Soil Nutrients and Fertilizers

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Soil Nutrients and Fertilizers

• 24.00 Explain the role of nutrients in quality
  plant growth

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Macro vs Micro Nutrients

• Macro nutrients are required by the plant in
  relatively large amounts
• Micro nutrients are required only in small
  amounts
• minor or trace elements

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Macro nutrients

• Non-mineral elements
• carbon (C)
• hydrogen (H)
• oxygen (O)
• Primary Nutrients
• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)

• Secondary Nutrients
• calcium (Ca)
• magnesium (Mg)
• sulfur (S)

4
Micro nutrients

• Iron (Fe)
• Copper (Cu)
• Zinc (Zn)
• Boron (B)
• Molybdenum (Mo)
• Manganese (Mn)
• Chlorine (Cl)

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Functions of Nitrogen

• Promotes growth of leaves and stems
• Gives dark green color and improves quality of
  foliage
• Necessary to develop cell proteins and chlorophyll

N
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Nitrogen

• Deficiency symptoms
• sick, yellow-green color
• short stems, small leaves, pale colored leaves
  and flowers
• slow and dwarfed plant growth

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Nitrogen deficiency
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Functions of Phosphorus

• Stimulates early formation and growth of roots
• Provides for fast and vigorous growth and speeds
  maturity
• Stimulates flowering and seed development
• Necessary for the enzyme action of many plant
  processes

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Phosphorus

• Deficiency symptoms
• decrease in growth
• slow maturity
• older leaves are purplish color

P
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Phosphorus Deficiency
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Functions of Potassium

• Used to form carbohydrates and proteins
• Formation and transfer of starches, sugars and
  oils
• Increases disease resistance, vigor and hardiness

K
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Potassium

• Deficiency symptoms
• mottled, spotted, streaked or curled leaves
• scorched, burned, dead leaf tips and margins

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Potassium Deficiency
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Functions of Calcium

• Improves plant vigor
• Influences intake and synthesis of other plant
  nutrients
• Important part of cell walls

Ca
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Calcium

• Deficiency symptoms
• small developing leaves
• wrinkled older leaves
• dead stem tips

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Calcium Deficiency
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Functions of Magnesium

• Influences the intake of other essential
  nutrients
• Helps make fats
• Assists in translocation of phosphorus and fats

Mg
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Magnesium

• Deficiency symptoms
• Interveinal chlorosis-yellowing of leaves between
  green veins
• leaf tips curl or cup upward
• slender, weak stalks

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Magnesium Deficiency
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Functions of Sulfur

• Promotes root growth and vigorous vegetative
  growth
• Essential to protein formation

S
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Sulfur

• Deficiency symptoms
• young leaves are light green with lighter color
  veins
• yellow leaves and stunted growth

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Sulfur Deficiency
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Iron

• Functions of Iron
• Essential for chlorophyll production
• Helps carry electrons to mix oxygen with other
  elements
• Deficiency symptoms
• mottled and interveinal chlorosis in young leaves
• stunted growth and slender, short stems

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Iron Deficiency
Fe
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Copper

• Functions
• Helps in the use of Iron
• Helps respiration
• Deficiency symptoms
• young leaves are small and permanently wilt
• multiple buds at stem tip

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Copper Deficiency
Cu
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Zinc

• Functions
• plant metabolism
• helps form growth hormones
• reproduction
• Deficiency symptoms
• retarded growth between nodes (rosetted)
• new leaves are thick and small
• spotted between veins, discolored veins

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Zinc Deficiency
Zn
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Boron

• Functions
• affects water absorption by roots
• translocation of sugars
• Deficiency Symptoms
• short, thick stem tips
• young leaves of terminal buds are light green at
  base
• leaves become twisted and die

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Boron Deficiency
B
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Manganese

• Functions
• plant metabolism
• nitrogen transformation
• Deficiency symptoms
• interveinal chlorosis
• young leaves die

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Manganese Deficiency
Mn
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Molybdenum

• Functions
• plant development
• reproduction
• Deficiency symptoms
• stunted growth
• yellow leaves, upward curling leaves, leaf
  margins burn

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Molybdenum Deficiency
Mo
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Chlorine

• Functions
• essential to some plant processes
• acts in enzyme systems
• Deficiency symptoms
• usually more problems with too much chlorine or
  toxicity than with deficiency

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Chlorine Deficiency
Cl
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Fertilizers
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Types of Fertilizers

• Complete
• Incomplete
• Organic
• Inorganic
• Soluble
• Insoluble

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Complete vs. Incomplete

• Complete has all three primary nutrients-nitrogen
  phosphorous potassium
• Examples 10-10-10, 15-30-15, 20-5-20
• Incomplete DOES NOT have all three primary
  nutrients
• Examples 20-0-0, 0-20-0, 12-0-44

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Organic Fertilizers

• Comes from plant or animal matter and contains
  carbon compounds
• Examples urea, sludge and animal tankage

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Advantages of Organic

• Slow release of nutrients
• Not easily leached from the soil
• Add organic components to growing media

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Disadvantages of Organic

• Hard to get
• Not sterile
• Low nutrient content
• Expensive

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Inorganic Fertilizers

• Comes from sources other than animals or plants
• Chemical products

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Advantages of Inorganic

• Can make the desired ratio of nutrients
• easy to get
• lower cost

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Disadvantages of Inorganic

• No organic material
• possible chemical building up in growing media

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Soluble Fertilizer

• Dissolve in water and are applied as a liquid
  solution
• Fertigation
• fertilizing through irrigation water
• big advantage

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Insoluble Fertilizer

• Includes granular and slow release applied to the
  growing media

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Granular vs. Slow Release

• Granular
• relatively inexpensive
• easy to find
• Slow Release
• more expensive because it is coated
• more uniform release of nutrients over time period

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Fertilizer Analysis

• Fertilizer analysis expresses weight as a percent
  of nitrogen, phosphorus and potassium

20-10-20
N
P
K
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Fertilizer Analysis

• For Example
• A 100 pound bag of fertilizer has an analysis of
  15-5-15. How many pounds of nitrogen, phosphorus
  and potassium are in the bag?
• Nitrogen 100lbs X 1515lbs
• Phosphorus 100lbs X 55lbs
• Potassium 100lbs X 1515lbs

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Fertilizer Ratios

• A fertilizer with a 10-10-10 analysis would have
  a 111 ratio
• A fertilizer with a 24-8-16 analysis would have a
  312 ratio
• What would be the ratio for a fertilizer with an
  analysis of 36-18-27?

423
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Application Procedures

• Banding
• Sidedressing
• Topdressing
• Perforating
• Broadcasting
• Foliar spraying
• Fertigation

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Banding

• Placing a band of fertilizer about two inches to
  the sides and about two inches below seed depth.
• DO NOT place below the seeds because fertilizer
  will burn the roots.

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Sidedressing

• Placing a band of fertilizer near the soil
  surface and to the sides after seedlings emerge
  from the soil.

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Topdressing

• Mixing fertilizer uniformly into the top one to
  two inches of growing media around the plant.

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Perforating

• Placing fertilizer in 12-18 holes drilled 18
  to 24 around the canopy drip line of fruit
  trees. Cover the holes and fertilizer slowly
  dissolves.

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Broadcasting

• Spreading fertilizer to cover the entire
  production area

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Foliar Spraying

• Spraying micronutrients in a solution directly on
  plant leaves.
• Quickly corrects nutrient deficiencies
• Fertilizer concentration should not be too high
  or leaf burning will occur.

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Fertigation

• Incorporating water-soluble fertilizer into the
  irrigation system of greenhouse and nursery
  crops.
• Concentrated solutions usually pass through
  proportioners or injectors to dilute to the
  correct ratio.
• Venturi-type
• Positive-displacement

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Venturi-type

• Simple and inexpensive
• less accurate
• depends on water pressure in the hose and in the
  smaller tube to proportion
• Example Hozon

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Positive-displacement

• More expensive
• very accurate
• physically inject and mix specific amounts of
  concentrated solution and water
• Examples commander proportioners, and Smith
  injectors

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Rules for applying fertilizers

• Method used should be practical, effective and
  cost efficient
• Method used affects nutrient availability for
  plant use
• Fertilizer must be dissolved and reach plant roots