitors
  • Gaseous losses of soil N
  • Ammonia Volatilization
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39
Q

Three reasons large amounts of N lost:

A
  • lack of adequate free O in the soil
  • energy source of organic matter for the bacteria
  • Warm, slightly acidic soils
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40
Q

Ammonia Volatilization

A
  • occur when ammonium is in alkaline environment
  • chemical process
  • losses occur from surface applications of ammonium/urea (can be ~30%, normally
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41
Q

N loss is most extensive under the following conditions:

A
  • high pH, calcareous soils
  • fertilizer left on soil surface
  • high temperatures
  • Low CEC soils
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42
Q

Materials supplying N

A
  • Ammonia and Aqueous N
  • Solid fertilizers
  • Ammonium Sulfate
  • UAN
  • Organic Wastes
  • Controlled-Release N fertilizers
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43
Q

Materials supplying N

A
  • Ammonia and Aqueous N
  • Solid fertilizers
  • Ammonium Sulfate
  • UAN
  • Organic Wastes
  • Controlled-Release N fertilizers
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44
Q

Ammonia and Aqueous N: Anhydrous Ammonia (NH3)

A
  • most common N fertilizer (>90% of all N fertilizers made up of some form of ammonia)
  • 82% N
  • Manufactured from atmospheric N using natural gas to supply H (Haber process); 1st usable fertilizer product of this process, other N fertilizers require more processing
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45
Q

Ammonia and Aqueous N: Anhydrous Ammonia (NH3)

A
  • most common N fertilizer (>90% of all N fertilizers made up of some form of ammonia)
  • 82% N
  • Manufactured from atmospheric N using natural gas to supply H (Haber process); 1st usable fertilizer product of this process, other N fertilizers require more processing
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46
Q

Anhydrous Ammonia

A
  • applied w/ chisels to ~5”
  • pressured liquid in the tank, gas at atmospheric pressure
  • least expensive N fertilizer (per unit N)
  • Very dangerous to handle (burns, blindness, inhalation risks, safety precautions)
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47
Q

when using Anhydrous Ammonia

A

-keeo

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48
Q

when using Anhydrous Ammonia

A
  • keep away from flames
  • keep away from ammonia clouds
  • have water available
  • store in proper tanks, don’t overfill
  • paint tanks white to reflect heat
  • inspect tanks regularly for leaks/problems
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49
Q

Materials supplying N

A
  • Ammonia and Aqueous N
  • Solid fertilizers
  • Ammonium Sulfate
  • Organic Wastes
  • Controlled-Release N fertilizers
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50
Q

Solid fertilizers

A

Uera

Ammonium Sulfate

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51
Q

Solid fertilizers

A

Uera
Ammonium Sulfate
UNA

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52
Q

Solid fertilizers

A

Uera
Ammonium Sulfate
UNA

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53
Q

Solid fertilizers: Uera

A
  • synthetic, organic fertilizer
  • cheaper per lb than any other solid N fertilizer
  • 45% N
  • Must be converted in the soil to NH4
  • readily soluble and leachable
  • stabilized and can be stored when converted in the soil to NH4
  • Popular; cheapest solid N source, soluble in water, convenient for application in sprinkler, spray, solution
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54
Q

Solid fertilizers: Uera

A
  • synthetic, organic fertilizer
  • cheaper per lb than any other solid N fertilizer
  • 45% N
  • Must be converted in the soil to NH4
  • readily soluble and leachable
  • stabilized and can be stored when converted in the soil to NH4
  • Popular; cheapest solid N source, soluble in water, convenient for application in sprinkler, spray, solution
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55
Q

Solid fertilizers: Ammonium Sulfate

A
  • 21% N
  • high cost
  • less popular
  • commonly used in rice
  • Ammonium is all available to plant
  • sulfate keeps it from being denitrified quickly
  • Strongest acidic N fertilizer
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56
Q

Solid fertilizers: Ammonium Sulfate

A
  • 21% N
  • high cost
  • less popular
  • commonly used in rice
  • Ammonium is all available to plant
  • sulfate keeps it from being denitrified quickly
  • Strongest acidic N fertilizer
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57
Q

Solid fertilizers: UAN

A
  • Urea-Ammonium Nitrate solution

- 28% N or 32% N

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58
Q

Organic Wastes

A
  • considered controlled-release fertilizers
  • nutrient concentration is low
  • depends on decomposition rates
  • may carry undesirables (wees seed, diseases, soluble salts, etc.)
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59
Q

Controlled-Release N Fertilizers

A
  • Standard N fertilize crop use rates ~40-70% (rest is leached, denitrified etc.)
  • Slow-release N fertilizers used to control proportion of fertilizers available at one time
  • More efficient use of N means more cost saving & less pollution
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60
Q

Controlled-Release N Fertilizers

A
  • Standard N fertilize crop use rates ~40-70% (rest is leached, denitrified etc.)
  • Slow-release N fertilizers used to control proportion of fertilizers available at one time
  • More efficient use of N means more cost saving & less pollution
  • slow release N products most commonly used in turf grass
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61
Q

Controlled-Release N Fertilizers: Urea-Formaldehyde

A
  • varying rates of urea & formaldehyde (greater urea, more available N
  • Environmental conditions must favor microbe activity to release N (losses may be ~20%)
62
Q

Controlled-Release N Fertilizers: Polymer-coated N

A
  • soluble form of N (urea) diffuses through polymer membrane
  • reliable, consistent control of N release
63
Q

Soil Phosphorus

A
  • Traditionally, 2nd most prescribed nutrient in the soil (K has now passed in use)
  • Essential part of nucleoproteins in cell nuclei (carry DNA)
  • Main component of cell energy currency (ATP)
64
Q

Soil Phosphorus: Roles

A
  • cell division
  • root growth
  • plant maturation
  • energy transformation w/in cells
  • Fruit/seed production
  • Animal/human nutrition (growth of bones and teeth)
65
Q

Young plants absorb soil P readily

A
  • most critical for plants to have available P sources early in development
    • Wheat from tillering to flowering
      • corn ~3 weeks into growing season
66
Q

Problems with P

A
  • soil forms of P very low solubility
  • P applied through fertilizer often combines w/ substances to reduce solubility
  • major problem to keep P soluble and available to the plants in the soils
  • soil P doesn’t leach
67
Q

Most P supplied to plants by ________ in the soil

A

diffusion

-diffusion rares extremely slow (.02-.1mm/hr)

68
Q

The P Problem:

A
  • Mineral P
  • Phosphates in Anaerobic soils
  • Organic Soil P
69
Q

The P Problem: Mineral P

A
  • available P critical: supply P in soils is low, P in soils not readily available
  • While there is lots of P in the soil, minute fractions actually available
  • Original natural source of P: apatite (rock phosphate), along with others, these can be used as low-quality fertilizers sources
  • Soluble P often reacts w/ other soil substances to form insoluble compounds (also readily absorbs other molecules, explains soil P buildup
  • Soil P most available at pH ~6.5
70
Q

The P Problem: Phosphates in anaerobic soils

A
  • phosphates more soluble than in aerated soils
  • iron phosphates are soluble in flooded soils, less tie-up for P
  • works out well for rice growers
71
Q

The P Problem: Organic soil P

A
  • phosphates used by plant roots and some microbes to split P from organic residues-making it available for absorption
  • P in organic residues tends to be more soluble therefore, more useful to plants (may comprise >50% of soluble soil P)
  • the more favorable conditions are for microbe decomposition, > available soil P
72
Q

Managing Soil P

A
  • major pollutant of surface waters

- Mycorrihzae helps plants access soil P (fumigated soils, non-healthy microbe population soils

73
Q

P Problem

A

-~6.5 pH optimal for P availability

74
Q

Phosphate fertilizer effectiveness

A
  • most efficient use when banded (row of plants and then right next to it a row of P application)
  • only 10-30% of soil applied P is actually used
75
Q

Excess P retained in the soil

A
  • can cause Zn deficiency

- P pollution from runoff

76
Q

Maximizing P efficiency

A
  • maintain soil pH 6-7
  • Promote healthy soil organic matter content
  • Band P fertilizer for row crops, broadcast and incorporate for non-row crops
77
Q

Places supplying P

A
  • U.S is world’s largest producer (estimated our supply may run out in 20 years at current usage, most comes from FL or western US)
  • Western Africa has 6x more supply than U.S
78
Q

Materials supplying P: Phosphate ores and deposits

A
  • rock phosphate mined, ground
  • mixed w/ sulfuric acid to form superphosphate (8-9% P, 48% gypsum)
  • Mixed w/ phosphoric acid to from tripled superphosphate (20-22% O (40-45% phosphate)
79
Q

Materials supplying P: Mixed N-P fertilizers

A

-Monoammonium and Diammonium Phosphate fertilizers (apply N and P with same product)

80
Q

Soil K ranks _____ to N in plant use and fertilizer applied

A

2nd

81
Q

Soil K

A

Chemical compounds of K very soluble, but mineral form is not

- can see considerable soil amounts of K, but much of it may not be available
- Decomposition of plant residues provides much soluble K
82
Q

Roles of soil K

A
  • cell division
  • Formation of CHO’s
  • Movement of sugars
  • Enzyme actions (>60 enzymes known to need K for activation)
  • Disease resistance
  • Cell permeability
  • Important for water balance
83
Q

Forms of Soil K

A
  • Most K used by plants in exchangeable or soluble from
    • exchangeable K forms as micas & feldspars weather, or as plant residues release
    • Exchangeable soil K in root zone may be small amount (often must supply 150-180lb/ar)
84
Q

K losses and Gains

A
  • K may be taken up in excess amounts by plants (Luxury Consumption)
  • May be expensive waste of K fertilizer
  • May inhibit Mg absorption
  • May not increase crop yield
85
Q

Soluble K losses

A
  • immobilized by microbes
  • leached
  • trapped in soil clay layers
  • Eroded
86
Q

K gains

A
  • Mineralization of organic matter K (can be used ~ as fast as water moves through soils)
  • held on cation sites in the soil
87
Q

Soil K is relatively ______ and ________ with temperature changes

A

stable and not volatile

88
Q

Supplying K to plants

A
  • K fertilizers usually very soluble (may not be very mobile in the soil)
  • Is held on cation sites, or will replace other ions on those sites
  • needs to be supplied in the root zone to be most effective
  • acidic soils often result in K deficiencies
  • Abundance of soil Ca, Mg, or K may antagonize uptake of one of the others (competition for plant absorption)
89
Q

KCl

A

cheapest K fertilizer source

-can choose sulfate or nitrate forms to add additional nutrients…. but more costly

90
Q

Managing Soil K

A
  • hay harvesting removes much K from the soil each year

- Highest K requirement during vegetative growth

91
Q

K management Keys

A
  • Maximize efficient use of added K
  • Minimize luxury consumption (split applications-especially in sandy soils)
  • Maximize use of natural K (organic matter sources)
  • Maintain soil pH 6-6.5, reduces leaching losses
92
Q

Materials supplying K

A
  • Potash
  • Most potash imported from Canada
  • Muriate of potash (KCl)-principle source (60%) potash
  • Potassium sulfate-2nd most used K fertilizer
  • Potassium-magnesium sulfate- provides 3 nutrients
  • Potassium nitrate- adds N with K
93
Q

Soil Ca

A

Occurs in many minerals, more plentiful in soils than any other plant nutrient

-Ca deficiency is rare due to wide range of Ca sources in soils

94
Q

Mobility of Ca

A
  • taken up as Ca
  • Strongly adsorbed to cations
    • large amounts may be leached simply due to large supply in the soil
  • mass flow usually supplies enough Ca to root zone
  • only absorbed through root tips
95
Q

Plant need for Ca

A
  • dividing cells-forms Ca pectate which cements cells together
  • Physical integrity and normal cell function
96
Q

Symptoms as Ca deficiencies

A
  • deformation of new leaves/necrotic appearance

- death of buds

97
Q

Ca is used more than _____ and less than ____

A

-Mg, K

98
Q

Ca needs ….

A

to be supplemented in greenhouses

-Ca deficiency common due to not enough fertilization with higher Ca Sources

99
Q

Ca fertilizers

A
  • Limestone
  • Usually only used on soils if they’ve become acidic
  • can use gypsum if pH raise not needed
100
Q

Mobility of Mg

A
  • Readily mobile in the soil
  • Most soluble/exchangeable forms supplied in the soil
  • reacts similar to Ca
  • Lower total leaching loss, less present
101
Q

Plant need for Mg

A
  • most supplied to the roots by mass flow
  • 1/5 of Mg used by plants for chlorophyll
  • stabilizes ribosome structure
  • enzyme activator
102
Q

Symptoms of Mg deficiency

A

-interveinal chlorosis of older leaves

103
Q

Soil Mg

A
  • Hypomagnesia (grass tetany); can occur in livestock grazing soils low in Mg
  • Mg can be tied up by heavy applications of K and/or ammonium fertilizers
104
Q

Mg fertilizers

A
  • Dolomitic limestone (Ca w/Mg)

- Can also use Mg salts

105
Q

Soil S

A
  • Constituent in 2 of the 20 amino acids
  • essential part of proteins
  • Also found in vitamins, oils
  • Much overlooked
106
Q

Factors increasing need for S fertilizers

A
  • Lower amounts of sulfate added incidentally with other nutrients
  • Lower pollution from sulfur oxide into air
  • Higher plant yields, greater demands on soils
107
Q

Sources of S

A
  • Availability of soil S hard to determine-major portions come from organic matter (depends on decomposition, climate, temperature, etc.)
  • Rainfall (can be toxic to fish, if S is too high)
  • S also supplied as part of other fertilizers (rarely need to supply S separately, but the need has been observed)
108
Q

Characteristics of Soil S

A
  • decomposition can release much S
  • Exists in many chemical forms, depending on the soil
  • Easily leached
  • Waterlogged soils can cause soil S source to convert to sulfide-toxic gas to plants
109
Q

Managing soil S

A
  • reduced air pollution,purer fertilizers, better understanding=reduced incidental S additions
  • Some increased reports of S deficiencies
110
Q

Sulfur Fertilizers or Amendments

A
  • Select ammonium sulfate or potassium sulfate

- Gypsum

111
Q

Soil B (Boron) is essential for

A
  • cell wall formation
  • sugar movement
  • pollination
112
Q

Symptoms of B deficiencies

A
  • terminal bud death
  • reduced flowering, retention of flowers
  • reduced pollen germination
  • less fruiting
113
Q

Soil Chemistry of B

A
  • Forms a weak acid
  • deficiencies common in high rainfall areas
  • various borates (forms) may exist in different soils
114
Q

Sources for B

A
  • Primary rocks and minerals
  • combined in soil organic matter
  • adsorbed in soil clays
  • Boric acid
115
Q

Boron Deficiency and Amendments

A
  • deficiency in grapes greatly reduces yield
  • cost to supplement relatively inexpensive (if over-supplemented can be toxic; fine line between adequate and excess amounts)
  • Supplemental B supplied by borax (very soluble, 11% B)
116
Q

Soil Cl

A

found in soil as Cl^-

  • very soluble, mobile
  • Not very reactive in the soil
117
Q

Cl role

A

osmotic role-maintains/equalizes cell charges

118
Q

Unique Features of Cl

A
  • cycles easily

- Supplied by manures, KCl, rainfall, etc.

119
Q

Cl can….

A

accumulate to toxic amounts

-especially in soils high in soluble salts

120
Q

Symptoms of Cl deficiencies

A
  • some diseases linked to Cl deficiencies
  • stripe rust
  • take-all root rot
  • leaf rust
121
Q

Cl Amendments

A
  • deficiencies rarely seen in the field

- Cl typically supplied incidentally with other fertilizers

122
Q

Soil Cu

A
  • essential for many enzymes
  • very low solubility (solubility related to soil pH)
  • Strongly adsorbed to soil clays
123
Q

Problem Soils and Susceptible plants: Deficiencies

A
  • Common in organic soils (bonds strongly to organic substances and won’t become soluble)
  • Sandy Soils
  • Calcareous soil-pH8-8.4
  • High competition w/ other metals

-less common than other micro deficiencies

124
Q

Symptoms of Cu deficiency

A
  • yellowing of younger leaves
  • off-color (bluish/green)
  • small dead spots
  • leaf curling
125
Q

Sensitive plants to Cu deficiency

A
  • Alfalfa
  • Rice
  • Wheat
  • Oats
126
Q

Cu amendments and their use

A
  • Successful, when applied
  • often only needed supplement few ppm/ac
  • CuSO4
  • Can be applied as foliar treatment
127
Q

Soil Fe

A
  • Important part of energy-providing reactions (Much Fe association w/ chloroplasts)
  • Very low solubility (difficult to keep Fe soluble for plants to absorb)
  • Very low amounts needed for plants
128
Q

Fe in soil solution- Chelates and availability

A
  • pH has dominant effect of iron solubility
  • Fe needs mostly provided by soil organic matter, stays bonded to something else to keep it soluble
  • some supplied in chelate form
129
Q

Fe in soil solution- Chelates and availability: pH has dominant effect of iron solubility;

A

very soluble at pH 3, solubility decreases by factor of 1000pH unit rise , at normal pH, soluble iron very low

130
Q

Fe in soil solution- Chelates and availability: some supplied in chelate form

A
  • Keep metals in a mobile/soluble form

- move to plant roots by diffusion or mass action

131
Q

Problem Soils, Susceptible plants, & Fe amendments

A
  • deficiencies common in calcareous soils

- high P levels also antagonize Fe

132
Q

Symptoms of Fe deficiency

A

-interveninal chlorosis

133
Q

Soluble _____ supplementation will often correct deficiencies

A

chelate

  • Foliar sprays (may need to be repeated)
  • Soil applications have longer residual, but much slower acting
  • keep organic matter high
134
Q

Soil Mn

A
  • Involved in enzyme systems
  • Solubility increases w/ pH increases
  • Organic matter decomposition aids Mn solubility
135
Q

Toxicity, Problem soils

A
  • Toxic concentrations more common than any other micro nutrient (soils may naturally have high Mn, conditions can cause Mn toxicity easily)
  • High Mn soils may show toxicities at pH just below 6, excessive water, or even at high pH’s
136
Q

Toxicity, Problem soils of Mn somewhat common in

A

Hawaii

treatment w/ lime and gypsum

137
Q

Symptoms of Mn deficiencies

A

chlorosis of younger leaves

138
Q

Soil Mo

A
  • exists and needed in minute amounts
  • important for enzyme function and N fixation
  • Strongly adsorbed, yet soluble
139
Q

Mo: Problems soils and susceptible plants

A

-deficiencies common in acid/sandy soils

-susceptible crops:
soybeans, alfalfa, corn, tomatoes, etc.

140
Q

Mo: Toxicities usually only show up in grazing animals

A
  • Known to happen on soils w/ high organic matter and neutral/alkaline pH
  • Problem related to imbalances of Cu and Mo
  • Stunted growth, bone deformation (feed, inject Cu will often correct)
141
Q

Mo amendments

A
  • Foliar sprays

- Lime acidic soils

142
Q

Soil Zn

A

essential for enzyme systems

143
Q

Zn in the soil solution

A
  • quite immobile in the soil (+ charge)

- can become deficient in flooded soils

144
Q

Problem soils and susceptible plants: Deficiencies:

A
  • occur in basic soils, limed soils, cropping with high Zn demand crops (corn, fruits, etc.)
  • most expected at high soil pH

cotton responds to Zn supplementation in SW US

145
Q

Symptoms of Zn deficiencies

A
  • interveinal chlorosis in young and old leaves
  • reduced stem elongation
  • bunched leaves
  • small, thick leaves
  • early defoliation
146
Q

Zn amendments

A
  • ZnSO4 most commonly used to cure deficiencies
    • Foliar application for treatment
    • Soil application if problem is anticipated
147
Q

Co

A
  • essential for microbes involved w/ N fixation

- can be deficient in high Ca soils, sandy, leached soils

148
Q

Si

A
  • very abundant in the environment
  • can be deficient in very weathered soils
  • appears to strengthen cell walls
149
Q

Na

A
  • essential for desert species to maintain turgor

- growers usually reluctant to add

150
Q

V (Vanadium)

A
  • essential for algae, microbes

- may substitute for Mo en enzyme activation

151
Q

Ni

A
  • raised to essential status in 1983
  • scientists still argue over its roles
  • suspected roles in plant metabolism (enzyme activator)
  • No fertilizer w/ Ni currently available
  • Soybeans have demonstrated a positive response to Ni treatment

Final Soil Fertility (4 decks)

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