Soil Nutrients and
Fertilizers
Essential Standard 6.00- Explain the role
of nutrients and fertilizers.
Objective 6.01
• Discuss macro and micro nutrients and
the role they play in plant deficiencies.
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
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)
Micro nutrients
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Iron (Fe)
Copper (Cu)
Zinc (Zn)
Boron (B)
Molybdenum (Mo)
Manganese (Mn)
Chlorine (Cl)
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
Nitrogen
• Deficiency symptoms
– sick, yellow-green color
– short stems, small leaves, pale colored
leaves and flowers
– slow and dwarfed plant growth
Nitrogen deficiency
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
Phosphorus
• Deficiency symptoms
– decrease in growth
– slow maturity
– older leaves are purplish color
Phosphorus Deficiency
Functions of Potassium
• Used to form carbohydrates and
proteins
• Formation and transfer of starches,
sugars and oils
• Increases disease resistance, vigor and
hardiness
Potassium
• Deficiency symptoms
– mottled, spotted, streaked or curled leaves
– scorched, burned, dead leaf tips and
margins
Potassium Deficiency
Secondary Nutrients
• Calcium (Ca)
• Magnesium (Mg)
• Sulfur (S)
Functions of Calcium
• Improves plant vigor
• Influences intake and synthesis of other
plant nutrients
• Important part of cell walls
Calcium
• Deficiency symptoms
– small developing leaves
– wrinkled older leaves
– dead stem tips
Calcium Deficiency
Functions of Magnesium
• Influences the intake of other essential
nutrients
• Helps make fats
• Assists in translocation of phosphorus
and fats
Magnesium
• Deficiency symptoms
– Interveinal chlorosis-yellowing of leaves
between green veins
– leaf tips curl or cup upward
– slender, weak stalks
Magnesium Deficiency
Functions of Sulfur
• Promotes root growth and vigorous
vegetative growth
• Essential to protein formation
Sulfur
• Deficiency symptoms
– young leaves are light green with lighter
color veins
– yellow leaves and stunted growth
Sulfur Deficiency
Micro Nutrients
• Also called “trace” elements
• Needed by plants in small amounts
Iron (Fe)
• 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
Iron Deficiency
Copper (Cu)
• Functions
– Helps in the use of Iron
– Helps respiration
• Deficiency symptoms
– young leaves are small and permanently
wilt
– multiple buds at stem tip
Copper Deficiency
Zinc (Z)
• 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
Zinc Deficiency
Boron (B)
• 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
Boron Deficiency
Manganese (Mn)
• Functions
– plant metabolism
– nitrogen transformation
• Deficiency symptoms
– interveinal chlorosis
– young leaves die
Manganese Deficiency
Molybdenum (Mo)
• Functions
– plant development
– reproduction
• Deficiency symptoms
– stunted growth
– yellow leaves, upward curling leaves, leaf
margins burn
Molybdenum Deficiency
Chlorine (Cl)
• Functions
– essential to some plant processes
– acts in enzyme systems
• Deficiency symptoms
– usually more problems with too much
chlorine or toxicity than with deficiency
Chlorine Deficiency
Fertilizers
Objective 6.02
• Discuss the advantages and
disadvantages of various fertilizers.
Types of Fertilizers
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Complete
Incomplete
Organic
Inorganic
Soluble
Insoluble
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
Organic Fertilizers
• Comes from plant or animal matter and
contains carbon compounds
• Examples: urea, sludge and animal
tankage
Advantages of Organic
• Slow release of nutrients
• Not easily leached from the soil
• Add organic components to growing
media
Disadvantages of Organic
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Hard to get
Not sterile
Low nutrient content
Expensive
Inorganic Fertilizers
• Comes from sources other than animals
or plants
• Chemical products
Advantages of Inorganic
• Can make the desired ratio of nutrients
• easy to get
• lower cost
Disadvantages of Inorganic
• No organic material
• possible chemical building up in growing
media
Soluble Fertilizer
• Dissolve in water and are applied as a
liquid solution
• Fertigation
– fertilizing through irrigation water
– big advantage
Insoluble Fertilizer
• Includes granular and slow release
applied to the growing media
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
Fertilizer Analysis
• Fertilizer analysis expresses weight as
a percent of nitrogen, phosphorus and
potassium
20-10-20
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 15%=15lbs
• Phosphorus: 100lbs X 5%=5lbs
• Potassium: 100lbs X 15%=15lbs
Fertilizer Ratios
• A fertilizer with a 10-10-10 analysis
would have a 1:1:1 ratio
• A fertilizer with a 24-8-16 analysis would
have a 3:1:2 ratio
• What would be the ratio for a fertilizer
with an analysis of 36-18-27?
4:2:3
Application Procedures
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Banding
Sidedressing
Topdressing
Perforating
Broadcasting
Foliar spraying
Fertigation
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.
Sidedressing
• Placing a band of fertilizer near the soil
surface and to the sides after seedlings
emerge from the soil.
Topdressing
• Mixing fertilizer uniformly into the top
one to two inches of growing media
around the plant.
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.
Broadcasting
• Spreading fertilizer to cover the entire
production area
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.
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
Venturi-type
• Simple and inexpensive
• less accurate
• depends on water pressure in the hose
and in the smaller tube to proportion
• Example: Hozon
Positive-displacement
• More expensive
• very accurate
• physically inject and mix specific
amounts of concentrated solution and
water
• Examples: commander proportioners,
and Smith injectors
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