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
• 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
• 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
• 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
• 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
Top Related